PHOSPHINIC VANADIUM COMPLEX, CATALYTIC SYSTEM COMPRISING SAID PHOSPHINIC VANADIUM COMPLEX AND PROCESS FOR THE (CO) POLYMERIZATION OF CONJUGATED DIENES

Abstract

Vanadium phosphinic complex having general formula (I) or (II):

V(X).sub.3[P(R.sub.1).sub.n(R.sub.2).sub.3-n].sub.2  (I)

V(X).sub.3[(R.sub.3).sub.2P(R.sub.4)P(R.sub.3).sub.2]  (II)

wherein: X represents an anion selected from halogens; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; R.sub.1, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2═CH—CH.sub.2—); or are selected from alkyl groups C.sub.1-C.sub.20, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; n is an integer ranging from 0 to 3; R.sub.2, identical or different among them, are selected from optionally substituted aryl groups; R.sub.3, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2═CH—CH.sub.2—); or are selected from alkyl groups C.sub.1-C.sub.20, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.4 represents a group —NR.sub.5 wherein R.sub.5 represents a hydrogen atom, or is selected from C.sub.1-C.sub.20 alkyl groups, linear or branched; or R.sub.4 represents an alkylene group —(CH.sub.2)p- wherein p represents an integer ranging from 1 to 5;
provided that in the general formula (I), in case n is equal to 1 and R.sub.1 is methyl, R.sub.2 is different from phenyl.
Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

Claims

1-6. (canceled)

7. A catalyst and at least one co-catalyst for (co) polymerization of conjugated dienes comprising: (a) said catalyst comprising at least one phosphinic vanadium complex having the general formula (I) or (II):
V(X).sub.3[P(R.sub.1).sub.n(R.sub.2).sub.3-n].sub.2  (I)
V(X).sub.3[(R.sub.3).sub.2P(R.sub.4)P(R.sub.3).sub.2]  (II) wherein: X represents a halogen anion; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate and dicarboxylate; R.sub.1, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2═CH—CH.sub.2—); or are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched, and an optionally halogenated, optionally substituted cycloalkyl group; n is an integer ranging from 0 to 3; R.sub.2, identical or different among them, represent an optionally substituted aryl group; R.sub.3, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2═CH—CH.sub.2—); or are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched, an optionally halogenated, optionally substituted cycloalkyl group, and an optionally substituted aryl group; R.sub.4 represents a group —NR.sub.5 wherein R.sub.5 represents a hydrogen atom, or is a C.sub.1-C.sub.20 alkyl group, linear or branched; or R.sub.4 represents an alkylene group —(CH.sub.2)p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and R.sub.1 is methyl, R.sub.2 is different from phenyl; provided that in the general formula (I) in case n is equal to 2, R.sub.1 is not methyl or ethyl; and provided that in the general formula (I) in case n is equal to 3, R.sub.1 is not methyl, ethyl or propyl; (b) said at least one co-catalyst selected from the following organo-derivatives of aluminum: (b.sub.1) an aluminum compound having general formula (III):
Al(R.sub.6)(R.sub.7)(R.sub.8)  (III) wherein R.sub.6 represents a hydrogen atom, or a fluorine atom, or is selected from a C.sub.1-C.sub.20 alkyl group, linear or branched, a cycloalkyl group, an aryl group, an alkylaryl group, an arylalkyl group, and an alkoxy group; R.sub.7 and R.sub.8, identical or different among them, are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched, a cycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group; (b.sub.2) an aluminoxane having general formula (IV):
(R.sub.9).sub.2—Al—O—[—Al(R.sub.10)—O—].sub.q—Al—(R.sub.11).sub.2  (IV) wherein R.sub.9, R.sub.10 and R.sub.11, identical or different among them, represent a hydrogen atom, or a halogen atom; or are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched, a cycloalkyl group, and an aryl group, said groups being optionally substituted with one or more atoms of silicon or germanium; and q is an integer ranging from 0 to 1000; (b.sub.3) an organo-derivative compound of aluminum partially hydrolyzed; (b.sub.4) a halogen aluminum alkyl having general formula (V) or (VI):
Al(R.sub.12).sub.n(X.sub.1).sub.3-n  (V)
Al.sub.2(R.sub.12).sub.m(X.sub.1).sub.6-m  (VI) wherein n is 1 or 2; m is an integer ranging from 1 to 5; R.sub.12, identical or different among them, are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched; X.sub.1 represents a chlorine or bromine atom; or mixtures thereof.

8. The catalyst and at least one co-catalyst for (co) polymerization of conjugated diener according to claim 7, wherein in said catalyst comprising said phosphinic vanadium complex having general formula (I) or (II): (i) X is an anion selected from halogen; R.sub.1, identical or different among them, are a hydrogen atom; or are selected from a C.sub.1-C.sub.20 alkyl group linear or branched; or are selected from an optionally substituted cycloalkyl group; n is an integer 0 or 1; R.sub.2, identical or different among them, are selected from an optionally substituted aryl group; or (ii) X is an anion selected from chlorine, bromine, and iodine; R.sub.1, identical or different among them, are a hydrogen atom; or are selected from C.sub.4-C.sub.20 alkyl linear or branched; or are selected from an optionally substituted cycloalkyl group; n is an integer 2; R.sub.2, identical or different among them, are selected from an optionally substituted aryl group; or R.sub.3, identical or different among them, are selected from a C.sub.1-C.sub.20 alkyl group, linear or branched; or are selected from an optionally substituted aryl group; R4 represents a group —NR.sub.5 wherein R.sub.5 is a hydrogen atom; or R.sub.4 is a group —(CH.sub.2)p- wherein p is 2.

9. The catalyst and at least one co-catalyst for (co) polymerization of conjugated diener according to claim 7, wherein in said catalyst comprising said phosphinic vanadium complex having general formula (I) or (II): (i) X is an anion selected from chlorine, bromine, and iodine; R.sub.1, identical or different among them, are a hydrogen atom; or are selected from methyl, ethyl, iso-propyl, and tert-butyl; or are selected from cyclopentyl and cyclohexyl; n is an integer 0; R2, identical or different among them, are phenyl; or (ii) X is an anion selected from chlorine, bromine, and iodine; R.sub.1, identical or different among them, are a hydrogen atom; or are tert-butyl; or are selected from cyclopentyl and cyclohexyl; n is an integer 2; R.sub.2, identical or different among them, are phenyl; or (iii) X is an anion selected from chlorine, bromine, and iodine; R.sub.1, identical or different among them, are a hydrogen atom; or are selected from methyl, ethyl, iso-propyl, and tert-butyl; or are selected from cyclopentyl and cyclohexyl; n is an integer 1; or R.sub.3, identical or different among them, are selected from methyl and ethyl; or are phenyl; R.sub.4 represents a group —NR.sub.5 wherein R.sub.5 is a hydrogen atom; or R.sub.4 is a group —(CH.sub.2)p- wherein p is 2.

10. The catalyst and at least one co-catalyst for (co) polymerization of conjugated dienes according to claim 7, wherein said co-catalyst is said aluminoxane (b.sub.2) having the general formula (IV).

11. The catalyst and at least one co-catalyst for (co) polymerization of conjugated dienes according to claim 10, wherein said said aluminoxane (b.sub.2) having the general formula (IV) is methylaluminoxane (MAO) as such or in the “dry” form (MAO-dry).

12. The catalyst and at least one co-catalyst for (co) polymerization of conjugated dienes according to claim 7 in contact with butadiene or isoprene.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0078] FIG. 1 shows XRD structure of complex VCl.sub.3(PMePh.sub.2).sub.2 (Example 1);

[0079] FIG. 2 shows XRD structure of complex VCl.sub.3(PEtPh.sub.2).sub.2 (Example 2);

[0080] FIG. 3 shows XRD structure of complex VCl.sub.3(PCyp.sub.3).sub.2 (Example 7);

[0081] FIG. 4 shows FT-IR spectrum of polybutadiene reported in Table 3: MM267 (Example 13);

[0082] FIG. 5 shows FT-IR spectrum of polybutadiene reported in Table 3: MM268 (Example 14);

[0083] FIG. 6 shows FT-IR spectrum of polybutadiene reported in Table 3: MM281 (Example 15);

[0084] FIG. 7 shows FT-IR spectrum of polybutadiene reported in Table 3: G1282 (Example 17);

[0085] FIG. 8 shows FT-IR spectrum of polybutadiene reported in Table 3: MM319 (Example 18);

[0086] FIG. 9 shows FT-IR spectrum of polybutadiene reported in Table 3: MM320 (Example 19);

[0087] FIG. 10 shows FT-IR spectrum of polybutadiene reported in Table 3: MM393 (Example 20);

[0088] FIG. 11 shows FT-IR spectrum of polybutadiene reported in Table 3: MM394 (Example 21);

[0089] FIG. 12 shows FT-IR spectrum of polybutadiene reported in Table 3: MM395 (Example 22);

[0090] FIG. 13 shows FT-IR spectrum of polybutadiene reported in Table 3: MM396 (Example 23);

[0091] FIG. 14 shows FT-IR spectrum of polybutadiene reported in Table 3: MM398 (Example 24);

[0092] FIG. 15 shows FT-IR spectrum of polybutadiene reported in Table 3: MM374 (Example 25);

[0093] FIG. 16 shows FT-IR spectrum of polybutadiene reported in Table 3: MM341 (Example 26);

[0094] FIG. 17 shows FT-IR spectrum of polybutadiene reported in Table 3: MM335 (Example 27);

[0095] FIG. 18 shows FT-IR spectrum of polybutadiene reported in Table 3: MM336 (Example 28);

[0096] FIG. 19 shows FT-IR spectrum of polybutadiene reported in Table 3: G1307 (Example 31);

[0097] FIG. 20 shows FT-IR spectrum of polybutadiene reported in Table 3: MM317 (Example 32);

[0098] FIG. 21 shows FT-IR spectrum of polybutadiene reported in Table 3: MM318 (Example 33);

[0099] FIG. 22 shows .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polybutadiene reported in Table 3: MM365 (Example 34);

[0100] FIG. 23 shows FT-IR spectrum of polybutadiene reported in Table 3: MM379 (Example 37);

[0101] FIG. 24 shows FT-IR spectrum of polybutadiene reported in Table 3: MM279 (Example 38);

[0102] FIG. 25 shows FT-IR spectrum of polybutadiene reported in Table 3: G1284 (Example 39);

[0103] FIG. 26 shows FT-IR spectrum of polyisoprene reported in Table 4: G1314 (Example 40);

[0104] FIG. 27 shows FT-IR spectrum of polyisoprene reported in Table 4: MM401 (Example 41);

[0105] FIG. 28 shows FT-IR spectrum of polyisoprene reported in Table 4: MM402 (Example 42);

[0106] FIG. 29 shows FT-IR spectrum of polyisoprene reported in Table 4: MM343 (Example 43);

[0107] FIG. 30 shows FT-IR spectrum of polyisoprene reported in Table 4: MM371 (Example 45);

[0108] FIG. 31 shows FT-IR spectrum of polyisoprene reported in Table 4: MM372 (Example 46);

[0109] FIG. 32 shows FT-IR spectrum of polyisoprene reported in Table 4: MM337 (Example 47);

[0110] FIG. 33 shows .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polyisoprene reported in Table 4: MM337 (Example 47);

[0111] FIG. 34 shows FT-IR spectrum of polyisoprene reported in Table 2: G1310 (Example 48);

[0112] FIG. 35 shows FT-IR spectrum of polyisoprene reported in Table 4: MM332 (Example 49); and

[0113] FIG. 36 shows FT-IR spectrum of polyisoprene reported in Table 4: MM375 (Example 50).

[0114] For the purpose of understanding the present invention better and to put it into practice, below are some illustrative and non-limitative examples thereof.

EXAMPLES

Reagents and Materials

[0115] The list below reports the reagents and materials used in the following examples of the invention, their optional pre-treatments and their manufacturer: [0116] trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3]: prepared as described by Manzer L. E. et al., “Inorganic Synthesis” (1982), Vol. 21, pag. 135-140; [0117] (methyl)diphenylphosphine (Strem): degree of purity 99%, used as it is; [0118] (ethyl)diphenylphosphine (Strem): degree of purity 99%, used as it is; [0119] (iso-propyl)diphenylphosphine (Aldrich): degree of purity 97%, used as it is; [0120] (cyclohexyl)diphenylphosphine (Strem): degree of purity 98%, used as it is; [0121] triphenylphosphine (Strem): degree of purity 99%, used as it is; [0122] tri(cyclohexyl)phosphine (Strem): degree of purity 97%, used as it is; [0123] tri(cyclopentyl)phosphine (Strem): degree of purity 95%, used as it is; [0124] di(cyclohexyl)phenylphosphine (Aldrich): degree of purity 95%, used as it is; [0125] tri(tert-butyl)phosphine (Strem): degree of purity 99%, used as it is; [0126] 1,2-bis(dimethylphosphino)ethane (Strem): degree of purity 98%, used as it is; [0127] 1,2-bis(diethylphosphino)ethane (Strem): degree of purity 98%, used as it is; [0128] N,N-bis(diphenylphosphino)amine (Strem): degree of purity min. 98%, used as it is; [0129] toluene (Fluka): degree of purity >99.5%, refluxed over sodium (Na) for about 8 hours, then distilled and stored over molecular sieves under nitrogen; [0130] pentane (Fluka): degree of purity 99%, refluxed over sodium/potassium (Na/K) for about 8 hours, then distilled and stored over molecular sieves under nitrogen; [0131] heptane (Aldrich): used as it is; [0132] 1,3-butadiene (Air Liquide): pure, ≥99.5%, evaporated from the container before each production, dried by passing it through a molecular sieve packed column and condensed inside the reactor that was pre-cooled to −20° C.; [0133] isoprene (Aldrich): pure, ≥99%, refluxed over calcium hydride for 2 hours, then distilled “trap-to-trap” and stored in a nitrogen atmosphere at 4° C., in the fridge; [0134] methylaluminoxane (MAO) (toluene solution 10% in weight) (Aldrich): used as it is, or in “dry” form (MAO-dry) obtained by removing the free trimethyl-aluminum along with the solvent from said toluene solution under vacuum and drying the residue obtained still under vacuum; [0135] methanol (Carlo Erba, RPE): used as it is, or optionally anhydrified by distillation on magnesium (Mg); [0136] hydrochloric acid in 37% aqueous solution (Aldrich): used as it is; [0137] 1,2-dichlorobenzene (Aldrich): degree of purity 99%, refluxed over calcium hydride (CaH.sub.2) for about 8 hours, then distilled and stored over molecular sieves under nitrogen; [0138] deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as it is; [0139] deuterated chloroform (CDCl.sub.3) (Acros): used as it is.

[0140] The analysis and characterization methodologies reported below were used.

Elementary Analysis

[0141] a) Determination of Vanadium (V)

[0142] To determine the quantity in weight of vanadium (V), in the vanadium phosphinic complexes object of the present invention, a precisely weighed aliquot, operating in dry-box under nitrogen flow, of about 30 mg-50 mg of sample, was placed in an approximately 30 ml platinum crucible, along with a 1 ml mixture of 40% hydrofluoric acid (HF) (Aldrich), 0.25 ml of 96% sulfuric acid (H.sub.2SO.sub.4) and 1 ml of 70% nitric acid (HNO.sub.3) (Aldrich). The crucible was then heated on a hot plate increasing the temperature until white sulfur fumes appeared (about 200° C.). The mixture thus obtained was cooled to room temperature (20° C.-25° C.), and 1 ml of 70% nitric acid (HNO.sub.3) (Aldrich) was added then it was left again until fumes appeared. After repeating the sequence another two times, a clear, almost colorless, solution was obtained. 1 ml of 70% nitric acid (HNO.sub.3) (Aldrich) and about 15 ml of water were then added, in the cold, then heated to 80° C. for about 30 minutes. The sample thus prepared was diluted with MilliQ pure water until it weighed about 50 g, precisely weighed, to obtain a solution on which the instrumental analytical determination was carried out using a Thermo Optek IRIS Advantage Duo ICP-OES (plasma optical emission) spectrometer, for comparison with solutions of known concentration. For this purpose, for every analyte, a calibration curve was prepared in the range 0 ppm-10 ppm, by measuring solutions of a known titre obtained by dilution by weight of certified solutions.

[0143] The solution of sample prepared as above was then diluted again by weight in order to obtain concentrations close to the reference ones, before carrying out spectrophotometric measurement. All the samples were prepared in double quantities. The results was considered acceptable if the individual repeated test data did not have a relative deviation of more than 2% with respect to their mean value.

[0144] b) Determination of Chlorine

[0145] For said purpose, samples of vanadium phosphinic complexes object of the present invention, about 30 mg-50 mg, were precisely weighed in 100 ml glass beakers in dry-box under nitrogen flow. 2 g of sodium carbonate (Na.sub.2CO.sub.3) (Aldrich) and, outside the dry-box, 50 ml of MilliQ water, were added. It was brought to the boil on the hot plate, under magnetic stirring, for about 30 minutes. It was left to cool, then ⅕ diluted sulfuric acid (H.sub.2SO.sub.4) (Aldrich) was added, until acid reaction and was then titrated with 0.1 N silver nitrate (AgNO.sub.3) (Aldrich) with a potentiometric titrator.

[0146] c) Determination of Carbon, Hydrogen and Nitrogen

[0147] The determination of carbon, hydrogen and nitrogen, in the vanadium phosphinic complexes object of the present invention, was carried out through a Carlo Erba automatic analyzer Mod. 1106.

X-Ray Diffraction (XRD)

[0148] For this purpose, samples of the vanadium phosphinic complexes object of the present invention, of about 1 g, were loaded onto the porous septum of a hot extractor for solids and continuously extracted with boiling pentane for about 2 days obtaining crystalline products (individual crystals) that were analyzed through X-ray diffraction (XRD) using a Bruker AXS Smart Apex II diffractometer equipped with CCD detector and an Oxford Cryostram unit for nitrogen flow assembled at the base of the goniometer to allow data to be collected at different temperatures, i.e. in a temperature range ranging from 100 K (−173.15° C.) to 300 K (26.85° C.): the operating conditions are reported in Table 1 and in Table 2.

[0149] Table 1 and Table 2 also report the crystallographic data of the samples analyzed.

.SUP.13.C-HMR and .SUP.1.H-HMR Spectra

[0150] The .sup.13C-HMR and .sup.1H-HMR spectra were recorded using a nuclear magnetic resonance spectrometer mod. Bruker Avance 400, using deuterated tetrachloroethylene (C.sub.2D.sub.2C.sub.14) at 103° C., and hexamethyldisiloxane (HDMS) (Aldrich) as internal standard, or using deuterated chloroform (CDCl.sub.3), at 25° C., and tetramethylsilane (TMS) (Aldrich) as internal standard. For this purpose, polymeric solutions were used with concentrations equal to 10% by weight with respect to the total weight of the polymeric solution.

[0151] The microstructure of the polymers was determined through the analysis of the aforementioned spectra on the basis of what reported in literature by Mochel, V. D., in “Journal of Polymer Science Part A-1: Polymer Chemistry” (1972), Vol. 10, Issue 4, pag. 1009-1018, for polybutadiene, and by Sato H. et al., in “Journal of Polymer Science: Polymer Chemistry Edition” (1979), Vol. 17, Issue 11, pag. 3551-3558, for polyisoprene.

FT-IR Spectra

[0152] The FT-IR spectra were recorded through Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophotometers.

[0153] The FT-IR spectra of the polymers were obtained from polymeric films on potassium bromide (KBr) tablets, said films being obtained through the deposition of a solution in hot 1,2-dichlorobenzene of the polymer to be analyzed. The concentration of the polymeric solutions analyzed was equal to 10% by weight with respect to the total weight of the polymeric solution.

Determination of the Molecular Weight

[0154] The determination of the molecular weight (MW) of the polymers obtained was carried out through GPC (Gel Permeation Chromatography) operating under the following conditions: [0155] Agilent 1100 pump; [0156] Agilent 1100 I.R. detector; [0157] PL Mixed-A columns; [0158] solvent/eluent: tetrahydrofuran (THF) (Aldrich); [0159] flow: 1 ml/min; [0160] temperature: 25° C.; [0161] molecular mass calculation: Universal Calibration method.

[0162] The weight-average molecular weight (Mw) and the Polydispersion Index (PDI) corresponding to the ratio M.sub.w/M.sub.n (M.sub.n=number-average molecular weight), are reported.

Example 1

[0163] Synthesis of VCl.sub.3(PMePh.sub.2).sub.2 [Sample MM261]

##STR00001##

[0164] 1.02 g (2.75×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium. [VCl.sub.3(THF).sub.3], 15 ml of toluene and, subsequently, 2.19 g (1.10×10.sup.−2 moles) of (methyl)diphenylphosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a purple powder. After about 3 hours, everything was filtered and the solid light purple residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 1.476 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=96.3%) of complex VCl.sub.3(PMePh.sub.2).sub.2 (molecular weight=557.53 gxmol.sup.−1).

[0165] Elementary analysis [found (calculated)] C: 56.20% (55.99%); H: 4.60% (4.70%); Cl: 19.20% (19.07%); P: 11.10% (11.11%); V: 9.20% (9.13%).

[0166] FIG. 1 reports the XRD structure of the VCl.sub.3(PMePh.sub.2).sub.2 complex obtained.

[0167] Table 1 and Table 2 report the crystallographic data of the VCl3(PMePh.sub.2).sub.2 complex obtained.

Example 2

[0168] Synthesis of VCl.sub.3(PEtPh.sub.2).sub.2 [sample G1298]

##STR00002##

[0169] 1.28 g (3.42×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 15 ml of toluene and, subsequently, 2.90 g (1.37×10.sup.−2 moles) of (ethyl)diphenylphosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 1 hour. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a purple/gray powder. After about 3 hours, everything was filtered and the solid gray/pink residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 1.8226 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=91.0%) of complex VCl.sub.3(PEtPh.sub.2).sub.2 (molecular weight=585.79 gxmol.sup.−1).

[0170] Elementary analysis [found (calculated)] C: 57.40% (57.41%); H: 5.10% (5.16%); Cl: 18.20% (18.16%); P: 10.07% (10.58%); V: 8.60% (8.70%).

[0171] FIG. 2 reports the XRD structure of the VCl.sub.3(PEtPh.sub.2).sub.2 complex obtained.

[0172] Table 1 and Table 2 report the crystallographic data of the VCl.sub.3(PEtPh.sub.2).sub.2 complex obtained.

Example 3

[0173] Synthesis of VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 [sample G1325]

##STR00003##

[0174] 1.28 g (3.42×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 15 ml of toluene and, subsequently, 2.90 g (1.37×10.sup.−2 moles) of (iso-propyl)diphenylphosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 1 hour. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a purple/gray powder. After about 3 hours, everything was filtered and the solid gray/pink residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 1.8226 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=91.0%) of complex VCl.sub.3(P.sup.iPh2).sub.2 (molecular weight=585.79 gxmol.sup.−1).

[0175] Elementary analysis [found (calculated)] C: 57.40% (57.41%); H: 5.10% (5.16%); Cl: 18.20% (18.16%); P: 10.07% (10.58%); V: 8.60% (8.70%).

Example 4

[0176] Synthesis of VCl.sub.3(PCyPh.sub.2).sub.2 [sample MM300]

##STR00004##

[0177] 0.86 g (2.30×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 20 ml of toluene and, subsequently, 2.40 g (9.0×10.sup.−3 moles) of diphenyl(cyclohexyl)phosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 60 minutes and, then, heated under reflux for 1 hour. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a dark powder. After about 3 hours, everything was filtered and the solid light blue/gray residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 1.30 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=81.4%) of complex VCl.sub.3(PCyPh.sub.2).sub.2 (molecular weight=693.97 gxmol.sup.−1).

[0178] Elementary analysis [found (calculated)] C: 62.40% (62.31%); H: 6.30% (6.10%); Cl: 15.50% (15.33%); P: 9.0% (8.93%); V: 7.20% (7.34%).

Example 5

[0179] Synthesis of VCl.sub.3(PPh.sub.3).sub.2 [sample MM295]

##STR00005##

[0180] 1.0 g (2.66×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 10 ml of toluene and, subsequently, 2.80 g (1.06×10.sup.−2 moles) of triphenylphosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 60 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a dark powder. After about 3 hours, everything was filtered and the solid very dark lilac residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 1.50 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=82.7%) of complex VCl.sub.3(PPh.sub.3).sub.2 (molecular weight=681.87 gxmol.sup.−1).

[0181] Elementary analysis [found (calculated)] C: 63.30% (63.41%); H: 4.50% (4.43%); Cl: 15.50% (15.60%); P: 9.0% (9.08%); V: 7.60% (7.47%).

Example 6

[0182] Synthesis of VCl.sub.3(PCy.sub.3).sub.2 [sample MM370]

##STR00006##

[0183] 0.827 g (2.20×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 18 ml of toluene and, subsequently, 2.47 g (8.82×10.sup.−2 moles) of tri(cyclohexyl)phosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 24 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a dark powder. After about 3 hours, everything was filtered and the solid purple residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.387 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=25.6%) of complex VCl.sub.3(PCy.sub.3).sub.2 (molecular weight=718.16 gxmol.sup.−1).

[0184] Elementary analysis [found (calculated)] C: 60.30% (60.21%); H: 9.20% (9.26%); Cl: 14.70% (14.81%); P: 8.70% (8.63%); V: 7.30% (7.09%).

Example 7

[0185] Synthesis of VCl.sub.3(PCyp.sub.3).sub.2 [sample G1286]

##STR00007##

[0186] 0.88 g (2.34×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 10 ml of toluene and, subsequently, 2.23 g (9.36×10.sup.−3 moles) of tri(cyclopentyl)phosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a purple powder. After about 3 hours, everything was filtered and the solid purple residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.802 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=54.1%) of complex VCl.sub.3(PCyp.sub.3).sub.2 (molecular weight=634.0 gxmol.sup.−1).

[0187] Elementary analysis [found (calculated)] C: 56.90% (56.83%); H: 8.70% (8.59%); Cl: 16.70% (16.78%); P: 9.80% (9.77%); V: 8.0% (8.03%).

[0188] FIG. 3 reports the XRD structure of the VCI3(PCyp3)2 complex obtained.

[0189] Table 1 and Table 2 report the crystallographic data of the VCl.sub.3(PCyp.sub.3).sub.2 complex obtained.

Example 8

[0190] Synthesis of VCl.sub.3(PCy.sub.2H).sub.2 [sample G1303]

##STR00008##

[0191] 0.955 g (2.0×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 10 ml of toluene and, subsequently, 1.5863 g (8.0×10.sup.−3 moles) of di(cyclohexyl)phosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 60 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a dark powder. After about 3 hours, everything was filtered and the solid brownish residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.3768 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=42.0%) of complex VCl.sub.3(PCy.sub.2H).sub.2 (molecular weight=553.87 gxmol.sup.−1).

[0192] Elementary analysis [found (calculated)] C: 52.20% (52.04%); H: 8.50% (8.37%); Cl: 19.30% (19.20%); P: 11.10% (11.18%); V: 9.40% (9.20%).

Example 9

[0193] Synthesis of VCl.sub.3(PtBu.sub.3).sub.2 [sample G1299]

##STR00009##

[0194] 0.466 g (2.16×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 4 ml of toluene and, subsequently, 1.74 g (8.64×10.sup.−2 moles) of tri(tert-butyl)phosphine (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a purple/gray powder. After about 3 hours, everything was filtered and the solid gray/violet residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.3768 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=31.0%) of complex VCl.sub.3(P.sup.tBu.sub.3).sub.2 (molecular weight=561.93 gxmol.sup.−1).

[0195] Elementary analysis [found (calculated)] C: 51.50% (51.30%); H: 9.50% (9.69%); Cl: 19.10% (18.93%); P: 11.20% (11.02%); V: 9.30% (9.07%).

Example 10

[0196] Synthesis of VCl.sub.3(dmpe) [sample G1275]

##STR00010##

[0197] 1.25 g (3.33×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 14 ml of toluene and, subsequently, 1.0 g (0.68×10.sup.−2 moles) of 1,2-bis(dimethylphosphino)ethane (P/V molar ratio=2) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a very fine powder. After about 3 hours, everything was filtered and the solid rather dark residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.895 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=87.6%) of complex VCl.sub.3(dmpe) (molecular weight=307.44 gxmol.sup.−1).

[0198] Elementary analysis [found (calculated)] C: 23.20% (23.44%); H: 5.30% (5.25%); Cl: 34.40% (34.60%); P: 20.40% (20.15%); V: 16.80% (16.57%).

Example 11

[0199] Synthesis of VCl.sub.3(depe) [sample G1274]

##STR00011##

[0200] 0.443 g (1.22×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 5 ml of toluene and, subsequently, 1.0 g (4.90×10.sup.−3 moles) of 1,2-bis(diethylphosphino)ethane (P/V molar ratio=4) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 3 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 25 ml of pentane were added, obtaining the precipitation of a very fine powder. After about 3 hours, everything was filtered and the solid green residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.411 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=92.6%) of complex VCl.sub.3(depe) (molecular weight=363.55 gxmol.sup.−1).

[0201] Elementary analysis [found (calculated)] C: 32.90% (33.04%); H: 6.40% (6.55%); Cl: 29.56% (29.26%); P: 17.24% (17.04%); V: 14.03% (14.01%).

Example 12

[0202] Synthesis of VCl.sub.3(dppa) [sample G1281]

##STR00012##

[0203] 0.748 g (2.09×10.sup.−3 moles) of trichlorotris(tetrahydrofuran)vanadium [VCl.sub.3(THF).sub.3], 10 ml of toluene and, subsequently, 1.444 g (3.75×10.sup.−3 moles) of N,N-bis(diphenylphosphino)-amine (P/V molar ratio=1.8) were placed into a 100 ml tailed flask. The mixture obtained was left, under vigorous stirring, at room temperature, for 15 minutes and, then, heated under reflux for 2 hours. The suspension obtained was filtered in the hot (60° C.) and the fraction collected was concentrated, under vacuum, at room temperature. Subsequently, drop by drop, under stirring, about 50 ml of pentane were added, obtaining the precipitation of a very fine powder. After about 3 hours, everything was filtered and the solid mustard residue obtained was washed with pentane (50 ml) and dried, under vacuum, at room temperature, obtaining 0.356 g (conversion with respect to starting [VCl.sub.3(THF).sub.3]=31.4%) of complex VCl.sub.3(dppa) (molecular weight=542.68 gxmol.sup.−1). Elementary analysis [found (calculated)] C: 53.23% (53.12%); H: 3.90% (3.90%); Cl: 19.88% (19.60%); N: 2.75% (2.58%); P: 11.50% (11.42%); V: 9.50% (9.39%).

Example 13 (MM267)

[0204] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 9.14 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (1.26 ml; 2.0×10.sup.−3 moles, equal to about 1.45 g) was added and, subsequently, the VCl.sub.3(PMePh.sub.2).sub.2 complex [sample MM261] (5.6 ml of toluene suspension at a concentration of 2 mg/ml; 2×10.sup.−5 moles, equal to about 11.2 mg) obtained as described in Example 1. Everything was kept, under magnetic stirring, at 20° C., for 72 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.241 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 77.2%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0205] FIG. 4 reports the FT-IR spectrum of the polybutadiene obtained.

Example 14 (MM268)

[0206] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 4.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PMePh.sub.2).sub.2 complex [sample MM261] (5.6 ml of toluene suspension at a concentration of 2 mg/ml; 2×10.sup.−5 moles, equal to about 11.2 mg) obtained as described in Example 1. Everything was kept, under magnetic stirring, at 20° C., for 4.5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.203 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 85.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0207] FIG. 5 reports the FT-IR spectrum of the polybutadiene obtained.

Example 15 (MM281)

[0208] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 11.6 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (1.6 ml; 2.56×10.sup.−3 moles, equal to about 0.145 g) was added and, subsequently, the VCl.sub.3(PMePh.sub.2).sub.2 complex [sample MM261] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in Example 1. Everything was kept, under magnetic stirring, at 20° C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.498 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 60%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0209] FIG. 6 reports the FT-IR spectrum of the polybutadiene obtained.

Example 16 (MM275)

[0210] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 7 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PMePh.sub.2).sub.2 complex [sample MM261] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in

[0211] Example 1. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.845 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 74.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

Example 17 (G1282)

[0212] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 7 ml of toluene were added and the temperature of the solution thus obtained was brought to −30° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PMePh.sub.2).sub.2 complex [sample MM261] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in Example 1. Everything was kept, under magnetic stirring, at −30° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.364 g of polybutadiene with prevalently 1,4-trans structure having a 1,4-trans unit content of 95.1%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0213] FIG. 7 reports the FT-IR spectrum of the polybutadiene obtained.

Example 18 (MM319)

[0214] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.75 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 20 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.364 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 85.4%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0215] FIG. 8 reports the FT-IR spectrum of the polybutadiene obtained.

Example 19 (MM320)

[0216] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.75 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 3 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.815 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 71.3%; further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0217] FIG. 9 reports the FT-IR spectrum of the polybutadiene obtained.

Example 20 (MM393)

[0218] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 9.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (3.15 ml; 5×10.sup.−3 moles, equal to about 0.29 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 2.5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.17 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 62.7%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0219] FIG. 10 reports the FT-IR spectrum of the polybutadiene obtained.

Example 21 (MM394)

[0220] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 12.4 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (0.63 ml; 1×10.sup.−3 moles, equal to about 0.058 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.483 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 61.7%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0221] FIG. 11 reports the FT-IR spectrum of the polybutadiene obtained.

Example 22 (MM395)

[0222] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 9.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (3.15 ml; 5×10.sup.−3 moles, equal to about 0.29 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.281 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 81.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0223] FIG. 12 reports the FT-IR spectrum of the polybutadiene obtained.

Example 23 (MM396)

[0224] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 12.4 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (0.63 ml; 1×10.sup.−2 moles, equal to about 0.058 g) was added and, subsequently, the VCl3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.203 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 80.2%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0225] FIG. 13 reports the FT-IR spectrum of the polybutadiene obtained.

Example 24 (MM398)

[0226] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 9.9 ml of 1,2-dichlorobenzene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in 1,2-dichlorobenzene solution (3.15 ml; 5×10.sup.−3 moles, equal to about 0.29 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of 1,2-dichlorobenzene solution at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 2.16 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.778 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 75.5%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0227] FIG. 14 reports the FT-IR spectrum of the polybutadiene obtained.

Example 25 (MM374)

[0228] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.235 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 84%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0229] FIG. 15 reports the FT-IR spectrum of the polybutadiene obtained.

Example 26 (MM341)

[0230] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.684 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 73.2%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0231] FIG. 16 reports the FT-IR spectrum of the polybutadiene obtained.

Example 27 (MM335)

[0232] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCyPh.sub.2).sub.2 complex [sample MM300] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 4. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.1 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 68.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0233] FIG. 17 reports the FT-IR spectrum of the polybutadiene obtained.

Example 28 (MM336)

[0234] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCyPh.sub.2).sub.2 complex [sample MM300] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 4. Everything was kept, under magnetic stirring, at 20° C., for 72 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.607 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 82%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0235] FIG. 18 reports the FT-IR spectrum of the polybutadiene obtained.

Example 29 (MM338)

[0236] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to −30° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCyPh.sub.2).sub.2 complex [sample MM300] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 4. Everything was kept, under magnetic stirring, at −30° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.449 g of polybutadiene with prevalently 1,4-trans structure having a 1,4-trans unit content of 95.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

Example 30 (G1306)

[0237] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl3(PPh.sub.3).sub.2 complex [sample MM295] (3.4 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.8 mg) obtained as described in Example 5. Everything was kept, under magnetic stirring, at 20° C., for 21 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.742 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 81%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

Example 31 (G1307)

[0238] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PPh.sub.3).sub.2 complex [sample MM295] (3.4 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.8 mg) obtained as described in Example 5. Everything was kept, under magnetic stirring, at 20° C., for 21 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.301 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 68.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0239] FIG. 19 reports the FT-IR spectrum of the polybutadiene obtained.

Example 32 (MM317)

[0240] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.tBu.sub.3).sub.2 complex [sample G1299] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in Example 9. Everything was kept, under magnetic stirring, at 20° C., for 20 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.819 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 86.5%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0241] FIG. 20 reports the FT-IR spectrum of the polybutadiene obtained.

Example 33 (MM318)

[0242] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.tBu.sub.3).sub.2 complex [sample G1299] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in Example 9. Everything was kept, under magnetic stirring, at 20° C., for 20 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.692 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 64.8%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0243] FIG. 21 reports the FT-IR spectrum of the polybutadiene obtained.

Example 34 (MM365)

[0244] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.55 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCyp.sub.3).sub.2 complex [sample G1286] (3.15 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.3 mg) obtained as described in Example 7. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.67 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 76.3%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0245] FIG. 22 reports the .sup.1H-NMR and .sup.13C-NMR spectra of the polybutadiene obtained.

Example 35 (G1376)

[0246] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCy.sub.3).sub.2 complex [sample MM370] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 6. Everything was kept, under magnetic stirring, at 20° C., for 15 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.461 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 81%; further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

Example 36 (MM378)

[0247] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.9 ml of heptane were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in heptane solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCy.sub.2H).sub.2 complex [sample G1303] (2.77 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.5 mg) obtained as described in Example 8. Everything was kept, under magnetic stirring, at 20° C., for 20 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.338 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 83.5%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

Example 37 (MM379)

[0248] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 6.9 ml of heptane were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in heptane solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCy.sub.2H).sub.2 complex [sample G1303] (2.77 ml of heptane suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.5 mg) obtained as described in Example 8. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.268 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 62.3%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0249] FIG. 23 reports the FT-IR spectrum of the polybutadiene obtained.

Example 38 (MM279)

[0250] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 8.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(dmpe) complex [sample G1275] (1.53 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.06 mg) obtained as described in Example 10. Everything was kept, under magnetic stirring, at 20° C., for 72 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.113 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 64.6%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0251] FIG. 24 reports the FT-IR spectrum of the polybutadiene obtained.

Example 39 (G1284)

[0252] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, in the cold (−20° C.), in a 25 ml test tube. Subsequently, 7 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(dppa) complex [sample G1281] (2.72 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.5 mg) obtained as described in Example 12. Everything was kept, under magnetic stirring, at 20° C., for 3.5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.445 g of polybutadiene with mixed cis/trans/1,2 structure having a 1,4-trans and 1,4-cis unit content of 73.1%: further characteristics of the process and of the polybutadiene obtained are reported in Table 3.

[0253] FIG. 25 reports the FT-IR spectrum of the polybutadiene obtained.

Example 40 (G1314)

[0254] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.75 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 18 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.860 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 81.4%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0255] FIG. 26 reports the FT-IR spectrum of the polyisoprene obtained.

Example 41 (MM401)

[0256] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.75 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 1.15 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.104 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 70.4%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0257] FIG. 27 reports the FT-IR spectrum of the polyisoprene obtained.

Example 42 (MM402)

[0258] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.75 ml of 1,2-dichlorobenzene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in 1,2-dichlorobenzene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PEtPh.sub.2).sub.2 complex [sample G1298] (2.95 ml of 1,2-dichlorobenzene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.9 mg) obtained as described in Example 2. Everything was kept, under magnetic stirring, at 20° C., for 1.15 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.207 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 63.5%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0259] FIG. 28 reports the FT-IR spectrum of the polyisoprene obtained.

Example 43 (MM343)

[0260] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.02 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 77.3%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0261] FIG. 29 reports the FT-IR spectrum of the polyisoprene obtained.

Example 44 (MM346)

[0262] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.65 ml of 1,2-dichlorobenzene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in 1,2-dichlorobenzene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 68.9%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

Example 45 (MM371)

[0263] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 5 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.249 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 74.2%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0264] FIG. 30 reports the FT-IR spectrum of the polyisoprene obtained.

Example 46 (MM372)

[0265] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.65 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.iPrPh.sub.2).sub.2 complex [sample G1325] (3.05 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.1 mg) obtained as described in Example 3. Everything was kept, under magnetic stirring, at 20° C., for 96 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.764 g of polyisoprene with prevalently 1,4-cis structure having a 1,4-cis unit content of 87%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0266] FIG. 31 reports the FT-IR spectrum of the polyisoprene obtained.

Example 47 (MM337)

[0267] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCyPh.sub.2).sub.2 complex [sample MM300] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 4. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.387 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 76.2%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0268] FIG. 32 reports the FT-IR spectrum of the polyisoprene obtained.

[0269] FIG. 33 reports the .sup.1H-NMR and .sup.13C-NMR spectra of the polyisoprene obtained.

Example 48 (G1310)

[0270] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PPh.sub.3).sub.2 complex [sample MM295] (3.4 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.8 mg) obtained as described in Example 5. Everything was kept, under magnetic stirring, at 20° C., for 2 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.12 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 75%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0271] FIG. 34 reports the FT-IR spectrum of the polyisoprene obtained.

Example 49 (MM332)

[0272] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(P.sup.tBu.sub.3).sub.2 complex [sample G1299] (2.8 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.6 mg) obtained as described in Example 9. Everything was kept, under magnetic stirring, at 20° C., for 24 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.415 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 86.2%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0273] FIG. 35 reports the FT-IR spectrum of the polyisoprene obtained.

Example 50 (MM375)

[0274] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.25 ml of toluene were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCy.sub.3).sub.2 complex [sample MM370] (3.45 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 6.9 mg) obtained as described in Example 6. Everything was kept, under magnetic stirring, at 20° C., for 19 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.358 g of polyisoprene with mixed cis/trans/3,4 structure having a 1,4-trans and 1,4-cis unit content of 76.8%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

[0275] FIG. 36 reports the FT-IR spectrum of the polyisoprene obtained.

Example 51 (MM377)

[0276] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 6.25 ml of heptane were added and the temperature of the solution thus obtained was brought to 20° C. Then, methylaluminoxane-dry (MAO-dry) in heptane solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the VCl.sub.3(PCy.sub.2H).sub.2 complex [sample G1303] (2.77 ml of heptane suspension at a concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 5.5 mg) obtained as described in Example 8. Everything was kept, under magnetic stirring, at 20° C., for 20 hours. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.674 g of polyisoprene with mixed cis/trans/3.4 structure having a 1,4-trans and 1,4-cis unit content of 82.7%: further characteristics of the process and of the polyisoprene obtained are reported in Table 4.

TABLE-US-00001 TABLE 1 Crystallographic data, Details of Data Collection and Refinement Results for the complexes VCl.sub.3(PMePh.sub.2).sub.2 (Example 1) (I), VCl.sub.3(PCyp.sub.3).sub.2 (Example 7) (II) and VCl.sub.3(PEtPh.sub.2).sub.2 (Example 2) (III) (I) (II) (III) formula, Mw C.sub.26H.sub.26Cl.sub.3P.sub.2V, 557.70 C.sub.30H.sub.54Cl.sub.3P.sub.2V, 633.96 C.sub.28H.sub.30Cl.sub.3P.sub.2V, 585.75 crystal system Triclinic Triclinic Monoclinic space group, Z, Z′ P-1, 4, 2 P-1, 2, 1 P21/c, 4, 1 Dcalc, g cm.sup.−3 1.393 1.349 1.393 a, Å 11.8722(7) 9.9362(15) 8.3234(12) b, Å 13.1864(7) 11.7793(18) 9.7489(14) c, Å 17.6804(10) 14.673(2) 34.500(5) α, ° 74.0516(8) 83.712(2) 90 β, ° 88.8531(9) 89.645(2) 93.804(2) γ, ° 88.1796(8) 66.242(2) 90 V, Å3 2659.8(3) 1561.0(4) 2793.3(7) crystal dimensions, mm 0.37 × 0.37 × 0.15 0.50 × 0.17 × 0.15 0.50 × 0.20 × 0.20 color, shape red, “tablet” red, “tablet” orange, “tablet” μ, mm.sup.−1, 0.807 0.696 0.773 Radiation MoKα MoKα MoKα T, K 130(2) 100(2) 130(2) 2θmax, ° 64.67 46.56 50.91 h, k, l ranges −17.fwdarw.17, −19.fwdarw.19, −11.fwdarw.11, −13.fwdarw.13, −10.fwdarw.10, −11.fwdarw.11, −26.fwdarw.26 −16.fwdarw.16 −41.fwdarw.41 decay intensity, % 0.00 0.00 0.00 absorption correction multi-scan multi-scan multi-scan Tmin, Tmax 0.680, 0.746 0.591, 0.745 0.660, 0.745 measured reflections 57731 16969 37054 Rint 0.0302 0.0395 0.0468 independent reflections 18106 4488 5141 reflections with I > 2σ(I) 13934 3859 4377 no. of parameters 581 325 309 R, wR [F2 > 2σ(F2)] 0.0483, 0.1225 0.0385, 0.0911 0.0261, 0.0564 goodness of convergence 1.028 1.066 1.035 Δp max, Δp min (eÅ−3) 1.595, −1.622 0.606, −0.940 0.286, −0.249

TABLE-US-00002 TABLE 2 Bond lengths (Å) and Angles (°) selected for complexes VCl.sub.3(PMePh.sub.2).sub.2 (Example 1) (I), VCl.sub.3(PCyp.sub.3).sub.2 (Example 7) (II) and VCl.sub.3(PEtPh.sub.2).sub.2 (Example 2) (III).sup.(a) (I) (II) (III) V—Cl 2.2287(8) 2.2384(12) 2.2408(6) V—P 2.5280(6) 2.5696(10) 2.5465(6) P—C.sub.ar 1.820(2) — 1.8251(19) P—C.sub.aliph 1.822(2) 1.847(3) 1.8332(19) Cl—V—Cl 119.98(3) 120.00(4) 119.99(2) P—V—P 169.02(2) 170.48(3) 177.87(2) C.sub.ar—P—C.sub.ar 103.73(10) — 103.85(8) C.sub.ar—P—C.sub.aliph 105.20(11) — 105.42(9) C.sub.aliph—P—C.sub.aliph — 105.46(15) — .sup.(a)Each value reported was obtained as the mean of all the corresponding parameters present in the structure.

TABLE-US-00003 TABLE 3 Polymerization of 1,3-butadiene with catalytic systems comprising vanadium phosphinic complexes Temperature Time Conversion N.sup.(a) 1,4-cis 1,4-trans 1, 2 M.sub.w Example (° C.) (h) (%) (h.sup.−1) (%) (%) (%) (g × mol.sup.−1) M.sub.w/M.sub.n 13 20 72 17.2 3 47.2 30 22.8 196224 1.8 14 20 4.5 14.5 42 72 13.8 14.2 164184 1.9 15 20 5 35.6 184 32 28 40 278725 1.8 16 20 2 60.4 782 30.3 44.5 25.2 212824 2.0 17 −30 24 26 28 0 95.1 4.9 345678 1.6 18 20 20 25.3 33 75.3 10.1 14.6 155879 1.9 19 20 3 58.2 503 25.2 46.1 28.7 202457 1.9 20 20 2.5 83.6 867 28.1 34.6 37.3 216794 1.9 21 20 5 34.5 179 36.3 25.4 38.3 237893 2.0 22 20 24 20 22 58.4 23.4 18.2 159985 1.8 23 20 24 14.5 16 25.7 54.5 19.8 170469 2.0    24.sup.(b) 20 2.16 55.6 667 59.9 15.6 24.5 236723 1.9 25 20 2 16.8 218 66.4 17.6 16 101894 2.6 26 20 2 48.9 633 53.4 19.8 26.8 112385 3.5 27 20 2 78.6 1019 37.3 31.5 31.2 115614 3.0 28 20 72 43 16 67.1 14.9 1.8 99968 2.9 29 −30 24 32 35 0 95.8 4.2 135469 2.4 30 20 21 51.7 64 62 19 19 290552 1.6 31 20 21 92.9 115 29.6 39.2 31.2 177455 4.2 32 20 20 58.5 76 52.6 33.9 13.5 188227 1.8 33 20 20 49.4 64 21 43.8 35.2 253345 3.1 34 20 2 47.9 620 42.1 34.2 23.7 183294 3.5 35 20 0.25 33 3414 45 36 19 192538 3.3 .sup. 36.sup.(c) 20 20 24 26 70.5 13 16.5 190482 3.0 .sup. 37.sup.(c) 20 2 43 559 41.1 21.2 37.7 244237 3.2 38 20 72 7.4 3 45.9 18.7 35.4 86135 2.3 39 20 3.5 31.8 235 26.6 46.5 26.9 211364 2.1 .sup.(a)number of moles of 1,3-butadiene polymerized per hour per mole of vanadium; .sup.(b)polymerization solvent 1,2-dichlorobenzene; .sup.(c)polymerization solvent heptane.

TABLE-US-00004 TABLE 4 Polymerization of isoprene with catalytic systems comprising vanadium phosphinic complexes Temperature Time Conversion N.sup.(a) 1,4-cis 1,4-trans 3, 4 M.sub.w Example (° C.) (h) (%) (h.sup.−1) (%) (%) (%) (g × mol.sup.−1) M.sub.w/M.sub.n 40 20 18 63.2 70 59.9 21.5 18.6 208350 1.8 41 20 1.15 7.6 133 52.1 18.3 29.6 184583 1.8    42.sup.(b) 20 1.15 15.2 265 47.0 16.5 36.5 216725 2.1 43 20 24 75 63 57.2 20.1 22.7 139100 1.7    44.sup.(b) 20 0.5 73.5 2941 51.0 17.9 31.1 302697 1.8 45 20 5 18.3 73 54.9 19.3 25.8 202365 1.9 46 20 96 56.2 12 87.0 0 13.0 200153 1.8 47 20 2 28.5 285 67.6 8.6 23.8 224023 2.5 48 20 2 8.8 88 55.5 19.5 25 108617 2.2 49 20 24 30.5 25 63.8 22.4 13.8 135921 2.3 50 20 19 26.3 28 56.9 19.9 23.2 128795 2.4 .sup. 51.sup.(c) 20 20 49.6 50 61.2 21.5 17.3 155698 2.5 .sup.(a)number of moles of isoprene polymerized per hour per mole of vanadium; .sup.(b)polymerization solvent 1,2-dichlorobenzene; .sup.(c)polymerization solvent heptane.