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

Abstract

Nitrogen titanium complex having general formula (I) or (II), wherein: R.sub.1 represents a hydrogen atom; or is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; R.sub.2, R.sub.3, R.sub.4 and R.sub.5, identical or different, represent a hydrogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, nitro groups, hydroxyl groups, amino groups; Y represents a NHR.sub.6 group wherein R.sub.6 represents a hydrogen atom, or is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; or a NR.sub.7 group wherein R.sub.7 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, identical or different, represent a halogen atom, such as, for example, chlorine, bromine, iodine, preferably chlorine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, OCOR.sub.8 or OR.sub.8 groups wherein R.sub.8 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15; or one of X.sub.1, X.sub.2 and X.sub.3 is selected from ethers, such as, for example, diethylether, tetrahydrofuran (THF), dimethoxyethane, preferably tetrahydrofuran (THF); n is 1 in the case wherein Y represents a NHR.sub.6 group wherein R.sub.6 has the same meanings reported above; or is 0 in the case wherein Y represents a NR.sub.7 group wherein R.sub.7 has the same meanings reported above, or in the case wherein one of X.sub.1, X.sub.2 and X.sub.3 is selected from ethers; R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7, identical or different, represent a hydrogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; X.sub.1 and X.sub.2, identical or different, represent a halogen atom such as, for example, chlorine, bromine, iodine, preferably chlorine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, OCOR.sub.8 groups or OR.sub.8 groups wherein R 8 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15; Y is selected from ethers such as, for example, diethylether, tetrahydrofuran (THF), dimethoxyethane, preferably is tetrahydrofuran (THF); or Y represents a group having general formula (III), wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7, have the same meanings as reported above; m is 0 or 1. Said nitrogen titanium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

Claims

1. A nitrogen titanium complex having general formula (I) or (II): ##STR00030## wherein: R.sub.1 represents a hydrogen atom; or is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; R.sub.2, R.sub.3, R.sub.4 and R.sub.5, identical or different, represent a hydrogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted, nitro groups, hydroxyl groups, and amino groups; Y represents a NHR.sub.6 group wherein R.sub.6 represents a hydrogen atom, or is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; or a NR.sub.7 group wherein R.sub.7 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, aryl groups optionally substituted; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, identical or different, represent a halogen atom including chlorine, bromine, and iodine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, OCOR.sub.8 groups or groups OR.sub.8 wherein R.sub.8 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups; or one of X.sub.1, X.sub.2 and X.sub.3 is selected from ethers such as diethylether and tetrahydrofuran (THF), dimethoxyethane; n is 1 in the case wherein Y represents a NHR.sub.6 group wherein R.sub.6 has the same meanings reported above; or is 0 in the case wherein Y represents a NR.sub.7 group wherein R.sub.7 has the same meanings reported above, or in the case wherein one of X.sub.1, X.sub.2 and X.sub.3 is selected from ethers; R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.7, identical or different, represent a hydrogen atom; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, optionally halogenated, cycloalkyl groups optionally substituted, and aryl groups optionally substituted; X.sub.1 and X.sub.2, identical or different, represent a halogen atom including chlorine, bromine, and iodine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, OCOR.sub.8 groups or OR.sub.8 groups wherein R.sub.8 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups; Y is selected from ethers including diethylether, tetrahydrofuran (THF), and dimethoxyethane; or Y represents a group having general formula (III): ##STR00031## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, and R.sub.7, have the same meanings as reported above; and m is 0 or 1.

2. The nitrogen titanium complex having general formula (I) or (II) according to claim 1, wherein: R.sub.1 represents a hydrogen atom; or is selected from C.sub.1-C.sub.20 alkyl groups; R.sub.2, R.sub.3, R.sub.4 and R.sub.5, mutually identical, represent a hydrogen atom; Y represents a NHR.sub.6 group or a NR.sub.7 group wherein R.sub.6 and R.sub.7 are selected from aryl groups optionally substituted; including phenyl, or phenyl substituted with one or more methyl, iso-propyl, and tert-butyl groups; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, identical or different, represent a halogen atom including chlorine, bromine, and iodine; or one of X.sub.1, X.sub.2, X.sub.3 is tetrahydrofuran (THF); n is 1 in the case wherein Y represents a NHR.sub.6 group wherein R.sub.6 has the same meanings reported above; or is 0 in the case wherein Y represents a NR.sub.7 group wherein R.sub.7 has the same meanings reported above, or in the case wherein Y represents a NR.sub.7 group wherein R.sub.7 has the same meanings reported above and one of X.sub.1, X.sub.2, X.sub.3, is tetrahydrofuran; R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5, mutually identical, represent a hydrogen atom; or are selected from C.sub.1-C.sub.20 alkyl groups; R.sub.6 and R.sub.7, mutually identical, are selected from linear or branched C.sub.1-C.sub.20 alkyl groups; X.sub.1 and X.sub.2, mutually identical, represent a halogen atom including chlorine, bromine, and iodine; Y is tetrahydrofuran or represents a group having general formula (III): ##STR00032## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, and R.sub.7, have the same meanings reported above; and m is 0 or 1.

3. A catalytic system for the (co)polymerization of conjugated dienes comprising: (a) at least one nitrogen titanium complex having general formula (I) or (II); (b) at least one co-catalyst selected from organic compounds of an element M different from carbon, said element M being selected from elements belonging to groups 2, 12, 13, or 14, of the Periodic Table of the Elements, including: boron, aluminum, zinc, magnesium, gallium and tin.

4. A catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (bi) aluminum alkyls having general formula (IV):
Al(X.sub.a).sub.n(R.sub.a).sub.3-p(IV) wherein X.sub.a represents a halogen atom including chlorine, bromine, iodine, or fluorine; R.sub.a is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, aryl groups, said groups being optionally substituted with one or more atoms of silicon or germanium; and n is an integer ranging from 0 to 2.

5. A catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (b.sub.2) organo-oxygenated compounds of an element M different from carbon belonging to groups 13 or 14 of the Periodic Table of the Elements, including compounds of aluminum, gallium, and tin.

6. A catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said co-catalyst (b) is selected from (b.sub.3) compounds or mixtures of organometallic compounds of an element M different from carbon able to react with the nitrogen titanium complex having general formula (I) or (II) according to claim 1 or 2, by extracting from it a ?-linked substituent X.sub.1, X.sub.2 or X.sub.3, to form at least one neutral compound or an ionic compound consisting of a cation containing the metal (Ti) coordinated by the ligand, and a non-coordinating organic anion containing the metal M, whose negative charge is delocalized on a multicenter structure.

7. A catalytic system for the (co)polymerization of conjugated dienes according to claim 4, wherein said aluminum alkyls (bi) having general formula (IV) are tri-ethyl-aluminum, tri-iso-butyl-aluminum (TIBA), or di-iso-butyl-aluminum hydride (DIBAH).

8. A catalytic system for the (co)polymerization of conjugated dienes according to claim 5, wherein said organo-oxygenated compounds (b2) are selected from aluminoxanes having general formula (V):
(R.sub.9).sub.2AlO[Al(R.sub.10)O-].sub.pAl(R.sub.11).sub.2(V) wherein R.sub.9, R.sub.10 and R.sub.11, identical or different, represent a hydrogen atom, a halogen atom including chlorine, bromine, iodine, or fluorine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, aryl groups, said groups being optionally substituted with one or more atoms of silicon or germanium; and p is an integer ranging from 0 to 1000.

9. A catalytic system for the (co)polymerization of conjugated dienes according to claim 8, wherein said organo-oxygenated compound (b.sub.2) is methylaluminoxane (MAO) or in the dry form (MAO-dry).

10. A catalytic system for the (co)polymerization of conjugated dienes according to claim 6, wherein said compounds or mixtures of compounds (b.sub.3) are selected from organic compounds of aluminum and boron, including those represented by the following general formulae:
[(R.sub.C).sub.WH.sub.4-W].[B(R.sub.D).sub.4].sup.?;B(R.sub.D).sub.3;Al(R.sub.D).sub.3;B(R.sub.D).sub.3Pir[Ph.sub.3C].sup.+.[B(R.sub.D).sub.4].sup.?;
[(R.sub.C).sub.3PirH].sup.+.[B(R.sub.D).sub.4].sup.?;
[Li].sup.+.[B(R.sub.D).sub.4].sup.?;[Li].sup.+.[Al(R.sub.D).sub.4].sup.? wherein w is an integer ranging from 0 to 3, each R.sub.C group independently represents an alkyl group or an aryl group having from 1 to 10 carbon atoms and each R.sub.D group independently represents an aryl group partially or totally fluorinated, having from 6 to 20 carbon atoms, and Pir is a pyrrole radical optionally substituted.

11. A process for the (co)polymerization of conjugated dienes, wherein the catalytic system is used according to claim 4.

12. A process for the (co)polymerization of 1,3-butadiene or of isoprene (2-methyl-1,3-butadiene), wherein the catalytic system is used according to claim 4.

Description

EXAMPLES

[0109] Reagents and Materials

[0110] The list below reports the reagents and materials used in the following examples of the invention, their potential pre-treatments and their manufacturer: [0111] 2,6-di-iso-propylaniline (Aldrich): used as such; [0112] 2-pyridinecarboxaldehyde (Aldrich): used as such; [0113] 2-acetylpyridine (Aldrich): used as such; [0114] 2-tert-butylaniline (Aldrich): used as such; [0115] titanium tetrachloride anhydrous (Aldrich): degree of purity 99.9%, distilled prior to use; [0116] titanium trichloride: tetrahydrofuran complex (1:3) [TiCl.sub.3(THF).sub.3] (Aldrich); used as such; [0117] n-butyl lithium (Aldrich): used as such; [0118] 2,4-pentanedione (Aldrich): used as such; [0119] aniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0120] 2,4,6-tri-methylaniline (Aldrich): used as such; [0121] p-toluidine (Aldrich): used as such; [0122] dichloromethane (Carlo Erba, RPE): used as such; [0123] formic acid (Aldrich): used as such; [0124] ethyl ether (Aldrich): used as such; [0125] sodium sulfate (Aldrich): used as such; [0126] tetrahydrofuran (THF) (Aldrich): used as such; [0127] toluene (Fluka): degree of purity >99.5%, refluxed over sodium (Na) for about 8 hours, then distilled and stored over molecular sieves under nitrogen; [0128] hexane (Aldrich): used as such; [0129] heptane (Aldrich): pure, ?99%, distilled over sodium (Na) in an inert atmosphere; benzene (Aldrich): used as such; [0130] sodium borohydride (Aldrich): used as such; [0131] ethyl acetate (Aldrich): used as such; [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 maintained in a nitrogen atmosphere at 4? C.; [0134] methylaluminoxane (MAO) (toluene solution 10% by weight) (Aldrich): used as such; [0135] methanol (Carlo Erba, RPE): used as such, or optionally anhydrified by distillation on magnesium (Mg); [0136] hydrochloric acid in 37% aqueous solution (Aldrich): used as such; [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] dichloromethane-d.sub.2 (CD.sub.2Cl.sub.2) (Aldrich): used as it is; [0139] deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; [0140] deuterated chloroform (CDCl.sub.3) (Acros): used as such; hexamethyldisiloxane (HDMS) (AldrichNMR grade): degree of purity ?99.5%, used as such; [0141] tetramethylsilane (TMS) (AldrichACS reagent, NMR grade): degree of purity ?99.9%, used as such.

[0142] The analysis and classification methodologies reported below were used.

[0143] Elemental Analysis

[0144] a) Determination of Titanium (Ti)

[0145] For the determination of the quantity by weight of titanium (Ti) in the nitrogen titanium complexes object of the present invention, an exactly weighed aliquot, operating in dry-box under nitrogen flow, of about 30 mg-50 mg of sample, was placed in a about 30 ml platinum crucible, together with a 1 ml mixture of 40% hydrofluoric acid (HF) (Aldrich), 0.25 ml of 96% sulphuric acid (H.sub.2SO.sub.4) (Aldrich) 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 brought again to the appearance of fumes. 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 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, measuring calibration solutions by dilution by weight of certified solutions.

[0146] 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.

[0147] Elemental Analysis

[0148] b) Determination of Chlorine

[0149] For said purpose, samples of nitrogen titanium 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) were added and, outside the dry-box, 50 ml of MilliQ water. It was brought to the boil on the hot plate, under magnetic stirring, for about 30 minutes. It was left to cool, then 1/5 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.

[0150] c) Determination of Carbon, Hydrogen and Nitrogen

[0151] The determination of carbon, hydrogen and nitrogen, in the nitrogen titanium complexes object of the present invention, as well as in the ligands used for the purpose of the present invention, was carried out through a Carlo Erba automatic analyzer Mod. 1106.

[0152] .sup.13C-HMR and .sup.1H-HMR Spectra

[0153] 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.2Cl.sub.4) at 103? C., and hexamethyldisiloxane (HDMS) as internal standard, or using deuterated chloroform (CDCl.sub.3) or dichloromethane-d.sub.2 (CD.sub.2Cl.sub.2), at 25? C., and tetramethylsilane (TMS) 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.

[0154] The microstructure of the polymers [i.e. 1,4-cis unit content (%) in polybutadiene; 1,4-cis unit content (%) and 3,4 unit content in polyisoprene] 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, pg. 1009-1018.

[0155] FT-IR Spectra (Solid StateATR)

[0156] The FTIR-ATR spectra were recorded using a Bruker IFS 48 spectrophotometer equipped with a Thermo Spectra-Tech horizontal ATR connection. The section wherein the samples to be analyzed are placed is a Fresnel ATR accessory (Shelton, Conn., USA) which uses crystals of zirconium selenide (ZrSe) with an angle of incidence of 45? in the horizontal direction.

[0157] The FT-IR spectra (solid stateATR) of the nitrogen titanium complexes used in the present invention, were obtained by inserting samples of the nitrogen titanium complex to be analyzed into said section.

[0158] FT-IR Spectra

[0159] The FT-IR spectra were recorded through Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophotometers.

[0160] 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 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.

[0161] Determination of the Molecular Weight

[0162] The determination of the molecular weight (MW) of the polymers obtained was carried out through GPC (Gel Permeation Chromatography) operating under the following conditions: [0163] Agilent 1100 pump; [0164] Agilent 1100 I.R. detector; [0165] PL Mixed-A columns; [0166] solvent/eluent: tetrahydrofuran (THF); [0167] flow rate: 1 ml/min; [0168] temperature: 25? C.; [0169] molecular mass calculation: Universal Calibration method.

[0170] The weight-average molecular weight (M.sub.w) and the Polydispersion Index (PDI) are reported, corresponding to the ratio M.sub.w/M.sub.n (M.sub.n=number-average molecular weight).

[0171] Gas Chromatography-Mass Spectrometry (GC-MS)

[0172] Gas chromatography-mass spectrometry (GC-MS) was carried out using a Thermo ISQ single quadrupole mass spectrometer. For that purpose, samples of the ligands used for the purpose of the present invention to be analyzed were dissolved in methylene chloride (CH.sub.2Cl.sub.2) at a concentration of 0.1 mg/ml and were analyzed using said spectrometer operating under the following conditions: [0173] ionization method: electronic ionization (EI); [0174] GC ramp: 50? C. for 2 minutes, heating at a speed of 10? C./min to 300? C.; [0175] injector temperature: 300? C.; [0176] injection volume: 1.30 ?l; [0177] transfer line temperature: 280? C.; [0178] ionic source temperature: 250? C.; [0179] quadrupole scan parameters: 35 amu-500 amu with scan time of 0.2 sec.

Example 1

Synthesis of Ligand Having Formula (L1)

[0180] ##STR00006##

1.1 Synthesis of Compound Having Formula (L1a)

[0181] ##STR00007##

[0182] In a 500 ml flask equipped with a Dean-Stark trap for the azeotropic removal of water, 2-pyridinecarboxaldehyde (16.86 g, 157.5 mmoles) was added to a solution of 2,6-di-iso-propylaniline (27.93 g, 157.5 mmoles) in dichloromethane (300 ml). The mixture obtained was heated under reflux for 20 hours and then dried under vacuum obtaining 41.7 g of a yellow solid (yield=99%) corresponding to the compound having formula (L1a).

[0183] Elemental analysis [found (calculated for C.sub.18H.sub.22N.sub.2)]: C: 81.14% (81.16%); H: 8.33% (8.32%); N: 10.6% (10.52%).

[0184] .sup.1H-NMR (CD.sub.2Cl.sub.2, ? ppm): 8.72 (d, 1H, PyH), 8.32 (s, 1H CH?N), 8.27 (d, 1H PyH), 7.86 (t, 1H PyH), 7.39 (m, 1H PyH), 7.11-7.20 (m, 3H ArH), 3.00 (sept, 2H CHMe.sub.2), 1.18 (d, 12H C(CH.sub.3).sub.2).

1.2 Synthesis of Ligand Having Formula (L1)

[0185] 28 g (105.1 mmoles) of the compound having formula (L1a) obtained as described above and 1800 ml of anhydrous methanol were loaded into a 2 liter reactor, equipped with a stirrer: the whole was cooled to 0? C. and, subsequently, sodium borohydride (70 g, 1850 mmoles) was added, in small portions. The mixture obtained was left, under stirring, at room temperature, all night, and then switched off with brine and extracted with ethyl acetate. The solvent was then removed by distillation at reduced pressure and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of hexane/ethyl acetate in ratio of 9/1 (v/v)], and subsequently treated with cold ethyl ether, obtaining 16.9 g of a crystalline white solid (yield=60%) corresponding to the ligand having formula (L1).

[0186] Elemental analysis [found (calculated for C.sub.18H.sub.24N.sub.2)]: C: 80.49% (80.55%); H: 8.99% (9.01%); N: 10.37% (10.44%).

[0187] FT-IR (solid stateATR): 3309, 1588, 1570, 1493, 1463, 1435.

[0188] .sup.1H-NMR (CDCl.sub.3, ? ppm): 8.61 (d, 1H,o-PyH), 7.66 (td, 1H, PyH), 7.30 (d, 1H, PyH), 7.21 (m, 1H, PyH), 7.04-7.12 (m, 3H, ArH), 4.20 (s, 2H, CH.sub.2), 4.10 (s, 1H, NH), 3.47 (m, 2H, CH(CH.sub.3).sub.2), 1.42 (d, 12H, CH(CH.sub.3).sub.2).

[0189] GC-MS: M.sup.+=m/z 268; [M-C.sub.3H.sub.7].sup.+=m/z 225; [M-C.sub.6H.sub.6N].sup.+=m/z 176; m/z 93 C.sub.6H.sub.7N.

Example 2

Synthesis of Ligand Having Formula (L2)

[0190] ##STR00008##

2.1 Synthesis of Compound Having Formula (L2a)

[0191] ##STR00009##

[0192] In a 500 ml flask, 2-acetylpyridine (9.1 g, 75 mmoles) was added to a solution of 2,6-di-iso-propylaniline (13.3 g, 75 mmoles) in methanol (300 ml): the mixture obtained was left, under stirring, at room temperature, for 48 hours. The precipitate obtained was filtered and subsequently dried under vacuum obtaining 14 g of a yellow crystalline powder (yield=67%) corresponding to the compound having formula (L2a).

[0193] Elemental analysis [found (calculated for C.sub.19H.sub.24N.sub.2)]: C: 81.37% (81.38%); H: 8.64% (8.63%); N: 10.01% (9.99%).

[0194] .sup.1H-NMR (CDCl.sub.3, ? ppm) 8.69 (d, 1H, PyH), 8.38 (d, 1H, PyH), 7.82 (t, 1H, PyH), 7.39 (m, 1H, PyH), 7.11-7.20 (m, 3H, ArH), 2.75 (m, 2H, CHMe.sub.2), 2.21 (s, 3H, N?CH-Me), 1.15 (d, 12H, CH(CH.sub.3).sub.2).

2.2 Synthesis of Ligand Having Formula (L2)

[0195] 24 g (85 mmoles) of the compound having formula (L2a) obtained as described above and 900 ml of anhydrous methanol were loaded into a 2 liter reactor, equipped with a stirrer: the whole was cooled to 0? C. and, subsequently, sodium borohydride (48.6 g, 1285 mmoles) was added, in small portions. The mixture obtained was left, under stirring, at room temperature, all night, and then switched off with brine and extracted with ethyl acetate. The solvent was then removed by distillation at reduced pressure and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of hexane/ethyl acetate in ratio of 9/1 (v/v)], and subsequently treated with cold ethyl ether, obtaining 11 g of a crystalline white solid (yield=46%) corresponding to the ligand having formula (L2).

[0196] Elemental analysis [found (calculated for C.sub.19H.sub.26N.sub.2)]: C: 81.03% (80.80%); H: 9.42% (9.28%); N: 10.01% (9.92%).

[0197] GC-MS: M.sup.+=m/z 282; [M-C.sub.3H.sub.7].sup.+=m/z 239; [M-C.sub.7H.sub.8N].sup.+=m/z 176; [M-C.sub.12H.sub.18N].sup.+=m/z 106.

[0198] .sup.1H-NMR (CDCl.sub.3, ? ppm): 8.64 (d, 1H, HPy), 7.53 (dt, 1H, HPy), 7.2 (d, 1H, HPy), 7.00-7.12 (m, 1H, HPy; m, 3H, ArH), 4.0-4.2 (m, 1H, NCH(CH.sub.3), m, 1H, NH), 3.30 (sept, 2H, CH(CH.sub.3).sub.2), 1.55 (d, 3H, NCH(CH.sub.3)), 1.10 (s, 12H, CH(CH.sub.3).sub.2).

Example 3

Synthesis of Ligand Having Formula (L3)

[0199] ##STR00010##

3.1 Synthesis of Compound Having Formula (L3a)

[0200] ##STR00011##

[0201] In a 500 ml flask, 2-acetylpyridine (12.9 g, 106.5 mmoles) was added to a solution of 2-tert-butylaniline (15.89 g, 106.5 mmoles) in methanol (300 ml): the mixture obtained was left, under stirring, at room temperature, for 48 hours. The solvent was subsequently removed by evaporation and the residue obtained was crystallized by methanol obtaining 20 g of a yellow crystalline powder (yield=75%) corresponding to the compound having formula (L3a).

[0202] Elemental analysis [found (calculated for C.sub.17H.sub.20N.sub.2)]: C: 81.17% (80.91%); H: 8.14% (7.99%); N: 10.91% (11.10%).

3.2 Synthesis of Ligand Having Formula (L3)

[0203] 28 g (111 mmoles) of the compound having formula (L3a) obtained as described above and 800 ml of anhydrous methanol were loaded into a 2 liter reactor, equipped with a stirrer: the whole was cooled to 0? C. and, subsequently, sodium borohydride (38 g, 1004 mmoles) was added, in small portions. The mixture obtained was left, under stirring, at room temperature, all night, and then switched off with brine and extracted with ethyl acetate. The solvent was then removed by distillation at reduced pressure and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of hexane/ethyl acetate in ratio of 9/1 (v/v)], and subsequently treated with cold ethyl ether, obtaining 11 g of a crystalline white solid (yield=39%) corresponding to the ligand having formula (L3).

[0204] Elemental analysis [found (calculated for C.sub.17H.sub.22N.sub.2)]: C: 80.00% (80.27%); H: 9.12% (8.72%); N: 11.31% (11.01%).

[0205] GC-MS: M.sup.+=m/z 254; [M-CH.sub.3].sup.+=m/z 239; [M-C.sub.4H.sub.9g]=m/z 197; m/z=183; m/z 132 C.sub.7H.sub.10N.sub.2; [M-C.sub.10H.sub.14N].sup.+=m/z 106; [M-C.sub.12H.sub.18N].sup.+=m/z 78.

[0206] .sup.1H-NMR (CDCl.sub.3, ? ppm): 8.64 (d, 1H, HPy), 7.7 (td, 1H, PyH), 7.36 (d, 1H, HPy), 7.25 (d, 1H, ArH), 7.18 (td, 1H, PyH), 6.98 (td, 1H, PyH), 6.98 (td, 1H, PyH), 6.48 (d, 1H, PyH), 5.0 (broad s, 1H, NH), 4.7 (q, 1H, NCH(CH.sub.3)), 1.57 (d, 3H, NCH(CH.sub.3)), 1.5 (s, 9H, C(CH.sub.3).sub.3).

Example 4

Synthesis of Ligand Having Formula (L4)

[0207] ##STR00012##

4.1 Synthesis of Compound Having Formula (L4a)

[0208] ##STR00013##

[0209] In a 500 ml flask, 2-pyridinecarboxaldehyde (30 g, 280 mmoles) and some drops of formic acid were added to a solution of aniline (26.1 g, 280 mmoles) in methanol (250 ml): the mixture obtained was left, under stirring, at room temperature, for 48 hours. Subsequently, the mixture obtained was dried under vacuum and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of heptane/ethyl acetate in ratio of 99/1 (v/v)], obtaining 38 g of a light yellow solid (yield=74.5%) corresponding to the compound having formula (L4a).

[0210] Elemental analysis [found (calculated for C.sub.12H.sub.10N.sub.2)]: C: 80.00% (79.10%); H: 5.83% (5.53%); N: 15.71% (15.37%).

[0211] .sup.1H-NMR (CDCl.sub.3, ? ppm) 8.70 (d, 1H, HPy), 8.59 (s, 1H CH?N), 8.19 (d, 1H, HPy), 7.77 (dt, 1H, HPy), 7.23-7.42 (m, 1H, HPy; m, 5H, Ar).

4.2 Synthesis of Ligand Having Formula (L4)

[0212] 13 g (71.3 mmoles) of the compound having formula (L4a) obtained as described above and 700 ml of anhydrous methanol were loaded into a 2 liter reactor, equipped with a stirrer: the whole was cooled to 0? C. and, subsequently, sodium borohydride (40 g, 1057 mmoles) was added, in small portions. The mixture obtained was left, under stirring, at room temperature, all night, and then switched off with brine and extracted with ethyl acetate. The solvent was then removed by distillation at reduced pressure and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of hexane/ethyl acetate in ratio of 9/1 (v/v)], and subsequently treated with cold ethyl ether, obtaining 9.12 g of a crystalline white solid (yield=69.5%) corresponding to the ligand having formula (L4).

[0213] GC-MS: M.sup.+=m/z 184; [M-C.sub.6H.sub.6N].sup.+=m/z 106; [M-C.sub.7H.sub.7N.sub.2].sup.+=m/z 77.

[0214] .sup.1H-NMR (CDCl.sub.3, ? ppm): 8.60 (dd, 1H, PyH), 7.64 (m, 1H, PyH), 7.35 (d, 1H, PyH), 7.22-7.17 (m, 1H, Py, 2H, ArH), 6.75 (dt, 1H, ArH), 6.69 (d, 2H, ArH), 4.8 (s, 1H, NH), 4.48 (s, 2H, Py-CH.sub.2N).

Example 5

Synthesis of Ligand Having Formula (L5)

[0215] ##STR00014##

5.1 Synthesis of Compound Having Formula (L5a)

[0216] ##STR00015##

[0217] In a 500 ml flask, 2-pyridinecarboxaldehyde (26.8 g, 250 mmoles) and some drops of formic acid were added to a solution of 2 6-dimethylaniline (31 g, 250 mmoles) in methanol (250 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. Subsequently, the mixture obtained was dried on sodium sulfate, filtered, and the solvent was removed by evaporation under vacuum: the residue obtained was washed with cold methanol, obtaining 47 g of an orange solid (yield=89%) corresponding to the compound having formula (L5a).

[0218] Elemental analysis [found (calculated for C.sub.14H.sub.14N.sub.2)]: C: 80.00% (79.97%); H: 6.81% (6.71%); N: 13.71% (13.32%).

[0219] .sup.1H-NMR (CDCl.sub.3, ? ppm) 8,70 (d, 1H, HPy), 8.33 (s, 1H, CH?N), 8.23 (d, 1H, HPy), 7.82 (dt, 1H, HPy), 7.38 (ddd, 1H, HPy), 6.91-7.15 (m, 5H, Ar), 2.16 (s, 6H, ArCH.sub.3).

5.2 Synthesis of Ligand Having Formula (L5)

[0220] 18 g (85.6 mmoles) of the compound having formula (L5a) obtained as described above and 800 ml of anhydrous methanol were loaded into a 2 liter reactor, equipped with a stirrer: the whole was cooled to 0? C. and, subsequently sodium borohydride (24 g, 634 mmoles) was added, in small portions. The mixture obtained was left, under stirring, at room temperature, all night, and then switched off with brine and extracted with ethyl acetate. The solvent was then removed by distillation at reduced pressure and the residue obtained was purified through elution on a silica gel chromatography column [eluent: mixture of hexane/ethyl acetate in ratio of 9/1 (v/v)], and subsequently treated with cold ethyl ether, obtaining 9.15 g of a crystalline white solid (yield=50.4%) corresponding to the ligand having formula (L5).

[0221] GC-MS: M.sup.+=m/z 212; [M-C.sub.6H.sub.6N].sup.+=m/z 120.

[0222] .sup.1H-NMR (CDCl.sub.3, ? ppm): 8.63 (d, 1H, PyH), 7.65 (dt, 1H, PyH), 7.27 (d, 1H, PyH), 7.20 (dd, 1H, PyH), 7.02 (d, 2H, ArH), 6.85 (m, 1H, ArH), 4.4 (broad s, 1H, NH), 4.31 (s, 2H, Py-CH2N), 2.35 (s, 6H, ArCH.sub.3).

Example 6

Synthesis of Ligand Having Formula (L6

[0223] ##STR00016##

[0224] In a 500 ml flask equipped with a Dean-Stark trap for the azeotropic removal of water, 5 g (50 mmoles) of 2,4-pentanedione were placed, together with 100 ml of methanol, some drops of formic acid and 4.66 g (50 mmoles) of aniline: the mixture obtained was heated to 85? C., for 4 hours. Subsequently, the mixture was cooled to room temperature, filtered on a porous septum and the filtrate obtained was evaporated under vacuum obtaining a solid product. Said solid product was dissolved in ethyl ether (40 ml) and placed in the freezer for 24 hours obtaining a precipitate. The precipitate obtained was recovered through filtration and dried, under vacuum, at room temperature, obtaining 7 g of a solid whitish product (yield=80%) having formula (L6).

[0225] Elemental analysis [found (calculated for C.sub.11H.sub.13NO)]: C: 75.20% (75.40%); H: 7.50% (7.48%); N: 8.00% (7.99%).

[0226] FT-IR (solid state, ATR, cm.sup.?1): 1590; 1571.

[0227] .sup.1H-NMR (CD.sub.2Cl.sub.2, ? ppm): 12.49 (s, 1H NH), 8.27 (d, 1H PyH), 7.34-7.28 (m, 2H ArH), 7.19-7.15 (m, 1H ArH), 7.10-7,08 (m, 2H ArH), 5.18 (s, 1H CH), 2.09 (s, 3H CH.sub.3), 1.97 (s, 3H CH.sub.3).

[0228] GC-MS: M.sup.+=m/z 175.

Example 7

Synthesis of Ligand Having Formula (L7)

[0229] ##STR00017##

[0230] In a 500 ml flask equipped with a Dean-Stark trap for the azeotropic removal of water, 5 g (50 mmoles) of 2,4-pentanedione were placed, together with 75 ml of benzene, some drops of hydrochloric acid and 6.76 g (50 mmoles) of 2,4,6-trimethylaniline: the mixture obtained was heated under reflux, for 24 hours. Subsequently, the mixture was cooled to room temperature, filtered on a porous septum and the filtrate obtained was evaporated under vacuum obtaining a solid product. Said solid product was dissolved in ethyl ether (10 ml) and placed in the freezer for 24 hours obtaining a precipitate. The precipitate obtained was recovered through filtration and dried, under vacuum, at room temperature, obtaining 4.8 g of a solid light yellow product (yield=44%) having formula (L7).

[0231] Elemental analysis [found (calculated for C.sub.14H.sub.19NO)]: C: 77.40% (77.38%); H: 9.00% (8.81%); N: 6.32% (6.45%).

[0232] FT-IR (solid state, ATR, cm.sup.?1): 1606; 1567.

[0233] .sup.1H-NMR (CD.sub.2Cl.sub.2, ? ppm): 1.61 (s, 3H CH.sub.3CN), 2.05 (s, 3H CH.sub.3CO), 2.18 (s, 6H 2-C.sub.6H.sub.2CH.sub.3), 2.28 (s, 3H 4-C.sub.6H.sub.2CH.sub.3), 5.21 (s, 1H CH), 6.92 (s, 2H C.sub.6H.sub.2), 11.82 (s, 1H NH).

[0234] GC-MS: M.sup.+=m/z 217.

Example 8

Synthesis of Ligand Having Formula (L8)

[0235] ##STR00018##

[0236] In a 500 ml flask equipped with a Dean-Stark trap for the azeotropic removal of water, 5 g (50 mmoles) of 2,4-pentanedione were placed, together with 75 ml of benzene, some drops of hydrochloric acid and 5.35 g (50 mmoles) of p-toluidine: the mixture obtained was heated under reflux, for 24 hours. Subsequently, the mixture was cooled to room temperature, filtered on a porous septum and the filtrate obtained was evaporated under vacuum obtaining a solid product. Said solid product was dissolved in ethyl ether (10 ml) and placed in the freezer for 24 hours obtaining a precipitate. The precipitate obtained was recovered through filtration and dried, under vacuum, at room temperature, obtaining 5.7 g of a solid white product (yield=60%) having formula (L8).

[0237] Elemental analysis [found (calculated for C.sub.12H.sub.15NO)]: C: 76.13% (76.16%); H: 7.87% (7.99%); N: 7.36% (7.40%).

[0238] .sup.1H-NMR (CD.sub.2Cl.sub.2, ? ppm): 1.93 (s, 3H, CH.sub.3), 2.05 (s, 3H, CH.sub.3), 2.31 (s, 3H, CH.sub.3), 5.15 (s, 1H, CH), 6.98 (d, 2H, Ph), 7.13 (d, 2H, Ph), 12.38 (s, 1H, NH).

[0239] GC-MS: M.sup.+=m/z 189.

Example 9

Synthesis of TiCl.SUB.4.(L2) [Sample BM2-211]

[0240] ##STR00019##

[0241] 3.6 ml of a 0.5 M titanium tetrachloride (TiCl.sub.4) solution in heptane (1.8 mmoles) were added, drop by drop, to a solution of 0.5 g of the ligand having formula (L2) (1.8 mmoles) obtained as described in Example 2, in heptane (15 ml), in a 100 ml tailed flask: the formation of an orange solid was immediately observed. The whole was left, under stirring, at room temperature, for 4 hours. The solid formed was recovered by filtration, washed with hexane (2?2 ml) and dried at reduced pressure, at room temperature, obtaining 0.76 g (yield=89%) of an orange microcrystalline solid product corresponding to the complex TiCl.sub.4(L2).

[0242] Elemental analysis [found (calculated for C.sub.19H.sub.26Cl.sub.4N.sub.2Ti)]: C: 48.00% (48.34%); H: 5.48% (5.55%); N: 5.75% (5.93%); Ti: 9.64% (10.14%); Cl: 29.01% (30.04%).

[0243] FIG. 1 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.4(L2) obtained.

[0244] FIG. 2 shows the .sup.1H-NMR spectrum of the complex TiCl.sub.4(L1) obtained.

Example 10

Synthesis of TiCl.SUB.4.(L1) [Sample BM2-217]

[0245] ##STR00020##

[0246] 3.8 ml of a 0.5 M titanium tetrachloride (TiCl.sub.4) solution in heptane (1.9 mmoles) were added, drop by drop, to a solution of 0.5 g of the ligand having formula (L1) (1.9 mmoles) obtained as described in Example 1, in heptane (20 ml), in a 100 ml tailed flask: the formation of an orange solid was immediately observed. The whole was left, under stirring, at room temperature, for 4 hours. The solid formed was recovered by filtration, washed with hexane (2?2 ml) and dried at reduced pressure, at room temperature, obtaining 0.76 g (yield=87%) of an orange microcrystalline solid product corresponding to the complex TiCl.sub.4(L1).

[0247] Elemental analysis [found (calculated for C.sub.18H.sub.24Cl.sub.4N.sub.2Ti)]: C: 47.12% (47.20%); H: 5.15% (5.28%); N: 5.97% (6.12%); Ti: 9.84% (10.45%); Cl: 29.76% (30.96%).

[0248] FIG. 3 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.4(L1) obtained.

[0249] FIG. 4 shows the .sup.1H-NMR spectrum of the complex TiCl.sub.4(L1) obtained.

Example 11

Synthesis of TiCl.SUB.3.(L1) [Sample BM2-227]

[0250] ##STR00021##

[0251] 1.5 ml of a 0.5 M titanium tetrachloride (TiCl.sub.4) solution in heptane (0.75 mmoles) were added to a solution of 0.2 g of the ligand having formula (L1) (0.74 mmoles) obtained as described in Example 1, in heptane (30 ml), in a 50 ml tailed flask: the mixture obtained was left, under stirring, at room temperature, for 30 minutes and, subsequently, heated under reflux, for 4 hours. The solid formed was recovered by filtration, washed with heptane (2?2 ml) and dried at reduced pressure, at room temperature, obtaining 0.29 g (yield=83%) of a yellow microcrystalline solid product corresponding to the complex TiCl.sub.3(L1).

[0252] Elemental analysis [found (calculated for C.sub.18H.sub.23Cl.sub.3N.sub.2Ti)]: C: 51.12% (51.28%); H: 5.35% (5.50%); N: 6.40% (6.64%); Ti: 10.84% (11.35%); Cl: 24.12% (25.23%).

[0253] FIG. 5 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.4(L1) obtained.

[0254] FIG. 6 shows the .sup.1H-NMR spectrum of the complex TiCl.sub.4(L1) obtained.

Example 12

Synthesis of TiCl.SUB.3.(L4) [Sample MT-11]

[0255] ##STR00022##

[0256] 1.37 ml of a 0.8 M titanium tetrachloride (TiCl.sub.4) solution in heptane (1.10 mmoles) were added, drop by drop, to a solution of 0.2 g of the ligand having formula (L4) (1.16 mmoles) obtained as described in Example 4, in heptane (20 ml), in a 100 ml tailed flask: the formation of a purple solid was immediately observed. The whole was left, under stirring, at reflux temperature, for 3 hours and then brought to room temperature obtaining a beige suspension. The solid formed was recovered by filtration, washed with hexane (2?3 ml) and dried at reduced pressure, at room temperature, obtaining 0.18 g (yield=48%) of a beige microcrystalline solid product corresponding to the complex TiCl.sub.3(L4).

[0257] Elemental analysis [found (calculated for C.sub.12H.sub.1Cl.sub.3N.sub.2Ti)]: C: 42.73% (42.71%); H: 3.32% (3.29%); N: 8.27% (8.30%); Ti: 13.52% (14.18%); Cl: 30.97% (31.52%).

[0258] FIG. 7 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.3(L4) obtained.

Example 13

Synthesis of TiCl.SUB.3.(L3) [Sample MT-27]

[0259] ##STR00023##

[0260] 1.09 ml of a 0.8 M titanium tetrachloride (TiCl.sub.4) solution in heptane (0.872 mmoles) were added, drop by drop, to a solution of 0.2 g of the ligand having formula (L3) (0.786 mmoles) obtained as described in Example 3, in heptane (20 ml), in a 100 ml tailed flask: the formation of an orange solid was immediately observed. The whole was left, under stirring, at reflux temperature, for 3 hours and then brought to room temperature obtaining an orange suspension. The solid formed was recovered by filtration, washed with hexane (2?3 ml) and dried at reduced pressure, at room temperature, obtaining 0.18 g (yield=56%) of an orange solid product corresponding to the complex TiCl.sub.3(L3).

[0261] Elemental analysis [found (calculated for C.sub.17H.sub.21Cl.sub.3N.sub.2Ti)]: C: 49.91% (50.09%); H: 5.00% (5.19%); N: 6.66% (6.87%); Ti: 10.95% (11.74%); Cl: 25.21% (26.09%).

Example 14

Synthesis of TiCl.SUB.3.(L5) [Sample MT-32]

[0262] ##STR00024##

[0263] 1.0 ml of a 0.8 M titanium tetrachloride (TiCl.sub.4) solution in heptane (0.80 mmoles) were added, drop by drop, to a solution of 0.167 g of the ligand having formula (L5) (0.787 mmoles) obtained as described in Example 5, in heptane (20 ml), in a 100 ml tailed flask: the formation of an orange solid was immediately observed. The whole was left, under stirring, at reflux temperature, for 3 hours and then brought to room temperature obtaining a brown suspension. The solid formed was recovered by filtration, washed with hexane (2?3 ml) and dried at reduced pressure, at room temperature, obtaining 0.27 g (yield=94%) of a brown solid product corresponding to the complex TiCl.sub.3(L5).

[0264] Elemental analysis [found (calculated for C.sub.14H.sub.15Cl.sub.3N.sub.2Ti)]: C: 45.33% (46.00%); H: 3.90% (4.14%); N: 7.45% (7.66%); Ti: 12.45% (13.10%); Cl: 28.32% (29.10%).

Example 15

Synthesis of TiCl.SUB.2.(THF)(L1) [Sample MT-22]

[0265] ##STR00025##

[0266] 0.307 g of the titanium trichloride complex:tetrahydrofuran (1:3) [TiCl.sub.3(THF).sub.3] (0.829 mmoles) were added, drop by drop, to a solution of 0.222 g of the ligand having formula (L1) (0.827 mmoles) obtained as described in Example 1, in toluene (20 ml), in a 100 ml tailed flask: the formation of a dark green suspension was immediately observed. The whole was left, under stirring, at reflux temperature, for 3 hours and then brought to room temperature obtaining a brown suspension. The solid formed was recovered by filtration, washed with hexane (2?3 ml) and dried at reduced pressure, at room temperature, obtaining 0.19 g (yield=59%) of a brown solid product corresponding to the complex TiCl.sub.2(THF)(L5).

[0267] Elemental analysis [found (calculated for C.sub.18H.sub.23Cl.sub.2N.sub.2Ti)]: C: 55.37% (55.98%); H: 5.75% (6.00%); N: 7.00% (7.25%); Ti: 12.02% (12.40%); Cl: 18.97% (18.36%).

Example 16

Synthesis of TiCl.SUB.2.(THF)(L6) [sample GT-341]

[0268] ##STR00026##

[0269] 1.7 ml of a 1.6 M n-butyl lithium solution in hexane (2.72 mmoles) were added, drop by drop, at ?78? C., to a suspension of 0.471 g of the ligand having formula (L6) (2.69 mmoles) obtained as described in Example 6, in toluene (20 ml), in a 50 ml tailed flask, obtaining a yellow mixture. The whole was brought to room temperature and left, at said temperature, under stirring, for 5 hours. Subsequently, 0.991 g of the titanium trichloride complex:tetrahydrofuran (1:3) [TiCl.sub.3(THF).sub.3] (2.67 mmoles) were added: the suspension obtained was left to react, under stirring, for 15 hours, at room temperature. The solid formed was recovered by filtration, washed with hexane (2?5 ml) and dried under vacuum, at room temperature, obtaining 0.738 g (yield=82%) of a dark brown solid product corresponding to the complex TiCl.sub.2(THF)(L6).

[0270] Elemental analysis [found (calculated for C.sub.11H.sub.12Cl.sub.2NOTi)]: C: 50.00% (49.35%); H: 5.25% (5.52%); N: 3.70% (3.84%); Ti: 13.78% (13.11%); Cl: 19.91% (19.42%).

[0271] FIG. 8 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.2(THF)(L6) obtained.

Example 17

Synthesis of TiCl.SUB.2.(THF)(L7) [Sample GT-342]

[0272] ##STR00027##

[0273] 1.6 ml of a 1.6 M n-butyl lithium solution in hexane (2.56 mmoles) were added, drop by drop, at ?78? C., to a suspension of 0.561 g of the ligand having formula (L7) (2.58 mmoles) obtained as described in Example 7, in toluene (20 ml), in a 50 ml tailed flask, obtaining a yellow mixture. The whole was brought to room temperature and left, at said temperature, under stirring, for 5 hours. Subsequently, 0.955 g of the titanium trichloride complex:tetrahydrofuran (1:3) [TiCl.sub.3(THF).sub.3] (2.58 mmoles) were added: the suspension obtained was left to react, under stirring, for 15 hours, at room temperature. The solid formed was recovered by filtration, washed with hexane (2?5 ml) and dried under vacuum, at room temperature, obtaining 0.873 g (yield=89%) of a dark brown solid product corresponding to the complex TiCl.sub.2(THF)(L7).

[0274] Elemental analysis [found (calculated for C.sub.14H.sub.18Cl.sub.2NOTi)]: C: 52.04% (53.09%); H: 6.01% (6.44%); N: 3.05% (3.44%); Ti: 10.84% (11.76%); Cl: 17.87% (17.41%).

[0275] FIG. 9 shows the FT-IR spectrum (solid stateATR) of the complex TiCl2(THF)(L7) obtained.

Example 18

Synthesis of TiCl.SUB.2.(L6).SUB.2 .[Sample GT-347]

[0276] ##STR00028##

[0277] 2.0 ml of a 1.6 M n-butyl lithium solution in hexane (3.20 mmoles) were added, drop by drop, at ?78? C., to a suspension of 0.563 g of the ligand having formula (L6) (3.21 mmoles) obtained as described in Example 1, in heptane (20 ml), in a 50 ml tailed flask, obtaining a yellow mixture. The whole was brought to room temperature and left, at said temperature, under stirring, for 5 hours. Subsequently, 3.1 ml of a 0.51 M solution of titanium tetrachloride (TiCl.sub.4) in heptane (1.58 mmoles) were added, drop by drop, at 0? C.: the suspension obtained was left to react, under stirring, for 15 hours, at room temperature. The solid formed was recovered by filtration, washed with hexane (2?5 ml) and dried under vacuum, at room temperature, obtaining 0.732 g (yield=90%) of a dark brown solid product corresponding to the complex TiCl.sub.2(L6).sub.2.

[0278] Elemental analysis [found (calculated for C.sub.22H.sub.24Cl.sub.4NOTi)]: C: 56.95% (56.56%); H: 5.25% (5.18%); N: 5.90% (6.00%); Ti: 10.45% (10.25%); Cl: 15.87% (15.18%).

[0279] FIG. 10 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.2(L6) obtained.

Example 19

Synthesis of TiCl.SUB.2.(L7).SUB.2 .[Sample GT-348]

[0280] ##STR00029##

[0281] 2.0 ml of a 1.6 M n-butyl lithium solution in hexane (3.20 mmoles) were added, drop by drop, at ?78? C., to a suspension of 0.696 g of the ligand having formula (L7) (3.20 mmoles) obtained as described in Example 7, in heptane (20 ml), in a 50 ml tailed flask, obtaining a yellow mixture. The whole was brought to room temperature and left, at said temperature, under stirring, for 5 hours. Subsequently, 3.1 ml of a 0.51 M solution of titanium tetrachloride (TiCl.sub.4) in heptane (1.58 mmoles) were added, drop by drop, at 0? C.: the suspension obtained was left to react, under stirring, for 15 hours, at room temperature. The solid formed was recovered by filtration, washed with hexane (2?5 ml) and dried under vacuum, at room temperature, obtaining 0.743 g (yield=74%) of a dark brown solid product corresponding to the complex TiCl.sub.2(L7).sub.2.

[0282] Elemental analysis [found (calculated for C.sub.28H.sub.38Cl.sub.4NOTi)]: C: 59.00% (60.99%); H: 6.0% (6.58%); N: 4.99% (5.08%); Ti: 7.99% (8.68%); Cl: 12.74% (12.86%).

[0283] FIG. 11 shows the FT-IR spectrum (solid stateATR) of the complex TiCl.sub.2(L7) obtained.

Example 20 (GL960)

[0284] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.5 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 TiCl.sub.4(L2) complex [sample BM2-211] (2.18 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.36 mg) obtained as described in Example 9. The whole was kept under magnetic stirring, at 20? C., for 60 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 0.270 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 82.2%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0285] FIG. 12 shows the FT-IR spectrum of the polybutadiene obtained.

Example 21 (GL981)

[0286] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.4 ml of toluene were added and the temperature of the solution thus obtained was brought to 20? C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1?10.sup.?2 moles, equal to about 0.58 g) was added and, subsequently, the TiCl.sub.3(L1) complex [sample BM2-227] (2.32 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.64 mg) obtained as described in Example 11. The whole was kept under magnetic stirring, at 20? C., for 7 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 0.601 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 82.5%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0287] FIG. 13 shows the FT-IR spectrum of the polybutadiene obtained.

[0288] FIG. 14 shows the GPC diagram of the polybutadiene obtained.

[0289] FIG. 15 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 22 (G1109)

[0290] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 8.02 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 TiCl.sub.3(L4) complex [sample MT-11] (1.68 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.36 mg) obtained as described in Example 12. The whole was kept under magnetic stirring, at 20? C., for 65 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 0.719 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 87.1%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0291] FIG. 16 shows the FT-IR spectrum of the polybutadiene obtained.

Example 23 (G1108)

[0292] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.66 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 TiCl.sub.3(L3) complex [sample MT-27] (2.04 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.08 mg) obtained as described in Example 12. The whole was kept under magnetic stirring, at 20? C., for 135 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 0.562 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 81.2%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0293] FIG. 17 shows the FT-IR spectrum of the polybutadiene obtained.

Example 24 (G1084)

[0294] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.88 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 TiCl.sub.3(L5) complex [sample MT-32] (1.82 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.64 mg) obtained as described in Example 14. The whole was kept under magnetic stirring, at 20? C., for 7 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 0.424 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 84.1%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0295] FIG. 18 shows the FT-IR spectrum of the polybutadiene obtained.

[0296] FIG. 19 shows the GPC diagram of the polybutadiene obtained.

Example 25 (G1085)

[0297] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.8 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 TiCl.sub.2(THF)(L1) complex [sample MT-22] (1.89 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.78 mg) obtained as described in Example 15. The whole was kept under magnetic stirring, at 20? C., for 5 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 1.4 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 84.4%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0298] FIG. 20 shows the FT-IR spectrum of the polybutadiene obtained.

Example 26 (IP2)

[0299] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.8 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 TiCl.sub.2(THF)(L6) complex [sample GT-341] (1.68 ml of toluene suspension at a concentration of 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.36 mg) obtained as described in Example 16. The whole was kept under magnetic stirring, at 20? C., for 1080 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 0.294 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content of 81.1%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0300] FIG. 21 shows the FT-IR spectrum of the polybutadiene obtained.

[0301] FIG. 22 shows the GPC diagram of the polybutadiene obtained.

Example 27 (IP3)

[0302] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.8 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 TiCl.sub.2(THF)(L7) complex [sample GT-342] (1.89 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.78 mg) obtained as described in Example 17. The whole was kept under magnetic stirring, at 20? C., for 1080 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 0.379 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 82.2%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0303] FIG. 23 shows the FT-IR spectrum of the polybutadiene obtained.

[0304] FIG. 24 shows the GPC diagram of the polybutadiene obtained.

[0305] FIG. 25 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 28 (IP4)

[0306] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 7.0 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 TiCl.sub.2(L6).sub.2 complex [sample GT-347] (2.76 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 5.52 mg) obtained as described in Example 18. The whole was kept under magnetic stirring, at 20? C., for 1350 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 0.239 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 86.0%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0307] FIG. 26 shows the FT-IR spectrum of the polybutadiene obtained.

Example 29 (IP7)

[0308] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (?20? C.) in a 25 ml test tube. Subsequently, 6.5 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 TiCl.sub.2(L7).sub.2 complex [sample GT-348] (3.19 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 6.38 mg) obtained as described in Example 19. The whole was kept under magnetic stirring, at 20? C., for 3900 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 0.252 g of polybutadiene with a prevalently 1,4-cis structure having a 1,4-cis unit content equal to 85.3%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

[0309] FIG. 27 shows the FT-IR spectrum of the polybutadiene obtained.

Example 30 (GR001)

[0310] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 7.5 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 TiCl.sub.4(L2) complex [sample BM2-211] (2.18 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.36 mg) obtained as described in Example 9. The whole was kept under magnetic stirring, at 20? C., for 300 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 0.289 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 57.1% and a 3,4 unit content equal to 42.9%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

Example 31 (GR002)

[0311] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 7.4 ml of toluene were added and the temperature of the solution thus obtained was brought to 20? C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1?10.sup.?2 moles, equal to about 0.58 g) was added and, subsequently, the TiCl.sub.3(L1) complex [sample BM2-227](2.32 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.64 mg) obtained as described in Example 11. The whole 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 0.757 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 56.5% and a 3,4 unit content equal to 43.5%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

Example 32 (G1113)

[0312] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 8.02 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 TiCl.sub.3(L4) complex [sample MT-11] (1.68 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.36 mg) obtained as described in Example 12. The whole was kept under magnetic stirring, at 20? C., for 100 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 0.214 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 55.2% and a 3,4 unit content equal to 44.8%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

[0313] FIG. 28 shows the FT-IR spectrum of the polyisoprene obtained.

[0314] FIG. 29 shows the GPC diagram of the polyisoprene obtained.

Example 33 (G1114)

[0315] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 8.02 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 TiCl.sub.3(L3) complex [sample MT-27] (2.04 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 4.08 mg) obtained as described in Example 13. The whole was kept under magnetic stirring, at 20? C., for 200 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 0.197 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 55.9% and a 3,4 unit content equal to 44.1%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

[0316] FIG. 30 shows the FT-IR spectrum of the polyisoprene obtained.

[0317] FIG. 31 shows the GPC diagram of the polyisoprene obtained.

Example 34 (IP26)

[0318] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 7.9 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 TiCl.sub.3(L5) complex [sample MT-32](1.83 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.66 mg) obtained as described in Example 14. The whole was kept under magnetic stirring, at 20? C., for 150 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 0.811 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 31.5% and a 3,4 unit content equal to 68.5%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

[0319] FIG. 32 shows the FT-IR spectrum of the polyisoprene obtained.

[0320] FIG. 33 shows the GPC diagram of the polyisoprene obtained.

[0321] FIG. 34 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polyisoprene obtained.

Example 35 (G1089)

[0322] 2 ml of isoprene equal to about 1.36 g were placed in a 25 ml test tube. Subsequently, 7.77 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 TiCl.sub.2(THF)(L1) complex [sample MT-22] (1.89 ml of toluene suspension at a concentration equal to 2 mg/ml; 1?10.sup.?5 moles, equal to about 3.78 mg) obtained as described in Example 15. The whole was kept under magnetic stirring, at 20? C., for 165 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 1.050 g of polyisoprene with a mixed structure having a 1,4-cis unit content equal to 39.4% and a 3,4 unit content equal to 61.6%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 2.

[0323] FIG. 35 shows the FT-IR spectrum of the polyisoprene obtained.

[0324] FIG. 36 shows the GPC diagram of the polyisoprene obtained.

[0325] FIG. 37 shows the .sup.1H-NMR spectrum of the polyisoprene obtained.

TABLE-US-00001 TABLE 1 Polymerization of 1,3-butadiene with catalytic systems comprising titanium complexes Time Yield Conversion 1,4-cis M.sub.w Example (min) (g) (%) (%) (g ? mol.sup.?1) M.sub.w/M.sub.n 20 60 0.270 19.3 82.2 285700 2.1 21 7 0.601 42.9 82.5 314600 2.0 22 65 0.719 51.4 87.1 305400 2.0 23 135 0.562 40.1 81.2 535800 1.9 24 7 0.424 30.3 84.1 654771 1.8 25 5 1.4 100 84.4 745300 2.1 26 1080 0.294 21 81.1 81200 1.8 27 1080 0.379 27 82.2 111600 2.0 28 1350 0.239 17 86.0 43800 1.9 29 3900 0.252 18 85.3 57900 1.7

TABLE-US-00002 TABLE 2 Polymerization of isoprene with catalytic systems comprising titanium complexes 1,4- Time Yield Conversion cis/3,4 M.sub.w M.sub.w/ Example (min) (g) (%) (%) (g ? mol.sup.?1) M.sub.n 30 300 0.289 21.3 57.1/42.9 248500 2.2 31 30 0.757 55.7 56.5/43.5 267600 2.1 32 100 0.214 15.7 55.2/44.8 453800 2.4 33 200 0.197 14.5 55.9/44.1 497100 2.0 34 150 0.811 59.6 31.5/68.5 351200 2.8 35 165 1.05 77.9 39.4/61.6 575643 2.0