Oxo-Nitrogenated Iron Complex, Catalytic System Comprising Said Oxo-Nitrogenated Iron Complex and Process for the (Co)Polymerization of Conjugated Dienes

Abstract

Oxo-nitrogenated iron complex having general formula (I): in which: R.sub.1 and R.sub.2, identical or different, represent a hydrogen atom; or they are selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.3 represents a hydrogen atom, or it is selected from linear or branched, optionally halogenated C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15 alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; X, identical or different, represent a halogen atom such as, for example, chlorine, bromine, iodine, preferably chlorine; or they are selected from. linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, —OCOR.sub.4 groups or —OR.sub.4 groups in which R.sub.4 is selected from linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups; n is 2 or 3. Said oxo-nitrogenated iron complex having general formula (I) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

##STR00001##

Claims

1. Oxo-nitrogenated iron complex having general formula (I): ##STR00025## in which: R.sub.1 and R.sub.2, identical or different, represent a hydrogen atom; or they are selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20 preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.3 represents a hydrogen atom, or it is selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; X, identical or different, represent a halogen atom such as chlorine, bromine, iodine, preferably chlorine; or they are selected from linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, —OCOR.sub.4 or —OR.sub.4 groups or groups in which R.sub.4 is selected from linear or branched C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups; n is 2 or 3.

2. Oxo-nitrogenated iron complex having general formula (I) according to claim 1, in which: R.sub.1 and R.sub.2, identical, are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably are a methyl group; R.sub.3 is selected from phenyl groups optionally substituted with linear or branched C.sub.1-C.sub.20 alkyl groups, preferably substituted with one or more methyl, ethyl, iso-propyl, tert-butyl groups; X, identical, are a halogen atom such as chlorine, bromine, iodine, preferably chlorine; n is 2 or 3.

3. Catalytic system for the (co)polymerization of conjugated dienes comprising: (a) at least one oxo-nitrogenated iron complex having general formula (I) according to claim 1 or 2; (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, preferably from: boron, aluminum, zinc, magnesium, gallium, tin, even more preferably from aluminum, boron.

4. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, in which said co-catalyst (b) is selected from (b.sub.1) aluminum alkyls having general formula (V):
Al(X′).sub.n(R.sub.5).sub.3-n  (V) in which X′ represents a halogen atom such as chlorine, bromine, iodine, fluorine; R.sub.5, identical or different, represent a hydrogen atom, or they 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 silicon or germanium atoms; and n is an integer ranging from 0 to 2.

5. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, in which said co-catalyst (b) is selected from organo-oxygenated compounds (b.sub.2) of an element M′ different from carbon belonging to groups 13 or 14 of the Periodic Table of the elements, preferably aluminum, gallium, tin compounds.

6. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, in which said co-catalyst (b) is selected from compounds or mixtures of organometallic compounds (b.sub.3) of an element M′ different from carbon able to react with the oxo-nitrogenated iron complex having general formula (I) according to claim 1 or 2, extracting from this a substituent X.sub.1 or X.sub.2σ-linked, to form on the one hand at least one neutral compound, and on the other hand a ionic compound consisting of a cation containing the metal (Fe) coordinated by the ligand, and of a non-coordinating organic anion containing the metal M′, whose negative charge is delocalized on a multicentric structure.

7. Catalytic system for the (co)polymerization of conjugated dienes according to claim 4, in which said aluminum alkyls (b.sub.1) having general formula (II) are di-iso-butyl-aluminum hydride (DIBAH), di-ethyl-aluminum chloride (DEAC), mono-ethyl aluminum dichloride (EADC), ethyl aluminum-sesquichloride (EASC).

8. Catalytic system for the (co)polymerization of conjugated dienes according to claim 5, in which said organo-oxygenated compounds (b.sub.2) are selected from aluminoxanes having general formula (VI):
(R.sub.6).sub.2—Al—O—[—Al(R.sub.7)—O-].sub.p-Al—(R.sub.8).sub.2  (VI) in which R.sub.6, R.sub.7 and R.sub.8, identical or different, represent a hydrogen atom, a halogen atom such as chlorine, bromine, iodine, fluorine; or they 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 silicon or germanium atoms; and p is an integer ranging from 0 to 1000.

9. Catalytic system for the (co)polymerization of conjugated dienes according to claim 8, in which said organo-oxygenated compound (b.sub.2) is methylaluminoxane (MAO).

10. Catalytic system for the (co)polymerization of conjugated dienes according to claim 6, in which said compounds or mixtures of compounds (b.sub.3) are selected from organic compounds of aluminum and especially of boron, such as those represented by the following general formula:
[(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.− in which 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, totally or partially, preferably totally fluorinated, having from 6 to 20 carbon atoms, Pir is a pyrrole radical optionally substituted.

11. Process for the (co)polymerization of conjugated dienes, characterized in that it uses the catalytic system according to anyone of claims 3 to 10.

12. Process for the (co)polymerization according to claim 11, in which said conjugated dienes are 1,3-butadiene, isoprene.

13. Process for the polymerization of 1,3-butadiene or isoprene, characterized in that it uses the catalytic system according to anyone of claims 3 to 10:

14. Process for the preparation of a ligand having general formula (II): ##STR00026## in which: R.sub.1 and R.sub.2, identical or different, represent a hydrogen atom; or they are selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.3 represents a hydrogen atom, or it is selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, alkyl groups optionally substituted cycloalkyl groups, optionally substituted aryl groups; comprising reacting at least one primary amine having general formula (III);
H.sub.2N—R.sub.3  (III) in which R.sub.3 has the above described meanings, with at least one compound having general formula (IV); ##STR00027## in which R.sub.1 and R.sub.2 have the same meanings described above; in the presence of water, at a temperature ranging from 18° C. to 30° C., preferably at room temperature, for a time ranging from 1 hour to 10 days, preferably ranging from 1.5 hours to 8 days; said primary amine having general formula (III) and said compound having general formula (IV) being used in a molar ratio ranging from 1:10 to 1:2, preferably ranging from 1:5 to 1:1.5.

15. Process for the preparation of a ligand having general formula (II) according to claim 14, in which said method comprises a step of fractional distillation.

Description

EXAMPLES

Reagents and Materials

[0111] The list below reports the reagents and materials used in the following examples of the invention, any pre-treatments thereof and their manufacturer: [0112] iron powder (Fe) (Aldrich): purity 99%, used as such; [0113] iron (III) chloride (FeCl.sub.3) (Aldrich): purity 99.9%, used as such; [0114] tetrahydrofuran (THF) (Aldrich): used as such; [0115] iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5]: prepared from iron powder (Fe) and iron (Ill) chloride (FeCl.sub.3), in tetrahydrofuran (THF) hot, according to the method reported by Calderazzo F. et al., in “Comptes Rendus Académie des Sciences” (1999), t. 2, Série II c, pg. 311-319; [0116] methylaluminoxane (MAO) (toluene solution 10% by weight) (Chemtura): used as such; [0117] 2,3-butanedione (Aldrich): used as such; [0118] aniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0119] o-toluidine (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0120] 2-iso-propylaniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0121] 2-tert-butylaniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0122] ethyl ether (Aldrich): pure, 99%, distilled over sodium (Na) in an inert atmosphere; [0123] 2,6-diethylaniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0124] 2,4,6-tri-methylaniline (Aldrich): distilled at reduced pressure and stored in an inert atmosphere; [0125] toluene (Aldrich): pure, ≥99.5%, distilled over sodium (Na) in an inert atmosphere; [0126] heptane (Aldrich): pure, ≥99%, distilled over sodium (Na) in an inert atmosphere; [0127] sodium sulfate (Na.sub.2SO.sub.4) (Aldrich used as such); [0128] 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.; [0129] 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.; [0130] methanol (Carlo Erba, RPE): used as such; [0131] hydrochloric acid in 37% aqueous solution (Aldrich): used as such; [0132] dichloromethane (CH.sub.2Cl.sub.2) (Acros): pure, ≥99.9%, used as such; [0133] hydrofluoric acid (HF) (40% aqueous solution) (Aldrich): used as such; [0134] sulfuric acid (H.sub.2SO.sub.4) (96% aqueous solution) (Aldrich): used as such, or diluted with distilled water (1/5); [0135] nitric acid (HNO.sub.3) (70% aqueous solution) (Aldrich): used as such; [0136] sodium carbonate (Na.sub.2CO.sub.3) (Aldrich): used as such; [0137] silver nitrate (AgNO.sub.3) (Aldrich): used as such; [0138] deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; [0139] hexamethyldisiloxane (HMDS) (Acros): used as such; [0140] deuterated acetone (C.sub.3D.sub.6O) (Aldrich): used as such; [0141] tetramethyldisiloxane (TMS) (Acros): used as such;

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

Elementary Analysis

a) Determination of Fe

[0143] For the determination of the quantity by weight of iron (Fe) in the oxo-nitrogenated iron complexes according to 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 30 ml platinum crucible, together with a 1 ml mixture of 40% hydrofluoric acid (HF), 0.25 ml of 96% sulfuric acid (H.sub.2SO.sub.4) and 1 ml of 70% nitric acid (HNO.sub.3). 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) 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 nitric acid (HNO.sub.3) and about 15 ml of water were then added 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 performed 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 solutions having a known titer obtained by dilution by weight of certified solutions.

[0144] The solution of sample prepared as above was then diluted again by weight in order to obtain concentrations close to the reference ones, before performing spectrophotometric measurement. All the samples were prepared in double quantities.

[0145] The results were considered acceptable if the individual repeated test data did not have a relative deviation of more than 2% with respect to their mean value.

b) Determination of Chlorine

[0146] For said purpose, samples of oxo-nitrogenated iron complexes according to 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) 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) was added, until acid reaction and was then titrated with 0.1 N silver nitrate (AgNO.sub.3) with a potentiometric titrator.

c) Determination of Carbon, Hydrogen and Nitrogen

[0147] The determination of carbon, hydrogen and nitrogen, in the oxo-nitrogenated iron complexes according to the present invention, as well as in the ligands used for the purpose of the present invention, was performed through a Carlo Erba automatic analyzer Mod. 1106.

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

[0148] 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 acetone (C.sub.3D.sub.6O), 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.

[0149] The microstructure of the polymers [i.e. 1,4-cis (%) 1,4-trans (%) and 1,2 (%) unit content for polybutadiene and 1,4-cis (%), 1,4-trans (%) and 3,4 (%) unit content for polyisoprene] was determined through the analysis of the aforementioned spectra based on the contents of literature by Mochel, V. D., in “Journal of Polymer Science Part A-1: Polymer Chemistry” (1972), Vol. 10, Issue 4, pg. 1009-1018 for polybutadiene, and by Sato H. et al. in “Journal of Polymer Science: Polymer Chemistry Edition” (1979), Vol. 17, Issue 11, pg. 3551-3558, for polyisoprene.

FT-IR Spectra (Solid State—UATR)

[0150] The FT-IR spectra (solid state—UATR) were recorded using a Bruker IFS 48 spectrophotometer equipped with a Thermo Spectra-Tech horizontal ATR connection.

[0151] The section in which 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.

[0152] The FT-IR spectra (solid state—UATR) of the oxo-nitrogenated iron complexes according to the present invention, were obtained by inserting samples of the oxo-nitrogenated iron complex to be analyzed into said section.

I.R. Spectra

[0153] The FT-IR spectra were recorded through Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophotometers.

[0154] The I.R. spectra (FT-IR) of the ligands used for the purpose of the present invention, were obtained by dispersing the ligand to be analyzed in anhydrous potassium bromide (KBr) (KBr disks), or in Nujol suspension.

[0155] 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

[0156] The determination of the molecular weight (MW) of the polymers obtained was performed through GPC (“Gel Permeation Chromatography”), using the Waters® Alliance® GPC/V 2000 System by Waters Corporation which uses two detection lines: “Refractive Index”—RI and “Viscometer” operating under the following conditions: [0157] two PLgel Mixed-B columns; [0158] solvent/eluent: o-dichlorobenzene (Aldrich); [0159] flow rate: 0.8 ml/min; [0160] temperature: 145° C.; [0161] molecular mass calculation: Universal Calibration method.

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

Mass Spectra (GC-MS)

[0163] The mass spectra of the ligands used for the purpose of the present invention were performed with a Trace DSQ single quadrupole mass spectrometer (Thermo ISQ) in Electronic Ionization—EI mode, operating under the following conditions: [0164] scanning: from 35 amu to 600 amu (amu=atomic mass unit); [0165] temperature of the source: 250° C.; [0166] transfer line temperature: 300° C.; [0167] capillary column: MDN-5S (Supelco) (length=30 m; diameter=0.25 mm; stationary phase thickness=0.25 μm); [0168] carrier gas: helium (He) with constant flow equal to 1 ml/min.

Example 1

Synthesis of Ligand Having Formula (L1)

[0169] ##STR00007##

[0170] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: deionized water (50 ml), 2,3-butanedione (28.45 g; 330.5 mmoles) and, by dripping, aniline (10.2 g; 109.5 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 2 hours, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase. Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 15 g of a yellow oil (yield=85%) corresponding to the ligand having formula (L1), which was stored, in an inert atmosphere, in the fridge.

[0171] Elementary analysis [found (calculated) for C.sub.10H.sub.11NO]: C: 74.47% (74.51%); H: 6.80% (6.88%); N: 8.63% (8.69%).

[0172] Molecular weight (MW): 161.20.

[0173] GC-MS: M.sup.+=m/z 161.

[0174] FT-IR (t.q.): 1701 cm.sup.−1 v.sub.(C═O); 1648 cm.sup.−1 v.sub.(C═N).

Example 2

Synthesis of Ligand Having Formula (L2)

[0175] ##STR00008##

[0176] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: deionized water (50 ml), 2,3-butanedione (24.52 g; 284.8 mmoles) and, by dripping, o-toluidine (10.08 g; 94.07 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 2 hours, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase. Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 15.5 g of a yellow oil (yield=94%) corresponding to the ligand having formula (L2), which was stored, in an inert atmosphere, in the fridge.

[0177] Elementary analysis [found (calculated) for C.sub.11H.sub.13NO]: C: 74.80% (75.40%); H: 6.96% (7.48%); N: 7.63% (7.99%).

[0178] Molecular weight (MW): 175.23.

[0179] GC-MS: M.sup.+=m/z 175.

[0180] FT-IR (t.q.): 1702 cm.sup.−1 v.sub.(C═O); 1647 cm.sup.−1 v.sub.(C═N).

Example 3

Synthesis of Ligand Having Formula (L3)

[0181] ##STR00009##

[0182] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: deionized water (70 ml), 2,3-butanedione (19.62 g; 227.9 mmoles) and, by dripping, 2-iso-propylaniline (13.56 g; 100.3 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 72 hours, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase. Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 20.1 g of a yellow oil (yield=98.6%) corresponding to the ligand having formula (L3), which was stored, in an inert atmosphere, in the fridge.

[0183] Elementary analysis [found (calculated) for C.sub.13H.sub.17NO]: C: 76.65% (76.81%); H: 8.25% (8.43%); N: 6.89% (6.89%).

[0184] Molecular weight (MW): 203.28.

[0185] GC-MS: M.sup.+=m/z 203.

[0186] FT-IR (t.q.): 1702 cm.sup.−1 v.sub.(C═O); 1650 cm.sup.−1 v.sub.(C═N).

[0187] .sup.1H-NMR [(C.sub.3D.sub.6O) δ ppm]: 1,15; 1,16 [both d, 3H each, CH(CH.sub.3).sub.2]; 1,90; 2,46 (both s, 3H each, CH.sub.3); 2,97 [m, 1H, CH(CH.sub.3).sub.2]; 6.61-7.34 (m, 4H, H.sub.Ar).

Example 4

Synthesis of Ligand Having Formula (L4)

[0188] ##STR00010##

[0189] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: 2,3-butanedione (19.62 g; 227.9 mmoles), deonized water (70 ml) and, by dripping, 2-tert-butylaniline (15.18 g; 101.7 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 24 hours, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase.

[0190] Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), diluted with ethyl ether (20 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 21.35 g of a yellow oil (yield=96.6%) corresponding to the ligand having formula (L4), which was stored, in an inert atmosphere, in the fridge.

[0191] Elementary analysis [found (calculated) for C.sub.14H.sub.19NO]: C: 76.76% (77.38%); H: 8.41% (8.81%); N: 6.28% (6.45%).

[0192] Molecular weight (MW): 217.31.

[0193] GC-MS: M.sup.+=m/z 217.

[0194] FT-IR (t.q.): 1702 cm.sup.−1 v.sub.(C═O); 1640 cm.sup.−1 v.sub.(C═N).

Example 5

Synthesis of Ligand Having Formula (L5)

[0195] ##STR00011##

[0196] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: 2,3-butanedione (14.71 g; 170.9 mmoles), deonized water (80 ml) and, by dripping, 2,6-diethylaniline (12.68 g; 85 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 7 days, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase.

[0197] Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 18.37 g of a yellow oil (yield=99%) corresponding to the ligand having formula (L5), which was stored, in an inert atmosphere, in the fridge.

[0198] Elementary analysis [found (calculated) for C.sub.14H.sub.19NO]: C: 76.59% (77.38%); H: 8.58% (8.81%); N: 6.23% (6.45%).

[0199] Molecular weight (MW): 217.31.

[0200] GC-MS: M.sup.+=m/z 217.

[0201] FT-IR (t.q.): 1704 cm.sup.−1 v.sub.(C═O); 1655 cm.sup.−1 v.sub.(C═N).

Example 6

Synthesis of Ligand Having Formula (L6)

[0202] ##STR00012##

[0203] The following were loaded into a 250 ml glass reactor, equipped with a magnetic stirrer, in this order: 2,3-butanedione (7.10 g; 82.4 mmoles), deonized water (40 ml) and, by dripping, 2,4,6-trimethylaniline (5.56 g; 41 mmoles). The reaction mixture obtained was left, under stirring, at room temperature, for 24 hours, obtaining the formation of two layered phases, i.e. an organic phase and an aqueous phase.

[0204] Subsequently, the organic phase was separated from the aqueous phase through a separator funnel, then it was washed, in succession, with deonized water (2×10 ml) and brine (15 ml), anhydrified on sodium sulfate (Na.sub.2SO.sub.4), filtered and finally purified by fractional distillation under vacuum using a Vigreux column, obtaining 7 g of a yellow/orange oil (yield=84%) corresponding to the ligand having formula (L6), which was stored, in an inert atmosphere, in the fridge.

[0205] Elementary analysis [found (calculated) for C.sub.13H.sub.17NO]: C: 76.76% (76.81%); H: 8.38% (8.53%); N: 6.73% (6.89%).

[0206] Molecular weight (MW): 203.28.

[0207] GC-MS: M.sup.+=m/z 203.

[0208] FT-IR (t.q.): 1704 cm.sup.−1 v.sub.(C═O); 1647 cm.sup.−1 v.sub.(C═N).

Example 7

Synthesis of FeCl.SUB.3.(L1) [Sample MG261]

[0209] ##STR00013##

[0210] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (201 mg; 1.24 mmoles; molar ratio L1/Fe=1) was added to a yellow solution of the ligand having formula (L1) (200 mg; 1.24 mmoles), obtained as described in Example 1, in toluene (20 ml). The mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 308 mg of a brown/black solid product corresponding to the complex FeCl.sub.3(L1), equal to a 77% conversion with respect to the iron (Ill) chloride (FeCl.sub.3) loaded.

[0211] Elementary analysis [found (calculated for C.sub.10H.sub.11Cl.sub.3FeNO)]: C: 36.59% (37.14%); H: 3.02% (3.43%); N: 4.02% (4.33%); Cl: 32.05% (32.89%); Fe: 17.45% (17.27%).

[0212] FIG. 1 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L1) obtained.

Example 8

Synthesis of FeCl.SUB.2.(L1) [Sample MG265]

[0213] ##STR00014##

[0214] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (235 mg; 0.97 mmoles; molar ratio L1/Fe=1) was added to a yellow solution of the ligand having formula (L1) (161 mg; 0.99 mmoles), obtained as described in Example 1, in tetrahydrofuran (THF) (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 268 mg of a grey solid product corresponding to the complex FeCl.sub.2(L1), equal to a 96% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0215] Elementary analysis [found (calculated for C.sub.10H.sub.11Cl.sub.2FeNO)]: C: 41.02% (41.71%); H: 3.59% (3.85%); N: 4.53% (4.86%); Cl: 24.01% (24.62%); Fe: 18.98% (19.39%).

[0216] FIG. 2 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L1) obtained.

Example 9

Synthesis of FeCl.SUB.3.(L2) [Sample MG262]

[0217] ##STR00015##

[0218] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (221 mg; 1.36 mmoles; molar ratio L2/Fe=1) was added to a yellow solution of the ligand having formula (L2) (238 mg; 1.36 mmoles), obtained as described in Example 2, in toluene (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 301 mg of a brown/black solid product corresponding to the complex FeCl.sub.3(L2), equal to a 66% conversion with respect to the iron (III) chloride (FeCl.sub.3) loaded.

[0219] Elementary analysis [found (calculated for C.sub.11H.sub.13Cl.sub.3FeNO)]: C: 39.46% (39.15%); H: 4.02% (3.88%); N: 4.01% (4.15%); Cl: 31.00% (31.52%); Fe: 16.11% (16.55%).

[0220] FIG. 3 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L2) obtained.

Example 10

Synthesis of FeCl.SUB.2.(L2) [Sample MG266]

[0221] ##STR00016##

[0222] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (155 mg; 0.64 mmoles; molar ratio L2/Fe=1) was added to a yellow solution of the ligand having formula (L2) (115 mg; 0.66 mmoles), obtained as described in Example 2, in tetrahydrofuran (THF) (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 164 mg of a grey solid product corresponding to the complex FeCl.sub.2(L2), equal to a 85% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0223] Elementary analysis [found (calculated for C.sub.11H.sub.13Cl.sub.2FeNO)]: C: 43.21% (43.75%); H: 4.01% (4.34%); N: 4.29% (4.64%); Cl: 22.98% (23.48%); Fe: 18.01% (18.49%).

[0224] FIG. 4 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L2) obtained.

Example 11

Synthesis of FeCl.SUB.3.(L3) [Sample MG267]

[0225] ##STR00017##

[0226] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (328 mg; 2.02 mmoles; molar ratio L3/Fe=1) was added to a yellow solution of the ligand having formula (L3) (411 mg; 2.02 mmoles), obtained as described in Example 3, in toluene (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 528 mg of a brown/black solid product corresponding to the complex FeCl.sub.3(L3), equal to a 72% conversion with respect to the iron (III) chloride (FeCl.sub.3) loaded.

[0227] Elementary analysis [found (calculated for C.sub.13H.sub.17Cl.sub.3FeNO)]: C: 42.23% (42.72%); H: 4.51% (4.68%); N: 3.23% (3.83%); Cl: 29.45% (29.10%); Fe: 15.56% (15.28%).

[0228] FIG. 5 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L3) obtained.

Example 12

Synthesis of FeCl.SUB.2.(L3) [Sample MG124]

[0229] ##STR00018##

[0230] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (193 mg; 0.80 mmoles; molar ratio L3/Fe=1) was added to a yellow solution of the ligand having formula (L3) (167 mg; 0.82 mmoles), obtained as described in Example 3, in toluene (30 ml): the mixture obtained was left, under stirring, at 80° C., for 4 hours, obtaining a suspension. The supernatant liquid was discarded and the solid obtained was washed with heptane (2×15 ml) and vacuum dried, at room temperature, obtaining 192 mg of a brown solid product corresponding to the complex FeCl.sub.2(L3), equal to a 73% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0231] Elementary analysis [found (calculated for C.sub.13H.sub.17Cl.sub.2FeNO)]: C: 47.85% (47.31%); H: 5.04% (5.19%); N: 4.48% (4.24%); Cl: 21.01% (21.48%); Fe: 16.25% (16.92%).

[0232] FIG. 6 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L3) obtained.

Example 13

Synthesis of FeCl.SUB.3.(L4) [Sample MG126]

[0233] ##STR00019##

[0234] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (102 mg; 0.63 mmoles; molar ratio L4/Fe=1) was added to a yellow solution of the ligand having formula (L4) (135 mg; 0.62 mmoles), obtained as described in Example 4, in toluene (15 ml): the mixture obtained was left, under stirring, at room temperature, for 18 hours, obtaining a suspension. The supernatant liquid was discarded and the solid obtained was washed with heptane (2×15 ml) and vacuum dried, at room temperature, obtaining 179 mg of a brown solid product corresponding to the complex FeCl.sub.3(L4), equal to a 75% conversion with respect to the iron (III) chloride complex (FeCl.sub.3) loaded.

[0235] Elementary analysis [found (calculated for C.sub.14H.sub.19Cl.sub.3FeNO)]: C: 44.00% (44.31%); H: 4.95% (5.05%); N: 3.48% (3.69%); Cl: 28.02% (27.58%); Fe: 14.00% (14.71%).

[0236] FIG. 7 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L4) obtained.

Example 14

Synthesis of FeCl.SUB.2.(L4) [Sample MG129]

[0237] ##STR00020##

[0238] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (221 mg; 0.91 mmoles; molar ratio L4/Fe=1) was added to a yellow solution of the ligand having formula (L4) (201 mg; 0.92 mmoles), obtained as described in Example 4, in toluene (20 ml): the mixture obtained was left, under stirring, at 80° C., for 4 hours, obtaining a suspension. The supernatant liquid was discarded and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 88 mg of a brown solid product corresponding to the complex FeCl.sub.2(L4), equal to a 28% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0239] Elementary analysis [found (calculated for C.sub.14H.sub.19Cl.sub.2FeNO)]: C: 48.00% (48.87%); H: 4.99% (5.56%); N: 3.68% (4.07%); Cl: 20.02% (20.61%); Fe: 16.50% (16.23%).

[0240] FIG. 8 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L4) obtained.

Example 15

Synthesis of FeCl.SUB.3.(L5) [Sample MG268]

[0241] ##STR00021##

[0242] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (268 mg; 1.65 mmoles; molar ratio L5/Fe=1) was added to a yellow solution of the ligand having formula (L5) (135 mg; 0.62 mmoles), obtained as described in Example 5, in toluene (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 460 mg of a brown/black solid product corresponding to the complex FeCl.sub.3(L5), equal to a 73% conversion with respect to the iron (Ill) chloride (FeCl.sub.3) loaded.

[0243] Elementary analysis [found (calculated for C.sub.14H.sub.19Cl.sub.3FeNO)]: C: 44.01% (44.31%); H: 5.25% (5.04%); N: 3.39% (3.69%); Cl: 27.59% (28.02%); Fe: 14.45% (14.71%).

[0244] FIG. 9 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L5) obtained.

Example 16

Synthesis of FeCl.SUB.2.(L5) [Sample MG134]

[0245] ##STR00022##

[0246] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (233 mg; 0.99 mmoles; molar ratio L5/Fe=1) was added to a yellow solution of the ligand having formula (L5) (214 mg; 0.99 mmoles), obtained as described in Example 5, in toluene (30 ml): the mixture obtained was left, under stirring, at 80° C., for 4 hours, obtaining a suspension. The supernatant liquid was discarded and the solid obtained was washed with heptane (2×15 ml) and vacuum dried, at room temperature, obtaining 279 mg of a brown solid product corresponding to the complex FeCl.sub.2(L5), equal to a 84% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0247] Elementary analysis [found (calculated for C.sub.14H.sub.19Cl.sub.2FeNO)]: C: 48.41% (48.87%); H: 5.02% (5.56%); N: 3.58% (4.07%); Cl: 21.02% (20.61%); Fe: 15.98% (16.23%).

[0248] FIG. 10 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L5) obtained.

Example 17

Synthesis of FeCl.SUB.3.(L6) [Sample MG269]

[0249] ##STR00023##

[0250] In a 100 ml Schlenk tube, iron (III) chloride (FeCl.sub.3) (209 mg; 1.29 mmoles; molar ratio L6/Fe=1) was added to a yellow solution of the ligand having formula (L6) (261 mg; 1.29 mmoles), obtained as described in Example 6, in toluene (20 ml): the mixture obtained was left, under stirring, at room temperature, for 24 hours. The suspension obtained was vacuum dried, at room temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at room temperature, obtaining 388 mg of a brown/black solid product corresponding to the complex FeCl.sub.3(L6), equal to a 82% conversion with respect to the iron (Ill) chloride (FeCl.sub.3) loaded.

[0251] Elementary analysis [found (calculated for C.sub.13H.sub.17Cl.sub.3FeNO)]: C: 42.31% (42.72%); H: 4.46% (4.68%); N: 3.59% (3.83%); Cl: 29.26% (29.10%); Fe: 15.70% (15.28%).

[0252] FIG. 11 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.3(L6) obtained.

Example 18

Synthesis of FeCl.SUB.2.(L6) [Sample MG133]

[0253] ##STR00024##

[0254] In a 100 ml Schlenk tube, the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] (356 mg; 1.47 mmoles; molar ratio L6/Fe=1) was added to a yellow solution of the ligand having formula (L6) (308 mg; 1.51 mmoles), obtained as described in Example 6, in toluene (30 ml): the mixture obtained was left, under stirring, at 80° C., for 4 hours, obtaining a suspension. The supernatant liquid was discarded and the solid obtained was washed with heptane (2×15 ml) and vacuum dried, at room temperature, obtaining 380 mg of a brown solid product corresponding to the complex FeCl.sub.2(L6), equal to a 78% conversion with respect to the iron (II) chloride:tetrahydrofuran complex (1:1.5) [FeCl.sub.2(THF).sub.1.5] loaded.

[0255] Elementary analysis [found (calculated for C.sub.13H.sub.17Cl.sub.2FeNO)]: C: 48.01% (47.31%); H: 5.02% (5.19%); N: 4.58% (4.24%); Cl: 21.03% (21.48%); Fe: 16.05% (16.92%).

[0256] FIG. 12 shows the FT-IR spectrum (solid state—UATR) of the complex FeCl.sub.2(L6) obtained.

Example 19 (G1534)

[0257] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 8.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L1) complex [sample MG261] (1.62 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.2 mg) obtained as described in Example 7. Everything was kept under magnetic stirring, at 25° C., for 10 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 having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0258] FIG. 13 shows the FT-IR spectrum of the polybutadiene obtained.

Example 20 (G1535)

[0259] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 13.8 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.63 ml; 1×10−3 moles, equal to about 0.058 g) was added, and, subsequently, the FeCl.sub.3(L1) complex [sample MG261] (1.62 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.5 moles, equal to about 3.2 mg) obtained as described in Example 7. Everything was kept under magnetic stirring, at 25° C., for 10 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 1.14 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0260] FIG. 14 shows the FT-IR spectrum of the polybutadiene obtained.

Example 21 (G1536)

[0261] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.063 ml; 1×10.sup.−4 moles, equal to about 0.0058 g) was added, and, subsequently, the FeCl.sub.3(L1) complex [sample MG261] (1.62 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.2 mg) obtained as described in Example 7. Everything was kept under magnetic stirring, at 25° C., for 20 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 having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0262] FIG. 15 shows the FT-IR spectrum of the polybutadiene obtained.

Example 22 (G1535/1)

[0263] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 13.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.63 ml; 1×10.sup.−3 moles, equal to about 0.058 g) was added, and, subsequently, the FeCl.sub.2(L1) complex [sample MG265] (1.45 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 2.9 mg) obtained as described in Example 8. Everything was kept under magnetic stirring, at 25° 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 1.4 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0264] FIG. 16 shows the .sup.1H-NMR (top) and .sup.13C-NMR (bottom) spectra of the polybutadiene obtained.

Example 23 (G1537)

[0265] 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 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L2) complex [sample MG262] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 9. Everything was kept under magnetic stirring, at 25° C., for 120 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 0.989 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0266] FIG. 17 shows the FT-IR spectrum of the polybutadiene obtained.

Example 24 (G1538)

[0267] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 13.7 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.63 ml; 1×10.sup.−3 moles, equal to about 0.058 g) was added, and, subsequently, the FeCl.sub.3(L2) complex [sample MG262] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 9. Everything was kept under magnetic stirring, at 25° C., for 120 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 0.922 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0268] FIG. 18 shows the FT-IR spectrum of the polybutadiene obtained.

Example 25 (G1539)

[0269] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.16 ml; 2.5×10.sup.−4 moles, equal to about 0.0145 g) was added, and, subsequently, the FeCl.sub.3(L2) complex [sample MG262] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 9. Everything was kept under magnetic stirring, at 25° C., for 420 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 0.434 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0270] FIG. 19 shows the FT-IR spectrum of the polybutadiene obtained.

Example 26 (G1539/1)

[0271] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.16 ml; 2.5×10.sup.−4 moles, equal to about 0.0145 g) was added, and, subsequently, the FeCl.sub.2(L2) complex [sample MG266] (1.5 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3 mg) obtained as described in Example 10. Everything was kept under magnetic stirring, at 25° C., for 600 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 0.690 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0272] FIG. 20 shows the .sup.1H-NMR (top) and .sup.13C-NMR (bottom) spectra of the polybutadiene obtained.

Example 27 (IP121/1)

[0273] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 7.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L3) complex [sample MG267] (1.83 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.65 mg) obtained as described in Example 11. Everything was kept under magnetic stirring, at 25° C., for 180 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 0.694 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0274] FIG. 21 shows the .sup.1H-NMR (top) and .sup.13C-NMR (bottom) spectra of the polybutadiene obtained.

Example 28 (IP121)

[0275] 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 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.2(L3) complex [sample MG124] (1.65 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.3 mg) obtained as described in Example 12. Everything was kept under magnetic stirring, at 25° C., for 180 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 0.737 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0276] FIG. 22 shows the FT-IR spectrum of the polybutadiene obtained.

Example 29 (IP124)

[0277] 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 25° 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 FeCl.sub.3(L4) complex [sample MG126] (1.9 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.8 mg) obtained as described in Example 13. Everything was kept under magnetic stirring, at 25° C., for 1380 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 0.368 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0278] FIG. 23 shows the FT-IR spectrum of the polybutadiene obtained.

Example 30 (IP122)

[0279] 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 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.2(L4) complex [sample MG129] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 14. Everything was kept under magnetic stirring, at 25° C., for 2880 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 0.651 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0280] FIG. 24 shows the FT-IR spectrum of the polybutadiene obtained.

Example 31 (IP123)

[0281] 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 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.2(L5) complex [sample MG134] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 16. Everything was kept under magnetic stirring, at 25° C., for 1680 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 0.179 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0282] FIG. 25 shows the FT-IR spectrum of the polybutadiene obtained.

Example 32 (IP123/1)

[0283] 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 25° 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 FeCl.sub.3(L5) complex [sample MG268] (1.9 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.8 mg) obtained as described in Example 15. Everything was kept under magnetic stirring, at 25° C., for 1680 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 0.248 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0284] FIG. 26 shows the FT-IR spectrum of the polybutadiene obtained.

Example 33 (IP125)

[0285] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 8.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.2(L6) complex [sample MG133] (1.65 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.3 mg) obtained as described in Example 18. Everything was kept under magnetic stirring, at 25° C., for 5760 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 0.152 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0286] FIG. 27 shows the FT-IR spectrum of the polybutadiene obtained.

Example 34 (IP125/1)

[0287] 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 7.9 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L6) complex [sample MG269] (1.83 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.65 mg) obtained as described in Example 17. Everything was kept under magnetic stirring, at 25° C., for 5760 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 0.280 g of polybutadiene having a mixed structure: further characteristics of the process and of the polybutadiene obtained are reported in Table 1.

[0288] FIG. 28 shows the FT-IR spectrum of the polybutadiene obtained.

Example 35 (G1534/1)

[0289] 8.1 ml of toluene and, subsequently, 2 ml of isoprene equal to about 1.36 g were placed into a 25 ml test tube; the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L1) complex [sample MG261] (1.62 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.2 mg) obtained as described in Example 7. Everything was kept under magnetic stirring, at 25° C., for 600 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 0.96 g of polyisoprene having a mixed structure: further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0290] FIG. 29 shows the FT-IR spectrum of the polyisoprene obtained.

Example 36 (G1535/2)

[0291] 13.9 ml of toluene and, subsequently, 2 ml of isoprene equal to about 1.36 g were placed into a 25 ml test tube; the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (0.63 ml; 1×10.sup.−3 moles, equal to about 0.058 g) was added, and, subsequently, the FeCl.sub.2(L1) complex [sample MG265] (1.45 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 2.9 mg) obtained as described in Example 8. Everything was kept under magnetic stirring, at 25° C., for 600 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 0.796 g of polyisoprene having a mixed structure: further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0292] FIG. 30 shows the FT-IR spectrum of the polyisoprene obtained.

Example 37 (G1537/1)

[0293] 8 ml of toluene and, subsequently, 2 ml of isoprene equal to about 1.36 g were placed into a 25 ml test tube; the temperature of the solution thus obtained was brought to 25° 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 FeCl.sub.3(L2) complex [sample MG262] (1.7 ml of toluene solution at concentration of 2 mg/ml; 1×10.sup.−5 moles, equal to about 3.4 mg) obtained as described in Example 9. Everything was kept under magnetic stirring, at 25° C., for 600 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 0.541 g of polyisoprene having a mixed structure: further characteristics of the process and of the polyisoprene obtained are reported in Table 2.

[0294] FIG. 31 shows the FT-IR spectrum of the polyisoprene obtained.

TABLE-US-00001 TABLE 1 Polymerization of 1,3-butadiene with catalytic systems comprising oxo-nitrogenated iron complexes Al/Fe Time Conversion 1,4-cis 1,4-trans 1.2 M.sub.w Example (molar ratio) (min) (%) (%) (%) (%) (g × mol.sup.−1) M.sub.w/M.sub.n 19 1000 10 100 38.6 0 61.4 285000 2.6 20 100 10 81.5 37.4 0 62.6 341420 2.5 21 10 20 100 39.7 0 60.3 405680 2.1 22 100 15 100 42.8 0 57.2 335800 2.4 23 1000 120 70.6 48.0 0 52.0 182100 2.7 24 100 120 65.9 46.4 0 53.6 253970 2.6 25 25 420 31.0 52.9 0 47.1 315400 2.2 26 25 600 49.3 54.5 0 45.5 298700 2.0 27 1000 180 49.6 36.2 0 63.8 201400 1.9 28 1000 180 52.6 32.0 0 68.0 197700 2.1 29 1000 1380 26.3 79.0 5.8 15.2 97700 2.2 30 1000 2880 46.5 76.3 5.9 17.8 94300 2.1 31 1000 1680 12.8 79.6 3.0 17.4 91400 2.2 32 1000 1680 17.7 78.9 4.2 16.9 87700 1.9 33 1000 5760 10.9 78.7 8.2 13.1 79400 2.3 34 1000 5760 20.0 80.9 6.5 12.6 73300 2.1

TABLE-US-00002 TABLE 2 Polymerization of isoprene with catalytic systems comprising oxo-nitrogenated iron complexes Al/Fe Time Conversion 1,4-cis 1,4-trans 3.4 M.sub.w Example (molar ratio) (min) (%) (%) (%) (%) (g × mol−.sup.1) M.sub.w/M.sub.n 35 1000 600 70.3 40.7 0 59.3 112000 2.0 36 100 600 58.5 33.7 0 66.3 99500 2.1 37 1000 600 39.8 23.1 0 76.9 87400 1.9