Bis-imine titanium complex, catalytic system comprising said bis-imine titanium complex and process for the (co)polymertzation of conjugated dienes

Abstract

Bis-imine titanium complex having general formula (I): wherein: R.sub.1 and R.sub.2, mutually identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally substituted cycloalkyl groups; R.sub.3 and R.sub.4, mutually identical or different, represent a hydrogen atom; or are selected from linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, optionally substituted cycloalkyl groups, optionally substituted aryl groups; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, mutually identical or different, represent a halogen atom such as chlorine, bromine, iodine; or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, —OCOR.sub.5 groups or —OR.sub.5 groups wherein R.sub.5 is selected from linear or branched C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15; or represent an acetylacetonate group (acac); provided that when R.sub.1 and R.sub.2 represent a methyl group and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 represent a chlorine atom, R.sub.3 and R.sub.4 are different from 2,6-di-isopropylphenyl. ##STR00001##

Claims

1. Bis-imine titanium complex having general formula (I): ##STR00022## wherein: R.sub.1 and R.sub.2, mutually identical represent a hydrogen atom; or linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl groups; R.sub.3 and R.sub.4, mutually identical represent phenyl groups optionally substituted with linear or branched C.sub.1-C.sub.20 alkyl groups; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, mutually identical represent at least one halogen atom chlorine, bromine, or iodine; provided that when R.sub.1 and R.sub.2 represent a methyl group and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 represent a chlorine atom, R.sub.3 and R.sub.4 are different from 2,6-di-iso-propylphenyl.

2. Catalytic system for the (co)polymerization of conjugated dienes comprising: (a) at least one bis-imine titanium complex having general formula (I) ##STR00023## wherein: R.sub.1 and R.sub.2, mutually identical or different, represent a hydrogen atom; linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl groups; or optionally substituted cycloalkyl groups; R.sub.3 and R.sub.4, mutually identical or different, represent a hydrogen atom; linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl groups; optionally substituted cycloalkyl groups; or optionally substituted aryl groups; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, mutually identical or different, represent at least one halogen atom chlorine, bromine, or iodine; linear or branched C.sub.1-C.sub.20 alkyl groups, —OCOR.sub.5 groups or —OR.sub.5 groups wherein R.sub.5 is linear or branched C.sub.1-C.sub.20 alkyl groups; or an acetylacetonate group (acac); provided that when R.sub.1 and R.sub.2 represent a methyl group and X.sub.1, X.sub.2, X.sub.3 and X.sub.4 represent a chlorine atom, R.sub.3 and R.sub.4 are different from 2,6-di-iso-propylphenyl; (b) at least one co-catalyst including organic compounds of an element M′ other than carbon, said M′ element being at least one of the elements boron, aluminum, zinc, magnesium, gallium, or tin.

3. Catalytic system for the (co)polymerization of conjugated dienes according to claim 2, wherein said co-catalyst (b) is (b.sub.1) an aluminum alkyl having general formula (II):
Al(X′).sub.n(R.sub.6).sub.3-n  (II) wherein X′ represents a halogen atom chlorine, bromine, iodine, or fluorine; R.sub.6, mutually identical or different, represent a hydrogen atom, or linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, or 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.

4. Catalytic system for the (co)polymerization of conjugated dienes according to claim 2, wherein said co-catalyst (b) is (b.sub.2) organo-oxygenated compounds of an element M′ other than carbon being aluminum, gallium, or tin compounds.

5. The catalytic system for the (co)polymerization of conjugated dienes according to claim 2, wherein said co-catalyst (b) is (b.sub.3) compounds or mixtures of organometallic compounds of an element M′ other than carbon capable of reacting with the bis-imine titanium complex titanium having general formula (I), thereby extracting a σ-linked substituent X.sub.1, X.sub.2, X.sub.3 or X.sub.4, to form at least one neutral compound and an ionic compound consisting of a cation containing the metal (Ti) coordinated by the ligand, and an uncoordinating organic anion containing the metal M′, whose negative charge is delocalized on a multicentric structure.

6. Catalytic system for the (co)polymerization of conjugated dienes according to claim 3, wherein said aluminum alkyls (b.sub.1) having general formula (II) are triethyl-aluminum (TEA), tri-n-propyl aluminum, tri-iso-butyl aluminum (TIBA), tri-hexyl-aluminum, di-iso-butyl aluminum hydride (DIBAH), or diethyl aluminum chloride (DEAC).

7. Catalytic system for the (co)polymerization of conjugated dienes according to claim 4, wherein said organoxygenated compounds (b.sub.2) are aluminoxanes having general formula (III):
(R.sub.7).sub.2—Al—O—[—Al(R.sub.8)—O—].sub.p—Al—(R.sub.9).sub.2  (III) wherein R.sub.7, R.sub.8 and R.sub.9, mutually identical or different, represent a hydrogen atom, a halogen atom chlorine, bromine, iodine, or fluorine; or linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, or 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.

8. Catalytic system for the (co)polymerization of conjugated dienes according to claim 7, wherein said organo-oxygenated compound (b.sub.2) is methylaluminoxane (MAO).

9. Catalytic system for the (co)polymerization of conjugated dienes according to claim 5, wherein said compound(s) or mixtures of compounds (b.sub.3) are organic aluminum or boron compounds, represented by the following general formulae:
[(R.sub.C).sub.WH.sub.4-W].[B(R.sub.D).sub.4]—;B(R.sub.D).sub.3;Al(R.sub.D).sub.3;B(R.sub.D).sub.3Pir;[Ph.sub.3C]+.[B(R.sub.D).sub.4]—;[(R.sub.C).sub.3PirH]+.[B(R.sub.D).sub.4]—;[Li]+.[B(R.sub.D).sub.4]—;[Li]+.[Al(R.sub.D).sub.4]—; 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 represents, independently, a partially or totally fluorinated, aryl group having from 6 to 20 carbon atoms, and Pyr represents an optionally substituted pyrrole radical.

10. Process for the (co)polymerization of conjugated dienes comprising contacting one or more conjugated dienes with the catalytic system according to claim 3 so as to (co)polymerize the one or more conjugated dienes.

11. Process for the (co)polymerization of 1,3-butadiene comprising contacting 1,3-butadiene with the catalytic system according to claim 3 so as to (co)polymerize the 1,3-butadiene.

12. A bis-imine titanium complex having general formula (I) according to claim 1, wherein: R.sub.1 and R.sub.2, mutually identical, are a hydrogen atom; or are a methyl group; R.sub.3 and R.sub.4, mutually identical, are phenyl groups substituted with one or more methyl, ethyl, iso-propyl, or tert-butyl groups; X.sub.1, X.sub.2, X.sub.3 and X.sub.4, mutually identical, are chlorine.

13. Process for the (co)polymerization of conjugated dienes comprising contacting one or more conjugated dienes with the catalytic system of claim 2 so as to (co)polymerize the one or more conjugated dienes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: FT-IR spectrum of the ligand (L1) described in Example 1;

(2) FIG. 2: FT-IR spectrum of the ligand (L2) described in Example 2;

(3) FIG. 3: .sup.1H-NMR spectrum of the ligand (L2) described in Example 2;

(4) FIG. 4: FT-IR spectrum of the ligand (L3) described in Example 3;

(5) FIG. 5: FT-IR spectrum of the ligand (L4) described in Example 4;

(6) FIG. 6: FT-IR spectrum of the ligand (L5) described in Example 5;

(7) FIG. 7: .sup.1H-NMR spectrum of the ligand (L5) described in Example 5;

(8) FIG. 8: FT-IR spectrum of the ligand (L6) described in Example 6;

(9) FIG. 9: FT-IR spectrum of the ligand (L7) described in Example 7;

(10) FIG. 10: FT-IR spectrum of the ligand (L8) described in Example 8;

(11) FIG. 11: FT-IR spectrum of the complex TiCl.sub.4(L1) [named sample MG270] described in Example 9;

(12) FIG. 12: FT-IR spectrum of the complex TiCl.sub.4(L2) [named sample MG291] described in Example 10;

(13) FIG. 13: FT-IR spectrum of the complex TiCl.sub.4(L3) [named sample MG274] described in Example 11;

(14) FIG. 14: FT-IR spectrum of the complex TiCl.sub.4(L3) [named sample MG290] described in Example 12;

(15) FIG. 15: FT-IR spectrum of the complex TiCl.sub.4(L4) [named sample MG271] described in Example 13;

(16) FIG. 16: FT-IR spectrum of the complex TiCl.sub.4(L5) [named sample MG284] described in Example 14;

(17) FIG. 17: FT-IR spectrum of the complex TiCl.sub.4(L6) [named sample MG288] described in Example 15;

(18) FIG. 18: FT-IR spectrum of the complex TiCl.sub.4(L6) [named sample MG402A] described in Example 16;

(19) FIG. 19: FT-IR spectrum of the complex TiCl.sub.4(L8) [named sample MG404A] described in Example 17;

(20) FIG. 20: FT-IR spectrum of the polybutadiene [named sample ZG305] described in Example 18;

(21) FIG. 21: FT-IR spectrum of the polybutadiene [named sample ZG311] described in Example 19;

(22) FIG. 22: FT-IR spectrum of the polybutadiene [named sample ZG310] described in Example 20;

(23) FIG. 23: FT-IR spectrum of the polybutadiene [named sample ZG309] described in Example 22;

(24) FIG. 24: FT-IR spectrum of the polybutadiene [named sample ZG307] described in Example 24;

(25) FIG. 25: FT-IR spectrum of the polybutadiene [named sample ZG308] described in Example 25;

(26) FIG. 26: FT-IR spectrum of the polybutadiene [named sample ZG312] described in Example 26; and

(27) FIG. 27: FT-IR spectrum of the polybutadiene [named sample G1603] described in Example 27.

Example 1

Synthesis of Ligand Having Formula (L1)

(28) ##STR00005##

(29) A solution of 10.72 g (100 mmol) of o-toluidine in methanol (50 ml) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution), cooled to 0° C. and kept under stirring and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, in a water/ice bath, until the formation of a precipitate was noted. Subsequently, everything was left to return to ambient temperature and the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 9.92 g of a yellow powder (yield=84%) corresponding to the ligand having formula (L1).

(30) FT-IR (nujol): 1605 cm.sup.−1 v.sub.(C═N).

(31) Molecular weight (MW): 236.32.

(32) Elementary analysis [found (calculated) for C.sub.16H.sub.16N.sub.2]: C: 81.28% (81.32%); H: 6.80% (6.82%); N: 11.83% (11.85%).

(33) FIG. 1 shows the FT-IR (solid state—UATR) spectrum of the ligand (L1) obtained.

Example 2

Synthesis of Ligand Having Formula (L2)

(34) ##STR00006##

(35) A solution of 10.72 g (100 mmol) of p-toluidine in methanol (50 ml) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution), cooled to 0° C. and kept under stirring and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, in a water/ice bath, until the formation of a precipitate was noted. Subsequently, everything was left to return to ambient temperature and the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 9 g of a yellow powder (yield=76%) corresponding to the ligand having formula (L2).

(36) FT-IR (nujol): 1608 cm.sup.−1 v.sub.(C═N).

(37) Molecular weight (MW): 236.32.

(38) Elementary analysis [found (calculated) for C.sub.16H.sub.16N.sub.2]: C: 81.29% (81.32%); H: 6.82% (6.82%); N: 11.87% (11.85%).

(39) .sup.1H-NMR (CDCl.sub.3, 5 ppm): 8.42 (s, 2H, CH), 7.23 (s, 8H, Ar—H), 2.39 (s, 6H, Ar—CH.sub.3).

(40) FIG. 2 shows the FT-IR (solid state—UATR) spectrum of the ligand (L2) obtained.

(41) FIG. 3 shows the .sup.1H-NMR spectrum of the ligand (L2) obtained.

Example 3

Synthesis of Ligand Having Formula (L3)

(42) ##STR00007##

(43) A solution of 14.92 g (100 mmol) of 2-tert-butylaniline in methanol (100 ml) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution), cooled to 0° C. and kept under stirring and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, in a water/ice bath, until the formation of a precipitate was noted. Subsequently, everything was left to return to ambient temperature and the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 12 g of a yellow powder (yield=75%) corresponding to the ligand having formula (L3).

(44) FT-IR (nujol): 1608 cm.sup.−1 v.sub.(C═N).

(45) Molecular weight (MW): 320.48.

(46) Elementary analysis [found (calculated) for C.sub.22H.sub.28N.sub.2]: C: 82.42% (82.45%); H: 8.80% (8.81%); N: 8.76% (8.74%).

(47) FIG. 4 shows the FT-IR (solid state—UATR) spectrum of the ligand (L3) obtained.

Example 4

Synthesis of Ligand Having Formula (L4)

(48) ##STR00008##

(49) A solution of 12.12 g (100 mmol) of 2,6-dimethylaniline in methanol (100) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution), cooled to ambient temperature and kept under stirring and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, in a water/ice bath, until the formation of a precipitate was noted. Subsequently, everything was left to return to ambient temperature and the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 12 g of a yellow powder (yield=90%) corresponding to the ligand having formula (L4).

(50) FT-IR (nujol): 1610 cm.sup.−1 v.sub.(C═N).

(51) Molecular weight (MW): 264.37.

(52) Elementary analysis [found (calculated) for C.sub.18H.sub.20N.sub.2]: C: 81.72% (81.78%); H: 7.61% (7.63%); N: 10.63% (10.60%).

(53) FIG. 5 shows the FT-IR (solid state—UATR) spectrum of the ligand (L4) obtained.

Example 5

Synthesis of Ligand Having Formula (L5)

(54) ##STR00009##

(55) A solution of 17.73 g (100 mmol) of 2,6-di-iso-propylaniline in methanol (50 ml) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution) in methanol and distilled water (30 ml+10 ml, respectively), cooled to 0° C. and kept under stirring, and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, at ambient temperature, until the formation of a precipitate was noted, which was filtered, washed with methanol, and vacuum dried, at ambient temperature, obtaining 14 g of a yellow powder (yield=74%) corresponding to the ligand having formula (L5).

(56) FT-IR (nujol): 1614 cm.sup.−1 v.sub.(C═N).

(57) Molecular weight (MW): 376.59.

(58) Elementary analysis [found (calculated) for C.sub.26H.sub.36N.sub.2]: C: 82.88% (82.93%); H: 9.85% (9.64%); N: 7.99% (7.44%).

(59) .sup.1H-NMR (CDCl.sub.3, ppm): 1.22 (d, 24H, CH(CH.sub.3).sub.2); 2.95 (m, 4H, CH(CH.sub.3).sub.2); 7.19-7.22 (m, 6H C.sub.6H.sub.3); 8.11 (s, 2H, NCH).

(60) FIG. 6 shows the FT-IR (solid state—UATR) spectrum of the ligand (L5) obtained.

(61) FIG. 7 shows the .sup.1H-NMR spectrum of the ligand (L5) obtained.

Example 6

Synthesis of Ligand Having Formula (L6)

(62) ##STR00010##

(63) A solution of 13.52 g (100 mmol) of 2,4,6-trimethylaniline in methanol (50 ml) was added, drop by drop, to a solution of 7.26 g (50 mmol) of glyoxal (40% by weight aqueous solution) in methanol (50 ml), cooled to ambient temperature and kept under stirring and, subsequently some drops of formic acid (85% by weight aqueous solution): the reaction mixture obtained was left, under stirring, in a water/ice bath, until the formation of a precipitate was noted. Subsequently, everything was left to return to ambient temperature and the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 12 g of a yellow powder (yield=82%) corresponding to the ligand having formula (L6).

(64) FT-IR (nujol): 1616 cm.sup.−1 v.sub.(C═N).

(65) Molecular weight (MW): 292.442.

(66) Elementary analysis [found (calculated) for C.sub.20H.sub.24N.sub.2]: C: 82.0% (82.15%); H: 8.28% (8.27%); N: 9.51% (9.58%).

(67) .sup.1H-NMR (CDCl.sub.3, ppm): 2.15 (s, 12H, 2,6-(CH.sub.3).sub.2—C.sub.6H.sub.2), 2.29 (s, 6H, 4-CH.sub.3—C.sub.6H.sub.2), 6.90 (s, 4H, C.sub.6H.sub.2), 8.09 (s, 2H, NCH).

(68) FIG. 8 shows the FT-IR (solid state—UATR) spectrum of the ligand (L6) obtained.

Example 7

Synthesis of Ligand Having Formula (L7)

(69) ##STR00011##

(70) Sequentially and under stirring, a solution of 9.3 g (100 mmol) of aniline in methanol (80 ml), a solution of 4.3 g (50 mmol) of 2,3-butandione in methanol (50 ml) and some drops of formic acid (85% by weight aqueous solution) were loaded into a 500 ml reactor. Everything was left, under stirring, at ambient temperature, for about 2 hours, until the formation of a precipitate was noted, which was left to rest for 14 hours, at ambient temperature. Subsequently, the precipitate obtained was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 12 g of a yellow powder (yield=98%) corresponding to the ligand having formula (L7).

(71) FT-IR (nujol): 1634 cm.sup.−1 v.sub.(C═N).

(72) Molecular weight (MW): 292.42.

(73) Elementary analysis [found (calculated) for C.sub.16H.sub.16N.sub.2]: C: 81.42% (81.32%); H: 6.33% (6.82%); N: 11.92% (11.85%).

(74) .sup.1H NMR (CDCl.sub.3 δ ppm) 7.06 (m, 2H); 7.29 (m, 4H); 6.85 (m, 4H); 2.19 (s, 6H).

(75) FIG. 9 shows the FT-IR (solid state—UATR) spectrum of the ligand (L7) obtained.

Example 8

Synthesis of Ligand Having Formula (L8)

(76) ##STR00012##

(77) Sequentially and under stirring, a solution of 13.43 g (90 mmol) of tert-butylaniline in methanol (50 ml), and some drops of formic acid (85% by weight aqueous solution) were loaded into a 500 ml reactor obtaining a solution. A solution of 3.87 g (45 mmol) of 2,3-butanedione in methanol (30 ml) was added to said solution drop by drop, under stirring. Everything was left, under stirring, at ambient temperature, for about 2 hours, until the formation of a precipitate was noted, which was left to rest for 14 hours, at ambient temperature. Subsequently, the precipitate was filtered, washed with methanol and vacuum dried, at ambient temperature, obtaining 14.1 g of a yellow powder (yield=90%) corresponding to the ligand having formula (L8).

(78) FT-IR (nujol): 1636 cm.sup.−1 v.sub.(C═N).

(79) Molecular weight (MW): 348.52.

(80) Elementary analysis [found (calculated) for C.sub.24H.sub.32N.sub.2]: C: 81.95% (82.71%); H: 9.26% (9.25%); N: 8.02% (8.01%).

(81) NMR (CDCl.sub.3 δ ppm) 7.42 (dd, 2H); 7.19 (m, 2H); 7.08 (m, 2H); 6.51 (dd, 2H); 2.21 (s, 6H); 1.36 (s 18H).

(82) FIG. 10 shows the FT-IR (solid state—UATR) spectrum of the ligand (L8) obtained.

Example 9

Synthesis of TiCl.SUB.4.(L1) [Sample MG270]

(83) ##STR00013##

(84) In a 100 ml Schlenk tube, titanium tetrachloride (TiCl.sub.4) (121 mg; 0.63 mmoles; molar ratio L1/Ti=1) was added to a solution of the ligand having formula (L1) (150 mg; 0.63 mmoles), obtained as described in Example 1, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 224 mg of an orange solid product corresponding to the complex TiCl.sub.4(L1), equal to an 83% conversion with respect to the titanium tetrachloride (TiCl.sub.4) loaded.

(85) Elementary analysis [found (calculated) for C.sub.16H.sub.16C.sub.14N.sub.2Ti]: C: 45.61% (45.11%); H: 3.56% (3.79%); N: 6.08% (6.58%); Cl: 33.00% (33.29%); Ti: 10.95% (11.24%).

(86) FIG. 11 shows the FT-IR spectrum of the complex TiCl.sub.4(L1) obtained.

Example 10

Synthesis of TiCl.SUB.4.(L2) [Sample MG291]

(87) ##STR00014##

(88) In a 100 ml Schlenk tube, the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2] (231 mg; 0.69 mmoles; molar ratio L2/Ti=1) was added to a solution of the ligand having formula (L2) (163 mg; 0.69 mmoles), obtained as described in Example 2, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 268 mg of a brown solid product corresponding to the complex TiCl.sub.4(L2), equal to a 91% conversion with respect to the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2].

(89) Elementary analysis [found (calculated) for C.sub.16H.sub.16C.sub.14N.sub.2Ti]: C: 45.73% (45.11%); H: 4.05% (3.79%); N: 6.32% (6.58%); Cl: 32.95% (33.29%); Ti: 10.87% (11.24%).

(90) FIG. 12 shows the FT-IR spectrum of the complex TiCl.sub.4(L2) obtained.

Example 11

Synthesis of TiCl.SUB.4.(L3) [Sample MG274]

(91) ##STR00015##

(92) In a 100 ml Schlenk tube, titanium tetrachloride (TiCl.sub.4) (119 mg; 0.63 mmoles; molar ratio L3/Ti=1) was added to a solution of the ligand having formula (L3) (200 mg; 0.62 mmoles), obtained as described in Example 3, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 236 mg of an ochre solid product corresponding to the complex TiCl.sub.4(L3), equal to a 75% conversion with respect to the titanium tetrachloride (TiCl.sub.4) loaded.

(93) Elementary analysis [found (calculated) for C.sub.22H.sub.28Cl.sub.4N.sub.2Ti]: C: 51.46% (51.80%); H: 5.23% (5.53%); N: 5.75% (5.49%); Cl: 27.20% (27.80%); Ti: 8.98% (9.38%).

(94) FIG. 13 shows the FT-IR spectrum of the complex TiCl.sub.4(L3) obtained.

Example 12

Synthesis of TiCl.SUB.4.(L3) [Sample MG290]

(95) ##STR00016##

(96) In a 100 ml Schlenk tube, the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2] (246 mg; 0.74 mmoles; molar ratio L3/Ti=1) was added to a solution of the ligand having formula (L3) (236 mg; 0.74 mmoles), obtained as described in Example 3, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 236 mg of a brown solid product corresponding to the complex TiCl.sub.4(L3), equal to a 61% conversion with respect to the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl4(THF).sub.2].

(97) Elementary analysis [found (calculated) for C.sub.22H.sub.28Cl.sub.4N.sub.2Ti]: C: 51.00% (51.80%); H: 4.92% (5.53%); N: 5.29% (5.49%); Cl: 26.98% (27.80%); Ti: 9.01% (9.38%).

(98) FIG. 14 shows the FT-IR spectrum of the complex TiCl.sub.4(L3) obtained.

Example 13

Synthesis of TiCl.SUB.4.(L4) [Sample MG271]

(99) ##STR00017##

(100) In a 100 ml Schlenk tube, (TiCl.sub.4) (144 mg; 0.76 mmoles; molar ratio L4/Ti=1) was added to a solution of the ligand having formula (L4) (200 mg; 0.76 mmoles), obtained as described in Example 4, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 236 mg of an ochre solid product corresponding to the complex TiCl.sub.4(L4), equal to an 85% conversion with respect to the titanium tetrachloride (TiCl.sub.4) loaded.

(101) Elementary analysis [found (calculated) for C.sub.18H.sub.20C.sub.14N.sub.2Ti]: C: 48.11% (47.61%); H: 4.58% (4.44%); N: 5.95% (6.17%); Cl: 31.00% (31.23%); Ti: 9.95% (10.54%).

(102) FIG. 15 shows the FT-IR spectrum of the complex TiCl.sub.4(L4) obtained.

Example 14

Synthesis of TiCl.SUB.4.(L5) [Sample MG284]

(103) ##STR00018##

(104) In a 100 ml Schlenk tube, the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2] (184 mg; 0.55 mmoles; molar ratio L5/Ti=1) was added to a solution of the ligand having formula (L5) (207 mg; 0.55 mmoles), obtained as described in Example 5, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 215 mg of a red solid product corresponding to the complex TiCl.sub.4(L5), equal to a 69% conversion with respect to the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2].

(105) Elementary analysis [found (calculated) for C.sub.26H.sub.36Cl.sub.4N.sub.2Ti]: C: 53.91% (55.15%); H: 6.70% (6.41%); N: 4.50% (4.95%); Cl: 28.30% (25.04%); Ti: 7.90% (8.45%).

(106) FIG. 16 shows the FT-IR spectrum of the complex TiCl.sub.4(L5) obtained.

Example 15

Synthesis of TiCl.SUB.4.(L6) [Sample MG288]

(107) ##STR00019##

(108) In a 100 ml Schlenk tube, the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2] (238 mg; 0.71 mmoles; molar ratio L6/Ti=1) was added to a solution of the ligand having formula (L6) (208 mg; 0.71 mmoles), obtained as described in Example 6, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 263 mg of a red solid product corresponding to the complex TiCl.sub.4(L6), equal to a 77% conversion with respect to the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2].

(109) Elementary analysis [found (calculated) for C.sub.20H.sub.24Cl.sub.4N.sub.2Ti]: C: 49.46% (49.83%); H: 4.98% (5.02%); N: 5.38% (5.81%); Cl: 28.40% (29.42%); Ti: 9.50% (9.93%).

(110) FIG. 17 shows the FT-IR spectrum of the complex TiCl.sub.4(L6) obtained.

Example 16

Synthesis of TiCl.SUB.4.(L7) [Sample MG402A]

(111) ##STR00020##

(112) In a 100 ml Schlenk tube, the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2] (185 mg; 0.55 mmoles; molar ratio L7/Ti=1) was added to a solution of the ligand having formula (L7) (131 mg; 0.55 mmoles), obtained as described in Example 7, in toluene (20 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×10 ml) and vacuum dried, at ambient temperature, obtaining 152 mg of an orange/brown solid product corresponding to the complex TiCl.sub.4(L7), equal to a 65% conversion with respect to the titanium tetrachloride:tetrahydrofuran complex (1:2) [TiCl.sub.4(THF).sub.2].

(113) Elementary analysis [found (calculated) for C.sub.16H.sub.16C.sub.14N.sub.2Ti]: C: 44.45% (45.11%); H: 3.86% (3.79%); N: 6.41% (6.58%); Cl: 32.29% (33.29%); Ti: 11.00% (11.24%).

(114) FIG. 18 shows the FT-IR spectrum of the complex TiCl.sub.4(L6) obtained.

Example 17

Synthesis of TiCl.SUB.4.(L8) [Sample MG404A]

(115) ##STR00021##

(116) In a 100 ml Schlenk tube, titanium tetrachloride (TiCl.sub.4) (67 mg; 0.35 mmoles; molar ratio L8/Ti=1) was added to a solution of the ligand having formula (L8) (123 mg; 0.35 mmoles), obtained as described in Example 8, in toluene (10 ml): the mixture obtained was left, under stirring, at ambient temperature, for 18 hours. The suspension obtained was vacuum dried, at ambient temperature, and the solid obtained was washed with heptane (2×15 ml) and vacuum dried, at ambient temperature, obtaining 88 mg of an orange solid product corresponding to the complex TiCl.sub.4(L8), equal to a 47% conversion with respect to the titanium tetrachloride (TiCl.sub.4) loaded.

(117) Elementary analysis [found (calculated) for C.sub.24H.sub.32Cl.sub.4N.sub.2Ti]: C: 52.99% (53.56%); H: 5.74% (5.99%); N: 5.06% (5.20%); Cl: 25.89% (26.35%); Ti: 8.59% (8.89%).

(118) FIG. 19 shows the FT-IR spectrum of the complex TiCl.sub.4(L8) obtained.

Example 18 (ZG305)

(119) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.6 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(L1) complex [sample MG270] (2.1 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 4.26 mg) obtained as described in Example 9. Everything was kept under magnetic stirring, at 25° C., for 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.74 g of polybutadiene having a 1,4-cis unit content of 85%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(120) FIG. 20 shows the FT-IR spectrum of the polybutadiene obtained.

Example 19 (ZG311)

(121) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.6 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 TiCl.sub.4(L2) complex [sample MG291] (2.1 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 4.26 mg) obtained as described in Example 10. Everything was kept under magnetic stirring, at 25° C., for 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.80 g of polybutadiene having a 1,4-cis unit content of 86%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(122) FIG. 21 shows the FT-IR spectrum of the polybutadiene obtained.

Example 20 (ZG310)

(123) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.15 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 TiCl.sub.4(L3) complex [sample MG290] (2.55 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 5.1 mg) obtained as described in Example 12. Everything was kept under magnetic stirring, at 25° C., for 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.87 g of polybutadiene having a 1,4-cis unit content of 80%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(124) FIG. 22 shows the FT-IR spectrum of the polybutadiene obtained.

Example 21 (ZG310/1)

(125) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.15 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 TiCl.sub.4(L3) complex [sample MG274] (2.55 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 5.1 mg) obtained as described in Example 11. Everything was kept under magnetic stirring, at 25° C., for 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.82 g of polybutadiene having a 1,4-cis unit content of 81%; further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

Example 22 (ZG309)

(126) 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 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 TiCl.sub.4(L4) complex [sample MG271] (2.3 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 4.54 mg) obtained as described in Example 13. Everything was kept under magnetic stirring, at 25° C., for 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.43 g of polybutadiene having a 1,4-cis unit content of 73%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(127) FIG. 23 shows the FT-IR spectrum of the polybutadiene obtained.

Example 23 (ZG302)

(128) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 6.9 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 TiCl.sub.4(L5) complex [sample MG284] (2.81 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 5.62 mg) obtained as described in Example 14. Everything was kept under magnetic stirring, at 25° C., for 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.29 g of polybutadiene having a 1,4-cis unit content of 60%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

Example 24 (ZG307)

(129) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 11.5 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (3.15 ml; 5×10.sup.−3 moles, equal to about 0.27 g) was added and, subsequently, the TiCl.sub.4(L5) complex [sample MG284] (1.4 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−6, equal to about 2.81 mg) obtained as described in Example 14. Everything was kept under magnetic stirring, at 25° C., for 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.12 g of polybutadiene having a 1,4-cis unit content of 60%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(130) FIG. 24 shows the FT-IR spectrum of the polybutadiene obtained.

Example 25 (ZG308)

(131) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 9.1 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (1.26 ml; 2×10.sup.−3 moles, equal to about 0.12 g) was added and, subsequently, the TiCl.sub.4(L5) complex [sample MG284] (5.64 ml of toluene suspension at a concentration of 2 mg/ml; 2×10.sup.−5, equal to about 11.24 mg) obtained as described in Example 14.

(132) 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 (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.68 g of polybutadiene having a 1,4-cis unit content of 62%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(133) FIG. 25 shows the FT-IR spectrum of the polybutadiene obtained.

Example 26 (ZG312)

(134) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.3 ml of toluene were added and the temperature of the solution thus obtained was brought to 25° C. Then, methylaluminoxane (MAO) in toluene solution (6.3 ml; 1×10.sup.−2 moles, equal to about 0.58 g) was added and, subsequently, the TiCl.sub.4(L6) complex [sample MG288] (2.4 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 4.8 mg) obtained as described in Example 15. Everything was kept under magnetic stirring, at 25° C., for 25 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.43 g of polybutadiene having a 1,4-cis unit content of 76%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(135) FIG. 26 shows the FT-IR spectrum of the polybutadiene obtained.

Example 27 (G1603)

(136) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.) in a 25 ml test tube. Subsequently, 7.57 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 TiCl.sub.4(L7) complex [sample MG402A] (2.13 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 4.26 mg) obtained as described in Example 16. 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 (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.799 g of polybutadiene having a 1,4-cis unit content of 82%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(137) FIG. 27 shows the FT-IR spectrum of the polybutadiene obtained.

Example 28 (G1604)

(138) 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 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 TiCl.sub.4(L8) complex [sample MG404A] (2.69 ml of toluene suspension at a concentration of 2 mg/ml; 1×10.sup.−5, equal to about 5.4 mg) obtained as described in Example 17. 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 (37% by weight aqueous solution). The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 0.334 g of polybutadiene having a 1,4-cis unit content of 79%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(139) 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) (%) (%) 1.2 (g × mol.sup.−1) M.sub.w/M.sub.n 18 60 0.74 52.8 85 15 101800 1.80 19 60 0.80 57.1 86 14 307603 2.21 20 60 0.87 62.1 80 20 169935 2.47 21 60 0.82 58.6 81 19 165800 2.24 22 30 0.43 30.7 73 27 297465 1.90 23 30 1.29 92.1 60 40 347000 1.88 24 60 1.12 80 60 43 317225 1.73 25 120 0.68 48.6 62 38 180660 1.82 26 25 0.43 30.7 76 24 129650 1.90 27 20 0.80 57.1 82 18 283800 2.10 28 120 0.33 23.9 79 21 305200 1.95