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1.
Bimetallic alkylidene complexes of tungsten (R′O)2(ArN)WCH-SiR2-CHW(NAr)(OR′)2 (R = Me (1), Ph (2)) and (R′O)2(ArN)WCH-SiMe2SiMe2-CHW(NAr)(OR′)2 (3) (Ar = ; R′ = CMe2CF3) have been prepared by the reactions of divinyl silicon reagents R2Si(CHCH2)2 with known alkylidene compounds R′′-CHMo(NAr)(OR′)2. (R′′ = But, PhMe2C) Complexes 1-3 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1-3 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and 3 and predominant cis-units content in the case of 2. 相似文献
2.
Hieronim Maciejewski Agnieszka Sydor Maciej Kubicki 《Journal of organometallic chemistry》2004,689(19):3075-3081
Reactions of the nickel(0) complexes [Ni(cod)2] (in the presence of PP or [Ni(PPh3)2C2H4] with vinyl-siloxanes, -silanes or -silazanes yield, by displacement of alkene ligand, the new nickel π-complexes [Ni(PPh3)2(η-CH2CHSi(OSiMe3)3)] (2), [{Ni(PPh3)}2{μ-(η-{(CH2CH)2SiMe}2O})] (4), [Ni(PPh3){η4-CH2CHSi(Me)(μ-O)}3] (5), [{Ni(η-CH2CHSiMe2)2O}(η-CH2CHSiMe3)] (7) and the known complexes [Ni(PPh3)2(η-CH2CHSiMe3)] (1), [{Ni(PPh3)}2{μ-(η-(CH2CH)4Si})] (3), [{Ni(PPh3)(η-CH2CHSiMe2)2NH}] (6) obtained by a simple one pot synthesis, more efficiently than in hitherto published reports. The X-ray crystal structure of (1) shows a trigonal planar environment around the nickel atom. 相似文献
3.
Javier Martínez José M. Antelo Ma Teresa Pereira José M. Vila 《Journal of organometallic chemistry》2006,691(13):2891-2901
Treatment of the thiosemicarbazones 4-FC6H4C(Me)NN(H)C(S)NHR, (R = Me, a; Ph, b) and 2-ClC6H4C(Me)NN(H)C(S)NHR (R = Ph, c) with lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid gave the tetranuclear cyclometallated complex [Pd{4-FC6H3C(Me)NNC(S)NHR}]4 (1a, 1b) and [Pd{2-ClC6H3C(Me)NNC(S)NHPh}]4 (1c). Reaction of these tetramers with the diphosphines dppe, t-dppe, dppp or dppb in a 1:2 molar ratio gave the dinuclear cyclometallated complexes [(Pd{4-FC6H3C(Me)NNC(S)NHR})2(μ-Ph2P(CH2)nPPh2)], (n = 2, 2a, 2b; 3, 4a, 4b; 4, 5a, 5b), [(Pd{4-FC6H3C(Me)NNC(S)NHPh})2(μ-Ph2PCHCHPPh2)], (3a, 3b) and [(Pd{2-ClC6H3C(Me)NNC(S)NHR})2(μ-Ph2P(CH2)nPPh2)], (n = 2, 2c, 2d; 3, 4c, 4d; 4, 5c, 5d), [(Pd{2-ClC6H3C(Me)NNC(S)NHPh})2(μ-PPh2CHCHPPh2)], (3c, 3d). The X-ray crystal structure of the ligand b and the complexes 3c, 4a and 4d were determined. The structures of complexes 4a and 4d show that the different disposition of the chain cyclometallated of the thiosemicarbazones (in the same orientation or in the opposite one) is due to the different H bonds produced. 相似文献
4.
Javier Martínez José M. Antelo Juan M. Ortigueira Jesús J. Fernández José M. Vila 《Journal of organometallic chemistry》2006,691(12):2721-2733
Treatment of the thiosemicarbazones 2-XC6H4C(Me)NN(H)C(S)NHR (R = Me, X = F, a; R = Et, X = F, b; R = Me, X = Cl, c; R = Et, X = Br, d) with potassium tetrachloropalladate(II) in ethanol, lithium tetrachloropalladate(II) in methanol or palladium(II) acetate in acetic acid, as appropriate, gave the tetranuclear cyclometallated complexes [Pd{2-XC6H3C(Me)NNC(S)NHR}]4 (1a-1d). Reaction of 1a-1d with the diphosphines Ph2PCH2PPh2 (dppm), Ph2P(CH2)2PPh2 (dppe), Ph2P(CH2)3PPh2 (dppp) or trans-Ph2PCHCHPPh2 (trans-dpe) in 1:2 molar ratio gave the dinuclear cyclometallated complexes [{Pd[2-XC6H3C(Me)NNC(S)-NHR]}2(μ-diphosphine-P,P)] (2a-5a, 3b, 3d, 4c, 5c). Reaction of 1a, 1b with the short-bite or long-bite diphosphines, dppm or cis-dpe, in a 1:4 molar ratio gave the mononuclear cyclometallated complexes [Pd{2-XC6H3C(Me)NNC(S)NHR}(diphosphine-P)] (6a, 6b, 7a). The molecular structure of ligand a and of complexes 1a, 3d, 5a, 5c, 6a, 6b and 7a have been determined by X-ray diffraction analysis. The structure of complex 7a shows that the long-bite cis-bis(diphenylphosphino)ethene phosphine appears as monodentate with an uncoordinated phosphorus donor atom. 相似文献
5.
6.
Selby A.R. Knox 《Journal of organometallic chemistry》2007,692(19):4119-4128
The diruthenium μ-allenyl complex [Ru2(CO)(NCMe)(μ-CO){μ-η1:η2-C(H)CC(Me)(Ph)}(Cp)2][BF4], 3b, reacts with halide anions to yield the neutral derivatives [Ru2(CO)2(X){μ-η1:η2-C(H)CC(Me)(Ph)}(Cp)2] [X = Cl, 4b; X = Br, 4c; X = I, 4d]. Complex 4b undergoes isomerization to the unprecedented bridging vinyl-chlorocarbene species [Ru2(CO)(μ-CO){μ-η1:η3- C(Cl)C(H)C(Me)(Ph)}(Cp)2], 10, upon filtration of a CH2Cl2 solution through an alumina column.Complex 3b reacts with an excess of NaBH4 to give five products: the allene complex [Ru2(CO)2{μ-η2:η2- CH2CC(Me)(Ph)}(Cp)2], 5; the hydride species trans-[Ru2(CO)2(μ-H){μ-η1:η2-CHCC(Me)(Ph)}(Cp)2], 6, and cis-[Ru2(CO)2(μ-H){μ-η1:η2-CHCC(Me)(Ph)}(Cp)2], 8; the vinyl-alkylidene [Ru2(CO)(μ-CO){μ-η1:η3- C(H)C(H)C(Me)(Ph)}(Cp)2], 9; and the cluster [Ru3(CO)3(μ-H)3(Cp)3], 7.Studies on the thermal stabilities of 5, 6, 8 and 9 have suggested a plausible mechanism for the formation of these complexes and for the synthesis of 10. 相似文献
7.
Michael I. Bruce Benjamin G. Ellis Allan H. White 《Journal of organometallic chemistry》2005,690(3):792-801
Whereas {Ru(dppm)Cp*}2(μ-CCCC) (2) is the only product formed by deprotonation of [{Ru(dppm)Cp*}2{μ(CCHCHC)}]+ with dbu, a mixture of 2 with Ru{CCCHCH(PPh2)2[RuCp*]}(dppm)Cp* (3) and {Cp*Ru(PPh2CHCCH-)}2 (4) is obtained with KOBut. A similar reaction with [{Ru(dppm)Cp*}2{μ(CCMeCMeC)}]+ (5) gave Ru{CCCMeCH(PPh2)2[RuCp*]}(dppm)Cp* (6). X-ray structures of 4, 5 and 6 confirm the presence of the 1-ruthena-2,4-diphosphabicyclo[1.1.1]pentane moiety, which is likely formed by an intramolecular attack of the deprotonated dppm ligand on C(1) of the vinylidene ligand. Protonation of {Ru(dppe)Cp*}2(μ-CCCC) (8-Ru) regenerates its precursor [{Ru(dppe)Cp*}2{μ(CCHCHC)}]2+ (7-Ru). Ready oxidation of the bis(vinylidene) complex affords the cationic carbonyl [Ru(CO)(dppe)Cp*]PF6 (9) (X-ray structure). 相似文献
8.
Victorio Cadierno 《Journal of organometallic chemistry》2005,690(8):2087-2096
The novel bis(iminophosphorano)methanes CH2[P{NP(S)(OR)2}Ph2]2 (R = Ph (1a), Et (1b)) have been obtained by oxydation of dppm with the corresponding thiophosphorylated azides (RO)2P(S)N3. Deprotonation of 1a,b with KH generates the methanide species KCH[P{NP(S)(OR)2}Ph2]2 (R = Ph (2a), Et (2b)). The ruthenium(II) dimer [{Ru(η6-p-cymene)(μ-Cl)Cl}2] reacts with 2a,b to afford the cationic complexes [Ru(η6-p-cymene)(κ3-C,N,S-CH[P{NP(S)(OR)2}Ph2]2)]+ (R = Ph (3a), Et (3b)), via selective κ3-C,N,S-coordination of the bis(iminophosphorano)methanide anions to ruthenium. The structure of [Ru(η6-p-cymene)(κ3-C,N,S-CH[P{NP(S)(OEt)2}Ph2]2)][PF6] (3b) has been confirmed by single-crystal X-ray crystallography. Deprotonation of complexes 3a,b with NaH leads to the neutral carbene derivatives [Ru(η6-p-cymene)(κ2-C,N-C[P{NP(S)(OR)2}Ph2]2)] (R = Ph (4a), Et (4b)). 相似文献
9.
The new ferrole Fe2(CO)6[μ-η2,η4-(Fc)CC{C(H)C(R)S}CC(SiMe3)] [R = SiMe3 (1) and R = Fc (2)] and ruthenoles Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(H)}CC(Fc)] 3 and Ru2(CO)6[μ-η2,η4-(Me3Si)CC(SCCFc)C(H)C(Fc)] 4, have been obtained from the reactions of M3(CO)12 (M = Fe, Ru) and FcCCSCCSiMe3 through S-C bond activations and C-C coupling reactions. Thermolysis of Ru2(CO)6[μ3-η2,η4,η3-(Me3Si)CC{SC(Fc)C(SCCSiMe3}Ru(CO)3}CC(Fc)] alone and in the presence of HCCFc, yielded the compounds Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(SCCSiMe3)}CC(Fc)] 5 and Ru2(CO)6[μ-η2,η4-(Me3Si)CC{SC(Fc)C(SCCSiMe3)C(H)C(Fc)}CC(Fc)] 6, respectively. The crystal structures of the compounds 1, 3, 4 and 6 are reported. 相似文献
10.
The crystal structures of amarine (1) and isoamarine (2), important intermediates in the preparation of 1,2-diphenyl-diaminoethane, were successfully determined. Their allylation products, 1,3-diallyl amarine (1)(CH2CHCH2)2Br (3) and isoamarine bromide (2)(CH2CHCH2)2Br (4) [the crystal structures of (1)(CH2CHCH2)2PF6(3-Br + PF6) and (2)(CH2CHCH2)2PF6 (4-Br + PF6) are also successfully determined to confirm allylation products], react with CuBr to afford (1)2(CH2CHCH2)4(Cu2Br4) (5) and (2)(CH2CHCH2)2(Cu2Br3) (6), respectively. Crystal structures of 5 and 6 reveal that 5 is an anion discrete complex without olefin moiety coordination, and 6 has a 1D infinite chain with olefin moiety coordination as a bridging spacer. The fluorescent emission spectra of 5 (λemax = 570 nm) and 6 (λemax = 642 nm) were measured, and display a significant difference that can be used for solid state fluorescent sensing them. 相似文献
11.
The synthesis of the new ruthenium(II) allenylidene complex [ClRu(dppe)2CCC11H6N2][OTf] (4) (dppe = 1,2-bis(diphenylphosphino)ethane) terminated with a 4,5-diazafluorene ligand is reported. Further coordination of that metal allenylidene to ruthenium and rhenium moieties leads to the bimetallic adducts [ClRu(dppe)2CCC11H6N2{Ru(bpy)2}][B(C6F5)4]3 (5a), [ClRu(dppe)2CCC11H6N2{Ru(tBu-bpy)2}][PF6]3 (5b) and [ClRu(dppe)2CCC11H6N2{Re(CO)3Cl}][OTf] (6). Their optical and electrochemical properties show that the allenylidene moiety is an attractive molecular clip for the access to larger original redox-active homo/heteronuclear multi-component supramolecular assemblies. The X-ray crystal structure of the allenylidene metal building block is also described. 相似文献
12.
Esther Delgado Elisa Hernández Avelino Martín 《Journal of organometallic chemistry》2010,695(3):446-11252
The multifunctional ligands [(Z)-FcCCSC(H)C(H)XR] [X = O, R = Me (2a); X = O, R = Et (2b); X = S, R = Ph (3); X = S, R = C6F5 (5)] and [(Z,Z)-Fc(SR)CC(H)SC(H)C(H)SR] [R = Ph (4), C6F5 (6)] have been prepared through hydroalkoxylation and hydrothiolation processes of the alkyne groups in the compound FcCCSCCH 1. Reactions between compound 3 and the carbonyl metals Co2(CO)8, Os3(CO)10(NCMe)2 and Fe2(CO)9 have allowed the synthesis of the polynuclear compounds [(Z)-{Co2(CO)6}(μ-η2-FcCCSC(H)C(H)SPh)] 9, [(Z)-Os3(CO)9(μ-CO){μ3-η2-FcCCSC(H)C(H)(SPh)}] 10 and [(Z)-{Fe3(CO)9}[μ3,η3-(CCS)-FcCCSC(H)C(H)(SPh)] 11. All the compounds have been characterized by elemental analysis, 1H and 13C{1H} NMR spectroscopy, mass spectrometry and the crystal structure of compounds [(Z)-FcCCSC(H)C(H)OMe] 2a and [{Co2(CO)6}2(μ-η2:η2-FcCCSCCSiMe3)] 7 have been solved by X ray diffraction analysis. 相似文献
13.
Katsuhiko Takeuchi 《Journal of organometallic chemistry》2011,696(6):1156-12481
The reaction of 1,1,4,4-tetrakis[bis(trimethylsilyl)methyl]-1,4-diisopropyltetrasila-2-yne 1 with secondary or primary amines produced amino-substituted disilenes R(R2′N)SiSiHR 2a-d (R = SiiPr[CH(SiMe3)2]2, R2′NEt2N (2a), (CH2CH2)2N (2b), tBu(H)N (2c), and Ph2N (2d)). Spectroscopic and X-ray crystallographic analyses of 2 showed that 2a-c have a nearly coplanar arrangement of the SiSi double bond and the amino group, giving π-conjugation between the SiSi double bond and the lone pair on the nitrogen atom, whereas 2d has a nearly perpendicular arrangement precluding such conjugation. Theoretical calculations indicate that π-conjugation between the π-orbital of the SiSi double bond and the lone pair on the nitrogen atom is markedly influenced by the torsional angle between the SiSi double-bond plane and the amino-group plane. 相似文献
14.
Fang Liu 《Journal of organometallic chemistry》2010,695(6):809-3960
A series of heterobinuclear ferrocene-ruthenium complexes Fc(CHCH)nRuCl(CO)(PMe3)3 (n = 1, 3; n = 2, 12), Fc(CHCH)RuCl(CO)(Py)(PPh3)2 (4), and trimetallic Fc(CHCH)RuCl(CO)(PPh3)2(Py-E-(CHCH)Fc) (6) have been prepared. The length of the molecular rods is extended by successive insertion of CHCH spacers in the bridging ligands or the ancillary ligands. The respective products have been fully characterized and the structures of 3 and 12 have been established by X-ray crystallography. Electrochemical studies have revealed that ethenyl heterobimetallic complexes display two successive one-electron processes, and that intermetallic electronic communication between the two endgroups is attenuated with the increase of the length of the conjugated bridge. The electrochemical behavior of the trimetallic complex reveals strong electronic communication between ruthenium and ferrocene transmitted through the ethenyl bridge, however, it also reveals a very weak interaction between ruthenium and ferrocene transmitted through the (E)-CHCH-Py bridge. 相似文献
15.
Nicholas A. Barnes Cheryl Fish James V. Morey Robin G. Pritchard John E. Warren 《Journal of fluorine chemistry》2010,131(11):1156-1164
The coordination chemistry of the fluorovinyl substituted phosphines PPh2(Z-CFCFH) and PPh2(E-CClCFH) with K2MX4 (M = Pd, Pt; X = Cl, Br, and I) salts has been investigated resulting in the first reported palladium(II) and platinum(II) complexes of phosphines containing partially fluorinated vinyl groups. The complexes have been characterised by a combination of multinuclear [1H, 13C{1H}, 19F, 31P{1H}] NMR spectroscopy, and IR/Raman spectroscopy. The single-crystal X-ray structures of trans-[PdX2{PPh2(CFCFH)}2], X = Cl (1), Br (2), I (3), trans-[PdCl2{PPh2(CClCFH)}2] (4), cis-[PtX2{PPh2(CFCFH)}2], X = Cl (5), Br (6), trans-[PtI2{PPh2(CFCFH)}2] (7), and both cis- and trans-[PtCl2{PPh2(CClCFH)}2] (8), have been determined. Results obtained from spectroscopic and crystallographic data suggest that replacement of a β-fluorine by hydrogen, whilst reducing the steric demand of the ligand, has little effect on the electronic character of the ligand. The presence of a proton in the vinyl group results in short proton-halide secondary interactions in the solid state (d(H?X) = 2.72(3) for 1, and 2.92(5) Å for 2) forming an infinite chain ribbon motif. 相似文献
16.
Rainer Schobert Rhett Kempe Alexander Gmeiner 《Journal of organometallic chemistry》2006,691(5):859-868
The metallacyclic complexes (OC)4MC(η2-NHCH2CHCHX)Fc (4; X = H) and (5; X = CH2OH) [M = Cr: a; Mo: b; W: c; Fc = ferrocenyl = CpFe(C5H4)] were obtained in good yields upon photo-decarbonylation of the bimetallic allylaminocarbene complexes (OC)5MC(NHCH2CHCHX)Fc (2; X = H)/(3; X = CH2OH). At room temperature complexes 2/3 exist as mixtures of E- and predominantly Z-isomers with regard to the C-N bond. The molecular structures of 4b and 4c were determined by X-ray diffraction analyses. The intermetallic communicative effects and the interplay of Fc and η2-alkene moieties of 4a and 4b were assessed by cyclovoltammetry. All complexes were also characterized in solution by one- and two-dimensional NMR spectroscopy (1H, 13C, 1H NOE, 1H/1H COSY, 13C/1H HETCOR). 相似文献
17.
Luigi Busetto Rita Mazzoni Stefano Zacchini 《Journal of organometallic chemistry》2008,693(19):3191-3196
The SPh functionalized vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(SPh)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C6H4OMe, R′ = Me, 2c; R = Xyl, R′ = CH2OH, 2d; R = Me, R′ = CH2OH, 2e; Xyl = 2,6-Me2C6H3] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe2{μ-η1:η3-Cγ(R′)Cβ(H)CαN(Me)(R)}(μ-CO)(CO)(Cp)2][SO3CF3] (1a-e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(SPh)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2][SO3CF3] (2f) was obtained from the corresponding vinyliminium complex [Ru2{μ-η1:η3-Cγ(Me)Cβ(H)CαN(Me)(Xyl)}(μ-CO)(CO)(Cp)2] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe2{μ-CN(Me)(4-C6H4OMe)}(SPh)(μ-CO)(CO)(Cp)2] (3).The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies. 相似文献
18.
Erika A. Shaffer Alicia M. Beatty Hans-Jörg Schanz 《Journal of organometallic chemistry》2007,692(23):5221-5233
The reaction of (Ph3P)3RuCl2 with 1,1-diphenyl-2-propyn-1-ol was investigated in various solvents. The reaction in thf under reflux is reported to produce the (PPh3)2Cl2Ru(3-phenylindenylidene) complex (3) which has undergone rearrangement of the allenylidene C3-spine. We have improved the reliability of the reported synthesis by adding acetyl chloride which converts the formed water of the reaction and thus increases the acidity of the reaction solution. Without the additive, we observed the exclusive formation of an intermediate of the transformation and identified it as dinuclear (PPh3)2ClRu(μ-Cl)3(PPh3)2RuCCCPh2 complex (5). The reaction of (Ph3P)3−4RuCl2 with 1,1-diphenyl-2-propyn-1-ol in CH2Cl2 or C2H4Cl2 under reflux in the presence of excess conc. aqueous HCl afforded the new, neutral (PPh3)2Cl3RuC-CHCPh2 carbyne complex (7), an HCl adduct of previously elusive (PPh3)2Cl2RuCCCPh2 complex 6 in high yields. In contrast to the formation of complex 3, the reaction in a non-coordinating solvent did not afford the rearrangement of the allenylidene C3-spine. Complex 7 was converted into complex 3 in thf under reflux under loss of a molecule HCl. Complex 7 was converted with triethylamine under loss of HCl to complex 6. Pentacoordinate complex 6 was crystallized in the presence of O-donor ligands (EtOH, MeOH and H2O) to give hexacoordinate (PPh3)2Cl2(ROH)RuCCCPh2 (R = H, CH3, C2H5) complexes (9)-(11) with the O-donor coordinating in trans-position to the allenylidene moiety. The reaction of complex 7 with 2 equiv. of 4-(N,N-dimethylamino)pyridine (DMAP) gave hexacoordinate (PPh3)2Cl2(DMAP)RuCCCPh2complex (12) with one molecule DMAP also coordinating in trans-position to the allenylidene group. Methanol and acetic acid in the absence of strong bases afforded the Fischer-carbene complexes (PPh3)2Cl2RuC(OCH3)-CHCPh2 (14) and (PPh3)2Cl2RuC(OAc)-CHCPh2 (15) where the nucleophile added to the α-carbon atom. The structures of complexes 5, 7, 9-11, 14, and 15 were solved via X-ray crystallography. 相似文献
19.
The interaction of tris(trimethylsilyl) phosphite (TMSO)3P and E-trifluoromethyl-β-alkoxyenones CF3C(O)CHCHOEt and CF3C(O)CHC(OMe)Me yielded mixtures of E-1,2- and Z-1,4-adducts, CF3C(OTMS)[P(O)(OTMS)2]CCH(OAlk)R 2 and CF3(OTMS)CCHCR(OAlk)[P(O)(OTMS)2] 3 where R and Alk = H and Me, or both Me. Conversion of these 1,2-adducts to 1,4-isomers was effected by increased temperature or by exposure to more tris(trimethylsilyl) phosphite. Acid hydrolysis of 2b (R and Alk = Me) gave ketophosphonic acid CF3C(OH)[P(O)(OH)2]CH2COMe in 88% yield, whereas hydrolysis of 2a (R = H and Alk = Et) with KOH in methanol gave CF3C(OH)[P(O)(OK)2]CHCHOEt in 37% yield. Acid hydrolysis of 3a (R = H and Alk = Et) and 3b (R and Alk = Me) gave phosphonic acid CF3C(OH)2CHCHP(O)(OH)2 in 82% yield and trifluoromethylated 1,2λ5σ4-oxaphosphol-3-en. 相似文献
20.
Kotohiro Nomura Junji Yamada Wei Wang Jingyu Liu 《Journal of organometallic chemistry》2007,692(21):4675-4682
Ligand effects on the catalytic activity [and norbornene (NBE) incorporation] for both ethylene polymerization and ethylene/NBE copolymerization using half-titanocenes (titanium half-sandwich complexes) containing ketimide ligand of type Cp′TiCl2[NC(R1)R2] [Cp′ = Cp (1), C5Me5 (Cp∗, 2); R1,R2 = tBu,tBu (a), tBu,Ph (b), Ph,Ph (c)]-methylaluminoxane (MAO) catalyst systems have been investigated. CpTiCl2[NC(tBu)Ph] (1b) CpTiCl2(NCPh2) (1c), and Cp∗TiCl2(NCPh2) (2c) were prepared and identified; the structure of Cp∗TiCl2(NCPh2) (2c) was determined by X-ray crystallography. The catalytic activity for ethylene polymerization increased in the order: 1a > 1b > 1c, suggesting that an electronic nature of the ketimide ligand affects the activity. However, molecular weight distributions for resultant (co)polymers prepared by 1b,c and by 2c-MAO catalyst systems were bi- or multi-modal, suggesting that the ketimide substituent plays a key role in order for these (co)polymerizations to proceed with single catalytically-active species. CpTiCl2(NCtBu2) (1a) exhibited both remarkable catalytic activity and efficient NBE incorporation for ethylene/NBE copolymerization. 相似文献