Synthesis, Structures, and Ring-Opening Polymerization Reactions of Substituted Cyclopentadienyl Complexes of Zinc
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- 作者：Dennis A. Walker ; Timothy J. Woodman ; Mark Schormann ; David L. Hughes ; and Manfred Bochmann
- 刊名：Organometallics
- 出版年：2003
- 出版时间：February 17, 2003
- 年：2003
- 卷：22
- 期：4
- 页码：797 - 803
- 全文大小：135K
- 年卷期：v.22,no.4(February 17, 2003)
- ISSN：1520-6041
文摘
The reaction of 2 equiv of the new pyrrole-substituted cyclopentadienyl ligand cyclo-C4H4NSiMe2C5H5 (2a, CppyH) with Zn[N(SiMe3)2]2 gives the bis(cyclopentadienyl)zinc complexZn(Cppy)2 (3a). The reaction of 2a and the related derivatives cyclo-2,5-Me2C4H2NSiMe2C5H5(2b, CppymeH) and 3,5-Me2C6H3CH2CMe2C5H5 (2c, CpmesH) with dibutylmagnesium givesthe corresponding magnesocenes MgCpR2 (3a-c). Prolonged heating of the appropriatecyclopentadiene with zinc dialkyls in toluene, or alternatively stirring with [XZnN(SiMe3)2]2in toluene at 40 
mages/entities/deg.gif">C for 1 h, gives the monocyclopentadienyl zinc alkyl complexes CpRZnX(6a, CpR = Cppy, X = Me; 6c, CpR = Cpmes, X = Me; 7a, CpR = Cppy, X = Et; 7c, CpR = Cpmes,X = Et), which provide spectroscopic evidence for a Zn···(hetero)arene interaction. Additionof tetramethylethylenediamine (TMEDA) gives CpRZnX(TMEDA) (8a, b, X = Me; 9a-c, X= Et). The crystal structures of 8b and 9c show mages/gifchars/eta.gif" BORDER=0 >2-bound cyclopentadienyl ligands, withone long and one short Zn-C interaction. The reaction of 7c with B(C6F5)3 in toluene proceedswith alkyl/C6F5 exchange to give CpmesZn(C6F5) (10). Treatment of 9c with B(C6F5)3 in tolueneresults in an ionic product, [CpmesZn(TMEDA)]+[EtB(C6F5)3]- (11). On the other hand, thereaction of 9a with B(C6F5)3 in toluene or dichloromethane proceeds with mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-H abstraction,with concomitant loss of ethene, as well as both ethyl and cyclopentadienyl abstraction.Both 11 and 9a/B(C6F5)3 mixtures catalyze the polymerization of cyclohexene oxide andmages/gifchars/epsilon.gif" BORDER=0 >-caprolactone.