η1-Vinylidene to η2-Alkyne Isomerization of Tungsten and Molybdenum Complexes
η1-Vinylidene to η2-Alkyne Isomerization of Tungsten and Molybdenum Complexes
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钨钼配合物的 η1-亚乙烯基异构化为 η2-炔烃
DOI：
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发表时间：
2003
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通讯作者：
S. Uhlig
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作者：
J. Ipaktschi;Javad Mohsseni;S. Uhlig
研究了η_1-亚乙烯基配合物[（η_5-C_5H_5）（CO）（NO）W=C= O] [5a，R = Si（CH_3）_2C（CH_3）_3; 5c，R = C（CH 3）3]以及[（η5-C5 H5）（CO）（NO）Mo=C=CHC（CH 3）3]（8）与相应的η2-1-炔配合物[（η5-C5 H5）（CO）（NO）W（η2-H-C <$C-R）] [7a，R = Si（CH3）2C（CH3）3; 7c，R = C（CH3）3]和[（η5-C5H5）（CO）（NO）Mo{η2-H-C <$C-CHC（CH3）3}]（9）的配合物。测定了5a在[D 6]苯中和8在[D8]甲苯和[D5]乙醇中异构化的活化参数。在[D8]甲苯中，η1-亚乙烯基络合物5a经历甲硅烷基从Cβ到Cα的单步1，2-移位。然而，复合物8表现出二分行为。异构化8 → 9，取决于所用的溶剂，通过两种不同的途径发生：在非极性溶剂中，8通过氢原子的1，2-迁移互变异构为9，在乙醇中，这种互变异构通过去质子化-质子化和随后的还原消除的多步骤过程进行。（© Wiley-VCH Verlag GmbH & Co. KGaA，69451魏因海姆，德国，2003）
The thermal isomerizations of η1-vinylidene complexes [(η5-C5H5)(CO)(NO)W=C=CHR] [5a, R = Si(CH3)2C(CH3)3; 5c, R = C(CH3)3] as well as [(η5-C5H5)(CO)(NO)Mo=C=CHC(CH3)3] (8), to the corresponding η2-1-alkyne complexes [(η5-C5H5)(CO)(NO)W(η2-H−C≡C−R)] [7a, R = Si(CH3)2C(CH3)3; 7c, R = C(CH3)3] and [(η5-C5H5)(CO)(NO)Mo{η2-H−C≡C−CHC(CH3)3}] (9) has been investigated. Activation parameters for the isomerization of 5a in [D6]benzene and 8 in [D8]toluene and [D5]ethanol were determined. In [D8]toluene η1-vinylidene complex 5a undergoes a single step 1,2-shift of the silyl group from Cβ to Cα. However, complex 8 shows dichotomous behavior. The isomerization 8 ⇄ 9, dependent upon the solvent applied, occurs by means of two different pathways: in a nonpolar solvent, 8 tautomerizes via the 1,2-migration of the hydrogen atom to 9 and in ethanol this tautomerization proceeds by a multi-step process via deprotonation-protonation and subsequent reductive elimination. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)