Further Studies on the Substitutional Behavior of 1,2-Mo<sub>2</sub>Br<sub>2</sub>(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>4</sub>. Alkyl, Amide, Phosphide, Alkoxide, and Thiolate for Bromide Exchange and Isomerizations of 1,1- and 1,2-Mo<sub>2</sub>X<sub>2</sub>(CH<sub>2</sub>SiMe<sub>3</sub>)<sub>4</sub> Compounds
作者:Malcolm H. Chisholm、Damon R. Click、John C. Huffman
DOI:10.1021/om0003584
日期:2000.9.1
presence of Me2NH2Br. The mechanisms of these metathetic reactions are discussed in terms of plausible pathways that may promote alkyl group migration across the Mo⋮Mo bond. Further studies of the bromide substitution by alkyl, aryl, alkoxide, thiolate, and phosphide ligands are described for 1,1‘-Mo2(NMe2)BrR4 and 1,2-Mo2Br2R4. The new compounds of formula Mo2(NMe2)YR4 (Y = CH2SiMe3, Ph, OtBu, OiPr,
在-50°C下于己烷中进行1,2-Mo 2 Br 2(CH 2 SiMe 3)4以及LiNMe 2和HNMe 2的反应,得到1,1'-Mo 2(NMe 2)BrR 4, R = CH 2 SiMe 3,作为在Mo 2 6+中心进行酰胺交换的Br的第一产物。与LiNMe 2反应中的进一步取代得到1,1-Mo 2(NMe 2)2 R 4,而与HNMe 2反应得到1,2-Mo 2(NMe2)形成2 R 4异构体。这两个不进行热互变(> 100°C),而是进行氨解(HNMe 2 - d 6)和醇解(t BuOH),并保留区域化学作用。Me 2 NH 2 Br的存在催化了Mo 2(NMe 2)2 R 4的1,1-到1,2-异构化。这些易位反应的机理已通过可能促进烷基迁移穿过Mo⋮Mo键的合理途径进行了讨论。关于1,1'-Mo的溴化物被烷基,芳基,醇盐,硫醇盐和磷化物配体取代的进一步研究2(NMe 2)BrR