Synthesis, Structure, and Dynamic Behavior of Tungsten Dihydride Silyl Complexes Cp*(CO)2W(H)2(SiHPhR) (R = Ph, H, Cl)
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- 作者：Hiroyuki Sakaba ; Takeshi Hirata ; Chizuko Kabuto ; Kuninobu Kabuto
- 刊名：Organometallics
- 出版年：2006
- 出版时间：October 9, 2006
- 年：2006
- 卷：25
- 期：21
- 页码：5145 - 5150
- 全文大小：122K
- 年卷期：v.25,no.21(October 9, 2006)
- ISSN：1520-6041
文摘
Dihydride silyl complexes Cp*(CO)2W(H)2(SiHPhR) (R = Ph, 7; H, 8) were synthesized by treatingthe donor-stabilized silylene complexes cis-Cp*(CO)2(H)W=SiRPh·Do (R = Ph, H; Do = Py, THF)with LiAlH4 to give Li[Cp*(CO)2W(H)(SiHPhR)] (R = Ph, 5; H, 6) followed by protonation using CF3COOH. X-ray analyses of the crystals of 7 and 8 revealed that the former adopts a distorted pseudo-octahedral structure (7a), while the latter possesses a pseudo-trigonal-prismatic structure (8b). In solution,both complexes exist as equilibrium mixtures of these two structural isomers: the distorted pseudo-octahedral isomer (7a/8a) and the pseudo-trigonal-prismatic isomer (7b/8b). In addition to thisinterconversion process, two dynamic processes involving site exchanges of hydride and silyl ligands inthe pseudo-trigonal-prismatic isomer were shown for 8b by detailed NMR studies. The addition of HClto cis-Cp*(CO)2(H)W=SiHPh·THF afforded Cp*(CO)2W(H)2(SiHPhCl) (9), which also gave anequilibrium mixture of the distorted pseudo-octahedral isomer (9a) and the pseudo-trigonal-prismaticisomer (9b). The presence of an additional dynamic process, hydride site exchange in the distorted pseudo-octahedral isomer, was revealed for 9a due to its chiral silicon center.