TRANSITION METAL SILYL COMPLEXES .54. HYDRIDO DISILANYL COMPLEXES LNM(H)SIR2SIR2H (LNM=MECP(CO)(2)MN, CP(CO)(2)RE, (CO)(3)(PPH3)FE)

摘要

Hydride disilanyl complexes of the type LnM(H)SiPh2SiPh2H are obtained from HPh2Si-SiPh2H by photochemical reaction with MeCp(CO)(3) or by ligand exchange reactions starting from MeCpMn(CO)(2)(THF), Cp(CO)(2)Re(THF) or (CO)(3)(PPh3)Fe(H) SiMe3. The dinuclear complex [MeCp(CO)(2)Mn(H) SiPh2](2) is additionally obtained in the photochemical reaction of a 2:1 mixture of MeCpMn(CO)(3) and HSiPh2SiPh2H. When HMePhSi-SiMePhH or HMe2Si-SiMe2H is used instead of HPh2Si-SiPh2H, the kind of products depends on the metal fragment. Both types of complexes are formed when HMePhSi-SiMePhH is reacted with MeCpMn(CO),(THF), but only the mononuclear complex is obtained from CpRe(CO)(2)(THF) or from (CO)(3)(PPh3)Fe(H) SiMe3. Photochemical reaction of HMe2Si-SiMe2H with MeCpMn(CO)(3) yields only the dinuclear complex. The outcome of the reaction of Cp(CO)(2)Re(THF) with HMe2Si-SiMe2H depends on the reaction temperature. At 25 degrees C only cis-Cp(CO)(2)Re(H) SiMe2SiMe2H was spectroscopically observed in low concentration. In refluxing THF, cis- and trans-Cp(CO)(2)Re(H) SiMe2SiMe2H, and [Cp(CO)(2)Re(H) SiMe2](2) are formed. Reaction of (CO)(3)(PPh3)Fe(H)SiMe3 with HMe2Si-SiMe2H gives both (CO)(3)(Ph3P)Fe(H)SiMeSiMe2H and [(CO)(3)(Ph3P)Fe(H) SiMe2](2). Photochemical reaction of Fe(CO)(4)PPh3 with HMe2Si-SiMe2H results in the formation of (CO)(2)(PPh3)(2)Fe(H)(2). The hydride-bridged complex [Cp(CO2)Re](2) (mu-H)(2) is formed as a by-product in the reactions of disilanes with CpRe(CO),(THF). Thermal or photochemical decomposition of the complexes LnM(H)SiPh2SiPh2H preferrentially proceeds by reductive elimination of the disilane. Only in the decomposition of MeCp(CO)(2)-Mn(H)SiPh2SiPh2H some H-2 is observed, which may be due to a 1,2-H-2 elimination. [References: 38]