Synthesis and structure of diphenylphosphine derivatives of molybdenocene

The phosphino molybdenocene complex [Cp2Mo(PPh2H)(2)][BF4](2) (1) (Cp = eta(5)-C5H5) was prepared by reaction of Cp2MoI2 with PPh2 and excess of TlBF4 in NCMe. The monocation [Cp2MoI(PPh2H)](+) (2) as the BF4- or I- salt was synthesised by treatment of Cp2MoI(SPh) with HBF4 followed by addition of PPh2H, or by reaction of Cp2MoI2 with PPh2H, respectively. The indenyl phosphine complex [IndMo(CO)(2)(PPh2H)(2)]BF4 (3) (Ind = eta(5)-C9H7) was prepared by reaction of IndMo(CO)(2)(eta(3)-C3H5) with HBF4 followed by addition of PPh2H. Deprotonation of 1 with dabco led to the formation of the phosphinophosphido molybdenocene [Cp2Mo(PPh2)(PPh2H)][BF4] (4). Treatment of I with two equivalents of LiBu in thf at -30 degreesC formed a thermally unstable complex (5) which could not be isolated. P-31 NMR and protonation to reform 1 support its formulation as CpMo(PPh2)(2). The molecular structures of [Cp2Mo(PPh2H)(2)][BF4](2) and [Cp2MoI(PPh2H)](+) have been determined by single-crystal X-ray diffraction. (C) 2004 Elsevier Ltd. All rights reserved.