The synthesis and X-ray structural characterisation of the decaphenylmolybdenocenium cation as its tetrafluoroborate salt

摘要

Decaphenylmolybdenocenium tetrafluoroborate is prepared in good yield from decaphenylmolybdenocene to which it can be reduced by magnesium or sodium borohydride. Decaphenylmolydenocene undergoes two reversible one-electron processes, [Mo(C5Ph5)(2)](+/0) at -0.46 V and [Mo(C5Ph5)(2)](0/-1) at -1.92 V (both vs. [Fe(C5H5)(2)](+/0)) in dichloromethane. Decaphenylmolybdenocene is assigned an [Mo(eta(5)-C5Ph5)(2)] (rather than a [Mo(eta(5)-C5Ph5)(eta(6)-(C6H5)C5Ph4)]) conformation, isostructural with the Fe, Co and Ni analogues. Decaphenylmolybdenocenium tetrafluoroborate, [Mo(C5Ph5)(2)]BF4, has been characterised by single crystal X-ray diffraction (refined to R = 0.063, R-w = 0.059). The compound crystallises as a mixed dichloromethane/water solvate. The Mo-(ring centroid), average Mo-C and C-C (of the C-5 ring) distances are 2.0401, 2.376 and 1.432 degrees respectively. (C) 2002 Published by Elsevier Science Ltd. [References: 61]