Some bonding questions prompted by studies of the fluxional molecule triscyclopentadienylnitrosylmolybdenum

Abstract

The compound (C₅H₅)₃MoNO has been prepared. Its proton magnetic resonance spectrum in solution has been studied as a function of temperature down to –110°. The crystal structure has been determined with relatively high precision at 22°. The combined results of these studies lead to some new observations concerning the manner in which cyclopentadienyl rings may be bonded to metal atoms. Specific conclusions are (a) that a trihapto (i.e., π-allylic) form of bonding is not a real possibility, and (b) unsymmetrical relationships of ring to metal, which cannot be readily described in terms of any simple limiting structure, are possible under certain conditions.