A DIMOLYBDENUM(III) AZIDO COMPOUND - ITS DECOMPOSITION INTO AMIDO ANDNITRIDO DERIVATIVES - CRYSTAL-STRUCTURE OF [MO-3(O)(N)CP-3(SME)(4)]

The thermal reaction of [Mo2Cp2(mu-SMe)(3)(mu-Cl)] 1 with NaN3 in THF/ EtOH gives a mixture of three compounds: [Mo2Cp2(mu-SMe)(3)(mu-N-3)] 2 , [Mo2Cp2(mu-SMe)(3)(mu-NH2)] 3 and [Mo-3(O)(N)Cp-3(SMe)(4)] 4. Only t he mu-azido derivative 2 is isolated if the time of thermolysis is sho rt. Its formation in the presence of EtOH leads in turn to the product s 3 and 4. Production of 3 from 2 requires N-2 loss followed by interm olecular reduction of the bimetallic system. Complete decomposition of the complexes occurs if the time of reaction is prolonged. An X-ray d iffraction study shows that 4 contains a [Mo2Cp2(mu-SMe)(3)(mu-N)] cor e that is linked through a Mo=N double bond to a CpMo(O)(SMe) unit. Th e resulting Mo-3(mu(3)-N) fragment, in which the N=Mo double bond is s upported by two Mo-N single bonds involving the directly bonded metal atoms, is the most striking structural feature of 4. The triply-bridgi ng nitrido nitrogen atom adopts a distorted trigonal planar coordinati on. (C) 1998 Elsevier Science S.A. All rights reserved.