A dimolybdenum(III) azido compound:: its decomposition into amido and nitrido derivatives.: Crystal structure of [Mo3(O)(N)Cp3(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 the mu-azido derivative 2 is isolated if the time of thermolysis is short. Its formation in the presence of EtOH leads in turn to the products 3 and 4. Production of 3 from 2 requires N-2 loss followed by intermolecular reduction of the bimetallic system. Complete decomposition of the complexes occurs if the time of reaction is prolonged. An X-ray diffraction study shows that 4 contains a [Mo2Cp2(mu-SMe)(3)(mu-N)] core that is linked through a Mo=N double bond to a CpMo(O)(SMe) unit. The resulting Mo-3(mu(3)-N) fragment, in which the N=Mo double bond is supported by two Mo-N single bonds involving the directly bonded metal atoms, is the most striking structural feature of 4. The triply-bridging nitrido nitrogen atom adopts a distorted trigonal planar coordination. (C) 1998 Elsevier Science S.A. All rights reserved.