A dimolybdenum(III) azido compound Its decomposition into amido and nitrido derivatives. Crystal structure of [Mo3(O)(N)Cp3(SMe)4]

International audienceThe thermal reaction of [Mo2Cp2(μ-SMe)3(μ-Cl)] 1 with NaN3 in THF/EtOH gives a mixture of three compounds [Mo2Cp2(μ-SMe)3(μ-N3)] 2, [Mo2Cp2(μ-SMe)3(μ-NH2)] 3 and [Mo3(O)(N)Cp3(SMe)4] 4. Only the μ-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 N2 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(μ-SMe)3(μ-N)] core that is linked through a Mo=N double bond to a CpMo(O)(SMe) unit. The resulting Mo3(μ3-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