Gold(I) heteroatom-substituted imido complexes.: Amino nitrene loss from [(LAu)3(μ-NNR2)]+

The heteroatom-substituted imido complexes [(LAu)(3)(mu-NX)](+) (X = NR2, R = Ph, Me, Bz; X = OH, Cl; L = a phosphine) have been prepared from the reactions of NH2X with [(LAu)(3)(mu-O)](+). Thermally unstable [(LAu)(3)-(mu-NNMe2)](+) (L = P(p-XC6H4)(3), X = H, F, Me, Cl, MeO) decompose to the gold cluster [LAu](6)(2+) and tetramethyltetrazene Me2NN=NNMe2. The decomposition is first-order overall with a rate constant that increases with increasing pK(a) of the phosphine ligand. Activation parameters for the decomposition are Delta H-not equal = 99(4) kJ/ mel and Delta S-not equal = 18.5(5) J/K.mol for L = PPh3 and Delta H-not equal = 78(3) kJ/mol and Delta S-not equal = -47(2) J/K mol for L = P(p-MeOC6H4)(3). The decomposition of analogous [(LAU)(3)(mu-NNBz(2))](+) produces bibenzyl, indicative of the release of free amino nitrene Bz(2)NN.