Disproportionation and reduction of hydrazine at a molybdenum-thiolate centre:: crystal structures of [MoH(SC6H2Pri3-2,4,6)3(NH3)(PMePh2)] and [MoH(SC6H2Pri3-2,4,6)3(NH2NHPh)(PMePh2)]

In the presence of [MoH(SC6H2Pr3i-2,4,6)(3)(PMePh2)] in tetrahydrofuran (thf), anhydrous N2H4 disproportionates to N-2 and NH3 or is reduced to NH3 by Zn-HOC6H3Pr2i-2,6 (69-81% conversion over 16 h). Reaction of [MoH(SC6H2Pr3i-2,4,6)(3)(PMePh2)] with anhydrous N2H4 in thf-MeOH at low temperature gave the complex [MoH(SC6H2Pr3i-2,4,6)(3)(NH3)(PMePh2)] which was shown by a crystal-structure determination to have a trigonal girdle of thiolate ligands with essentially apical NH3 and PMePh2 ligands [d(Mo-N), 2.298(15); d(Mo-S) (mean), 2.339(5) Angstrom]. A similar reaction using NH2NHPh instead of N2H4 gave [MoH(SC6H2Pr3i-2,4,6)(3)(NH2NHPh)(PMePh2)], which has an analogous crystal structure to [MoH(SC6H2Pr3i-2,4,6)(3)(NH3)(PMePh2)] [d(Mo-N), 2.278(5); d(Mo-S) (mean), 2.332(2); d(N-N) 1.451(7) Angstrom]. Spectroscopic data for these compounds are discussed in terms of their structures. The unstable adduct [MoH(SC6H2Pr3i-2,4,6)(3)(NH2NMe2)(PMePh2)] has been characterised spectroscopically in solution.