Sulfur and Selenium Complexes of the Hydrido-tri(3,5-dimethyl-1-pyrazolyl) borate Nitrosylmolybdenum Fragment, [Tp*Mo(NO)]. An X-Ray Crystal Structure Determination of Tp*Mo(NO)(Se5)

Abstract

The reactions of hydrido-tri(3,5-dimethyl-1-pyrazolyl)borate nitrosylmolybdenum diiodide, Tp*Mo(NO)I2 (2), with the oligochalcogenides (NH4)2S10 and (NEt4)2Se6 in THF solution lead to mononuclear cyclo-pentachalcogenido complexes, Tp*Mo(NO)(E5) (E = S (3a), Se (3b)). In the presence of either H2S or H2Se (generated by slow “in situ” hydrolysis of AI2E3 in moist THF solution) 2 is converted into binuclear chalcogenido-bridged products, Tp* 2Mo2(NO)2(μ-E)2(E = S (4a), Se (4b)) which are more conveniently obtained from 3a,b by dechalcogenation with tri(″butyl)phosphane (1:4,5). The new chalcogen complexes 3a,b and 4a,b were characterized by IR, NMR and mass spectroscopy and compared with the related chalcogen compounds derived from pentamethylcyclopentadienyl nitrosylmolybdenum diiodide, Cp*Mo(NO)l2. The molecular structure of Tp*Mo(NO)(Se5) (3b) has been determined; the complex contains a sixmembered MoSe5; metallacycle in the chair conformation and a linearly coordinated nitrosyl ligand (angle Mo-N-O 178.9(17)°).