Reactivity of molybdenum complexes containing both NHNPhR and NNPhR ligands (R = Ph, Me) toward hydridotris(pyrazolyl)borate, Tp and hydridotris(3,5-dimethylpyrazolyl0borate, Tp *, ligands. X-ray crystal structure of [TpMo(NNMePh) 2Cl

Abstract

Molybdenum complexes containing mixed disubstituted organohydrazido(1−) and organohydrazido(2−) ligands, [Mo(NHNPhR)(NNPhR)(acac)Cl 2], R = Ph ( I), R = Me ( II), react in acetonitrile with sodium hydridotris(pyrazolyl)borate, NaTp, or in toluene with potassium hydridotris (3,5-dimethylpyrazolyl) borate, KTp *, to afford the neutral six-coordinated species formulated as [TpMo(NNPhR) 2Cl], R = Ph ( III), R = Me ( IV) and [Tp*Mo(NNPhR) 2Cl], R = Ph ( V), R = Me ( VI). These compounds have been characterized by elemental analysis, by IR, UV-visible, 1H and 13C NMR spectroscopy, and by mass spectrometry. The electrochemical behavior of complexes III–VI has also been studied by cyclic voltammetry. The X-ray crystal structure of IV has been determined. Crystals are parallelepiped, space group Pbnm, with a = 7.468(2), b = 18.483(3), c = 19.052(3) Å, α = β = γ = 90° and Z = 4. The structure was solved and refined by full-matrix, least-squares methods to R and R w, values of 0.038 and 0.049, respectively. The complex displays a distorted octahedral geometry with symmetrical organohydrazido(2−) ligands adopting the nearly linear mode (Mo-N-N = 169.4(3)°). This linearity and the short bond distances (Mo-N = 1.771(4), N-N = 1.308(5) Å) indicate an extensive π-electronic delocalization throughout the Mo-N-N fragment.