Rhenium-(III) and -(V) hydride complexes with modified poly(pyrazolyl)borates

Abstract

The hydrides [ReH2{κ3-(OR)(µ-OR)B(pz)2}(PPh3)2] (R = Me 1 or Et 2) and [ReH4{κ3-(H)(µ-OR)B(3,5-Me2pz)2}(PPh3)] (R = Me 3 or Et 4) have been obtained by treating [ReOCl3(PPh3)2] with Na[H2B(pz)2] or Na[H2B(3,5-Me2pz)2] in alcohols (ROH, R = Me or Et) at room temperature. The same type of reaction with Na[Ph2B(pz)2], using methanol as solvent, gave [ReO(OMe){κ2-Ph2B(OMe)(pz)}2] 5, although in a very low yield. The characterization of the new compounds involved IR and 1H NMR spectroscopies, 31P-{1H} NMR, variable temperature 1H and 31P NMR studies, T1 and JH-D measurements. The crystal structures of the complexes 1, 4 and 5 were also determined. The structural parameters of the hydride ligands in 1 and 4 have not been obtained, but were tentatively assigned by X-ray diffraction associated with molecular orbital calculations of ab initio and extended Huckel type.