Bonding interactions between three adjacent hydrogen ligands. Preparation and spectroscopic properties of the tantalum and niobium complexes [Ta(H)3(C5H5–nRn)2](R = SiMe3, n= 1 or 2) and [Nb(H3)(C5H5–nRn)2](n= 1, R = Me or SiMe3; n= 2, R = SiMe3)

Abstract

The new title complexes of tantalum are true hydrides whereas the niobium complexes have bonding interactions among the three hydrogen atoms, as evidenced by short n.m.r. T₁ values and unusual couplings ¹J(H,H) which vary with temperature from less than 3 to about 100 Hz.