Tantalum(iv) pyrazolate: new wine in the old wineskin

Abstract

Reaction of Ta(NMe₂)₅ with 5 equivalents of pyrazole (Hpz) in toluene unexpectedly resulted in metal reduction from Ta(V) to Ta(IV) and formation of homoleptic binuclear pyrazolate [Ta₂(pz)₈] (1). Despite an elongated Ta–Ta distance (3.1895(7) Å), density functional theory calculations support the presence of metal–metal bonding in 1.