Cyanoscorpionate ligands: agostic interactions in a series of metal complexes containing the Tris(4-cyano-3-phenylpyrazolyl)borate and Bis(4-cyano-3-phenylpyrazolyl)borate ligands

Abstract

Scorpionate chemistry has long featured sandwich complexes with two trispyrazolylborate (Tp) or two bispyrazolylborate (Bp) ligands coordinated to a transition metal. Less common are complexes in which one Tp and one Bp ligand are coordinated to the metal. We report herein five such complexes of Ni-II, Mn-II, Co-II, or Fe-II involving Tp and Bp ligands comprising either 3-phenyl-4-cyanopyrazole or 3-phenylpyrazole, as well as a related Co-II complex with two Tp ligands, one of which is coordinated in a (2) fashion. All complexes feature an agostic interaction with a B-H hydrogen atom.