Dihydrobis(4-cyanopyrazol-1-yl)borate, [Bp4CN], a functionalized heteroscorpionate ligand with cross-linking potential.

Abstract

Dihydrobis(4-cyanopyrazol-1-yl)borate, Bp4CN, the first example of a polypyrazolylborate ligand capable of intermolecular cross-linking, was synthesized. It forms chelates as a bidentate ligand but retains additional coordinating ability through the two 4-CN groups, leading to polymeric structures in M[Bp4CN]2 complexes or in the heteroleptic Co[Bp4CN][TpCy]. These −CN cross-links are broken by DMF, and the octahedral complexes M[Bp4CN]2(DMF)2 (M = Zn, Co) were structurally characterized. No −CN coordination was found in Rh[Bp4CN](COD) or in the sterically hindered heteroleptic complex Co[Bp4CN][TpNp], which contained five-coordinate cobalt.