Dimetal-Binding Scaffold 2-(Pyridin-2-yl)imidazo[1,5-b]pyridazine-7-ylidene: Synthesis of Trinuclear Heterobimetallic Complexes Involving Gold-Metal Interactions.

Abstract

As a dimetal-binding rigid scaffold, 2-(pyridin-2-yl)imidazo[1,5-b]pyridazine-7-ylidene was introduced. The scaffold was first converted into a meridional Au,N,N-tridentate ligand through binding of a Au(I)Cl moiety at the carbene center. The Au(I) center and the N,N-chelating moiety were expected to function as metallophilic and 4e-σ-donative interaction sites, respectively, in the binding of the second metal center. In this manner, various trinuclear heterobimetallic complexes were synthesized with different 3d-metal sources, such as cationic CuI, CuII, NiII, and CoII salts. SC-XRD analysis showed that the mono-3d-metal di-gold(I) trinuclear heterobimetallic complexes were constructed through gold(I)-metal interactions. Metallophilic interactions were also investigated by quantum chemical calculations including the AIM and IGMH methods.