Structural, Electronic, and Magnetic Characterization of a Dinuclear Zinc Complex Containing TCNQ^- and a μ-[TCNQ-TCNQ]^2- Ligand

A dinuclear zinc complex containing both a σ-dimerized 7,7,8,8-tetracyanoquinodimethane (TCNQ) ligand ([TCNQ-TCNQ]^2-) and TCNQ^- was synthesized for the first time. This is the first instance of a single molecular complex with a bridging [TCNQ-TCNQ]^2- ligand. Each zinc center is coordinated with two 2,2′-bipyrimidines and one TCNQ^-, and the remaining coordination site is occupied by a [TCNQ-TCNQ]^2- ligand, which bridges the two zinc centers. The complex facilitates π-stacking of TCNQ^- ligands when crystallized, which gives rise to a near-IR charge-transfer transition and strong antiferromagnetic coupling.