Structural distortions of the spin-crossover material [Co(pyterpy)2](TCNQ)2 mediated by supramolecular interactions.

Abstract

The incorporation of TCNQ˙− (7,7,8,8-tetracyanoquinodimethane) radicals as counterions for the spin-crossover material [Co(pyterpy)2](TCNQ)2·solvent (pyterpy = 4′-(4′′′-pyridyl)-2,2′:6′,2′′-terpyridine) leads to structural distortions of the [Co(pyterpy)2]2+ spin-crossover cation as compared to [Co(pyterpy)2](PF6)2. Variable temperature structural and magnetic studies indicate that the supramolecular π-stacking interactions between the terminal pyridyl groups and TCNQ radicals play a crucial role in the spin-crossover properties.