Spin Transition and Structural Transformation in a Mononuclear Cobalt(II) Complex.

A mononuclear compound, [CoII(pyterpy)2](PF6)2·2CH3OH [2; pyterpy = 4′-(4‴-pyridyl)-2,2′:6′,2″-terpyridine], shows a phase-transition-coupled, abrupt spin transition with a 9 K wide hysteresis that can transform to a spin-crossover compound, [CoII(pyterpy)2](PF6)2·2CH2Cl2·CH3OH (3).