Switchable on-off spin-crossover properties of iron(ii) compounds by trimming intermolecular hydrogen bonds.

Reversible single crystal-to-single crystal transformations from [FeL2(NCS)(2)]center dot 3MeOH (1.3MeOH, L = 2-(anthracen-10-yl)-1H-imidazo[4,5-f][1,10]phenanthroline) to 1 and 1.2H(2)O were reported, which were accompanied by on-off switching of the spin-crossover properties.