Two- and one-step cooperative spin transitions in Hofmann-like clathrates with enhanced loading capacity.

Structural, magnetic, calorimetric and Mossbauer studies of the cooperative spin crossover naphthalene and nitrobenzene clathrates of the novel Fe-II Hofmann-like porous metal-organic framework {Fe(bpb)[Pt(CN)(4)]}-2Guest are described (bpb = bis(4-pyridyl)butadiyne).