LAUSR

Two new 3D spin crossover (SCO) Hofmann-type coordination polymers {Fe(2,6-naphthy)[Ag(CN)2][Ag2(CN)3]} (1) and {Fe(2,6-naphthy)[Au(CN)2]2}·(0,5)PhNO2 (2) (2,6-naphthy = 2,6-naphthyridine) have been synthesized and characterized. Both derivatives are made up of infinite stacks of {Fe[Ag(CN)2]2[Ag2(CN)3]}n and {Fe[Au(CN)2]2}n layered grids pillared by 2,6-Naphthy ligands coordinated to the axial positions of the FeII centers of alternate layers. The in situ generated [Ag2(CN)3]- linkers define wide rectangular windows that favor the interpenetration of three identical 3D networks, strong argentophilic interactions between them and generation of a densely packed structure without accessible void spaces. In contrast, the smaller rhombus-shaped windows' size in 2 affords a structure made up of doubly interpenetrated 3D networks with strong aurophilic interactions between them and accessible voids partially occupied by nitrobenzene molecules. 1 displays a relatively abrupt two-step SCO in the temperature interval 150-215 K whereas 2 features an incomplete one-step SCO behavior (T1/2 = 166 K) that extends over 150 K.