Cyanido‐Bridged FeII–MI Dimetallic Hofmann‐Like Spin‐Crossover Coordination Polymers Based on 2,6‐Naphthyridine.

Two new 3D spin‐crossover (SCO) Hofmann‐type coordination polymers {Fe(2,6‐naphthy)[Ag(CN)2][Ag2(CN)3]} (<bold>1</bold>; 2,6‐naphthy = 2,6‐naphthyridine) and {Fe(2,6‐naphthy)[Au(CN)2]2}<bold>·</bold>0.5PhNO2 (<bold>2</bold>) were synthesized and characterized. Both derivatives are made up of infinite stacks of {Fe[Ag(CN)2]2[Ag2(CN)3]}<italic>n</italic> and {Fe[Au(CN)2]2}<italic>n</italic> layered grids connected by pillars of 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 the generation of a densely packed structure without accessible void spaces. In contrast, the smaller rhombus‐shaped window in <bold>2</bold> affords a structure made up of doubly interpenetrated 3D networks with strong aurophilic interactions between them and accessible voids partially occupied by nitrobenzene molecules. Compound <bold>1</bold> displays a relatively abrupt two‐step SCO in the temperature interval 150–215 K, whereas <bold>2</bold> features an incomplete one‐step SCO behavior (<italic>T</italic>1/2 = 166 K) that extends over 150 K. [ABSTRACT FROM AUTHOR]