Guest-Effected Spin-Crossover in a Novel Three-Dimensional Self-Penetrating Coordination Polymer with Permanent Porosity

Porous and nonporous 3D heterobimetallic coordination polymers based on the 1,4-di­(pyridin-4-yl)­benzene ligand (dpb), [Fe­(dpb)­{Ag­(CN)2}­{Ag2(CN)3}]·nSolv (1·nSolv; nSolv = DMF·EtOH, 2DMF·MeCN) and [Fe­(dpb)2{Ag­(CN)2}2] (2), have been synthesized by diffusion technique, respectively. Single-crystal X-ray analysis shows that 1·nSolv consists of a 3D self-penetrating network with in-situ-generated [Ag2(CN)3]− species and displays one of the largest volume values of porosity (299 Å3 per iron atom) after desolvation for the Hoffman-like porous SCO coordination polymers to date. In contrast, nonporous compound 2 is composed of two independent interpenetrated 3D nets with in-situ-generated [Ag­(dpb)­(CN)2]− species. Their significant distinctions of structural architectures lead to dramatically different magnetic properties: 1·nSolv displays two-step guest-effected SCO with hysteresis, whereas 2 presents characteristic paramagnetic behavior.