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)}{Ag-2(CN)(3)}]center dot nSolv (1 center dot nSolv; nSolv = DMF center dot EtOH, 2DMF center dot 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 center dot 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 angstrom(3) 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 center dot nSolv displays two-step guest-effected SCO with hysteresis, whereas 2 presents characteristic paramagnetic behavior.