Larger pores and higher Tc: {[Ni(cyclam)]3[W(CN)8]2·solv}n – a new member of the largest family of pseudo-polymorphic isomers among octacyanometallate-based assemblies

Abstract

A new crystalline pseudo-polymorphic form of the 2D microporous honeycomb-like magnetic network {[Ni(cyclam)]₃[W(CN)₈]₂·solv}_n was obtained from the reaction between methanol-soluble {Ni[Ni(MeOH)₃]₈[W(CN)₈]₆} clusters and the [Ni(cyclam)]²⁺ complex in an acetonitrile-rich solvent mixture. In comparison to the three earlier characterised pseudo-polymorphs, which all crystallised in the triclinic space group P, the new form shows higher symmetry of C2/m, greater porosity of ca. 40% solvent accessible volume, and the highest magnetic ordering temperature of 12 K. It undergoes an irreversible single-crystal-to-single-crystal transformation to the hexadecahydrate form that is stable in air at ambient temperature. A new synthetic pathway leading directly to methanol solvate of the same network, which was previously obtained by sorption of MeOH into the anhydrous form, is also reported.