Stabilization of interpenetrating cluster-based frameworks promoted by N–H⋯X hydrogen bonds: synthesis, structures and properties of {[Cd(NH 3 ) 4 ] 3 [Re 3 Mo 3 Se 8 (CN) 6 ]}X (X = Cl, Br and I)

International audience; Control of covalent coordination polymer structures using non-covalent interactions is a promising way for obtaining functional materials by self-assembly in solution. Here we report the crucial role of halide anions in the formation of interpenetrating frameworks based on cyanometalate clusters. It was found that the interaction of [Re3Mo3Se8(CN)(6)](5-) cluster anions and Cd2+ cations in aqueous ammonia led to the formation of the 1D polymeric compound {[Cd(NH3)(5)](2)[Cd(NH3)(4)](3)[Re3Mo3Se8(CN)(6)](2)}5H(2)O (1). Compound 1 is unstable outside the mother liquor due to the rapid loss of NH3 and H2O molecules. Addition of KX (X = Cl, Br, I) to the reaction mixture led to selective formation of 3D framework compounds {[Cd(NH3)(4)](3)[Re3Mo3Se8(CN)(6)]}X (2-4 for X = Cl, Br, I, respectively) stabilized by N-HX hydrogen bonding. Compounds 2-4 demonstrate high thermal stability as well as reversible loss of ammonia and reversible oxidation in the solid state.