Microwave-Assisted Construction of Ferromagnetic Coordination Polymers of [W^V(CN)₈]^3- with Cu^II-pyrazole Synthons

The microwave-mediated self-assembly of [WV(CN)8]3- with CuII in the presence of pyrazole ligand resulted in the formation of three novel assemblies: CuII2(Hpyr)5(H2O)[WV(CN)8](NO3)·H2O (1), {CuII5(Hpyr)18[WV(CN)8]4}·[CuII(Hpyr)4(H2O)2]·9H2O (2), and CuII4(Hpyr)10(H2O)[WV(CN)8]2(HCOO)2·4.5H2O (3) (Hpyr =1H-pyrazole). Single-crystal X-ray structure of 1 consists of cyanido-bridged 1-D chains of vertex-sharing squares topology. The structure of 2 reveals 2-D hybrid inorganic layer topology with large coordination spaces occupied by {Cu(Hpyr)2(H2O)4}2+ ions. Compound 3 contains two types of cyanido-bridged 1-D chains of vertex-sharing squares linked together by formate ions in two directions forming hybrid inorganic–organic 3-D framework (I1O2). The magnetic measurements for 1–3 reveal a weak ferromagnetic coupling through CuII–NC–WV bridges.