A rare polyniobotungstate-based framework and its structural transformation in a single-crystal-to-single-crystal process induced by iodide ions.

The first transition-metal-bridged polyniobotungstate-based 3D framework has been hydrothermally synthesized, which is constructed from bi-[CuII(en)2(H2O)]-decorating [Nb3W3O19]5− polyoxoanions linked together by CuI ions. Interestingly, the 3D polyniobotungstate framework can undergo a solid–liquid reaction with KI solution to generate a 1D copper halide of [Cu(en)2][CuI2]2 in a single-crystal-to-single-crystal process. [ABSTRACT FROM AUTHOR]