From Diamondoid Network to (4,4) Net: Effect of Ligand Topology on the Supramolecular Structural Diversity

While N,N‘-bis(4-pyridyl)urea affords a 5-fold interpenetrated
diamondoid network, its positional isomer N,N‘-bis(3-pyridyl)urea
gave a net-to-net hydrogen-bonded (4,4) net (square grid network)
displaying temperature-dependent anion-induced reversible single-crystal-to-single-crystal disorder−order phase transition, when the
ligands are reacted with zinc perchlorate.