Two 1D Coordination Polymers with Bis[4-(pyridin-4-yl)pyrimidinyl]disulfide (4-ppds) as Bridging Ligand

Solution assembly of heterocyclic disulfide ligand, 4-ppds {4-ppds = bis[4-(pyridin-4-yl)pyrimidinyl]disulfide}, with Cu(OAc)(2) and ZnI2 resulted in two 1D (one-dimensional) coordination polymers 1 and 2, which were well characterized by infrared spectroscopy, elemental analysis, powder X-ray diffraction, single-crystal X-ray diffraction, diffuse-reflectance UV/Vis as well as photoluminescence spectroscopy. Single crystal X-ray crystallography discloses that 1 shows an achiral zigzag chain structure built up by alternate linking of paddlewheel Cu-2(OAc)(4) dicopper unit and 4-ppds ligand with opposite configurations, whereas 2 exhibits a helical chain structure constructed by alternate linkage of tetrahedral zinc atom and 4-ppds ligand with the same chirality (P- or M-configuration). It is supposed that the flexible coordination environment around the tetrahedral Zn-II ion might be beneficial to homochiral arrangement of 4-ppds ligand.