New copper aryl phosphonates with auxiliary nitrogen ligands

Five new copper aryl phosphonates containing 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) as auxiliary ligands with the formulae Cu[(phen)(O3SC6H4PO3H)]·H2O (1), Cu(phen)(H2O)(O2CC6H4PO3H) (2), [Cu(phen)]2(HO3PC6H4PO3H)(HO3PC6H4PO3H2)2·H2O (3), Cu(bipy)(HO3PC6H4PO3H) (4) and [Cu(phen)2]2(H2O3PC6H4PO3H2)(HO3PC6H4PO3H) (5) were prepared by a hydrothermal synthesis. Three different functionalized phenylphosphonates were used as the main ligands, with sulfonic, carboxyl and phosphonic groups in the para position of the benzene ring. Four compounds contain divalent copper in a square pyramidal coordination and, in the fifth compound, univalent copper is in a tetrahedral coordination. The structure of 1 is based on corrugated layers in which the phenanthroline molecules of the neighboring layers are interdigitated allowing π–π interactions between the layers. Compound 2 is one-dimensional and composed of helical chains. Compound 3 is also one-dimensional, forming a fishbone-like string in which the benzenediphosphonate moieties serve as bridging and terminal ligands. The structure of 4 is layered with pendant bipy ligands. Compound 5 contains univalent copper, which is tetrahedrally coordinated by two molecules of phen. The benzenediphosphonate ligands are not coordinated to the copper atom but are hydrogen bonded to each other and form a two-dimensional supramolecular net.