Novel copper materials based on the self-assembly of organophosphonic acids and bidentate amines

The hydrothermal synthesis and crystal structure of seven new supramolecular, heterocyclic adducts of copper organophosphonates are presented. Compounds 1 - 4, [CuX(D)(2)][C6H5P(O)(OH)(2)] [C6H5P(O)(2)(OH)], where D = 1,10-phenanthroline (phen) and X = Cl (1), Br (2), I (3), and NCS (4), are ionic in nature and possess a monoclinic structure, with the copper(II)-halide bond lying along a two-fold crystallographic axis. The crystals exhibit an alternating, lamellar structure in which 1-D 'ribbons' of [CuX(phen)(2)](+) cations are interleaved with 2-D 'sheets' of anionic [C6H5P(O)(OH)(2)][C6H5P(O)(2)(OH)](-) dimers. The ribbons are associated through pi-pi bonding of the heterocyclic rings, and the acid sheets through a combination of p - p bonding of the aromatic rings, and hydrogen-bonding between the P=O and P-OH of neighbouring acid dimers. Analogous derivatives have also been prepared by the reaction of [Cu(phen)(2)] Br with benzylphosphonic acid ( 5), [Cu(2,2'-bipy)(2)] I with phenylphosphonic acid ( 6) and [ Cu( phen) 2] I with phenylsulfonic acid ( 7). These complexes did not produce crystals suitable for single-crystal analysis. However, compounds (5) and (7) are thought to have similar structures to 1 - 4, whilst compound ( 6) has a different ( 2 : 2 : 3) ratio of copper : phosphonate : amine. Thus the supramolecular structure is robust for phenyl- and benzyl-phosphonic acids, with Cl, Br, I and NCS copper( II) phen complexes, and slightly varied by the presence of phenylsulfonic acid, but is not observed in the presence of 2,2'-bipy.