A Novel Two-dimensional Lead(Ⅱ) Coordination Polymer Based on Dinuclear Lead(Ⅱ) Unit Containing(5-Chloro-quinolin-8-yloxy) Acetate

A novel two-dimensional lead(II) coordination polymer 1, C11H7Cl2NO3Pb]n, has been prepared by solvothermal reaction of new bridging ligand(5-chloro-quinolin-8-yloxy)acetic acid(HL) with PbCl2, and its structure was characterized by IR, elemental analysis, TG-DTA and single-crystal X-ray diffraction analysis. The crystal is of monoclinic system, space group P21/c with a = 16.7603(7), b = 8.6907(4), c = 8.4745(3), β = 101.1110(11)°, C11H7Cl2NO3 Pb, Mr = 479.27, V = 1211.25(9)3, Z = 4, Dc = 2.628 g/cm3, F(000) = 880, μ = 14.367 mm-1, R = 0.0173 and wR = 0.0508. The asymmetric unit contains one lead(II) cation, one(5-chloro-quinolin-8-yloxy)acetate(L) ligand and a chloride ion. The PbII center is hepta-coordinated in a distorted pentagonal bipyramidal geometry. The coordination sphere of the Pb atom is completed by two oxygen atoms and one nitrogen atom of the same L ligand, two bridging chloride ions and two bridging oxygen atoms of two adjacent L ligands. Two PbII centers are linked by the two L ligands to form a C2-symmetric dimer unit with a planar Pb2O2] ring. Each dimer unit acts as a secondary building unit(SBU) and links adjacent four dimer units by the chloride atoms and oxygen atoms of carboxylate groups of L, forming a two-dimensional array. Such two-dimensional layers are packed through intermolecular C–H···Cl hydrogen bonds into a three-dimensional supramolecular structure. When the dimer unit is viewed as a 4-connected node, 1 is simplified as a 4-nodal 2-D network with square lattices of the diagonal lengths to be 6.079(1). The fluorescence emission peak of complex 1 appears near 407 nm.