Syntheses and Characterizations of Two Copper Coordination Polymers Constructed by 4,4'-Bipyridine

Two new copper coordination polymers [Cu(μ2-4,4?-bipyridine)(NO2)2]n (C10H8- N4O4Cu, Mr = 311.75) 1 and [Cu(μ2-4,4?-bipyridine)2(H2O)2]n?2n(4,4?-bipyridine)?2nClO4?nH2O (C40H38N8O11Cl2Cu, Mr = 941.22) 2 were synthesized by hydrothermal reaction and determined by X-ray diffraction method. Compound 1 crystallizes in monoclinic, space group P2/m with a = 4.7740(10), b = 11.039(2), c = 5.6752(14) ?, β = 91.394(9)o, V = 299.00(11) ?3, Z = 1, Dc = 1.731 g/cm3, F(000) = 157 and μ(MoKa) = 0.7107 mm-1. Compound 2 crystallizes in monoclinic, space group P2/n with a = 12.916(2), b = 11.149(1), c = 15.006(2) ?, β =106.642(6)o, V = 2070.3(5) ?3, Z = 2, Dc = 1.510 g/cm3, F(000) = 970 and μ(MoKa) = 0.7107 mm-1. In the structure of compound 1, the metal atom is in a slightly distorted octahedral CuO4N2 geometry surrounded by four O atoms of two NO2 ligands in the equatorial positions and two N atoms from 4,4?-bipyridine ligands in the axial sites, and the 4,4?-bipyridine ligands bridge the neighboring Cu2+ atoms to form polymeric chains in the lattice. Compound 2 has a 2D square-grid network structure. The square grids are superposed on each other to form a channel framework. The square cavity has dimensions of 11.148(2)? ×11.229(3)?. Every two guest 4,4?-bipyridine molecules are clathra- ted in each hydrophobic host cavity and further stabilized by π-π stacking and hydrogen bonding interactions.