Syntheses, Structures, and Physical Properties of Camphorate Coordination Polymers Controlled by Semirigid Auxiliary Ligands with Variable Coordination Positions and Conformations

A series of new coordination polymers, {[Zn(1,2-bimb)(d-ca)]·2H2O}n (1), [Zn(1,3-bimb)(d-ca)]n (2), [Cd(1,3-bimb)(d-ca)]n (3), [Zn(1,4-bimb)(d-ca)]n (4), and {[Cd2(dpys)(d-ca)2(H2O)2]·H2O}n (5), (d-H2ca = d-camphoric acid, 1,2-bimb =1,2-bis(imidazol-1-ylmethyl)-benzene, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl) -benzene, 1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)-benzene, dpys = 4,4′-dipyridylsulfide), have been prepared under hydrothermal conditions and characterized by elemental analyses, IR, vibrational circular dichroism, thermogravimetric and X-ray structural analyses. Their structures and properties can be tuned by variable coordination positions and conformations of the auxiliary ligands. Complex 1 features a three-dimensional (3D) supramolecular framework with a one-dimensional (1D)-nanosized channel. Complexes 2 and 3 show acentric 1D double-stranded chains. The chiral two-dimensional sheet with (4,4) topology is found in compound 4. Compound 5 displays a 1D ladderlike chain. Photoluminescent properties of 1 and 5 are studied. Compounds 2−5 display a second-order nonlinear optical effect and ferroelectric behaviors.