Syntheses and Structural Characterization of a One-Dimensional Chain, Two-Dimensional Noninterpenetrated Grid, and Three-Dimensional Polycatenane Coordination Polymers Assembled from Flexible Bidentate Imidazolyl Ligands

Eight novel coordination polymers, [Mn(L)2(H2O)2]Cl2·2H2O (1, L1 = bis(N-imidazolyl)methane), [Fe(L1)2(NCS)2]
(2), [Zn(nba)2L] (3, nba = p-nitrobenzoate, L2 = 1,4-bis(N-imidazolyl)butane), [Ni(L2)(hba)2(MeOH)2]·2MeOH (4, hba =
p-hydroxybenzoate), [Cd(L2)1.5(NCS)2] (5), [Cd(L2)2(NO3)2] (6), [Cd(L2)2(tos)2] (tos = p-tolylsulfonate, 7), and [Ni(L2)3](NO3)2
(8), were obtained from self-assembly of the corresponding metal salts with the flexible ligands, and their structures were fully
characterized. X-ray diffraction analyses revealed that complexes 1 and 2 exhibit one-dimensional (1D) double-stranded chain structures
resulting from doubly bridged [Mn(L1)2(H2O)2] and [Fe(NCS)2], respectively. Complexes 3 and 4 have 1D zigzag chain structures
in which [Zn(nba)2] and [Ni(hba)2(MeOH)2] units are held together by L2 bridges, respectively. The polymeric cadmium complexes
5−7 have two-dimensional (2D) grid network structures with (4,4) topology. Complex 8 is a cationic polycatenane, and the nitrate
anions occupy the triangular channels formed by the interpenetrating networks. Complexes 2, 3, 5, and 6 are stable up to 300 °C.
Photoluminescent studies show that complexes 3 and 5−7 display intense blue emissions.