Synthesis, structure, and fluorescence of the novel cadmium(II)-trimesate coordination polymers with different coordination architectures

Three novel complexes, Cd(3)tma(2).13H(2)O (1), Cd(3)tma(2).dabco.2H(2)O (2), and Cd(3)Htma(3).8H(2)O (3) (tma = trimesate), of cadmium(II)-trimesate coordination polymers are obtained from hydrothermal reaction. 1 (C18H32O25Cd3) crystallizes in the monoclinic C2/c space group [a = 18.985(2) Angstrom, b = 7.3872(6) Angstrom, c = 20.432(2) Angstrom, beta = 97.1660(10)degrees, and Z = 4]. 2 (C24H22N2O14Cd3) crystallizes in the monoclinic P2(1)/c space group [a = 10.1323(2) Angstrom, b = 19.5669(5) Angstrom, c = 13.15880(10) Angstrom, = 108.9810(10)degrees, and Z = 4]. 3 (C27H28O26Cd3) belongs to the trigonal P31 c space group [a = 15.7547(3) Angstrom, b = 15.7547(3) Angstrom, c = 7.93160(10) Angstrom, and Z = 2]. The Cd(II) centers in the three complexes are bridged by tma ligands in the coordination fashion of unidentate, bridging unidentate, bidentate, chelating bis-bidentate, chelating/bridging bis-bidentate, or chelating/bridging bidentate to form the T-shaped molecular bilayer motif for 1, chicken-wire-like motif for 2, and honeycomb-like porous structure for 3, respectively, in which the T-shaped molecular bilayer motif and chicken-wire-like motif are further interlinked in interdigitating or alternating fashion to construct the different coordination architectures. These three complexes exhibit strong fluorescent emission bands at 355 nm (lambda(ex) = 220 nm) for 1, 437 nm (lambda(ex) = 365 nm) for 2, and 353 nm (lambda(ex) = 218 nm) for 3 in the solid state at room temperature.