Synthesis, Structure, and Fluorescence of the Novel Cadmium(II)−Trimesate Coordination Polymers with Different Coordination Architectures

Three novel complexes, Cd3tma2·13H2O (1), Cd3tma2·dabco·2H2O (2), and Cd3Htma3·8H2O (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) Å, b = 7.3872(6) Å, c = 20.432(2) Å, β = 97.1660(10)°, and
Z = 4]. 2 (C24H22N2O14Cd3) crystallizes in the monoclinic P2(1)/c space group [a = 10.1323(2) Å, b = 19.5669(5)
Å, c = 13.15880(10) Å, β = 108.9810(10)°, and Z = 4]. 3 (C27H28O26Cd3) belongs to the trigonal P31c space
group [a = 15.7547(3) Å, b = 15.7547(3) Å, c = 7.93160(10) Å, 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 (λex = 220 nm) for 1, 437 nm (λex = 365 nm) for 2, and 353 nm (λex = 218 nm) for 3 in the
solid state at room temperature.