Synthesis, Structure and Photoluminescence of One Zinc-based Metal-metallosalen Framework

Dicarboxyl-functionalized salen ligand 1,2-phenylendiamine-N,N?-bis(3-tert-butyl- 5- (carboxyl)-salicylide-ene (H_4L) was synthesized in good yield from 3-tert-butyl-5-formyl-4-hy- droxybenzoic acid and used to construct a 2D zinc complex, (ZnL)Zn3/2(BDC)1/2(DMSO)2]?3DMSO (ZnL)Zn_(3/2)(BDC)_(1/2)(DMSO)_2]·3DMSO (1, BDC = 1,4-benzenedicarboxylate), under mild reaction conditions. 1 was characterized by IR, microanalysis, TGA and single-crystal X-ray crystallography. It crystallizes in triclinic space group P_1~- with a = 11.3860(4), b = 13.2636(5), c = 17.5503(7) , α = 92.2240(10), β = 94.5070(10), γ = 96.0580(10)°, V = 2624.52(17) ~3, Z = 2, M_r = 1143.62, D_c = 1.448 g/cm3, F(000) = 1186, μ = 1.395 mm~(-1), GOOF = 0.993, the final R = 0.0380 and wR = 0.1280 for 21752 observed reflections with I > 2σ(I). The 2D coordination polymer 1 is further assembled into a 3D supramolecular network structure via π…π interactions between the aromatic rings of the ligands in adjacent layers. Thermal gravimetric analysis demonstrates that 1 is a thermally robust structure with network decomposition temperatures of 420 ℃ and it also exhibits strong photoluminescence in the visible region.