Hydrothermal Syntheses, Crystal Structures and Photoluminescent Properties of Three Metal-Cluster Based Coordination Polymers Containing Mixed Organic Ligands

摘要

Three novel metal-cluster based coordination polymers (MCCPs) with formulae [Zn_4(μ_3-OH)_2(H_2O)_2(sip)2(4,4'-bpy)_2]·3H_2O (MCCP-4), [Cd_4(μ_3-OH)_2(H_2O)_2(sip)_2(4,4-bpy)_4]·H_2O (MCCP-5) and [Cd_6(μ_3-OH)_4(μ_2-OH_2)_2(OH_2)_2 (nip)_4(4,4'-bpy)_3]·3H_2O (MCCP-6) [H_2sip = 5-sulfoisophthalic acid, H_2nip = 5-nitroisophthalic acid and 4,4-bpy = 4,4-bipyridyl] were hydrothermally synthesized and characterized by single-crystal X-ray diffraction studies. MCCP-4 crystallizes in the triclinic space group P with a = 10.106(2), b = 10.851(2), c = 11.125(2) A, α = 105.66(3), β = 112.63(3), γ= 98.18(3)°, V = 1041.8(4) A~3, and Z = 2. MCCP-5 crystallizes in the monoclinic space group C2/c with a = 25.602(1), b = 16.571(1), c = 13.322(1) A, β = 92.524(1)°, V = 5646.4(2) A~3, and Z = 4. MCCP-4 and -5 consist of similar [M_4(μ_3-OH)_2]~(6+) tetranuclear building units that are joined through sip and 4,4'-bpy ligands to generate a two-dimensional structure (MCCP-4) and a three-dimensional structure (MCCP-5), respectively. MCCP-6 crystallizes in the triclinic space group P with a = 14.295(2), b = 14.472(2), c = 20.204(3) A, α= 73.362(3), β= 82.200(3), γ= 62.769(2)°, V = 3560.9(10) A~3, and Z = 2. MCCP-6 contains unprecedented [Cd_6(μ3-OH)4(μ2-OH_2)_2]~(8+) hexanuclear building units which are linked through nip and 4,4-bpy ligands to afford a two-dimensional structure. The infrared spectroscopy, thermal stability and photoluminescence of the three complexes were studied.