Assembly of Polyoxometalate-Based Metal–Organic Frameworks with Silver(I)-Schiff Base Coordination Polymeric Chains as Building Blocks

Abstract

Six crystalline polyoxometalate-based three-dimensional (3D) metal–organic frameworks {[AgL4(DMF)][AgL4]2(PMo12O40)·DMF·3H2O}n (1), {[AgL4]3(PW12O40)·6H2O}n (2), {[AgL5]3(PMo12O40)·(CH3CN)3}n (3), {[AgL5(PW12O40)][AgL5(H2O)0.25(MeOH)0.25)][AgL5]0.5·DMF·(H2O)1.5}n (4), {[AgL6]3(PMo12O40)·DMF·H2O}n (5), and {[AgL7]3(PMo12O40)·DMF·(CH3CN)3}n (6) have been successfully synthesized based on one-dimensional (1D) coordination polymers constructed by the coordination of polydentate Schiff-base ligands and silver cations and saturated α-Keggin polyoxoanion [PM12O40]3– (M = W, Mo) as building blocks, where L4, L5, L6, and L7 are 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene, 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene, 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene, and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene, respectively. Compounds 1–6 are structurally characterized by elemental analyses, IR spectroscopy, thermogravimetric analyses (TG), powder X-ray diffraction (XRD), and complete single-crystal X-ray diffraction ana...