| Abstrakt: |
Three new ligand-pillared hybrid solids, AgCu(pzc)MOF ( I, M = Mo, x = 2; II, M = W, x = 2; III, M = Nb, x = 1) (pzc = pyrazine-2-carboxylate) were synthesized via hydrothermal reactions at 150 °C, and their structures were determined by single-crystal X-ray diffraction ( P2/ n (No. 14), Z = 2; a = 7.2302(1), 7.2124(2), 7.2715(2) Å; b = 7.9460(1), 7.9270(2), 7.98436(3) Å; c = 13.9173(2), 13.8959(4), 13.8226(5) Å, for I, II, and III, respectively). All three are isostructural and contain unusual trimetallic (AgCuMOF) layers that consist of [AgOF] and [CuMOF] chains that alternate within the layers. Each structure also contains [MOF] octahedra with fully disordered O/F positions and with an inversion center on the M sites, i.e., Mo, W and Nb. Magnetic susceptibility measurements can be fitted to the Curie-Weiss law with a Curie constant consistent with a single non-interacting Cu(II) (S = ½) site per formula unit. Thermogravimetric analyses indicate that these hybrid compounds are stable up to ~280 °C, with each exhibiting a single weight-loss step beginning at ~300 °C that corresponds to the loss of all pyrazine-2-carboxylate ligands and additional O/F atoms via oxidation of the ligand during its removal. UV-Vis diffuse reflectance measurements show that each exhibits an optical bandgap size of ~2.8 eV, and which electronic-structure calculations show arise from excitations between the Cu(II)-based valence orbitals and the M-based conduction band orbitals. Graphical Abstract: Three new ligand-pillared hybrid solids, AgCu(pzc)MOF (M = Mo, W, Nb) were synthesized and contain unusual trimetallic (AgCuMOF) layers. Each exhibits an optical bandgap size of ~2.8 eV, and which electronic-structure calculations show arise from excitations between the Cu(II)-based valence orbitals and the M-based conduction band orbitals.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR] |
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