Topologically novel copper molybdate phases based on 3,4'-dipyridylketone: Hydrothermal synthesis, structural characterization, and magnetic properties

摘要

Hydrothermal treatment of CuCl2-2H(2)O, MoO3, and 3,4'-dipyridylketone (3,4'-dpk) in 1: 1:2 mole ratio afforded the new mixed metal oxide phases [Cu-2(MoO4)(2)(3,4'-dpk)(H2O)] (1) or [Cu-4(3,4'-dpk)(4)(Mo8O26)] (2), depending on the pH of the initial reaction mixture. Compound 1 possesses unique one-dimensional (1-D) [Cu-2(MoO4)(2)(H2O)](n) ribbons constructed from the linkage of {(Cu4O6)-O-II} tetrameric units through isolated [MoO4](2-) tetrahedra. These ribbons in turn are connected into a two-dimensional (2-D) coordination polymer structure by tethering 3,4'-dpk ligands. Compound 2, containing monovalent copper ions, manifests an unprecedented "X-rail" 1-D extended structure with (6(2)8)(4)(6(6)) topology formed from the bracketing of discrete [beta-Mo8O26](4-) anions by four [Cu-I(3,4'-dpk)](n)(n+),," chains. The variable temperature magnetic susceptibility behavior of 1 was fit to a linear tetramer model, with g = 2.03(3), J(1) = 25.8(7)cm(-1) and J(2) = -46(1) cm(-1). Antiferromagnetic inter-tetramer interactions (zJ' = -0.21(3) cm(-1)) were also evident. Crystallographic data: 1 monoclinic, P2(1)/c, a = 10.3911(11) angstrom, b = 6.9502(6) angstrom, c = 22.958(2)angstrom, beta = 100.658(7)degrees, V = 1629.5(3) angstrom(3), R-1 = 0. 1256, and wR(2) = 0.2038; 2 triclinic, P (1) over tilde, a = 10.9000(3) angstrom, b = 11.7912(4) angstrom, c = 13.5584(4) angstrom, alpha = 102.482(2)degrees, beta = 102.482(2)degrees, gamma = 117.481(2)degrees, V = 1450.98(8) angstrom(3), R-1 = 0.0428, and wR(2) = 0.0630. (C) 2008 Elsevier Inc. All rights reserved.