Novel Layered 2D and Triply Interpenetrating 3D Cobalt-Functionalized Diaza-12-crown Based Coordination Polymers: Synthesis, Structure, and Magnetic Properties
journal contributionposted on 06.03.2013, 00:00 by Conrad W. Ingram, Liang Liao, John Bacsa, Issifu Harruna, Daniel Sabo, Z. John Zhang
Two novel coordination polymers with formulas CoL1·3H2O [1, L1 = 3,3′-((1,7-dioxa-4,10-diazacyclododecane-4,10-diyl)bis(methylene) dibenzenecarboxylate] and Co2L2(H2O)2·2(H2O) [2, L2 = 5,5′-((1,7-dioxa-4,10-diazacyclododecane-4,10-diyl)bis(methylene)) diisophthalate] were synthesized, where one Co(II) ion coordinates the crown-4 moiety of the ligand. Compound 1 crystallizes in the space group C2 as an infinite two-dimensional chiral layered coordination network with a tetragonal 44 sql net topology. The structural unit consists of the coordinated Co(II) ion and the deprotonated ligand. The Co(II) ion is 6-coordinate with two nitrogen atoms and two oxygen atoms of the crown 1,7-diaza-12-crown-4, and two carboxylate oxygen atoms from neighboring ligands, and exhibits a highly distorted octahedral geometry. Compound 2 crystallizes in the monoclinic space group P21/n as a triply interpenetrating 3D network with the uncommon sqc528/dmd system, the first coordination polymer with a 3-fold interpenetrating dmd topology. It exhibits two distinct Co(II) ions. One is in the center of the crown-4 along with two cis-coordinated water molecules in a highly distorted octahedral geometry; the other is 4-coordinate with tetrahedral geometry and a node in the framework. Weak antiferromagnetic interactions exist between the cobalt centers in both compounds.