Novel Layered 2D and Triply Interpenetrating 3D Cobalt-Functionalized Diaza-12-crown Based Coordination Polymers: Synthesis, Structure, and Magnetic Properties

Two novel coordination polymers with formulas Co<b>L1</b>·3H₂O [<b>1</b>, <b>L1</b> = 3,3′-((1,7-dioxa-4,10-diazacyclododecane-4,10-diyl)­bis­(methylene) dibenzenecarboxylate] and Co₂<b>L2</b>(H₂O)₂·2­(H₂O) [<b>2</b>, <b>L2</b> = 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 <b>1</b> crystallizes in the space group <i>C</i>2 as an infinite two-dimensional chiral layered coordination network with a tetragonal 4⁴ <b>sql</b> 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 <b>2</b> crystallizes in the monoclinic space group <i>P</i>2₁/<i>n</i> as a triply interpenetrating 3D network with the uncommon <b>sqc</b>528/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 <i>cis</i>-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.