New Structural Topologies in a Series of 3d Metal Complexes with Isomeric Phenylenediacetates and 1,3,5-Tris(1-imidazolyl)benzene Ligand: Syntheses, Structures, and Magnetic and Luminescence Properties

In this article we present the syntheses, characterizations, magnetic and luminescence properties of five 3d-metal complexes, [Co­(tib)­(1,2-phda)]n­·(H2O)n (1), [Co3(tib)2­(1,3-phda)3­(H2O)]n­·(H2O)2n (2), [Co5(tib)3­(1,4-phda)5­(H2O)3]n­·(H2O)7n (3), [Zn3(tib)2­(1,3-phda)3]n­·(H2O)4n (4), and [Mn­(tib)2­(H2O)2]n­·(1,4-phdaH)2n­·(H2O)4n (5), obtained from the use of isomeric phenylenediacetates (phda) and the neutral 1,3,5-tris­(1-imidazolyl)­benzene (tib) ligand. Single crystal X-ray structures showed that 1 constitutes 3,5-connected 2-nodal nets with a double-layered two-dimensional (2D) structure, while 2 forms an interpenetrated 2D network (3,4-connected 3-nodal net). Complex 3 has a complicated three-dimensional structure with 10-nodal 3,4,5-connected nets. Complex 4, although it resembles 2 in stoichiometry and basic building structures, forms a very different overall 2D assembly. In complex 5 the dicarboxylic acid, upon losing only one of the acidic protons, does not take part in coordination; instead it forms a complicated hydrogen bonding network with water molecules. Magnetic susceptibility measurements over a wide range of temperatures revealed that the metal ions exchange very poorly through the tib ligand, but for the Co­(II) complexes the effects of nonquenched orbital contributions are prominent. The 3d10 metal complex 4 showed strong luminescence with λmax = 415 nm (for λex = 360 nm).