Structures and third-order nonlinear optical properties of two cobalt(II) coordination polymers constructed from bis(imidazol-l-yl-methyl) benzene and aromatic dicarboxylic ligands

Two new cobalt(II) coordination polymers, {[Co(OBA)(1,3-bib)](2)}n H2O (1) and [Co(OBA) (1,2-bib)](n) H2O (2), (H(2)OBA = 4,4'-oxydibenzoic acid; 1, 3-bib = 1,3-bis(imidazol-1-yl-methyl)benzene; 1, 2-bib = 1,2bis(imidazol-1-yl-methyl)benzene), have been obtained by the hydrothermal reactions. Compound 1 displays a two-dimensional grid net. Compound 2 exhibits a three-dimensional porous network with 12.5% porosity. Their third-order nonlinear optical (NLO) properties were determined by Z-scan technique in DMSO solution. Two compounds show strong third-order nonlinear optical absorption and self-focusing effects with absorptive coefficients 13(MKS) 8.29 x 10(-11) m.W-1 for 1 and 6.89 x 10(-11) m.W-1 for 2, and the refractive indexes y(MKS) 437 x 10(-18) m(2) W 1 for 1 and 5.22 x 10(-18) m(2) W-1 for 2. The third-order NLO susceptibility x13) are calculated to be 1.86 x 10(-11) for I, 1.58 x 10(-11) esu for 2. These values are larger than those of C-60, phtbalocyanine derivatives and semiconductor materials. (C) 2014 Elsevier B.V. All rights reserved.