Syntheses, structures and magnetic properties of four coordination polymers based on nitrobenzene dicarboxylate and various N-donor coligands

Abstract

Four new coordination polymers {[Ni(4-Nbdc)(bpa)(H2O)]}n (1), {[Co(4-Nbdc)(bpp) (H2O)]}n (2), {[Ni(4-Nbdc)(bpp)(H2O)]·H2O}n (3), and {[Mn2(3-Nbdc)2(bib)3]·2H2O}n (4) (4-Nbdc=4-nitrobenzene-1,2-dicarboxylate, 3-Nbdc=3-nitrobenzene-1,2-dicarboxylate, bpa=1,2-bi(4-pyridyl)ethane, bpp=1,3-bis(4-pyridyl)propane, and bib=1,4-bis(1-imidazoly)benzene), were synthesized by hydrothermal reactions, and characterized by single-crystal X-ray diffractions, elemental analysis, FT-IR, PXRD, TGA and magnetic analysis. Complexes 1 and 2 display quasi-trapezoidal chain and brick-wall layer, and both of them contain metal–carboxylate binuclear units. Complexes 3 and 4 exhibit three-dimensional frameworks with the (66) dia topology and (44.610.8)(44.62) fsc topology, and both of them contain metal–carboxylate chains. The carboxyl groups with syn-anti coordination mode mediate effectively the weak ferromagnetic coupling interaction within Ni(II)–carboxylate binuclear in 1 (J=1.27cm−1) and Ni(II)–carboxylate chain in 3 (J=1.44cm−1), respectively, and the carboxyl groups with anti-anti coordination mode leads to the classic antiferromagnetic coupling interaction within Mn(II)–carboxylate chain in 4 (J=−0.77cm−1).