Two fluorescent coordination polymers constructed from mixed rigid and flexible carboxylate ligands: Formation of cross-linking helical and zigzag chains

摘要

Two 3D coordination polymers with different structure motifs, [Zn-2(PCPA)(2)(IN)(2)](n) (1) and [Co(PCPA)(IN)](n) (2) (PCPA = p-chlorophenoxyacetate, IN = isonicotinate), first constructed from mixed rigid and flexible carboxylate ligands, have been obtained under hydrothermal condition and characterized by elemental analyses, IR spectra, thermogravimetric analysis, fluorescent spectra and single crystal X-ray diffraction analysis. The most intriguing structural feature is that each complex exhibits both infinite helical Zn(mu(2)-carboxylate) or Co(mu(3)-carboxylates) chain units with 2(1) helices and zigzag M-2(IN)(2) (M = zinc and cobalt) chain units by reason of two different carboxylate ligands coordinating to metal centers. Additionally, compounds 1 and 2 show similar blue fluorescence in the solid state at room temperature. (C) 2006 Elsevier Inc. All rights reserved.