Three mixed ligand coordination polymers: Syntheses, characterization and detailed study of the structural transformations

Abstract

Post synthetic modification of coordination polymers have been extensively studied through years, to obtain several marvelous functional materials. Apart from the usual metal or ligand exchange, irreversible structural transformation strategy may also be a useful approach to perform post synthetic modification in coordination polymers for creating functional materials. Considering this approach, three coordination polymer of Zn(II) and Co(II) namely, {[Zn(beb)(dmglut)]}n (1), {Co2(beb)2(hipt)2(H2O)1.5(MeOH)}]n (2) and {[Zn2(beb)2(fum)2]}n (3) (Whereas beb = 1-(2-(1H-benzoimidazol-1-yl)ethyl)-1H-benzoimidazole, dmglut = 3,3′-dimethylglutarate, hipt = 5-hydroxyisophthalate and fum = fumarate) have been synthesized from flexible beb ligand and three different dicarboxylates. Compound 1 and 2 are with a two dimensional structure which are adjoined by weak forces to form a supramolecular three dimensional architecture. Compound 3 has a three dimensional structure with unidirectional channels. Compound 2 and 3 have undergone irreversible structural transformation. These transformations are thoroughly monitored by PXRD analysis, UV–vis spectroscopy, and IR spectroscopy. Solid state emission spectral analyses for two Zn(II) CPs and gas sorption analyses for all the compounds has been also performed.