Crystal structure of a Zn complex with terephthalate and 1,6-bis(1,2,4-triazol-1-yl)hexane

Abstract

A new zinc coordination polymer with rigid benzene-1,4-dicarboxylate (bdc) and flexible 1,6-bis(1,2,4-triazol-1-yl)hexane (btrh), namely poly [[( 2 -benzene-1,4-dicarboxylato)[ 2 -1,6-bis(1,2,4-triazol-1-yl)hexane]zinc] dimethylformamide monosolvate], [Zn(C 8 H 4 O 4 )(C 10 H 16 N 6 )]ÁC 3 H 7 NO, was synthesized. According to the single-crystal XRD analysis, the product crystallizes in the P1 space group and has a layered structure. Analysis of the layered structure reveals {Zn(bdc)} chains which are connected by pairs of btrh ligands. The layers are packed tightly perpendicular to the [122] direction, separated by one nondisordered dimethylformamide solvent molecule per formula unit. According to thermogravimetric analysis, the product completely loses this solvent at 453 K; the desolvated compound is stable up to 503 K. As a result of the lack of hydrogen-donor groups, hydrogen bonds are not observed in the structure of the complex; however, an intermolecular C-HÁ Á Á contact of 3.07 Å occurs. Chemical contextCoordination polymers with flexible bitopic ligands have attracted great interest as prospective materials for gas separation, sensing materials, electrochemical devices or catalysis (Pettinari et al., 2016). One of the favoured classes of bitopic ligands are bis(azol-1-yl) alkanes, which have been used for the preparation of various transition metals coordination polymers with different topologies (Alkorta et al., 2017;Pellei et al., 2017;Manzano et al., 2016;Liu et al., 2012). Bitopic bis(azol-1-yl)alkanes have two separated metalbinding sites that allow them to form a wide variety of polymeric structures. Thus, coordination compounds based on these ligands could be applied in the design of various functional materials with a wide range of potential applications. Recently, we have synthesized three new Zn coordination polymers based on bis(triazol-1-yl)propane and terephtalate anions (Semitut et al., 2017). By varying the conditions, it was possible to synthesize three different polymeric compounds, which have interesting luminescent properties. As part of our studies with the aim of preparing new coordination polymers with flexible bis(triazol-1-yl)alkane ligands, we report herein the synthesis and crystal structure of [Zn(bdc)(btrh)]ÁDMF (bdc = benzene-1,4-dicarboxylate, btrh = 1,6-bis(1,2,4-triazol-1-yl)hexane, DMF = dimethylformamide).