Crystal structure of triaqua-cis-bis((2-carboxybenzene)sulfonylglycinato) zinc(II), Zn(H2O)3(C9H8NO6S)2

Abstract

C18H22N2O15S2Zn, orthorhombic, Pnna (no. 52), a = 11.0915(9) A, b = 42.064(4) A, c = 5.0972(4) A, V = 2378.1 A, Z = 4, Rgt(F) = 0.030, wRref(F) = 0.088, T = 292 K. Source of material The mixture of ZnCl2 · 2H2O (1 mmol) and 3-(sulfonyl-glycine)benzoic acid (2 mmol) was stirred into 15mL aqueous solution at room temperature. Then the pH was adjusted to approximately 7 with 1 M KOH solution. And then 5 mL ethanol solution of 4,4 bipyridine (1 mmol) was added. The reaction mixture was then heated on awater bath for 6 h at 70 °C, and then filtered. Colorless crystal were obtained from themother liquor by slow evaporation at room temperature after 6 weeks. Experimental details All hydrogen atoms were first found in the difference electron densitymaps, and then placed in the calculated positions. The hydrogen atoms of carboxylate group and water molecules were found from Fourier difference maps and refined freely. The remaining H atoms were refined by riding model with Ueq(H) = 1.2Ueq(C). Discussion Crystal engineering ofmetal-organic frameworks (MOFs) is realizable by the choice of metals and the numerous choice and design of ligands, which bears the weight of prospective applications in new chemical separation, ion exchange, and gas adsorption [1-6]. In particular, carboxylate ligands have been frequently employed in the construction of microporous inorganic/organic hybrid materials for gas storage purposes. In this context, benzenedicarboxylic acid and their derivatives (such as 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid or 5-hydroxyisophtalic acid) are widely used as building blocks to link metal ions to produce interesting metal-organic framework structures and properties [7-10]. However, much fewer studies on coordination chemistry of flexible carboxylate-containing ligands have been carried out. On the other hand, the main strategies used in the field of crystal engineering are basically on the use of either conventional coordinative bonds or weak interactions. Among the non-covalent interactions, hydrogen bonding interactions play important role in designing superstructures and have attracted much interest due to their relative strength and directionality [11-12]. 3-(Sulfonyl-glycine)benzoic acid can act not only as hydrogen bond acceptors but also as hydrogen bond donors,whichmake it a wonderful candidate for the construction of supramolecular networks. The crystal structure consists of the mononuclear molecules. The coordinating 3-(sulfonyl-glycine)benzoic acid exists as a monoanion acting as a monodentate ligand. In the complex, zinc atom is five-coordinated in a distorted trigonal-bipyramidal ZnO5 environment, in which the basal coordination sites are occupied by three oxygen atoms (O1, O1A, O7), with the bond lengths of 1.968(1) A, 1.968(1) A and 2.071(3) A, respectively. The axial position is occupied by two oxygen atoms (O8, O8A) fromwater molecules, with the bond lengths of both 2.076(2) A. There exist intermolecular hydrogen bonds between carboxylate oxygen atoms fromC6H5COOgroup (O···O distances of 2.635A), forming 1D hydrogen bonded chains in which six-membered-ring and mononuclear units are alternately arranged along [100]. These chains are assembled by hydrogen bonds between carboxylate oxygen atoms from amino acid and water molecules from adjacent chains to give rise to 2D layer supramolecular structure (O···O distances of 2.835 A). At the same time, several weaker O–H···O hydrogen bonds are formed: (a) hydrogen bonding between water oxygen atoms and oxygen atoms of sulfonamide groups (O8–H2W···O5) with the bond distance of 3.211(2) A and bond angle of 117(3)°, (b) hydrogen bonding betweenwater oxygen atoms and oxygen atoms of amino acid groups (O7–H3W···O1 and O7–H3W···O2), with the bond distances of 3.117(3) A and 3.035(2)Aandbond angles of 118(3)° and 147(4)°, respectively. Z. Kristallogr. NCS 222 (2007) 435-436 / DOI 10.1524/ncrs.2007.0184 435 © by Oldenbourg Wissenschaftsverlag, Munchen