Yazhou Xu, Wei-Ping Tang
Sep 1, 2010
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Zeitschrift für Kristallographie - New Crystal Structures
Abstract
C48H42N8O8S2Zn, monoclinic, P21/n (no. 14), a = 7.2030(9) Å, b = 17.855(2) Å, c = 37.092(4) Å, ) = 94.220(2)°, V = 4757.5 Å, Z = 4, Rgt(F) = 0.062, wRref(F ) = 0.137, T = 296 K. Source of material A mixture of 5-tert-butylisophthalic acid (H2tbip, 0.2 mmol), 2,5bis(4-pyridyl)-1,3,4-thiadiazole (bpydtz, 0.2 mmol), Zn(OAc)2 · 2H2O (0.1 mmol), KOH (0.1 mmol) and H2O (16 mL) was placed in a Teflon-lined stainless steel vessel, heated to 450 K for 3 days, and then cooled to room temperature over 24 h. Colorless blockshaped crystals of the complex were obtained. Discussion Designing the solid state compounds with molecules that encode well-defined non-covalent motifs has recently become a rapidly growing area of research due to their fascinating molecular and/or supramolecular structural diversity and potential applications for catalysis [1-4] and material sciences [5,6]. A successful strategy in building such networks is to employ appropriate bridging ligands that can bind metal ions in different modes and provide a possible way to achieve more robust polymeric structures [7,8]. In this context, benzenedicarboxylic acid and its derivatives, such as 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, 5-hydroxyisophthalic acid are widely used as building blocks to link metal ions to produce metal-organic frameworks with interesting structures and properties [9]. The interesting results inspired us to investigate its analogues 5-tert-butylisophthalic acid for the following reasons: (a) it has two carboxyl groups which may be completely or partially deprotonated, inducing rich coordination modes and allowing interesting structures with higher dimensions; (b) it can act not only as hydrogen-bond acceptor but also as hydrogen-bond donor, depending upon the numbers of deprotonated carboxyl groups. The asymmetric unit consists of one Zn(II) ion, two Htbip anions, and two bpydtz molecules. Each four-coordinated Zn(II) ion is bound by two N atoms from two bpydtz ligands and two oxygen atoms from two Htbip ligands. The Zn—O bond lengths, 1.933(3) and 1.966(3) Å, are within the range reported for Zn in tetrahedral environments. The Zn—N bond lengths, 2.072(4) and 2.110(4) Å, are also similar to those found in other tetrahedral zinc complexes of bpa. The coordination of the zinc ion is a distorted tetrahedral with angles ranging from 91.6(1)° ("O5–Zn1–N4A) to 123.8(2)° ("O1–Zn1–N1). Each bpydtz ligand adopts the bismonodentated coordination mode to connect two adjacent zinc(II) ions and form chains. Htbip ligand adopts the monodentated coordination mode. The uncoordinated bpydtz ligands engage in hydrogen bonding with Htbip anions, and connect the chains into a 2D layer. These layers are further interconnected by weak intermolecular C–H···O, C–H···N, and C–H···S hydrogen bonds to generate a 3D network. 444 Z. Kristallogr. NCS 225 (2010) 444-446 / DOI 10.1524/ncrs.2010.0195 © by Oldenbourg Wissenschaftsverlag, München Crystal: colorless block, size 0.08 × 0.11 × 0.46 mm Wavelength: Mo K* radiation (0.71073 Å) -: 6.66 cm 1 Diffractometer, scan mode: Bruker SMART CCD, #/% 2+max: 51° N(hkl)measured, N(hkl)unique: 35899, 8848 Criterion for Iobs, N(hkl)gt: Iobs > 2 ((Iobs), 5734 N(param)refined: 623 Programs: SHELXS-97, SHELXL-97, SHELXTL [10] Table 1. Data collection and handling.