Xiaodong Li, Zhige Shi
2010
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Journal
Zeitschrift für Kristallographie - New Crystal Structures
Abstract
C30H27CuN4O6S, monoclinic, C12/c1 (no. 15), a = 14.693(3) Å, b = 18.784(4) Å, c = 21.396(5) Å, * = 90.068(3)°, V = 5905.1 Å, Z = 8, Rgt(F) = 0.047, wRref(F ) = 0.126, 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 (0.1 mmol), Cu(OAc)2.·.2H2O (0.2 mmol), KOH (0.10 mmol) and H2O (15 mL) was placed in a Teflon-lined stainless steel vessel, heated to 160 °C for 2 days, and then cooled to room temperature over 24 h. Blue blockshaped crystals of the title compound were obtained. Experimental details The carbon atoms (C18-C21) of tert-butyl groups have departed into two parts and their site occupation was set to 0.5. The restraints are needed to restrict the large Ueq of tert-butyl groups. Discussion The rational design and well-controlled construction of metalorganic frameworks (MOFs) is a very fertile research focus in recent years, mostly motivated by the potential applications as functional materials via supramolecular chemistry and crystal engineering of the constituent building blocks using the tools of the modern synthetic chemistry [1-6]. In order to build these molecular architectures, polycarboxylates are often employed as bridging ligands to construct coordination polymers owing to their versatile coordination modes and high structural stability. As for isophthalic acid, carboxyl groups in which coexisting at an angle of 120° are beneficial to the formation of low and high dimensional coordination polymers, it seems to have the potential to build novel MoFs. The crystal structure of the title compound has a 1D double chain architecture. The fundamental unit contains one Cu(II) cation, one 2,5-bis(4-pyridyl)-1,3,4-thiadiazole ligand, one hydrogen 5tert-butylisophthalate (Htbip) and half 5-tert-butylisophthalate (tbip). Each Cu(II) ion is five-coordinated by two nitrogen atoms of two 2,5-bis(4-pyridyl)-1,3,4-thiadiazole ligands and three oxygen atoms from one Htbip and one tbip, forming a distorted square-pyramidal environment (figure, top). The Cu—N bond lengths are 2.008(3) Å and 2.015(3) Å, and the Cu—O bond lengths are in the range of 1.972(2) 2.385(3) Å. The tbip (Htbip) ligands exhibit two kinds of coordination modes. In the first mode, two carboxylate groups of tbip act as bis-monodentate ligands to bridge two Cu atoms. In the second mode, one carboxylate group of Htbip act as bidentate chelating. Along [010], the Cu(II) ions are bridged by the 2,5-bis(4pyridyl)-1,3,4-thiadiazole ligands to generate a 1D chain. The 1D chains are further connected by tbip ligands to form a 1D double chain. These 1D double motifs are decorated with Htbip ligands at two sides. Hydrogen bonding between uncoordinated carboxylate oxygen atoms of Htbip and uncoordinated oxygen atoms of carboxylate group of tbip (O3–H3···O6 with the bond distances of 2.625(4) Å and bond angles of 164.6° is observed in the crystal structure. These 1D double chain are linked by this weak hydrogen bond to form a 2D supramolecular network (figure, bottom). Z. Kristallogr. NCS 225 (2010) 393-395 / DOI 10.1524/ncrs.2010.0173 393 © by Oldenbourg Wissenschaftsverlag, München