Crystal structure of catena-poly[bis(glycol-1 k2O,O')-(μ2- tetrafluoroterephthalato)zinc(II)], Zn(C8F4O4)(C2H6O2)2

C12H12F4O8Zn, triclinic, P1 (no. 2), a = 5.1044(7) Å, b = 8.808(1) Å, c = 9.384(1) Å, + = 116.500(1)°, * = 95.646(2)°, & = 93.160(2)°, V = 373.4 Å, Z = 1, Rgt(F) = 0.024, wRref(F) = 0.066, T = 296 K. Source of material By placing a CH3OH solution (10 ml) of tetrafluoroterephthalic acid (tfbdc, 23.8 mg, 0.1 mmol) at the bottom of a straight glass tube and then carefully added a buffer of glycol (10 ml), above which a CH3OH solution (10 ml) containing ZnCl2 (13.6 mg, 0.1.mmol) was placed in this tube. The resulting slow diffusion of solvents across the boundary layer results in excellent colorless block-shaped crystals growing there over a period of two weeks. Experimental details H atoms bound to methylene carbon atoms were assigned to calculated positions with d(C—H) = 0.97 Å and refined using a riding model, with Uiso(H) = 1.2 Ueq(C). Hydroxyl H atoms were positioned geometrically with d(O—H) = 0.84 Å and Uiso(H) = 1.5 Ueq(O). Discussion The design and synthesis of metal-organic frameworks constructed from transition metal ions and 1,4-benzenedicarboxylic acid (1,4-H2BDC) ligand have attracted intensive attention in recent years because of their intriguing structural topologies and tailor-made applications as functional solid materials [1-3]. Recent studies have shown the remarkable analogy of 1,4-BDC-type ligands with bulky methyl [4], fluorine [5], chlorine [6] or bromine [7] groups, since they not only provide astonishing thermal and chemical stability and stereo-chemical characteristics, but also prevent interpenetration phenomena of resultant polymeric networks. In the asymmetric unit, one Zn ion lying on an inversion center [at (0 0 1⁄2)] is coordinated by six oxygen atoms in a nearly ideal octahedral configuration. The Zn ion is chelated by four O atoms from two glycol molecules in the equatorial plane and two axial O atoms from two centrosymmetric tetrafluoroterephthalate (tfbdc) ligands. Because of the steric hindrance of the fluorine atoms located at the ortho positions of carboxylate, the rotation angle of tetrafluorined phenyl ring relative to carboxylate is 47.3(2)°, which is quite similar to that of a recent reported Mn-tfbdc polymer [8]. Each tfbdc anion bridges two Zn centers in a bismonodentate fashion to afford a linear chain along the [1 1 1] with adjacent Zn···Zn separation of 11.503(1) Å. Within the polymeric chain, one hydroxyl of the glycol molecule is involved in the strong intramolecular O4–H4···O2 bond (i = –x,–y+2,–z+ 1) to the uncoordinated O2 atom of tfbdc moiety. Moreover, intermolecular O3–H3···O1 bonds (ii = x–1,y,z) connect adjoining chains into a two-dimensional network. Z. Kristallogr. NCS 224 (2009) 619-620 / DOI 10.1524/ncrs.2009.0272 619 © by Oldenbourg Wissenschaftsverlag, München Crystal: colorless block, size 0.30 × 0.30 × 0.32 mm Wavelength: Mo K+ radiation (0.71073 Å) .: 17.33 cm−1 Diffractometer, scan mode: Bruker SMART APEX CCD, #/% 2,max: 55.04° N(hkl)measured, N(hkl)unique: 3233, 1718 Criterion for Iobs, N(hkl)gt: Iobs > 2 )(Iobs), 1668 N(param)refined: 115 Program: SHELXTL [9] Table 1. Data collection and handling.