Noncovalent Interactions under Extreme Conditions: High-Pressure and Low-Temperature Diffraction Studies of the Isostructural Metal - Organic Networks (4-Chloropyridinium)[sub2][CoX[sub4]] (X = Cl, Br).
The crystal structures of the two isostructural metal-organic salts, (4-chloropyridinium)[sub2][CoX[sub4], X = Cl (1), Br (2), have each been determined at nine temperatures from 30 to 300 K and at nine pressures from atmospheric pressure to 4.2 GPa. A 5% reduction in unit cell volume is observed up...
| Publicado en: | Journal of the American Chemical Society Vol. 130; no. 28; pp. 9058 - 9072 |
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| Autores principales: | , , , , , |
| Formato: | Artículo |
| Publicado: |
American Chemical Society
7/16/2008
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=33403190&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 33403190 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 7/16/2008 vid: 130 iid: 28 pid: 997 pub: American Chemical Society artinfo: ui: 33403190 10.1021/ja8010868 ppf: 9058 ppct: 14 formats: tig: atl: Noncovalent Interactions under Extreme Conditions: High-Pressure and Low-Temperature Diffraction Studies of the Isostructural Metal - Organic Networks (4-Chloropyridinium)[sub2][CoX[sub4]] (X = Cl, Br). aug: au: Espaliargas, Guillermo Mínguez Brammer, Lee Allan, David R. Pulham, Cohn R. Robertson, Neil Warren, John E. affil: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K. School of Chemistry, University of Edinburgh, King's Buildings, Edinburgh EH9 3JJ, U.K. Diamond Light Source, STFC Rurheiford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, U.K. Synchrotron Radiation Source, STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, U.K. su: Optical diffraction Chemical bonds Halogen compounds Hydrogen bonding Metals at low temperatures Pressure measurement Anisotropy sug: subj: Optical diffraction Chemical bonds Halogen compounds Hydrogen bonding Metals at low temperatures Pressure measurement Anisotropy ab: The crystal structures of the two isostructural metal-organic salts, (4-chloropyridinium)[sub2][CoX[sub4], X = Cl (1), Br (2), have each been determined at nine temperatures from 30 to 300 K and at nine pressures from atmospheric pressure to 4.2 GPa. A 5% reduction in unit cell volume is observed upon temperature reduction, whereas an 18-19% reduction is observed upon increasing the pressure over the ranges studied. The structures adopt a tape arrangement propagated by bifurcated N-H⋯X[sub2]Co hydrogen bonds and by Co-X⋯Cl-C halogen bonds. Intertape interactions include type I Co-X⋯Cl-C and C-Cl⋯Cl-C halogen-halogen interactions as well as offset π-stacking between the aromatic rings of the cations. Although little anisotropy in compression is seen upon temperature reduction, marked anisotropy in compression is observed upon pressure increase. Compression between tapes far exceeds compression along the tape, consistent with the strong attractive nature of the intratape N-H⋯X[sub2]Co and Co-X Cl-C interactions and the weaker dispersion dominated Co-X⋯Cl-C and C-Cl⋯Cl-C halogen-halogen interactions and π-stacking interactions. Increased distortion of the [CoX[sub4]][sup2-] anions from idealized tetrahedral geometry arises upon pressure increase, consistent with local changes in the electric field that result from compression of the pairs of π-stacked cations. The study of the isostructural pair of compounds permits a rare opportunity for quantitative evaluation of the "internal" or "chemical" pressure exerted by changing the [CoBr[sub4]][sup2-] anion for the smaller [CoCI[sub4]][sup2-] anion. Thus, crystal structures of 1 and 2 with equivalent unit cell volumes require an additional pressure of ca. 1 GPa exerted upon the structure containing the larger [CoBr[sub4]][sup2-] anion (2). This internal pressure increases to ca. 1 .9 GPa at the highest pressures used in this study. Most significant is that examination of the isovolumetric pairs of structures shows that the structures containing the [CoCl[sub4]][sup2-] anion are contracted along the <101> vector, the direction of tape propagation, by ca. 1.2% and correspondingly expanded in other directions, relative to those containing the [CoBr[sub4]][sup2-] anion. Since the effect of difference in anion size has been removed by application of pressure, this anisotropy in dimensions clearly indicates that the N-H⋯X[sub2]Co hydrogen bonds and Co-X⋯CI-C halogen bonds are more strongly attractive for X = CI rather than X = Br. Use of internal pressure thereby provides unique insight into the relative strength of intermolecular interactions. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2008 holdings: @attributes: islocal: N |
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