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Title
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Vibrational spectra and relative stability of the Van der Waals complexes of boron trifluoride with **cis**-2-butene, **trans**-2-butene and 2-methyl propene
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Author
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Abstract
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| The mid-infrared spectra (4000-400 cm(-1)) of mixtures of BF3 with cis-2-butene, trans-2-butene and 2-methylpropene, dissolved in liquefied argon (88-127 K), have been investigated. In all spectra, evidence was found for the formation of a 1:1 van der Waals complex, while at higher concentrations of BF3 weak bands indicating the presence of a 1:2 complex were also observed. Using spectra recorded at different temperatures, the complexation enthalpies Delta H degrees for cis-2-butene.BF3, trans-2- butene.BF3 and 2-methylpropene.BF3 were determined to be - 12.5(2), - 12.4(2) and 12.7(2) kJ mol(-1), respectively. For all 1:1 complexes studied, the equilibrium geometry and the vibrational frequencies were obtained from density functional calculations at the B3LYP/6-311++G(d,p) level. Using statistical thermodynamics to account for the zero-point vibrational and thermal contributions, the complexation enthalpies of the 1:1 complexes were transformed into complexation energies Delta E. The resulting values, -14.5(4), -14.9(5) and -14.8(5) kJ mol(-1), respectively, are compared with the values predicted at the B3LYP/6-311 + + G(d,p) and the BSSE corrected MP2/6-311 + + G(3df,2pd)//B3LYP/6-311 + + G(d,p) levels. (C) 2000 Elsevier Science B.V. All rights reserved. |
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Language
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English
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Source (journal)
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Journal of molecular structure. - Amsterdam
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Publication
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Amsterdam
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2000
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ISSN
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0022-2860
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Volume/pages
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550
(2000)
, p. 389-398
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ISI
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000089379100030
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Full text (Publisher's DOI)
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