Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10558285 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2005 | 13 Pages |
Abstract
Mid-infrared spectra of cyclopropene (c-C3H4) mixtures with HCl or BF3, dissolved in liquefied argon and in liquefied nitrogen have been examined. Evidence was found for the formation of two different isomers of the 1:1 complexes: a Ï-type complex in which the interaction occurs with the Ï-bond of cyclopropene, and a Ï-type complex in which the electron acceptors interact with one of the CC single bonds. At lower temperatures, indications for the formation of a 1:2 chain-type complex were found. Using spectra recorded between 90 and 124 K in liquid argon, the complexation enthalpies for the Ï- and Ï-complexes with HCl were determined to be â8.8(3) and â7.9(3) kJ molâ1, respectively. For the Ï-complex with BF3 a value of â7.4(3) kJ molâ1 was found. Structural and spectral information on the 1:1 complexes was obtained from B3LYP/6-311++G(d,p) and MP2(FC)/6-31+G(d) calculations. Using Free Energy Perturbation Monte Carlo simulations to calculate the solvent influences, and statistical thermodynamics to account for zero-point vibrational and thermal contributions, the solution enthalpies were transformed into complexation energies with values of â15.5(6) and â13.8(8) kJ molâ1 for the Ï- and Ï-isomers of c-C3H4·HCl, respectively, and of â12.7(8) kJ molâ1 for the Ï-type BF3 complex.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Gert P. Everaert, Wouter A. Herrebout, Benjamin J. van der Veken,