Microwave Spectrum and Structure of Methylcyclopropane.cntdot.HCl

Forest, Susan E.; Andrews, Anne M.; Kuczkowski, Robert L.

doi:10.1021/j100059a012

Cited by 10 publications

(9 citation statements)

References 7 publications

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“…Our high-level molecular orbital (MO) calculations provide strong support for the formation of a weak and non-conventional complex of cyclopropane-ammonia which has been found experimentally [9]. In this complex the ammonia umbrella is pointed up, stacked onto the ring of cyclopropane and the hydrogen atoms prefer a staggered arrangement, and the whole complex is found to be stable.…”

Section: Discussionsupporting

confidence: 72%

“…These structures are found to be less stable than those where ammonia acts as a proton acceptor. Forest and Kuczkowski [9] investigated the C 3 H 6 ..NH 3 complex experimentally using Fourier Transform Microwave (FTMW) spectroscopy and showed that the ammonia molecule acts as a proton acceptor. The R CM..N is found to be in good agreement with their value (3.66 A Ê ) for the staggered confomer.…”

Section: Resultsmentioning

confidence: 99%

“…These results qualitatively support the Coulson and Mott [8] bent banana bond model of cyclopropane. However, in a recent study using microwave spectroscopy, Forest and Kuczkowski [9] have shown that the C 3 H 6 ..NH 3 complex does not conform to this pattern, where the C 3 H 6 acts as a proton donor. Taking their results into consideration, a question arises [9] regarding the binding of ammonia with propane which lacks these bent-bond features.…”

Section: Introductionmentioning

confidence: 97%

“…However, in a recent study using microwave spectroscopy, Forest and Kuczkowski [9] have shown that the C 3 H 6 ..NH 3 complex does not conform to this pattern, where the C 3 H 6 acts as a proton donor. Taking their results into consideration, a question arises [9] regarding the binding of ammonia with propane which lacks these bent-bond features. In the present work, we investigate these complexes using the EPIC model followed by an ab initio investigation for determining various structures and their interaction energies.…”

Section: Introductionmentioning

confidence: 97%

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Complexes of ammonia with propane and cyclopropane: electrostatic guidelines for ab initio treatment

Gadre

Bhadane

1998

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

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A model based on the molecular electrostatic potential (MESP) is employed for the investigation of structures and energies of complexes of ammonia with propane and cyclopropane. The electrostatic model geometries are employed as starting points for an ab initio investigation at the self-consistent ®eld and second-order Mùller-Plesset (MP2) levels. The most stable structures of C 3 H 6 ..NH 3 and C 3 H 8 ..NH 3 complexes have the interaction energies of 10.07 kJ/mol and 8.15 kJ/mol, respectively, at the MP2/6-31G(d,p) level. The energy rank order of the structures is not altered with the use of the 6-31++G(d,p) basis set, and the basis set superposition error has little eect. The interaction energy decomposition analysis shows that the electrostatic component is dominant over the other ones. MESP topography thus seems to oer valuable hints for predicting the structures of weakly bonded complexes.

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Section: Discussionsupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

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Complexes of ammonia with propane and cyclopropane: electrostatic guidelines for ab initio treatment

Gadre

Bhadane

1998

Theoretical Chemistry Accounts: Theory, Computation, and Modeli

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“…Following Truscott et al, we will refer to this isomer as the asymmetric complex. The complex of methylcyclopropane with HCl has also been investigated by Forest et al, who report on pulsed nozzle Fourier transform microwave spectroscopy, supported by theoretical calculations. Their distributed multipole electrostatic calculations suggest that the symmetric isomer, in which HCl interacts with the C−C bond opposite to the methyl substituent, should be more stable, by approximately 0.6 kJ mol -1 , than the asymmetric complex.…”

Section: Introductionmentioning

confidence: 85%

Ab Initio and Cryospectroscopic Investigation of the Van der Waals Complexes of Methylcyclopropane with Hydrogen Chloride and Boron Trifluoride

Everaert¹,

Herrebout²,

Veken³

2001

J. Phys. Chem. A

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The mid infrared spectra of methylcyclopropane-HCl and methylcyclopropane-BF 3 mixtures, dissolved in liquid argon (LAr) or liquid nitrogen (LN 2 ), have been examined. In LAr solutions, evidence was found for the formation of two different isomers of the 1:1 van der Waals complexessan asymmetric complex, in which the electron acceptor interacts with the C-C bond adjacent to the methyl group, and a symmetric complex in which the interaction occurs with the opposite C-C bond. At higher concentrations, indications were found for the formation of a chain-type 1:2 complex. In LN 2 solutions, only the two 1:1 isomers of the HCl complex have been observed. Using spectra recorded at different temperatures, the complexation enthalpy ∆H°in LAr was determined to be -9.5(4) and -8.3(3) kJ mol -1 for the symmetric and asymmetric MCP‚ HCl complexes, and -9.1(2) and -6.7(5) kJ mol -1 for the symmetric and asymmetric MCP‚BF 3 complexes, respectively. In addition, for all investigated species, full MP2/6-31+G(d,p) geometry optimizations and B3LYP/6-311++G(d,p) frequency calculations were performed, and the complexation energies were calculated at the MP2/6-311++G(3df,2pd) level. These calculations indicate that the isomers of the MCP‚HCl complex are of comparable strength, while the asymmetric MCP‚BF 3 complex is significantly less stable than its symmetric counterpart. Using Free Energy Perturbation Monte Carlo simulations to calculate the solvent influences, and using statistical thermodynamics to account for zero-point vibrational and thermal contributions, from the experimental complexation enthalpies, the complexation energies are estimated to be -15.7(8) and -16.0(9) kJ mol -1 for the symmetric and asymmetric MCP‚HCl complexes, which is in agreement with the ab initio results, and -14.0(8) and -15.3(5) kJ mol -1 for the corresponding MCP‚BF 3 species.

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2 Asymmetric Top Molecules, Data, Part 4

Demaison¹,

Vogt²,

Wlodarczak³

Rotational Constants of Diamagnetic Asymmetric Top Molecules

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Microwave Spectrum and Structure of Methylcyclopropane.cntdot.HCl

Cited by 10 publications

References 7 publications

Complexes of ammonia with propane and cyclopropane: electrostatic guidelines for ab initio treatment

Complexes of ammonia with propane and cyclopropane: electrostatic guidelines for ab initio treatment

Ab Initio and Cryospectroscopic Investigation of the Van der Waals Complexes of Methylcyclopropane with Hydrogen Chloride and Boron Trifluoride

2 Asymmetric Top Molecules, Data, Part 4

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