Molecular Structure of Chlorodifluoronitrosomethane, CClF2NO, As Determined in the Gas Phase by Electron Diffraction and ab Initio Calculations
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- 作者：Bruce A. Smart ; Paul T. Brain ; Heather E. Robertson ; and David W. H. Rankin
- 刊名：Inorganic Chemistry
- 出版年：1998
- 出版时间：June 1, 1998
- 年：1998
- 卷：37
- 期：11
- 页码：2687 - 2692
- 全文大小：84K
- 年卷期：v.37,no.11(June 1, 1998)
- ISSN：1520-510X
文摘
The gas-phase structure of chlorodifluoronitrosomethane,CClF2NO, has been determined by electrondiffractionand calculated ab initio. Theoretically, CClF2NOis predicted to consist of two conformers havingCs (
= 0
)and C1 ( = 105) symmetry, which are neardegenerate in energy, 
E = 1.1 kJ mol-1[TZ2P/MP2 + ZPE(DZP/MP2)], and separated by a barrier of around 1 kJ mol-1.Equivalent C1 conformers are predicted tobe connectedby a barrier of around 5-10 kJ mol-1. The lowpredicted barriers to interconversion of the twoconformerssuggest that the rotation of the nitroso group can be regarded as beingbarely restricted over most values of thetorsional angle at room temperature. This conclusion is supportedby the gas-phase electron diffraction data, forwhich a dynamic model employing 11 conformations was needed to obtainan accurate fit to the experimentaldata. The final refined values of structural parameters for thetwo conformers(Cs/C1) are(r
/pm,</deg) asfollows: C(1)-N(2) 156.7(5)/155.9(5), N(2)-O(3)117.5(3)/117.9(3), C(1)-Cl(4)173.9(2)/174.2(2), C(1)-F132.0(2)/132.1(2) and 131.0(2), C(1)-N(2)-O(3)110.8(12)/110.7(12), N(2)-C(1)-Cl(4)117.5(5)/108.9(5), N(2)-C(1)-F 103.7(2)/104.2(2) and 111.6(2),Cl(4)-C(1)-N(2)-F 123.6(14)/119.2(14) and123.7(14).
= 0)and C1 ( = 105) symmetry, which are neardegenerate in energy, E = 1.1 kJ mol-1[TZ2P/MP2 + ZPE(DZP/MP2)], and separated by a barrier of around 1 kJ mol-1.Equivalent C1 conformers are predicted tobe connectedby a barrier of around 5-10 kJ mol-1. The lowpredicted barriers to interconversion of the twoconformerssuggest that the rotation of the nitroso group can be regarded as beingbarely restricted over most values of thetorsional angle at room temperature. This conclusion is supportedby the gas-phase electron diffraction data, forwhich a dynamic model employing 11 conformations was needed to obtainan accurate fit to the experimentaldata. The final refined values of structural parameters for thetwo conformers(Cs/C1) are(r/pm,</deg) asfollows: C(1)-N(2) 156.7(5)/155.9(5), N(2)-O(3)117.5(3)/117.9(3), C(1)-Cl(4)173.9(2)/174.2(2), C(1)-F132.0(2)/132.1(2) and 131.0(2), C(1)-N(2)-O(3)110.8(12)/110.7(12), N(2)-C(1)-Cl(4)117.5(5)/108.9(5), N(2)-C(1)-F 103.7(2)/104.2(2) and 111.6(2),Cl(4)-C(1)-N(2)-F 123.6(14)/119.2(14) and123.7(14).