ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The molecular structure of cyclopropylisothiocyanate, c-C3H5NCS, has been investigated at 35 °C by gas phase electron diffraction. Two distinct conformers, trans and cis, were identified with the isomeric proportion being 72±5% trans at this temperature. The structural parameters were determined by combining the electron diffraction data with the previously published rotational constants. A quadratic force field was used to calculate vibrational corrections. The important distances (r@B|av,A(ring)) and angles ((angle)*av, deg) with their uncertainties in parentheses were determined to be for the trans conformer: r(C1–C2)=1.520(3), r(C2–C3) =1.515(3), r(N=C)=1.193(3), r(C=S)=1.574(3), r(C1–N)=1.387(5), r(C–H) =1.072(5), (angle)C1NC=149.1(15), (angle)C2C1N=118.9(6), (angle)HCH=115.0(fixed), (angle)C2C1H=117.35(fixed), and (angle)NCS=177.7(20), whereas those that differed for the cis conformer were found to be: r(C1–N)=1.413(5), (angle)C1NC=150.8(17), and (angle)C2C1N=116.2(15). The rms amplitudes of vibration with their associated uncertainties have been determined for some of the distances. In addition, the geometry has been calculated by ab initio Hartree–Fock gradient calculations with geometry optimization at the STO-3G level and it is found that the computed structure is in reasonable agreement to the one derived from the electron diffraction experiment. Features of the structure are compared with those of similar molecules and discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.452747
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