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Microwave and photoelectron study of cis- and trans-isocyanato ethene, CH2CHNCO (vynyl isocyanate)

1978; Elsevier BV; Volume: 70; Issue: 2 Linguagem: Inglês

10.1016/0022-2852(78)90156-x

1096-083X

C. Kirby, Harold W. Kroto,

Atmospheric Ozone and Climate

The microwave and photoelectron spectra of isocyanato ethene CH2CHNCO have been studied. The microwave results indicate that the species is planar and possesses both a cis and a trans form. The appearance of dense and complicated vibrational satellite lines indicates that the molecule is quite flexible, a general property of molecules containing the isocyanate group. The rotational constants are: cis: A0 = 20 146.8, B0 = 3107.267, C0 = 2689.513 MHz; trans: A0 = 62 584.051, B0 = 2437.730, C0 = 2346.507 MHz These constants are shown to be consistent with structures in which r(CN) = 1.382 ± 0.005 Å, ∠(CCN) = 122 ± 1° (for both conformers), and ∠(CNC) = 142.4 ± 0.5° (cis) and 138.4 ± 1.5° (trans). The dipole moments are μ(cis) = 2.120 ± 0.015 and μ(trans) = 2.207 ± 0.007 D. Several distinct peaks are observed in the photoelectron spectrum; however, the structure is not resolved into features belonging to the different isomers. The first ionization potential lies at 9.80 ± 0.1 eV. The spectrum has been assigned with the aid of theoretical calculations.