Theoretical Calculation of the Rotational Barrier, Valence Force Constants and Experimental Electronic Spectrum of Chlorocarbonylsulphenyl Chloride (CIC(O)SCI)

The rotational barrier around the C-S bond in chlorocarbonylsulphenyl chloride (CIC(O)SCI)is investigated using the INDO, PCILO and GAUSSIAN-70 techniques. The results confirm the existence of planar cis and trans conformers with a higher stability of the latter, as suggested by previous vibrational results. The origin of the rotational barrier is due to an increase of electronic delocalization as demonstrated by INDO and PCILO calculations. The optimized geometrical parameters obtained by means of the ab-initio method with an STO-3G basis set are reported for the different conformers. Valence force constants have been calculated and the values obtained compare fairly well with the results from a previous normaI coordinate calculation. The experimental electronic spectrum, maximum molar absortivities, oscillator strengths and atentative assignrnent of its electronic bands, are reported.