The molecular structure of ethyl chlorothioformate in solid phase by X-Ray diffraction

RODRIGUEZ PIRANI, LUCAS SEBASTIÁN; ERBEN, MAURICIO FEDERICO; BOESE, ROLAND; FANTONI, ADOLFO; POZZI, C. GUSTAVO; DELLA VÉDOVA, CARLOS OMAR

ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2011 vol. 2011 p. 350 - 356

0108-7681

The molecular structure of ethyl chlorothioformate, ClC(O)SCH2CH3, has been investigated in the solid phase by X-ray diffraction analysis at low temperature using a miniature zone-melting procedure and IR laser radiation. The crystalline solid consists exclusively of molecules with thesynperiplanar conformation with respect to the CO double bond and the SC single bond, and gauche orientation of the ethyl group (syn-gauche). These results coincide with previous studies devoted to gas-phase conformational properties. The conformational preference for the  ClC(O)SY (Y = Cl, CF3, CH3 and CH2CH3) series of molecules was rationalized using the natural bond orbital (NBO) scheme. It was found that both resonance (mesomeric) and anomeric (hyperconjugation) intermolecular charge-transfer interactions are important for describing the syn/anti equilibrium, also illustrating the effect of electronegativity of the substituent in the  conformation preference of the ClC(O)S moiety. On the basis of the atoms in molecules (AIM) theory, intermolecular interactions have been characterized in the B3LYP/6-31G** periodic  boundary electron density.