Molecular Structure of Monochloromethyl Chloroformate

The Chemistry of Chloroformates

“…The greater than tetrahedral value of the Cl-C-0 angle in methyl chloroformate was also suggestive of double bond character of the C-0 bond; the 0-0=0 angle being close to the value (125°) of the classical model. A similar study (372) of the structure of chloromethyl chloroformate indicated that it possessed the trans (V) configuration (Table III). The chlorine of the chloromethyl group was trans to the carboxyl carbon atom, and the carboxyl C-0 bond showed about 5% double bond character.…”

Structure and Conformational Composition of Chloromethyl Chloroformate: An Electron-Diffraction and ab Initio Molecular Orbital Investigation

“…The absence of a syn−syn form is probably due to the steric strain the molecule would experience in such a conformer. An early electron-diffraction investigation of chloromethyl chloroformate reported a OC−O−C torsion angle of about 90° and with the chlorine atom in the −CH 2 Cl group anti to the carboxyl carbon atom. Since no other similar molecules have been found with such a OC−O−C torsion angle, the earlier result seems quite unlikely and a later vibrational spectroscopic investigation did indeed conclude that chloromethyl chloroformate had a syn−gauche conformation where the CH 2 Cl group, as expected, was syn to CO, and CH 2 −Cl was gauche to C−O.…”