VIBRATIONAL CONFORMATIONAL-ANALYSIS OF ISOPROPYL FLUOROFORMATE

Infrared spectra of vapour and low temperature amorphous and crystalline phases, and Raman spectra of the vapour, liquid and low temperature crystalline phases of isopropyl fluoroformate (FCOOCH(CH3)2) and four isotopically substituted derivatives (FCOOCD(CH3)2, FCOOCH(CH3) (CD3), FCOOCH(CD3)2 and FCOOCD(CD3)2) are reported. The spectra indicate the presence of the same single conformer in each of these phases. Asymmetric top infrared contour simulation of the carbonyl stretching vibration in methyl, tert-butyl and isopropyl fluoroformate shows that in the isopropyl ester the ester function has the s-cis conformation, while the isopropyl group shows a quasi-gauche orientation.