CONFORMATIONAL-ANALYSIS AND VIBRATIONAL-SPECTRA OF ISOPROPYL FORMATE AND SOME DEUTERATED ISOTOPOMERS

Raman spectra of vapor, liquid and low-temperature crystalline phases and infrared spectra of vapor and low-temperature amorphous and crystalline phases of isopropylformate [HCOOCH(CH3)2] and of four of its isotopomers, DCOOCH(CH3)2, DCOOCH(CD3)2, HCOOCD(CD3)2 and DCOOCD(CD3)2, are reported. The spectra indicate one dominant conformer in all the phases studied. In the vapor and liquid phases, however, indications are found for the presence of a small amount of a second conformer which is believed to have the s-trans ester conformation. Vapor-phase asymmetric-top infrared contour simulation of the carbonyl stretching vibration shows that for the principal conformer the ester function has s-cis conformation whereas the isopropyl group shows a quasi-gauche orientation.