VIBRATIONAL-SPECTRA AND ROTATIONAL-ISOMERISM OF TERT-BUTYL FORMATE

The IR and Raman spectra of HCOOC(CH3)3, DCOOC(CH3)3 and HCOOC(CD3)3 are measured in the liquid, solid and gaseous states in the IR region of 4000-200 cm-1 and the Raman region of 4000-10 cm-1. The vibrational spectra show that two isomers exist in the liquid and gaseous states and only one in the solid state. The vibrational assignments of the spectra are made for each isomer by means of the deuteration effect and comparison with other molecules. Normal coordinate calculations for three isotopic species of the planar configurations are performed and the normal vibrational frequencies for different conformations then calculated keeping the F matrix constant. These calculations suggest that the observed isomers are almost cis and trans about the CO ester bond and that the one remaining in the solid state is cis. © 1979.