SPECTROSCOPY OF 1,4,4-TRIFLUOROCYCLOBUTENE

A new compound, 1,4,4-trifluorocyclobutene (144FCB), has been obtained as a byproduct in the reduction of perfluorocyclobutene with sodium borohydride. A comprehensive spectroscopic study of 144FCB has been undertaken including microwave, IR, Raman and NMR data. Ground state rotational constants, A=3629.34, B=2600.74, and C=2098.93 MHz, were derived from the microwave data and used to distinguish 144FCB from other possible isomers and to propose a structure. NMR chemical shifts and coupling constants and the vibrational fundamentals are assigned and compared to other members of the cyclobutene family. Frequencies of vibrational fundamentals of 144FCB (cm-1) are: (a′) 3126, 2967, 1679, 1457, 1377, 1245, 1179, 1045, 914, 752, 690, 577, 453, 263, 213; (a″) 3000, 1198, 1061, 938, 821, 577, 381, 190, -. A small amount of 3,3,4-trifluorocyclobutene has also been found in the products of the reduction reaction, and its NMR spectra and its IR spectrum are reported. © 1990.