Solvent, Temperature, and Pressure Effects on the Reaction Between Tetracyanoethylene and Styrene

Abstract

A new absorption band discovered in the region 300–350 nm by varying solvents, temperature, and pressure was assigned to the zwitterionic intermediate postulated so far in the thermal (2+2) cycloaddition. The PMR spectrum was taken at low temperature. The rate of the intermediate formation depended strongly on solvent polarity.

Effect of pressure on the [2 + 2 .fwdarw. 4] cycloaddition reaction of tetracyanoethylene to enol ethers

“…However, in toto AV¿ can be as low as -60 mL/mol. Osugi et al28 deduced also such extremely negative reaction volumes from the pressure dependence of the visible spectra of the TCNE-styrene system. It is worth mentioning that the zwitterion has no fixed conformation.…”