SOLVENT, TEMPERATURE, AND PRESSURE EFFECTS ON THE REACTION BETWEEN TETRACYANOETHYLENE AND STYRENE
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.