Intermolecular interaction in complexes of tetracyanoethylene with amines

Solutions of tetracyanoethylene (TCE) in pyridine and its homologs (piperidine and triethylamine) and also a solution of the complex of 2,2-dipyridyl with TCE in acetone were investigated. The EPR spectra of these systems show hyperfine structure of nine components with splitting constants characteristic of TCE radical anions. This indicates complete electron transfer from the nitrogen atom in the amine to the TCE molecule. In isolated cases, there was a more complex structure in the EPR spectra, and this was interpreted as the result of formation of associates between the TCE radical anions and the amine molecules. The existence of such associates was confirmed by considerable difference in the proton relaxation times T₁ and T₂ in TCE solutions in pyridine, -picoline, and 2,6-lutidine. A formation mechanism and proposed structure are given for associates in these systems.T. Ya. Lavrenyuk and V. M. Ogenko took part in the experimental work.The author thanks Academician A. I. Brodskii of the Academy of Sciences of the Ukrainian SSR for discussing the results.