non-Kekulé molecules
Molecules that are fully conjugated, but each of whose Kekulé structures contains at least two atoms that are not π-bonded. Examples of non-Kekule @H02889@ are trimethylenemethane (2-methylidenepropane-1,3-diyl) 1, m-benzodiquinomethane (benzene-1,2-diyldimethyl) 2, and 1,2,4,5 - tetramethylenebenzene (benzene-1,2,4,5-tetrayltetramethyl) 3.
PAC, 1999, 71, 1919. (Glossary of terms used in theoretical organic chemistry) on page 1955 [Terms] [Paper]