On Chromic Isomerism in Dianthrone and its Analogs

摘要

Two possible ways in which intramolecular overcrowding in dianthrone can be relieved are shown to lead to two stable, interconvertible molecular configurations, separated by a potential barrier. The two molecular configurations are briefly described. The height of the potential barrier is estimated, and found to agree well with that observed between the two isomersmdash;referred to as chromic isomersmdash;responsible for the thermochromic behavior of dianthrone. It is therefore suggested that the two molecular configurations described are identical with the two chromic isomers, and that this model applies also to analogous compounds. Some observed phenomena are discussed in support of the proposed model.