Stereoisomerism among Derivatives of Diphenyl

Abstract

DR. TURNER'S remarks (NATURE, September 22, p. 439) appear to have been made without his having seen my letter of some eighteen months ago (NATURE, May 6, 1922, p. 581), which was concerned with the importance of stereoisomerism among diphenyl derivatives in relation to Sir William Bragg's conclusions as to the molecular structure of benzene in the crystal. At that time, reasons for reviving the Dewar para-linkage formula for benzene had not been published (Ingold, Trans. Chem. Soc., 1922, 1143), but since this bridged formula “is stereochemically identical with the disposition of atoms suggested by Sir William Bragg for the molecule of benzene” (Challenor and Ingold, Trans. Chem. Soc., 1923, 2068), it will scarcely be maintained that Dr. Turner's suggestion of a possible stable para-linkage in diphenyl derivatives introduces any essentially novel consideration to the question of the structure of these compounds. I also referred in my letter to the remarkable behaviour of diphenyl towards ozone, mentioned by Dr. Turner, as well as to certain other noteworthy properties of the compound.