No abstract

Steric Nature of the Ortho Effect 1137 sistent with the moments of the chloro and methyl derivatives, 117 ± 3°, indicates that if tautomerism exists, the keto form is present in the tautomeric mixture to a very small extent.If dioxane were to break the OH-N bonds in these anils, forming O-HO bonds, the solvated salicylideneaniline molecules should have a configuration similar to that of the methyl ether, with a moment of about 3.6. The calculated moments of salicvlidene-^-toluidine and salicylidene-^chloroaniline with this configuration in dioxane are 3.3 and 4.6. Assuming no rupture of the OH-N bonds, the moments of these anils should be about 0.15 unit higher in dioxane than in benzene, a portion of this increase being due to the interaction of dioxane with the H-C=N hydrogen atoms. The addition of this increment gives values of 2.55, 2.78 and 2.42, respectively, for the calculated moments of salicylideneaniline, salicyl-idene-£-toluidine and salicylidene-J>-chloroaniline. The moments obtained for these three compounds in dioxane are 2.57, 2.74 and 2.49, indicating that dioxane does not break the OH-N bonds in the anils. SummaryElectric moments reveal that about 83% of salicylonitrile molecules have a cis configuration in carbon tetrachloride, indicating a weak OH-N bond. Very many of these bonds are broken when this compound is dissolved in benzene, and almost all are broken in dioxane.An analysis of the moments of several anils indicates the presence of an 0-H-N bridge in salicylideneaniline which is not broken in dioxane. The keto form is present to a very small extent, if at all, in this compound.Notre Dame, Indiana

It is proposed that molecules having the same or closely similar molecular dimensions be termed "homomorphs." By consideration of the strains present in representative molecular addition compounds, an estimate is reached of the strains present in related homomorphic molecules. It is concluded that strains of 5.4 kcal./mole are present in homomorphs of di-Z-butylmethane, strains of 17 kcal./mole in homomorphs of 2,6-dimethyl-Z-butylbenzene, and strains of at least 25 kcal./mole in homomorphs of o-di-Z-butylbenzene. The strains in homomorphs of hemimellitene (1-2 kcal.) and o-Z-butyltoluene (4-6 kcal.) are somewhat smaller. In all of these cases it is possible to follow the effect of the strain upon the chemical properties of a wide variety of homomorphic derivatives. The concept of homomorphs permits a useful correlation between the chemical properties of molecules of widely different functions, but of similar sizes and shapes. o

Communications to the Editor 877 ticularly interesting in view of the fact that the work of Erlenmeyer, Schoenauer and Schwarzen-bach3 indicates that all three hydrogen atoms of hypophosphorus acid exchange rapidly with deuterium oxide. Apparently in the deamination reaction a hydrogen atom was extracted from another aromatic nucleus, since that is the only source of hydrogen which is not equilibrated with deuterium.