Volume 2

Recent advances in organic chemistry / by Alfred W. Stewart.

  • Stewart, Alfred W. (Alfred Walter), 1880-1947.
Date:
1931
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Recent advances in organic chemistry / by Alfred W. Stewart. Source: Wellcome Collection.

    365/458 (page 345)
    CHAPTER XIV OTHER CASES OF ABNORMAL VALENCY A.—Introductory In view of the interest excited by the triphenylmethyl problem from 1900 onwards, it seems strange that no one at that time appears to have thought of examining other compounds which show some structural analogy with hexaphenyl-ethane. (C6H5)3C.C(C6H5)3 (C6H5)„N.N(C0H5)2 c6h6.o.o.c6h5 (C6H5)3Pb.Pb(C6H5)3 (C6Hg)2As.As(C6Hs)2 C6H6.S.S.C6H5 In each of the formulse shown above there is a symmetrical structure ; all the formulae contain a central single bond in the molecule ; and the various substances represent the highest possible phenyl-substitution product of their type. Tetraphenylhydrazine was already known at the time when triphenylmethyl was arousing interest by its peculiar nature ; yet no one seems to have been struck by the analogy between it and hexaphenyl-ethane ; and it was quite accidentally, in 1906, that the close correspondence between the two series was first brought out in practice. It has since been shown that, just as the free radicle triphenylmethyl can exist in solution, so can the corresponding diphenylhydrazyl grouping (C6H5)2N appear in the free state ; and if carbon is to be considered as a trivalent element in certain circumstances, we cannot deny the possibility of divalent nitrogen derivatives. Between the two series a strong resemblance undoubtedly exists, though the bond N—N is much less readily ruptured than the single linkage between the central carbon atoms of Gomberg’s hydrocarbon. With regard to the analogous phenyl derivatives of the divalent elements, it is found that experimental evidence points