Kristall- und Molekülstruktur von „Imido-tetraphenyl-dithiophosphinsäure" und Imido - tetraphenyl- diphosphinsäure / Crystal and Molecular Structure of "Imido-tetraphenyl-dithio-phosphinic Acid" and Imido-tetraphenyl-diphosphinic Acid

Abstract

The crystal structures of the title compounds have been investigated in order to gain information on the problem of tautomerism associated with these and related compounds. [Ph2P(S)]2NH crystallizes in the triclinic space group P 1̄. Its structure is represented by the above formula, e.g. as a disubstituted amine with its nitrogen atom being sp2-hybridized. In contrast, ,,[Ph2P(O)]2NH" in the solid state is present as its tautomer Ph2P(O)-N = PPh2OH. It is an imidodiphosphinic acid as previously suggested. The crystals are monoclinic, space group P 21/n, Z - 2. Crystallographic inversion centers are occupied by the N- and the unique H-atom. Therefore a linear PNP arrangement as well as a symmetric OH-O-hydrogen bridge are characteristic for the structure of this molecule. The short PN bonds suggest a high bond order approaching 2. A consequence of the hydrogen bonded oxygen atoms are fairly long PO distances. The crystal structure of is made up of infinite zig-zag chains of Ph2P(0)NPPh2ÖH molecules along the crystals b-axis