A 7-BOND COUPLING, (7)J(PP) OR THROUGH-SPACE COUPLING IN THE AZINE DIPHOSPHINE Z,Z-PPH2CH2C(BU(T))=N-N=(BU(T))CCH2PPH2 - CRYSTAL-STRUCTURE OF Z,Z-P(=O)PH2CH2(BU(T))=N-N=(BU(T))-CCH2P(=O)PH2
Sd. Perera et al., A 7-BOND COUPLING, (7)J(PP) OR THROUGH-SPACE COUPLING IN THE AZINE DIPHOSPHINE Z,Z-PPH2CH2C(BU(T))=N-N=(BU(T))CCH2PPH2 - CRYSTAL-STRUCTURE OF Z,Z-P(=O)PH2CH2(BU(T))=N-N=(BU(T))-CCH2P(=O)PH2, Inorganica Chimica Acta, 207(2), 1993, pp. 175-178
Analysis of the (C{H})-C-13-H-1 NMR spectrum of ZZ-PPh2CH2C(But)=N-N=C
(But)CH2PPh2 (1) gives second order patterns for the C(ipso), C(ortho)
, C(meta), PCH2 and C=N carbons caused by a non-zero seven-bond coupli
ng, 7J(PP). Simulation of the spectra gives 7J(PP)=4.8 Hz. The corresp
onding diphosphine dioxide 2 gives first order (C{H})-C-13-H-1 spectra
, i.e. 7J(PP) approximately 0 Hz. Possible explanations for this unusu
ally large value of 7J(PP) are discussed. Crystals of 2 are orthorhomb
ic, space group Pbca, with a=1592.2(3), b=1196.1(2), c=1663.0(3) pm an
d Z=4; final R factor 0.0381 for 1780 observed reflections.