meso- and dl - .alpha.,.alpha.' -Bis(difluoramino)bibenzyls. Preparation and nuclear magnetic resonance spectra

Stereochemistry of aminophosphines

“…The importance of lone pair repulsions seems to be indicated by the fact that the aminophosphines considered here seem to have gauche conformations. As 14 shows, the angle between the phosphorus lone pair CH CH3 14 (arbitrarily assumed to be tetrahedrally hybridized) and the nitrogen lone pair in a pure 2p orbital is 90°. The preferred orthogonality of lone pair electrons is also apparent in compounds with N-N,4 N-S,11 O-0,46 and S-S47 bonds.…”

Nuclear magnetic resonance spectrometry

“…I n perfluorophenyl phosphorous compounds the meta-and para-shifts and some meta couplings correlate with urn-values of the substituents on phosphorous, but the ortho shifts do not (152). The absorption of fluorine at the 2-position in quinolines is sharpened sufficiently at -24' C to resolve H-F splittings (699) . A number of N-F compounds have been reported: CF30NF2 (1894); CY,CY '-bis(difluoroamine) bibenzyls (1051) ; PhCFzSFCR3 (1444) ; fluorinated ureas and urethanes (120); and N-fluorimino nitrites (1286). The para-fluorine shift in pentafluorophenyl boron compounds is useful to characterize dn-pr interaction (352).…”