
%0 Journal Article
%A Bowmaker, GA 
%A Williams, JP 
%T Synthesis and N.M.R. Studies of New Unsymmetrically Substituted Ditertiary Phosphines
%J Australian Journal of Chemistry
%D 1994/03/01
%V 47
%N 3
%P 451-460
%K 
%R https://doi.org/10.1071/CH9940451
%U https://www.publish.csiro.au/paper/CH9940451 
%X The synthesis and characterization of rac- and meso-(E)-1,2-C2H2( PMePh )2 (1), 1,2-C6H4( PMePh )(PPh2)(2),1,2-C6H4( PBuPh )(PPh2)(3) and 1,2-C6H4(Pme2)(PPh2) (4) are reported. Reaction of (1) with MeI (1:2) gives [(E)-1,2-C2H2(Pme2Ph)2]I2 (5). The compound [(E)-1,2-C2H2(PPh2)(PmePh2)]I (6) was synthesized from (E)-1,2-C2H2(PPh2)2 and MeI (1:1). 1H n.m.r. spectra are reported for (2), (3), (5) and 6. 31P n.m.r. spectra are reported for (1)-(3), (5), (6) and [(E)-1,2-C2H2(PmePh2)2]I2 (7). 2J(PV,H) and trans 3J(H,H) coupling were observed in the 1H n.m.r. spectra of (6). Substitution of one Ph group for one Me group at phosphorus in a ditertiary  phosphine produces a change in chemical shift of 19.5 and 21.8 ppm for (E)-CH=CH and 1,2-C6H4 interphosphorus linkages respectively. The interphosphorus linkage in a ditertiary  phosphine produces large 3J(P,P) coupling constants (c. 155 Hz), and an increase in screening of the phosphorus nuclei (c. 10 ppm ). 
