PHOSPHORUS SULFIDE CAGE MOLECULES WITH EXOCYCLIC PHOSPHORUS-CENTERED SUBSTITUENTS - NMR PARAMETERS FOR ALPHA-TETRAPHOSPHORUS TRISULFIDE COMPOUNDS WITH PPH2, P(S)PH2 OR MU-PPH LIGANDS

The symmetric compounds alpha-P4S3(PPh2)2 and alpha-P4S3[P(S)Ph2]2, an d the two series of unsymmetric compounds alpha-P4S3(PPh2)R and alpha- P4S3[P(S)Ph2]R (R = I, NMePh or SPh), have been made in solution and s tudied by P-31 NMR, allowing a comparison to be made of the effects of the PPh2 and P(S)Ph2 ligands on NMR coupling constants and chemical s hifts. A statistical study of symmetric compounds alpha-P4S3R2 contain ing these ligands or 15 others showed that four out of six of the endo cyclic NMR parameters of the alpha-P4S3 cage could be summarized by re gression formulae involving two electronic and one steric substituent constants. Reaction of alpha-P4S3I2 with PhPH2 in the presence of Et3N gave the PPh-bridged molecule alpha-P4S3(mu-PPh).