Equilibrium and<sup>31</sup>P Chemical Shifts of the Adducts of Trialkylphosphines and Isothiocyanates, and Reactions of Triethylphosphine and Benzoyl Isothiocyanate
The adducts (3) of triethylphosphine (1) and several isothiocyanates (2) were prepared. Equilibrium constants of the adducts (5) from tributylphosphine (4) and phenyl (2b), benzoyl (2e), and p-toluenesulfonyl isothiocyanates (2f) were determined in some solvents. The 31P chemical shifts of 5 were measured in DMF, and correlated with Hammett σp constants. Reactions of 3e with 1 and 2e gave phosphonium