A study of the reactions between halamines and varieties of phosphorus species

Abstract

In this work the oxidation of various low-valent phosphorus species with halomines and halogens has been studied. (^31)P nuclear magnetic resonance spectroscopy has been used to follow the reactions, and the pairwise additivity rule has been tested to determine if it is possible to predict the chemical shifts of the new species prepared. The reaction of Me(_2)NX (X = C1 or Br) with a number of phosphorus(III)species produced the phosphonium salt of the corresponding halide by simple amination at the phosphorus atom. This reaction occurred for(Me(_2)N)(_n)PX((_3-n)), (X = F, C1, Br and n = 1, 2) except for Me(_2)NPF(_2); for Ph(_n)PR((_3-n)) (R = Me, C(_6)H(_11), Me(_2)N, and n = 0-3) except for (Me(_2)N)(_3)P; and for the species Me(_2)PC1, MePC1(_2), (C(_6)H(_11))(_2)PC1 and Bu(^n)(_3)P. The fluorine containing phosphorus species studied, where there was more than one fluorine on the phosphorus (PF(_3) and Me(_2)NPF(_2)), gave more complex reactions which probably occurred due to rearrangement of the intially formed phosphorus(V) species. The overall stoichiometery of one such reaction was found to be: 2Me(_2)NPF(_2) + 3Me(_2)NBr = [(Me(_2)N)(_3)PF]Br + (Me(_2)N)(_2)PF(_3) + Br(_2) In the case of (Me(_2)N)(_3)P halogenation was found to occur with formation of tetramethylhydrazene. Reaction of dimethylchloramine and dimethyl bromamine with phosphorus(III) species containing the MeO group ((MeO)(_n)PX((_3-n), X -= C1 or Ph and n = 1-3) may well have formed a phosphonium salt but the observed products were the halomethane and a phosphorus(V) species contain a P=0 bond, e.g. (MeO)(_3)P + Me(_2)NBr = Me(_2)NPO(OMe)(_2) + MeBr. In the case of the aryl and thioesters studied ((MeS)(_3)P and (PhO)(_3)P) the intermediate species are observed.