SIMPLE PREPARATIONS OF NEW MONOMERIC TRIHALOGENOPHOSPHINE IMIDES

The oxidation of alogeno(2,4,6-tri-tert-butylphenylimino)phosphines [( 2,4,6-Bu3tC6H2)NPX, X = Cl, Br or 1] with dihalogens (Cl2, Br2 or I2) resulted in the formation of trihalogeno(N-2,4,6-tri-tert-butylphenyl) phosphine imides. The imides (2,4,6-Bu3tC6H2)NPCl3 and (2,4,6-Bu3tC6H2 )NPBr3 were obtained quantitatively from the corresponding halogenoimi nophosphine with PhICl2 and Br2, respectively, and were crystallograph ically characterized [(2,4,6-Bu3tC6H2)NPCl3,: Cm, a = 11.960(3), b = 1 4.696(2), c = 5.954(2) angstrom, beta = 97.71 (2)-degrees, Z = 2, R = 0.036, R' = 0.047; (2,4,6- Bu3tC6H2)NPBr3: P2(1)/c, a = 1 8.841 (8), b = 9.480 (4), c = 1 2.1 86 (5) angstrom, beta = 98.00(3)-degrees, Z = 4, R = 0. 068, R' = 0. 074]. Reactions involving a halogenoiminophosph ine and a different halogen are accompanied by halide exchange and giv e mixtures of products, most of which can be assigned and include the mixed trihalides, (2,4,6-Bu3tC6H2)NPX2X'. No reaction is observed betw een (2,4,6-Bu3tC6H2)NPI and I2, but one iodo derivative has been isola ted and characterized spectroscopically and by X-ray crystallography a s (2,4,6-Bu3tC6H2)NPCl2I, which is formed in the disproportionation re action of (2,4,6-Bu3tC6H2)NPCl and I2. The trihalides are monomeric in the solid state and exhibit extremely short N-P bonds with large angl es at the nitrogen centres.