EFFECT OF THE PROTONATION AND OF THE ORTHO-SUBSTITUTION ON THE STRUCTURE OF ARYLIMINOPHOSPHORANES

Phenyltriphenylphosphoranylideneammonium tetrafluorophosphate, (I), C24H21NP+.BF4-, M(r) = 441.21, monoclinic, Pn, a = 24.6077 (18), b = 9.0071 (3), c = 10.0690 (4) angstrom, beta = 100.824 (5)-degrees, V = 2192.0 (2) angstrom3, Z = 4, D(x) = 1.337 g cm-3, lambda(Cu Kalpha) = 1.5418 angstrom, mu =15.009 cm-1, F(000) = 912, T = 295 K, R = 0.045 for 3641 observed reflections. 2-Amino-1-triphenylphosphoranylideneaminobenzene, (II), C24H21N2P, M(r) = 368.42, monoclinic, I2/a, a = 30.4088 (15), b = 11.5561 (3), c = 22.9996 (10) angstrom, beta = 101.437 (3)-degrees, lambda = 7921.7 (6) angstrom3, Z = 16, D(x) = 1.236 g cm-3, lambda(Cu Kalpha) = 1.5418 angstrom, mu = 12.805 cm-1, F(000) = 3104, T = 295K, R = 0.041 for 5873 observed reflections. The elongation of the P=N bond in (I) reflects the protonation of its N atom [1.621 (4) and 1.635 (4) angstrom in (I); 1.570 (2) and 1.572 (2) angstrom in (II)]. The endo- and exocyclic angular deformations of the benzene ring at C(1) (up to 3 and 6-degrees respectively) could result from the electron-donor character of the iminophosphorane group and also, in (II), from the N-H...N intramolecular hydrogen bond [N...N 2.695 (3) and 2.675 (3) Angstrom].