MU(2)-HALOGENO COMPLEXES OF N-BROMOSUCCINIMIDE AND N-BROMOPHTHALIMIDE - THE CRYSTAL-STRUCTURES OF PPH(4)[X(N-BROMOSUCCINIMIDE)2] AND PPH(4)[X(N-BROMOPHTHALIMIDE)(2)] WITH X=CL AND BR

The mu(2)-halogeno complexes PPh(4)[X(N-bromosuccinimide)(2)] and PPh(4)[X(N-bromophthalimide)(2)] with X = Cl and Br have been prepared by reactions of N-bromosuccinimide and N-bromophthalimide, respectively, with the corresponding tetraphenylphosphonium halides PPh(4)X in acetonitrile solutions. The compounds form pale yellow crystal needles, which were characterized by IR spectroscopy and by crystal structure determinations. PPh(4)[Cl(N-Bromosuccinimide)(2)] (1): Space group P2(1)/n, Z = 4, structure solution with 2516 observed unique reflections, R = 0.040. Lattice dimensions at -25 degrees C: a = 1775.9(1), b = 764.3(1), c = 2341.7(2) pm, beta = 101.84(1)degrees. PPh(4)[Br(N-Bromosuccinimide)(2)] (2): Space group P2(1)/n, Z = 4: structure solution with 5620 observed unique reflections, R = 0.061. Lattice dimensions at 20 degrees C: a = 1776.9(9), b = 762.2(3), c = 2331(1) pm, beta = 103.02(3)degrees. PPh(4)[Cl(N-Bromophthalimide)(2)] (3): Space group P (1) over bar, Z = 4, structure solution with 3812 observed unique reflections, R = 0.039. Lattice dimensions at -50 degrees C: a = 918.5(2), b = 1115.0(3), c = 2584.4(5) pm, alpha = 88.22(3)degrees, beta = 83.20(3)degrees, gamma = 85.10(3)degrees. PPh(4)[Br(N-Bromophthalimide)(2)] (4): Space group P (1) over bar, Z = 2, structure solution with 3413 observed unique reflections, R = 0.044. Lattice dimensions at -50 degrees C: a = 1120.2(2), b = 1308.6(3), c = 1343.2(3) pm, alpha = 105.10(3)degrees, beta = 104.16(3)degrees, gamma = 92.99(3)degrees. The structures of 1-4 consist of PPh(4)(+) ions, anions [X(N-bromosuccinimide)(2)](-) and [X(N-bromophthalimide)(2)](-), respectively, in which the halide ions X(-) are coordinated by the bromine atoms of N-bromosuccinimide and N bromophthalimide molecules, respectively. The bond angles Br...X...Br are 86.48(5)degrees for 1, 85.1(1)degrees for 2, 102.31(6)degrees and 93.61(6)degrees for 3, and 91.86(4)degrees for 4. The bend angles N-Br...X are nearly linear.