The compounds (PPh3)3CuOClO3 and (PPh3)3CuONO2(as its mono-ethanol solvate) have been characterized by single-crystal structure analysis. Crystals of the perchlorate are trigonal , P3, a 18.748(8), c 11.731(6)Ǻ, Z 3, and are isomorphous with the chloride and tetrafluoroborate structures. R was 0.062 for No = 1452 independent 'observed' reflections. Cu-P distances are 2.314(5), 2.313(7) and 2.317(8)Ǻ for each of the three molecules in the unit cell. P-Cu-P angles are 114.5(3), 114.4(3) and 115.6(3)°; Cu-O are 2.32(3), 2.23(3) and 2.23(3)Ǻ. Crystals of the nitrate are monoclinic, P21/n, a 14.875(5), b 23.349(7), c 14.141(7) Ǻ, β 91.73(3)°, Z 4. R was 0.045 for No = 4066. Cu-P distances are 2.312(2), 2.337(2) and 2.339(2)Ǻ; P- Cu-P angles are 114.15(7), 121.37(6) and 113.42(6)°. The nitrate group is monodentate with Cu-O, 2.174(4)Ǻ and Cu-O-N, 124.8(4)°.

Valiev's suggestion of excitation of the vibrational modes of the octahedron is considered as a spin relaxation mechanism for 59Co spins in some symmetric, bidentate CoIII complexes. His theory is extended to the spin 7/2 system; the efficiency of the mechanism is very sensitive to the molecular size with larger complexes having much shorter T1 values. Experimental evidence in support of the mechanism is provided by the contradictory values of quadrupole coupling constants calculated experimentally by assuming rotational reorientation to be the dominant time process and by measurements on a variety of CoIII complexes. Rotational correlation times were measured from 13C T1 values of protonated carbons in the complex. An X-ray structure determination of tris(tropolonato)-cobalt(III) is reported in support of the suggested relaxation mechanism. The differences between T1 and T2 in some CoN6 complexes are shown to arise from unresolved 59Co-14N scalar coupling.

Adducts (1 : 1) of copper(I) chloride, bromide and thiocyanate with quinoline have been synthesized and have been the subject of single-crystal X-ray structure determinations at 295 K. Crystals of the chloride are orthorhombic, P 212121, a 15.358(7), b 14.309(6), c 3.801(2)Ǻ, Z 4; R was 0.055 for 541 'observed' reflections. Crystals of the bromide are monoclinic, C2/c, a 19.417(5), b 14.048(4), c 15.753(6) Ǻ, β 125.31(2)°, Z 4 tetramers; R was 0.049 for 1138 'observed' reflections. Crystals of the thiocyanate are monoclinic, P 21/c, a 5.682(1), b 10.412(2), c 16.838(5)Ǻ, β 97.48(2)°, Z 4 f.u .; R was 0.045 for 914 'observed' reflections. The chloride takes the form of the common 'stair' polymer, unexpectedly, while the thiocyanate is an expanded version of the same. The bromide provides a second example of a novel tetrameric 'basket' structure exemplified previously by the iodide analogue.

Tetrameric 1:1 complexes of butyldiphenylphosphine (PPh2Bu) with silver halides AgX (X = Cl , Br and I) have been synthesized, and characterized in the solid state by single-crystal X-ray diffraction studies and solid-state 31P n.m.r. Crystals of [(PPh2Bu) AgCl ]4 and [(PPh2Bu) AgBr ]4 are isostructural, crystallizing in the tetragonal space group 14 with a 16.853(4), c 11.697(4) Ǻ and R 0.060 for 999 'observed' reflections for X = Cl, and a 16.944(4), c 11.893(9) Ǻ and R 0.044 for 835 'observed' reflections for X = Br. The structures consist of 'cubane' units with core distances of Ag-P 2.365(8), Ag- Cl 2.712(7), 2.682(6) and 2.569(6) Ǻ for the chloride, and Ag-P 2.408(6), Ag-Br 2.819(3), 2.806(3) and 2.670(3) Ǻ for the bromide. Crystals of [(PPh2Bu) AgI ]4 crystallize in the same space group with similar cell dimensions, a 16.559(4) and c 12.819(3) Ǻ, and R 0.053 for 638 'observed' reflections. However, the tetramers in this complex are rotated by 45° around the c axis with apparent relaxation of strain at the Ag-P bond. The ligand conformation is such that the butyl groups are oriented along the c axis rather than lying in the ab plane as found for the chloride and bromide structures. The bond distances for the I3AgP core are Ag-P 2.43(1), Ag-I 2.928(4), 2.882(4) and 2.885(4) Ǻ. The ligand substituents in this complex exhibit very high thermal motion although no disorder is resolved. Solid-state CPMAS 31P n.m.r. spectra of the chloride and bromide complexes each show a simple doublet with line spacing of 640 and 595 Hz respectively assignable to 1J(107,109Ag,31P) scalar coupling. The spectrum of the iodide complex, however, consists of a broad single peak suggestive of a high degree of disorder in the crystal lattice, consistent with the structural results.

A single-crystal X-ray structure determination of bis[{N,N'-(1,3-dimethylpropanediyldene)dianilinato)(1-)]nickel(II) at 295 K shows that, within each of the two independent molecules of the complex within the structure, the nickel atom is chelated by two of the bidentate ligands and is thus four-coordinate. Because of the intramolecular interactions between the phenyl substituents of the ligands, the metal atom environments are highly irregular, although consistent between the two molecules. There are no significant deviations in the Ni-N distances from the mean of 1.965�; but the interligand N-Ni-N angles about the nickel range from 110.4 to 134.7�. A theoretical calculation of the 13C and 1H nuclear relaxation times using the X-ray-determined metal-nuclear separations reproduces the experimentally observed relaxation times for selected positions within the complex, provided ligand-centred effects are taken into account. Mathematical complexity prevents a complete theoretical calculation of the relaxation times for ligand atoms with varying distances from the nickel atom.