Lewis-base adducts of Group 11 metal(I) compounds .67. Synthesis, spectroscopy and structural systematics of some 1:3 adducts of silver(I) compounds with triphenylarsine, [(Ph3As)(3)AgX], X = Cl, Br, I, SCN

The syntheses and room-temperature single-crystal X-ray structure determination of 1:3 adducts formed between silver(I) (pseudo-)halides, AgX, and triphenylarsine, AsPh3, are described (X = Cl, Br, I, SCN), [(Ph3As)(3)AgX], (1)-(4). The chloride (1) has been previously described as its acetone hemisolvate; other solvates (1a-d) (0.75 MeCN, MeOH, 1.5 pyridine, 0.75 2,6-dimethylpyridine) are isomorphous, being triclinic, <P(1)over bar>, a approximate to 13.5, b approximate to 14.0, c approximate to 14.25 Angstrom, alpha approximate to 83, beta approximate to 87, gamma approximate to 76 degrees, V approximate to 2600 Angstrom(3), Z = 2f.u. The bromide (2), iodide (3) and thiocyanate (4) are isomorphous with [(Ph3P)(3)AgI], monoclinic, P(2)1/n, a approximate to 19.1, b approximate to 14.0, c approximate to 17.7 Angstrom, beta approximate to 97 degrees, Z = 4 f.u. In the chlorides, Ag-Cl are 2.494(5)-2.525(6) Angstrom, with appreciably different Cl-Ag-As ranges (99.7(1)-114.3(1)degrees in the acetonitrile solvate; 104.8(2)-110.2(1)degrees in the 2,6-dimethylpyridine solvate) and more compact As-Ag-As distributions (overall range: 109.93(8)-113.26(3)degrees). For the bromide and iodide, Ag-X are 2.627(1) and 2.779(1) Angstrom respectively, while for the thiocyanate Ag-S is 2.550(5) Angstrom with Ag-S-C 104.2(3)degrees; the latter complexes also display wide ranges for many of the associated bonding parameters about the silver atom. The far-infrared spectra of [(Ph3As)(3)AgX] (X = Cl, Br, I) show v(AgX) bands at 217, 145 and 124 cm(-1) respectively. The relationship between the v(AgX) wavenumbers and the Ag-X bond length r(AgX) is found to be the same as that for a range of AgX complexes with phosphine ligands, and is similar to that observed previously for analogous CuX complexes.