Lewis-Base Adducts of Group 11 Metal(I) Compounds. LXVII Synthesis, Spectroscopy and Structural Systematics of Some 1 : 3 Adducts of Silver(I) Compounds with Triphenylarsine, [(Ph3As)3AgX], X = Cl, Br, I, SCN

Abstract

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)₃AgX], (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, a ≈ 13·5, b ≈ 14·0, c ≈ 14·25 Å, α ≈ 83, β ≈ 87, γ ≈ 76°, V ≈ 2600 ų, Z = 2 f.u. The bromide (2), iodide (3) and thiocyanate (4) are isomorphous with [(Ph₃P)₃AgI], monoclinic, P2₁/n, a ≈ 19·1, b ≈ 14·0, c ≈ 17·7 Å, β ≈ 97°, Z = 4 f.u. In the chlorides, Ag–Cl are 2·494(5)–2·525(6) Å, with appreciably different Cl–Ag–As ranges (99·7(1)–114·3(1)° in the acetonitrile solvate; 104·8(2)–110·2(1)° in the 2,6-dimethylpyridine solvate) and more compact As–Ag–As distributions (overall range: 109·93(8)–113·26(3)°). For the bromide and iodide, Ag–X are 2·627(1) and 2·779(1) Å respectively, while for the thiocyanate Ag–S is 2·550(5) Å with Ag–S–C 104·2(3)°; the latter complexes also display wide ranges for many of the associated bonding parameters about the silver atom. The far-infrared spectra of [(Ph₃As)₃AgX] (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.