Lewis-base adducts of Group 11 metal(I) compounds .72. Synthesis, spectroscopy and structural systematics of some 1:2 binuclear complexes of silver(I) halides with triphenylstibine, [(Ph3Sb)(2)Ag(mu-X)(2)Ag(SbPh3)(2)], X = Cl, Br, I

Syntheses and room-temperature single-crystal X-ray structural characterization of binuclear 1:2 adducts formed between silver(I) halides, AgX (X = Cl, Br, I), and triphenylstibine, SbPh3, are described. The three complexes are isomorphous, being triclinic, <P(1)over bar>, a approximate to 18.5, b approximate to 14.6, c approximate to 14.5 Angstrom, alpha approximate to 62.5, beta approximate to 74, gamma approximate to 77 degrees, Z = 2 centrosymmetric dimers. Conventional R on \F\ were 0.043, 0.038 and 0.046 for 4984, 8479 and 4166 independent, 'observed' (I > 3 sigma(I)) reflections respectively. In [(Ph3Sb)(2)Ag(mu-X)(2)Ag(SbPh3)2], Ag-Sb range between 2.702(1) and 2.744(2) Angstrom, lengthening slightly from chloride to iodide; Ag-X are 2.567(5)-2.628(4) (Cl), 2.684(1)-2.737(1) (Br) and 2.826(3)-2.869(3) Angstrom (I). The far-infrared spectra of [(Ph3Sb)(2)Ag(mu-X)(2)Ag(SbPh3)(2)] show v(AgX) bands at 178, 158 (X = Cl), 121 (X = Br) and 110 cm(-1) (X = I). The splittings and band widths reflect a decrease in the degree of distortion of the Ag(mu-X)(2)Ag units from a symmetrically bridged structure from X = Cl to I.