Synthesis and Structural Characterization of Some 1:1 and 1:2 Adducts of Silver(i) Salts with Hindered Pmes3, PPhmes2 and PPh2mes Bases (ph = Phenyl, Mes = 2,4,6-Trimethylpheny1))

A number of 1:2 or 1:1 Ag(I)X:L complexes formed between silver(I) salts, Ag(I)X, and P-donor ligands (L) PPh((3- n))mes(n) ('mes' = 2,4,6-trimethylphenyl) have been synthesized and spectroscopically and structurally characterized. Ag(I)X:Pmes(3) (1:2) (solvated) are of the ionic form [Ag(Pmes(3))(2)]X-+(-), with linear two-coordinate silver atom environments; for X = C1O(4)(-), CF3SO3- (= 'tfs(-)'); with X = NO3-, the 1:1 complex [(mes(3)P)Ag(O, O'-NO3)] is obtained but with Ag(I)tfa ('tfa(-)' = CF3CO2-), [(mes(3)P)Ag(O,O'-tfa)(NCMe)] has been defined, incorporating MeCN solvent. The 1:2 adducts with PPhmes(3)/NO3- and PPh(2)mes(3)/C1O(4)(-), tfs(-), NO3-, tfa(-), ac(-) (=CH3CO2-), SCN- are all of the form [(X-O,O')AgL2] (unidentate SCN excepted). Ag(I)I:PPhmes(2) (1:1) takes the 'cubane' tetramer form, while Ag(I)SCN:PPh(2)mes (1:1) adopts the (expanded) chair tetramer alternative. A remarkable Ag(I)I:PPh(2)mes adduct has been isolated, being of 4:3 (x2) Ag(I)I:L stoichiometry, comprising a pair of Ag4I4 cubane units each with three associated phosphine ligands, fused through a central Ag4I4 four-membered ring, the array being centrosymmetric.