Structural and spectroscopic studies on copper, silver and gold complexes of mixed phosphathia ligands and their chalcogenide derivatives

Reaction of [Cu(MeCN)(4)]PF6 or AgBF4 with 1 molar equivalent of Ph(2)P(E)(CH2)(2)SZS(CH2)(2)(E)PPh(2) [Z = (CH2)(2), E = S (L(1b)) or Se (L(1c)); Z = (CH2)(3), E = none (L(2a)), S (L(2b)) or Se (L(2c)); Z = o-C6H4, E = none (L(3a)), S (L(3b)) or Se (L(3c))] in degassed acetone followed by addition of diethyl ether yielded the mononuclear complexes [ML]X (M = Cu, X(-) = PF6-; M = Ag, X(-) = BF4-) in high yield. The gold(I) species [AuL]PF6 were obtained by reaction of L (= L(1b), L(1c), L(2b), L(2c) or L(3a)-L(3c)) with 1 molar equivalent of [AuCl(tht)] (tht = tetrahydrothiophene) and TlPF6. All of these products have been characterised by H-1, P-31-{H-1} (and in some cases Se-77-{H-1} and Ag-109) NMR and IR spectroscopy, FAB or electrospray mass spectrometry and microanalyses. The data indicate four-co-ordination for all of the copper(I) and silver(I) species and this assignment has been confirmed by single-crystal structure determinations on three copper(I) examples. Spectroscopic studies on [AuL]PF6 indicated linear two-co-ordination on average, via the phosphine, phosphine sulfide or phosphine selenide functions as appropriate. Variable-temperature P-31-{H-1} (and Se-77-{H-1}) studies showed that the chalcogenide complexes are considerably more labile in solution than the phosphathia ligand complexes. Crystal structure determinations on [CuL(3a)](+), [CuL(1c)](+) C, [AgL(1c)](+) and [CuL(2b)](+) each showed the metal ion co-ordinated to all four donor atoms of a single ligand in the solid state, giving an overall distorted-tetrahedral stereochemistry. In the case of [CuL(1c)](+) then is a slight lengthening of the P-Se bond length compared to that of the unco-ordinated form of L(3c). Syntheses for the new pro-ligands are also detailed.