Influence of a thioether function in short-bite diphosphine ligands on the nature of their silver complexes: structure of a trinuclear complex and of a coordination polymer

Abstract

New cationic Ag(I) complexes were prepared by reaction of AgBF₄ with two thioether-functionalized bis(diphenylphosphino)amine ligands, Ph₂PN(p-ArSMe)PPh₂ (L1) and Ph₂PN(n-PrSMe)PPh₂ (L2), and compared with those obtained from the unfunctionalized ligands Ph₂PN(Ph)PPh₂ (L3) and Ph₂PN(n-Bu)PPh₂ (L4), respectively. The complex [Ag₃(μ₃-Cl)₂(μ₂-L1-P,P)₃](BF₄) (1·BF₄) contains a triangular array of Ag centres supported by three bridging L1 ligands and two triply-bridging chlorides. In contrast, ligand L2 led to the coordination polymer [{Ag₂(μ₃-L2,-P,P,S)₂(MeCN)₂}{Ag₂(μ₂-L2-P,P)₂(MeCN)₂}(BF₄)₄]_n (2) in which the tethered thioether group connects intermolecularly a Ag₂ unit to the diphosphine bridging the other Ag₂ unit. With L3 and L4, two similar complexes were obtained, [Ag₂(μ₂-L3)(BF₄)₂] (3) and [Ag₂(μ₂-L4)(BF₄)₂] (4), respectively, with bridging diphosphine ligands and a BF₄ anion completing the coordination sphere of the metal. Complexes 1·BF₄·CH₂Cl₂, 2·THF, 3·3CH₂Cl₂ and 4 have been fully characterized, including by single crystal X-ray diffraction.