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.