X-Ray photoelectron spectroscopic characterization of [{Pt(PPh3)2(µ3-S)}2PtCl2], [{Pt2(PPh3)4(µ3-S)2Cu}2(µ-dppf)][PF6]2[dppf = Fe (C5H4PPh2)2] and other heterometallic aggregates derived from [{Pt(PPh3)2(µ-S)}2]

Abstract

Lewis acid–base reactions between [{Pt(PPH₃)₂(µ-S)}₂] and [{Cu(NO₃)(µ-dppf)}₂]–NH₄PF₆[dppf = Fe(C₅H₄PPh₂)₂] and [PtCl₂(NCMe)₂] gave hexanuclear [{Pt₂(PPh₃)₄(µ₃-S)₂Cu}₂(µ-dppf)][PF₆]₂ and trinuclear [{Pt(PPh₃)₂(µ₃-S)}₂PtCl₂] respectively. X-Ray photoelectron spectroscopic (XPS) studies of these sulfur aggregates were made together with other known alkylated complexes [Pt₂(PPh₃)₄(µ-S)(µ-SR)]X (R = Me, X = 1; R = CH₂Cl, X = Cl; R = CHCl₂, X = PF₆; R = CH₂Ph, X = PF₆) and metallated complexes [{Pt₂(PPh₃)₄(µ-S)₂}_xML]ⁿ⁺nX^–[M = Ni, L = Ph₂PCH₂CH₂PPh₂(dppe), X = PF₆, x= 1; M = Pd₂, L =(µ-Cl)₂, X = PF₆, x= 2; M = Ag₂, X = NO₃, x= 2; M = Au, L = PPh₃, X = PF₆, x= 1; M = Hg, X = PF₆, x= 2; M = Hg, L = dppe, X = PF₆, x= 1; n= 2 for all M except Au where n= 1]. The observed binding energies are related to the charge distribution and nucleophilicity of the sulfur centres. The possibility of using multinuclear XPS [S(2p), P(2p), Cl(2p), Pt(4f)] to distinguish chemically inequivalent nuclei is examined.