Stability of Methyl Platinum Complexes in Water: The Role of pH and Geometry

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• 作者：Derrick W. Lucey ; Derrik S. Helfer ; and Jim D. Atwood
• 刊名：Organometallics
• 出版年：2003
• 出版时间：February 17, 2003
• 年：2003
• 卷：22
• 期：4
• 页码：826 - 833
• 全文大小：120K
• 年卷期：v.22,no.4(February 17, 2003)
• ISSN：1520-6041

文摘

Several water-soluble platinum(II) complexes containing methyl ligands have beenprepared, PtMe₂L₂ and Pt(Cl)(Me)L₂ (L₂ = two P(m-C₆H₄SO₃Na)₃, TPPTS; (m-C₆H₄SO₃Na)₂PCH₂CH₂P(m-C₆H₄SO₃Na₂), DPPETS; (m-C₆H₄SO₃Na)₂PCH₂CH₂CH₂P(m-C₆H₄SO₃Na)₂,DPPPTS; or (m-C₆H₄SO₃Na)₂PCH₂CH₂CH₂CH₂P(m-C₆H₄SO₃Na)₂, DPPBTS), to establish thestability of the platinum methyl bond in aqueous solution. From pH = 3 to 14 there is noreaction other than ligand substitution of H₂O or OH^- for Cl^-; there is no CH₃OH elimination.At lower pH's protonolysis of the Pt-Me bond occurs, producing CH₄. Dissolving PtMe₂L₂into a solution of HCl at pH = 1 rapidly produces PtCl₂L₂ for the bidentate ligands, buttrans-Pt(Cl)(Me)L₂ is observed for the monodentate ligands. trans-PtClMe(TPPTS)₂ undergoesprotonolysis very slowly, indicating an important role for geometry in protonolysis reactions.The protonolysis reactions occur stereospecifically but are sometimes accompanied by cis-trans isomerization. The cis or trans thermodynamic preferences, cis-PtCl₂L₂, cis-PtMe₂L₂,cis-Pt(OH)(Me)L₂, trans-Pt(Cl)(Me)L₂, and trans-Pt(H₂O)(Me)L₂⁺, are not easily explained.