Combined Kinetico‐Mechanistic and Theoretical Elucidation of the Oxidative Addition of Iodomethane to Cycloplatinated(II) Complexes: Controlling the Rate of trans/cis Isomerization. Issue 20 (31st May 2017)

• Record Type: Journal Article
• Authors: Shahsavari, Hamid R.; Babadi Aghakhanpour, Reza; Babaghasabha, Mojgan; Golbon Haghighi, Mohsen; Nabavizadeh, S. Masoud; Notash, Behrouz
• Is Part Of: European journal of inorganic chemistry. Issue 20(2017)
• Page Start: 2682
• Page End: 2690
• Publication Date: 2017-05-31
• Subjects: Oxidative addition -- Platinum -- Kinetics -- Reaction mechanisms -- Density functional calculations; Chemistry, Inorganic -- Periodicals; Organometallic chemistry -- Periodicals; Bioinorganic chemistry -- Periodicals; Solid state chemistry -- Periodicals; 546
• DOI: 10.1002/ejic.201700088
• Languages: English
• ISSNs: 1434-1948

Abstract

Abstract : The oxidative addition of iodomethane to cycloplatinated(II) complexes containing allyldiphenylphosphane (PPh2 allyl) ligands, namely, [Pt(C ^ N)Me(PPh2 allyl)] [1 –4 ; C ^ N = deprotonated 2‐phenylpyridyne (ppy), 1 ; 2, 2′‐bipyridine (bpy), 2 ; 2, 2′‐bipyridine N ‐oxide (O‐bpy), 3 ; and 7, 8‐benzoquinoline (bzq), 4 ], occurs readily with trans stereochemistry to give the trans ‐Pt IV isomers1a –4a, which then transform slowly to the cis ‐Pt IV isomers1b –4b . All of the complexes were characterized by NMR spectroscopy, and the structures of1b, 3a, and3b were determined by single‐crystal X‐ray diffraction. Kinetic studies through UV/Vis spectroscopy suggested that the oxidative addition reaction proceeded through an SN 2 reaction. The rate of the oxidative addition reaction was measured at different temperatures, and large negative Δ S ≠ values consistent with the proposed mechanism were found for each reaction. This reaction was also monitored by NMR spectroscopy to determine a correct value for the rate of the trans/cis isomerization. The theoretical aspects of the mechanism for the oxidative addition reaction were also studied by density functional theory (DFT) calculations to support the claimed experimental results. Abstract : The isolation of the trans geometric isomer from the oxidative addition of iodomethane to cycloplatinated(II) complexes depends on the nature of the cyclometalated moiety, and a comprehensive kinetico‐mechanistic study of this reaction is described.