JM Pearson

Publications (8)0 Total impact

• Article: DRAMATIC ACCELERATION OF MIGRATORY INSERTION IN [MEIR(CO)(2)I-3](-) BY METHANOL AND BY TIN(II) IODIDE

  JM Pearson, A Haynes, GE Morris, GJ Sunley, PM Maitlis
  Journal Of The Chemical Society D-Chemical Communications. 01/1995;
• Article: Relative Reaction-Rates for Rhodium and Iridium - Oxidative Addition of Methyl-Iodide to M(I) and the Migratory Insertion in M(Iii) Methyl Carbonyl-Complexes

  M Bassetti, D Monti, A Haynes, JM Pearson, IA Stanbridge, PM Maitlis
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  ABSTRACT: Oxidative addition of MeI to an Ir(I) centre is 4-120 times faster than that to an analogous Rh(I) centre, whereas the migration of methyl onto coordinated CO in the cor-responding systems is 10(5)-10(6) times faster for Rh(III) than Ir(III).
  Gazzetta chimica Italiana 01/1992; 122(9):391-393.
• Article: Cis-trans isomerism in [M(CO)(2)I-4](-) (M = Rh, Ir): Kinetic, mechanistic and spectroscopic studies

  A Haynes, J McNish, JM Pearson
  Journal Of Organometallic Chemistry. 551:339-347.
• Article: Model reactions of a carbonylation catalyst: phosphite induced migratory CO insertion in [MeIr(CO)(2)I-3](-)

  A Haynes, JM Pearson, PW Vickers, JPH Charmant, PM Maitlis
  Inorganica Chimica Acta. 270:382-391.
• Article: Oxidative addition of methyl iodide to [Rh(CO)(2)I](2): synthesis, structure and reactivity of neutral rhodium acetyl complexes, [Rh(CO)(NCR)(COMe)I-2](2)

  A Haynes, PM Maitlis, IA Stanbridge, S Haak, JM Pearson, H Adams, NA Bailey
  Inorganica Chimica Acta. 357(10):3027-3037.
• Article: Oxidative Addition of Alkyl-Halides to Rhodium(I) and Iridium(I) Dicarbonyl Diiodides - Key Reactions in the Catalytic Carbonylation of Alcohols

  PR ELLIS, JM Pearson, A Haynes, Harry Adams, NA Bailey, PM Maitlis
  Organometallics. 13(8):3215-3226.
• Article: Theoretical and experimental evidence for S(N)2 transition states in oxidative addition of methyl iodide to cis-[M(CO)(2)I-2](-) (M=Rh, Ir)

  TR Griffin, DB Cook, A Haynes, JM Pearson, D Monti, GE Morris
  Journal Of The American Chemical Society. 118(12):3029-3030.
• Conference Proceeding: Kinetics and thermodynamics of C-Cl boric activation by [Ir(Co)(2)Cl-2](-)

  PW Vickers, JM Pearson, T Ghaffar, H Adams, A Haynes
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  ABSTRACT: Kinetic measurements are reported for the oxidative addition reactions of methyl chloride and acetyl chloride with [Ir(CO)(2)Cl-2](-). At 40degreesC the second-order rate constant for MeCOCI addition is estimated to be nearly 40000 times larger than that for MeCl addition. The Ir(III) products, [Ir(CO)(2)Cl3R](-) (R =Me, COMe) have been isolated and characterised by spectroscopy and x-ray crystallography. In the absence of excess organic chloride, both Ir(III) complexes undergo reductive elimination of RCI. Kinetic measurements show these reactions to be first order in the Ir(III) complex with elimination of MeCOCl estimated to be ca 7000 times faster than MeCl elimination at 40degreesC. Combination of activation parameters for the forward and reverse reactions allows calculation of thermodynamic parameters for oxidative addition. Both MeCl and MeCOCl additions are exothermic (by 44 and 68 kJ mol(-1), respectively) but disfavoured entropically. The trends are predicted satisfactorily by ab initio and DFT computational methods. The results for MeCl addition to [Ir(CO)(2)Cl-2](-) are compared with data for MeI addition to [Ir(CO)(2)I-2](-). Kinetic data are also reported for carbonylation of [Ir(CO)(2)Cl3Me](-) into [Ir(CO)(2)Cl-3(COMe)](-) under mild conditions in PhCl-MeOH. It is concluded that the low activity of iridium-chloride carbonylation catalysts is due primarily to the relatively slow reaction of [Ir(CO)(2)Cl-2](-) with MeCl. Copyright (C) 2004 John Wiley Sons, Ltd.