- BOND ENERGIES AND THERMAL DECOMPOSITION OF 2> COMPLEXES
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The thermal decomposition of the complexes trans- (L = P(C2H5)3; X = Cl, Br, I, CN) in decalin at 170 and 200 deg affords methane, platinum metal and .The kinetics of the decomposition of the complexes were determined by monitoring the appearance of methane by GLC.The observed first-order rate constant was found to be independent on the nature of the ligand X.The thermal decomposition of the trideuteriomethyl complexes (X = I, CN) in decalin-d18 at 170 and 200 deg C was studied by GLC/MS.The thermolysis affords CD3H and CD4 in ratios which are independent of the nature of X and of the temperature used.The mass spectra of the complexes were also examined.A relative scale of platinum-to-methyl bond dissociation energies has been established by measuring the appearance potential of the fragment ion + and the ionization energies in the series .Ionization potentials and Pt-CH3 bond energies show a clear dependence on the nature of X which is not reflected in corresponding changes in the decomposition rates.
- Morvillo, A.,Favero, G.,Turco, A.
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p. 111 - 118
(2007/10/02)
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- δ-Hydrogen Abstraction from Alkyl and Phosphine Ligands Co-ordinated to Platinum(II); Formation of Benzoplatinacyclopentene Complexes
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Reactions of (cod = cyclo-octa-1,5-diene) with Mg(CH2C6H4Me-o)Br and tertiary phosphines (PR3) afford cis- (R = Et or Ph), which on refluxing in xylene give the benzoplatinacyclopentene complexes via δ-hydrogen abstraction reactions.Using PPh2(C6H4Me-o), metallation of the phosphine is preferred and the first obtained product after refluxing in xylene is >.On further refluxing in xylene, this compound again eliminates o-xylene to give the known .Using P(C6H4Me-o)3, the bulkiness of the phosphine makes alkylation unfavourable and the fluxional Br> is obtained.The variable-temperature n.m.r. spectra of this compound are interpreted in terms of hindered rotation around the Pt-P and P-C bonds giving rise to two different conformers at low temperature, each with all methyl groups non-equivalent.The compounds have been identified by their spectroscopic properties and some of their reaction chemistry is discussed.
- Chappell, S. David,Cole-Hamilton, David J.
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p. 1051 - 1058
(2007/10/02)
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