Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. XII. Dissociation of the Olefin in trans-Dichloro(4-methyl-1-pentene)(4-substituted pyridine 1-oxide)platinum(II) Complexes

Publisher Website
Google Scholar
Abstract
The rates of dissociation of the olefin in the title compounds were determined by the dynamic NMR technique by taking advantage of the line shape change due to the isopropyl-methyl protons. The rates of dissociation were independent of concentration in bromoform-d solutions. The free energy of activation was between 17.0 and 19.1 kcal mol−1 at 353 K for the compounds, of which line shapes were fully analyzed, depending upon the substituent in the pyridine ring and electron-withdrawing substituents giving low activation energy. The solvent effect was noticed on the dissociation rates: Aromatic hydrocarbons give higher rates of dissociation than halogenated hydrocarbons. Although solvents of strong affinity toward platinum(II) tend to decompose the complex, tetrahydrofuran-d8 was found to give definitely higher rates of dissociation of the olefin in trans-dichloro(4-methoxycarbonylpyridine 1-oxide)(3-methyl-1-butene)platinum(II) than bromoform-d, when it was used as a solvent. The mechanism of dissociation was discussed from the available data.

This publication has 20 references indexed in Scilit: