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207Pb, 13C and 1H Nuclear Magnetic Resonance Studies of Lead(IV) Carboxylates in Solution

✍ Scribed by T. D. W. Claridge; E. J. Nettleton; M. G. Moloney

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 374 KB
Volume: 35
Category: Article
ISSN: 0749-1581
DOI: 10.1002/(sici)1097-458x(199703)35:3<159::aid-omr51>3.0.co;2-p

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✦ Synopsis

Lead(IV) reagents are widely used for the mediation of oxidation and carbon-carbon bond-forming reactions, which are postulated to proceed by mechanisms involving ligand exchange processes at the metal centre. This paper reports multinuclear (207Pb, 13C and 1H) magnetic resonance studies on lead(IV) carboxylates containing acetate, benzoate and cinnamate ligands, either as single-ligand or as mixed-ligand species. At ambient

) probe temperatures (ca. 300 K), averaged spectra were observed for all solution species, arising from rapid intermolecular ligand exchange. At 225 K, exchange was sufficiently slow for mixed-ligand complexes, of general formula to exhibit spectra of Ðve distinct complexes, which were shown to correspond to

4-m Analysis of the low-temperature spectra presented an overall picture of chemical shift changes throughout the complexes when ligand exchange takes place. These data provide some insight into the behaviour of these complexes in solution which help explain the observed chemistry of more elaborate lead(IV) carboxylates.

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