Isotopic labelling applied to the infrared spectra of metal complexes

Engelter, Carola

Isotopic labelling applied to the infrared spectra of metal complexes

Doctoral Thesis

1977

Publisher

University of Cape Town

Department

Department of Chemistry

Faculty

Faculty of Science

Abstract

The infrared spectra of pyridine adducts of first transition series metal(II) acetylacetonates are discussed in relation to the band shifts induced by ¹⁵N-labelling and deuteration of the pyridine ring and by metal ion substitution. ¹⁵N-Labelling aids in establishing the pyridine ring vibrations, while deuteration and metal substitution are more useful in assigning the νM-L frequencies. Results of the isotopic labelling study lead to a revision of previously-reported νM-O and vC---O frequencies. This technique also facilitates assignment of the νM-N vibrations, observed in the region below 200 cm⁻¹. The occurrence of these bands in this spectral region was expected because of the known relative weakness of the M-N bond strength in pyridine adducts. The effects on the spectra resulting from introduction of a variety of substituents into the pyridine ring are discussed on the basis of the electronic effects of the substituents. After allowing for mass effects, electron-withdrawing substituents are found to decrease νNi-N frequencies while electron-releasing substituents exert negligible effect on the νNi-N bands. An opposite trend is, however, observed for the νNi-O bands and is explained. An investigation of a series of aniline and p-toluidine complexes of first transition metal(II) isothiocyanates is reported.

Keywords

Chemistry

Inorganic Chemistry

Reference:

Collections

PhD / Doctoral

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