Photochemical synthesis and characterization of mono- and bi-nuclear tungsen tetracarbonyl complexes of 2,2'-biquinoline and 2,3-bis(2- pyridyl) pyrazine
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Date
2002
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Abstract
The mononuclear and binuclear complexes of the type [W(CO)4JL] and [{W(CO)4}2]L, where L= 2,3-bis(2-pyridyl)pyrazine(BPPX 2,2' -biquinoline^QN), 2,2,-bipyrimidine(BPY]Vf)J and 2,2'-bipyidine(BPY), have been synthesized by direct photolysis of the metal hexacarbonyl and indirect route via THF substitution. In the second method, tungsten hexacarbonyl was first irradiated in THF to yield [W(CO)sTHF| and the THF was then replaced by the desired ligand.
All complexes were characterised by a combination of infrared, UV-visible, *H NMR, mass spectroscopy and elemental analysis. Infrared spectra indicate that the complexes have approximately Cz* local symmetry. The absorption spectra of the complexes show intraligand band in the UV region and a broad metal-to-ligand charge-transfer (MLCT). The latter bands are red-shifted in the binuclear complexes. For comparison purposes, the properties of free ligands have also been studied. The complexes have electronic spectra dominated by intense MLCT transition in the visible region of the spectrum.
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Submitted to the Faculty of Science and Agriculture in partial fulfillment of the requirement for the award of the degree of Master of Science in the Department of Chemistry at the University of Zululand, South Africa. 2002.
Keywords
Photochemistry, Chemistry