engleski

New molybdenum(VI) complexes: models for molybdoenzymes

Molybdenum plays an essential role in the active site of many hydroxylases such as e.g. sulfite oxidase, nitrate reductase, xanthine oxidase. All these enzymes contain a common cofactor (Moco) composed of an oxo-molybdenum unit. The involvement and importance of molybdenum as oxo-metal species in their respective metalloenzymes has led to renewed interest in the chemistry of molybdenum(VI) model compounds. Similarly, the heteroconjugated systems such as beta'-hydroxy-beta-enaminones are of interest when studying the correlation of their steric, electronic and hydrogen bonding effects with their possible relevance to some biological processes. As an extension to our previous work on the molybdenum(V) complexes with beta'-hydroxy-beta-enaminones we report here a series of novel molybdenum(VI) complexes of general formula MoO2L2. These complexes were prepared by the reactions of [MoO_2(acac_2] (acac = acetilacetonate ion) with beta'-hydroxy-beta-enaminones containing different substituent at the nitrogen atom (R = phenyl, o-anisidine or p-anisidine). L is coordinated to molybdenum in a didentate manner through the deprotonated hydroxyl groups and ketone moieties. The complexes were characterized by means of chemical analyses, IR-spectroscopy and by X-ray crystallography.

molybdoenzymes; molybdenum(VI) complexes; enaminones

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