STRUCTURE AND REACTIVITY OF THE (ETA-6-MESITYLENE)(ETA-2-MALEIC ANHYDRIDE) CHROMIUM-DICARBONYL COMPLEX

The structure of (η6-mesitylene)(η2-maleic anhydride) chromium-dicarbonyl was studied and it was established that the olefin ligand is symmetrically bonded with the chromium atom, the double bond turns out to be practically parallel to the benzene ring plane, the double bond length (1.433(10) Å) considerably exceeding its value in the non-coordinated molecule of maleic anhydride (1.303 Å). The five-membered heterocyclic is not completely planar, the oxygen atom deviates by 0.09 Å from the mean plane of the remaining four atoms of the cycle. The hydrogen isotope exchange reaction of the complex in CF3COOD was investigated and it was established that replacement of the CO ligand by the stronger electron accepting ligand maleic anhydride leads to an approximately 20-fold decrease of the rate constant of this reaction. © 1979.