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Esr of organometallics

1981; Elsevier BV; Volume: 212; Issue: 1 Linguagem: Inglês

10.1016/s0022-328x(00)85527-8

1872-8561

Niall J. Gogan, Ian L. Dickinson, James Alfred Doull, J. R. Patterson,

Free Radicals and Antioxidants

The radical anions RC6H4COC6H4R1Cr(CO)3− (R = H, o-CH3, p-CH3, p-OCH3, p-Cl, p-F and R1 = H; R = H, R1 = o-CH3, p-CH3) were prepared by potassium reduction in 1,2-dimethoxyethane and their ESR spectra measured. Each has a spectrum width of about half that of the corresponding ligand. Both coordination isomers of the o-CH3 complexes and the ligand have spectra consisting of four lines assigned to splittings from the para- and ortho-protons of the unsubstituted ring with Ap = Ao. The p-CH3 complexes both have 7-line spectra assigned to splittings from the two sets of o-protons one set having half the hyperfine splitting of the other. The reduction in hyperfine splitting of the uncomplexed as well as the complexed ring protons is an indication that the unpaired electron density is delocalized throughout the ligand system.