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The kinetics of the reactions of 1-(2-pyridylazo)-2-naphthol with the ions of nickel(II), copper(II) and zinc(II)

1977; Pergamon Press; Volume: 39; Issue: 8 Linguagem: Inglês

10.1016/0022-1902(77)80301-1

1878-1225

Colin D. Hubbard, Dagoberto Pacheco A.,

Molecular spectroscopy and chirality

The kinetics of formation of the 1:1 complexes of 1-(2-pyridylazo)-2-naphthol with the ions of nickel(II), copper(II) and zinc(II) have been determined by the stopped-flow spectrophotometric method. Second-order formation rate constants are smaller than might be expected on the basis of a mechanism in which the release of a metal-coordinated water molecule from the outer sphere complex is rate determining. It is suggested that the reaction rates are governed by the closure of the second chelate ring, as a consequence of the need to break, in the ligand, an internal hydrogen bond before full complexation can occur.