Spectrophotometric Studies of the Metallic Chelates of 2-Picolylamine. I. The Electronic Absorption Spectra of Some Nickel, Copper(II) and Cobalt(III) Chelates

Abstract 1) In addition to the nickel chelates (1:2 and 1:3) and copper chelates (1:2) already described by Sutton, it has been found that 2-picolylamine also forms 1:1 chelates (chlorides and sulfates) with these metals, which can be obtained in the state of crystals, and the chelate ions [Cu pic3]2+ of low stability, in solution. 2) A comparison of the electronic absorption spectra of all these chelates and two cobalt(III) chelates of 2-picolylamine with those of the chelates of ethylenediamine and 2, 2′-bipyridine has indicated that, in general, the spectrum of a 2-picolylamine chelate is intermediate between the spectra of the corresponding chelates of the latter two ligands; however, the similarity to the ethylenediamine chelate is more apparent in most cases. 3) Certain structural features of the 2-picolylamine chelates have been discussed on the basis of these spectral data.