Adduct formation of zinc oxinate chelate with some nitrogen bases

Article abstract of DOI:10.1016/0584-8539(85)80245-2

Visible and u.v. spectra of zinc oxinate chelate in chloroform showed bathochromic shifts on addition of nitrogen bases.These shifts, large compared to those due to solvent effects alone, were attributed to adduct formation.From a quantitative evaluation of the data, the formation constants of what proved to be 1:2 adducts were determined.The stabilities of these adducts were found to increase in the order: neocuproin <2,2'-bipyridyl < ethylenediamine <= 1,10-phenanthroline.The formation of a very weak adduct in the case of neocuproin is attributed to the sterically hindering methyl groups ortho to nitrogen atoms in the molecule.