A. Emandi, I. C. Vasiliu, C. Constantinescu, I. Stamatin, Solvatochromic properties of azo and azomethin tridentate ligands in coordinative compounds with [Er(ONO)] chromophores, Digest Journal of Nanomaterials and Biostructures, 5/4 (2010) 851-858.

Title: Solvatochromic properties of azo and azomethin tridentate ligands in coordinative compounds with [Er(ONO)] chromophores

Abstract: The relationship between structure and solvatochromic properties of some tridendate organic ligands with (ONO) donor atoms belong to azo dyes o, o'-dihydroxi azobenzene L(1)H(2), 1-(azo-beta-naphtyl)-2-hydroxi-5-chlor-benzen L(2)H(2), and Schiff bases o, o'-dihydroxi phenyl azomethin naphatalene L(3)H(2), o, o'-hidroxy phenyl - carboxy azomethin naphatalene L(4)H(2) as well as the effects of Er(3+) as [Er(ONO)] chromophore, on the organic moiety were investigated. The free organic ligands and their Er(3+) complexes were prepared and characterized by elemental analysis, thermal gravimetry, UV/VIS and FTIR spectroscopy. The solvatochromic behaviour of the free organic ligands and their complexes were investigated by electronic spectra of their 10(-4)-10(-5) M solutions, in five different solvents. The solvatochromism was explained as a combination of the solvent polarity, nature and position of D/A couple and the size of the pi conjugated system.

Key words: erbium complexes; azo-dyes complexes; azomethine complexes; solvatochromism