Optical Properties of Europium Compounds with L- and DL-α-Alanine-Hydroxamic Acids

Abstract

Two of europium complexes with L-and DL-α-alanine-hydroxamic acids were synthesized. To our knowledge tley are the frrst examples of X-ray and spectral data of lanthanide single crystals with hydroxamic acid derivatives. Both compounds consist of dlmers in their structures, formed by two OH bridging groups of amino-hydroxamic acid molecules. Besides, two metal ions are chelated by CO and OH groups, forming frve-membered rings. In the complex with L-ligand, differennt than in the DL-one, two additional perchloric acid molecules are included in crystal cavities and form hydrogen bondings witl nitrogen and oxygen atoms of the ligand. Absorption, emission and excitation spectra were measured and analyzed at room and low temperatures. Structural effect of ligand chirality was found and its spectroscopic conseqnences are reported. Tle effect of the dimeric structure on spectroscopic properties is discussed.

Structure and Spectroscopy of Selected Lanthanide Compounds with Coordination Number from 9 to 6

“…Again two types of dimer structures will be presented now: (a) complexes with DL-and L-isoleucine [20], and (b) lanthanide compounds with DL-and L-aminohydroxamic acids [21].…”

“…Figures 9 and 1 in [21] show the dimer structures of crystals. Besides the evidence for the ligand chirality effect on the creation of the centro and noncentrosymmetric dimer, in the above systems a role of the size and the kind of the ligand carbon chain on separation of Ln-Ln ions in the dimer, as well as on the spectroscopic properties of this dimeric system were found.…”