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Spectroscopy of lanthanide single crystals with glycylglycine, Ln(Gly-Gly)2(ClO4)3·4H2O (Ln = Nd, Eu)

1993; Elsevier BV; Volume: 12; Issue: 19 Linguagem: Inglês

10.1016/s0277-5387(00)83058-2

1873-3719

Ewa Huskowska, J. Legendziewicz,

Electron Spin Resonance Studies

The lanthanide(III) compound with a simple dipeptide (glycylglycine) of the formula Ln(Gly-Gly)2(ClO4)3·4H2O was obtained in the form of mono-crystals. These are the first known single crystals of lanthanides with a dipeptide. Well-resolved absorption and luminescence spectra at room and helium temperatures are reported and analysed. The bonding mode of the Ln3+ ions with a simple peptide is compared with the available X-ray data for the calcium compounds with diglycine and triglycine. Absorption spectra were measured along the a-axis in the region 9000–40,000 cm−1. The probabilities of f-f transitions were analysed and the temperature effect on the intensities considered. Single-ion relaxation processes and cooperative effects are discussed. Stark components were determined and point symmetry was assigned. Energy level diagrams for 4I92 and 4I1112 states are proposed. Spectroscopy results are compared with the X-ray data.