Synthesis, chirality and complexation phenomena of two diastereoisomeric dinuclear lanthanide(III) complexes

Two diastereoisomeric ditopic ligands have been synthesised by linking (SSS)-hepatadenate triamide derivative of cyclen with a central (SS)- or (SR)- 1, 2-diphenyl-1, 2-diaminoethane derivative. Complexes of selected Ln ^III ions (Ln = Eu, Tb, Yb) have been characterized and circularly polarised luminescence spectra of the Eu systems revealed significant differences, consistent with a change in overall complex chirality associated with the local helicity at the metal centre. Stepwise binding constants for the formation of 1:1 and 2:1 ternary adducts with (S)-lactate and (S)-O-phospho-tyrosine have been determined, by least-squares analysis of spectral titration data, and emission and ¹H NMR spectroscopic data compared with the mononuclear analogue.