Synthesis, NMR, relaxometry and circularly polarised luminescence studies of macrocyclic monoamidetris(phosphinate) complexes bearing a remote chiral centre

Abstract

Lanthanide complexes of macrocyclic monoamidetris(phosphinate) ligands are partially hydrated in aqueous solution. Introduction of a chiral centre into the amide group leads to the formation of only two non-interconverting complex diastereoisomers (2∶1 for α-phenylethyl and 4∶1 for α-1-naphthylethyl). Proton, ³¹P NMR and circularly polarised luminescence studies indicated that the configuration at the chiral carbon centre determines the helicity of the layout of the pendent arms and the macrocyclic ring conformation, with an RRR or SSS configuration preferred at the phosphorus centres.