Chiral luminescent lanthanide complexes possessing strong (samarium, Sm-III) circularly polarised luminescence (CPL), and their self-assembly into Langmuir-Blodgett films

摘要

The lanthanide directed self-assembly of chiral amphiphilic 2,6-pyridinedicarboxylic acid based ligands 1 and 2 with various Ln(CF3SO3)(3) (Ln = Tb-III, Sm-III, Lu-III, Dy-III) salts was studied in CH3CN and evaluated with the expected 1 : 3 and 1 : 1 Ln : Ligand species forming in solution. Ligand chirality was retained and transferred, as depicted by circular dichroism (CD) and circularly polarised luminescence (CPL) measurements (for Tb-III and Sm-III), to the lanthanide centre upon complexation with high dissymmetry factor values for the Sm-III complexes obtained (g(lum) = -0.44 and 0.29 and 0.45 and -0.23 for the (4)G(5/2) -> H-6(5/2) and the (4)G(5/2) -> H-6(7/2) transitions of Sm center dot 1(3) and Sm center dot 2(3), respectively). The ability of the complexes to form stable Langmuir monolayers at the air-water interface was also established while Langmuir-Blodgett films of Tb center dot L-3 and Sm center dot L-3 exhibited lanthanide luminescent emission.