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

• Published in: Dalton transactions : an international journal of inorganic chemistry 2019-08, Vol.48 (3), p.11317-11325
• Main Authors: Barry, Dawn E, Kitchen, Jonathan A, Mercs, Laszlo, Peacock, Robert D, Albrecht, Martin, Gunnlaugsson, Thorfinnur
• Format: Article
• Language: English
• Subjects: Chirality; Circular polarization; Dichroism; Langmuir-Blodgett films; Ligands; Luminescence; Monomolecular films; Samarium; Self-assembly
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c9dt02003a

The lanthanide directed self-assembly of chiral amphiphilic 2,6-pyridinedicarboxylic acid based ligands 1 and 2 with various Ln(CF 3 SO 3 ) 3 (Ln = Tb III , Sm III , Lu III , Dy III ) salts was studied in CH 3 CN 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 → 6 H 5/2 and the 4 G 5/2 → 6 H 7/2 transitions of Sm· 1 3 and Sm· 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· L 3 and Sm· L 3 exhibited lanthanide luminescent emission. The lanthanide directed self-assembly of chiral amphiphilic pda based ligands 1 and 2 with Tb III , Sm III , Lu III and Dy III salts was studied in CH 3 CN solution and as SAM LB-films.