Novel Erbium(III)-encapsulated complexes based on π-extended anthracene ligands bearing G3-aryl-ether dendron: synthesis and photophysical studies

• Published in: Macromolecular research 2009, 17(9), , pp.672-681
• Main Authors: Baek, Nam Seob, Kim, Yong Hee, Roh, Soo-Gyun, Lee, Dong Hyun, Seo, Kang Deuk, Kim, Hwan Kyu
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Nanochemistry; Nanotechnology; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; 고분자공학
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/BF03218927

A series of inert and photo-stable Er(III)-encapsulated complexes based on β-extended dendritic anthracene ligands bearing G3-aryl-ether dendron ([G3-AnX]-CO 2 H), which retain different π-bridging systems, such as single (X= S), double (X= D) and triple (X= T) bonds was designed and synthesized to establish the structure-property relationship. The near infrared emission intensities of Er(III)-encapsulated complexes were enhanced dramatically by increasing the π-conjugated extension of anthracene ligands. The time-resolved luminescence spectra show monoexponential decays with a lifetime of 2.0∼2.4 ms for Er 3+ ions in thin films, and calculated intrinsic quantum yields of Er 3+ ions are in the range of 0.025∼0.03%. As a result, all Er(III)-encapsulated dendrimer complexes exhibit the near IR emission with the following order: Er 3+ -[G3-AnD] 3 (terpy) > Er 3+ -[G3-AnS] 3 (terpy) ≈ Er 3+ -[G3-AnT] 3 (terpy), because Er 3+ -[G3-AnD] 3 (terpy) has a higher relatively spectral overlap J value and energy transfer efficiency. In addition, the lack of detectable phosphorescence and no significant spectral dependence of the π-extended anthracene moieties on the solvent polarity support energy transfer from their singlet state to the central Er 3+ ion taking place in Er 3+ -[G3-AnX] 3 (terpy).