Energy Transfer Pathway in Luminescent Lanthanide Complexes Based on Dansyl-N-methylaminobenzoic Acid through Intramolecular Charge Transfer State for Near Infrared Emission

Bulletin of the Korean chemical society

Hwan Kyu Kim¹  Yong Hee Kim¹  Nam Seob Baek¹  Soo-Gyun Roh¹ 

关键词: Luminescent lanthanide complexes;    Dansyl-N-methylaminobenzoic acid;    Energy transfer;    Intramolecular charge transfer;    Time-resolved luminescence;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

We have investigated the photophysical properties of dansyl-N-methylaminobenzoic acid (DABAH) as a ligand and its lanthanide (Ln³⁺)-cored complexes (Ln³⁺-(DABA)₃(terpy)) in order to determine the main energy transfer pathway for sensitized near infrared emission of Ln3+ ions (Ln³⁺ = Nd³⁺ and Er³⁺) in Ln3+- (DABA)₃(terpy). The fluorescence spectrum of DABAH shows a large Stokes shift with increasing solvent polarity. This large Stokes shift might be due to the formation of a twisted intramolecular charge transfer (TICT) state, as demonstrated by the large dipole moment in the excited state. It is in good agreement with the result that the phosphorescence even in the Gd³⁺-cored complex based on the DABAH ligand was not observed, maybe due to the highly forbidden character of the S1 �? T1 transition in the DABAH ligand. A short decay component (ca. 1 ns) was observed in Er³⁺-(DABA)₃(terpy) whereas the fluorescence lifetimes of DABAH and its Gd³⁺-(DABA)₃(terpy) are observed about ~10 ns. The short component could be originated from the energy transfer process between the ligand and the Ln³⁺ ion. Based on the fluorescence of DABAH its Ln³⁺- (DABA)₃(terpy), the sensitization of Ln³⁺ luminescence in the Ln³⁺-(DABA)₃(terpy) takes place by the energy transfer via the TICT state of DABAH in the excited singlet state rather than via the excited triplet state.

【 授权许可】

Unknown