Absorption and fluorescence spectroscopy of 3-hydroxy-3-phenyl-1- o-carboxyphenyltriazene and its copper (II), nickel (II) and zinc (II) complexes: a novel fluorescence sensor

• Published in: Journal of luminescence 2005-02, Vol.111 (3), p.121-129
• Main Authors: Ressalan, S., Iyer, C.S.P.
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronics; Exact sciences and technology; Fluorescence spectroscopy; Molecular electronics; Molecular electronics, nanoelectronics; Molecular sensor; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photo-induced electron transfer; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transition metal switches
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2004.02.011

Absorption and fluorescence spectroscopic properties of 3-hydroxy-3-phenyl-1- o-carboxyphenyltriazene (HT) are studied. The mechanism of photo-induced electron transfer (PET) followed by energy transfer process of the ligand and the Cu (II), Ni (II) and Zn (II) metal complexes have been investigated. The excited state photo induced intramolecular hydrogen transfer from N–OH to triazene 1-nitrogen atom is explained. The effect of pH, solvent and concentration on the absorption and fluorescence of the ligand is studied and it has been found that the absorption and fluorescence of HT is highly pH, solvent and concentration dependent. Participation of the N–OH proton of HT in the solvent assisted O to N-proton transfer has also been proposed. The fluorescence band shift and changes in intensity is modulated by protonation and complexation with metal ions. This fluorophore can thus be used as a pH dependent and M ( n+1)+ /M n+ redox on/off switchable molecular sensor.