title: Spectroscopic and theoretical studies of charge-transfer interaction of 1-(2-pyridylazo)-2-napthol with nitroaromatics.
abstract: 1-(2-Pyridylazo)-2-napthol (hereafter 1Q) is widely used as a chelating ligand applied in chelatometric, spectrophotometric analysis of metal ions. It appeared from the literature survey that no inclusion complex of 1Q was reported with nitroaromatics. The formation of charge-transfer complex gives an opportunity to improve the physico-chemical properties of different donors. So the complex of 1Q with 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), picric acid (PA), and 3,5-dinitrosalicylic acid (3,5-DNSA) was described in this work in methanol medium. The ground and excited state binding constants and other spectroscopic data have been determined using UV-vis and fluorescence spectroscopic studies. All the complexes have been synthesized and characterized using FT-IR,1H NMR, and elemental analysis. Spectroscopic data reveal that 1Q joins by a N+HO-type hydrogen bond with nitroaromatics. Job's plot of the continuous variation of absorbance indicates that stoichiometry of CT-complex was 1:1. Thermal stability of the synthesized complex has determined by TGA-DTA analysis. Energy-minimization DFT calculation further supported the formation of the H-bonded charge-transfer adduct.
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, West Bengal, India. Electronic address: animeshlaltu@gmail.com.
authors.forename: Animesh
authors.initials: A
authors.lastname: Karmakar
authors.affiliation: Department of Chemistry, Visva-Bharati, Santiniketan 731235, West Bengal, India. Electronic address: singhbula@rediffmail.com.
authors.forename: Bula
authors.initials: B
authors.lastname: Singh
keywords: 1-(2-Pyridylazo)-2-napthol (1Q); Charge-transfer; DFT; Fluorescence quenching; Hydrogen bond; Nitroaromatics