Karmakar A, Singh B. Spectroscopic and theoretical studies of charge-transfer interaction of 1-(2-pyridylazo)-2-napthol with nitroaromatics.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017;
179:110-119. [PMID:
28236682 DOI:
10.1016/j.saa.2017.01.047]
[Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 01/06/2017] [Accepted: 01/24/2017] [Indexed: 05/24/2023]
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.
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