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Jayabharathi J, Thanikachalam V, Ramanathan P, Arunpandiyan A. Intramolecular excited proton transfer of 1-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)naphthalen-2-ol--a combined experimental and quantum chemical studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 121:551-558. [PMID: 24291432 DOI: 10.1016/j.saa.2013.10.097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 10/18/2013] [Accepted: 10/31/2013] [Indexed: 06/02/2023]
Abstract
Synthesis of the 1-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)naphthalen-2-ol [PPIN] is reported, spectral and fluorescent properties of the title compound are investigated. The feasibility of excited state intramolecular proton transfer (ESIPT) has been argued from the changeover of relative stability of the enol and the keto forms on photoexcitation from the S0-PES to the S1-PES. Critical evaluation on the modulations of geometrical parameters other than the proton transfer reaction coordinate has also been undertaken. The intramolecular hydrogen bonding (IMHB) interaction in PPIN has been explored by calculation of the hyperconjugative charge transfer interaction from the lone electron pair of ring nitrogen atom to the σ(∗) orbital of O-H bond, under the provision of Natural Bond Orbital (NBO) analysis. However, DFT calculations together with the experimental results reveal that the excited species with the intramolecular N⋯HO hydrogen bond type undergoes rapid radiationless deactivation. This leads to a conclusion that the low-intensity dual-band fluorescence of the title compound in solution originates from the traces of the conformation with the -OH bond to azomethine nitrogen atom (ESIPT).
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Affiliation(s)
- J Jayabharathi
- Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.
| | - V Thanikachalam
- Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - P Ramanathan
- Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
| | - A Arunpandiyan
- Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India
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Jayabharathi J, Thanikachalam V, Jayamoorthy K, Srinivasan N. Synthesis, spectral studies and solvatochromism of some novel benzimidazole derivatives--ESIPT process. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 105:223-228. [PMID: 23314216 DOI: 10.1016/j.saa.2012.12.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/02/2012] [Accepted: 12/11/2012] [Indexed: 06/01/2023]
Abstract
Some novel benzimidazole derivatives were synthesized and characterized by (1)H, (13)C NMR mass and elemental analysis. XRD analysis was carried out for 1-(4-methylbenzyl)-2-p-tolyl-1H-benzo[d]imidazole. The solvent effect on the absorption and fluorescence bands has been analyzed. The energetic analysis of the potential energy surface (PES), HOMO and LUMO levels [DFT/B3LYP/6-31G(d,p)] evidenced the existence of excited state intramolecular proton transfer (ESIPT) in hydroxy benzimidazole derivative.
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Affiliation(s)
- J Jayabharathi
- Department of Chemistry, Annamalai University, Annamalainagar 608 002, Tamil Nadu, India.
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Photophysical properties of 4,4-diaminodiphenyl sulfone in micelles and the role of BF-anion on micellar aggregation. J Photochem Photobiol A Chem 2012. [DOI: 10.1016/j.jphotochem.2012.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Samanta A, Paul BK, Guchhait N. Studies of bio-mimetic medium of ionic and non-ionic micelles by a simple charge transfer fluorescence probe N,N-dimethylaminonapthyl-(acrylo)-nitrile. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:1525-1534. [PMID: 21393054 DOI: 10.1016/j.saa.2011.01.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 01/11/2011] [Accepted: 01/26/2011] [Indexed: 05/30/2023]
Abstract
In this report we have studied micellization process of anionic, cationic and non-ionic surfactants using N,N-dimethylaminonapthyl-(acrylo)-nitrile (DMANAN) as an external fluorescence probe. Micropolarity, microviscosity, critical micellar concentration of these micelles based on steady state absorption and fluorescence and time resolved emission spectroscopy of the probe DMANAN show that the molecule resides in the micelle-water interface for ionic micelles and in the core for the non-ionic micelle. The effect of variation of pH of the micellar solution as well as fluorescence quenching measurements of DMANAN provide further support for the location of the probe in the micelles.
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Affiliation(s)
- Anuva Samanta
- Department of Chemistry, University of Calcutta, Kolkata, West Bengal, India
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Sahoo D, Chakravorti S. Dye-Surfactant Interaction: Modulation of Photophysics of an Ionic Styryl Dye. Photochem Photobiol 2009; 85:1103-9. [DOI: 10.1111/j.1751-1097.2009.00582.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Sharma N, Jain SK, Rastogi RC. Solubilization of 5-methoxy tryptamine molecular probes in CTAB and SDS micelles: a cmc and binding constant study. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 69:748-56. [PMID: 17602856 DOI: 10.1016/j.saa.2007.05.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Accepted: 05/10/2007] [Indexed: 05/16/2023]
Abstract
To understand the change in environmental conditions when a probe is incorporated in micelles, an absorption and fluorescence spectral study on the solubilization behaviour of 5-methoxy tryptamine (5-MT) and N,N-dimethyl-5-methoxy tryptamine (5-NMT) has been made in CTAB and SDS for their neutral and cationic forms. The blue shift in emission wavelength is accompanied by increase in intensity with increasing surfactant concentration for almost all the cases except for the cationic probe in CTAB surfactant. This exceptional behaviour can be attributed to the quenching of emission intensity caused by Br(-) ions. Spectral correlations with solvent polarity parameters indicate relatively less polar binding sites in CTAB and SDS as compared to water. The binding constant and cmc values have been determined for CTAB and SDS using both the neutral and the cationic probes, which are in good agreement with the literature values. Higher value of binding constant and lower polarity of the binding sites justify 5-NMT as a better binding probe as the two methyl groups make the molecule more hydrophobic and drag it to the interior of both the micelles.
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Affiliation(s)
- Neera Sharma
- Department of Chemistry, University of Delhi, Delhi 110007, India
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Mishra H. Photo-induced relaxation and proton transfer in some hydroxy naphthoic acids in polymers. J Phys Chem B 2007; 110:9387-96. [PMID: 16686481 DOI: 10.1021/jp052371d] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photophysical and photochemical properties of 3-hydroxy-2-naphthoic acid [3,2-HNA] and 1-hydroxy-2naphthoic acid [1,2-HNA] in different aprotic, protic, and ion exchange (Nafion) polymers have been described in this article. In both molecules, intramolecular hydrogen bond (IMHB) exists between OH and COOH functional groups. Both 3,2-HNA and 1,2-HNA form different emitting species in different polymeric media. Fluorescence characteristic of 3,2-HNA is found to depend on its concentration, nature of the microenvironment, and wavelength of excitation, while 1,2-HNA is less susceptible to these changes. 3,2-HNA exhibits dual fluorescence band (normal and large Stokes shifted) in aprotic and only a single large Stokes shifted fluorescence in protic polymers, while 1,2-HNA shows a single fluorescence band along with weak phosphorescence emission in these polymers. Both excited-state inter and intramolecular proton transfer (ESPT) take place in 3,2-HNA in aprotic and protic polymers, resulting in large Stokes shifted emission band. A competition between ESIPT and excimer formation is observed by the appearance of rise time on increasing the concentration of 3,2-HNA in protic polymer. In Nafion film, 3,2-HNA is present as a cationic as well as neutral species. The presence of extra protons in Nafion film facilitates excited-state intramolecular proton transfer (ESIPT) in the neutral species of 3,2-HNA and gives large Stokes shifted emission (10 500 cm(-1)). No such effect is observed in 1,2-HNA doped in Nafion film. It is observed that, depending on the position of the IMHB ring, the electronic spectra get modified and the strength of IMHB is affected by the micro-environment of the polymer which alters the photophysics of these molecules.
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Affiliation(s)
- Hirdyesh Mishra
- Photophysics Laboratory, Department of Physics, Kumaun University, Nainital-263 001, India.
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Adhikary TP, Chowdhury P, Chakravorti S. Modulation of photophysics of 2-hydroxy 1-naphthaldehyde in non-ionic micelles. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Excited state intramolecular proton transfer (ESIPT) in a dioxotetraamine derived schiff base and its complexation with Fe(III) and Cr(III). J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.12.027] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Murari BM, Anand S, Gohil NK, Chaudhury NK. Fluorescence spectroscopic study of dip coated sol-gel thin film internal environment using fluorescent probes Hoechst33258 and Pyranine. JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY 2007; 41:147-155. [DOI: 10.1007/s10971-006-0515-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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12
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Theoretical predictions for occurrence of charge transfer complex within the two synthesized bichromophores considering the role of their spacers in interactions with the π-orbitals of the redox centers. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.07.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Effect of pH in the photophysics of 2-hydroxy 1-naphthaldehyde in micellar systems. J Photochem Photobiol A Chem 2006. [DOI: 10.1016/j.jphotochem.2005.07.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gupta R, Mozumdar S, Chaudhury NK. Effect of ethanol variation on the internal environment of sol–gel bulk and thin films with aging. Biosens Bioelectron 2005; 21:549-56. [PMID: 16202867 DOI: 10.1016/j.bios.2004.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 12/06/2004] [Accepted: 12/06/2004] [Indexed: 11/28/2022]
Abstract
Sol-gel derived bulk and thin films were prepared from different compositions at low pH ( approximately 2.0) containing varying concentrations of ethanol from 15 to 60% at constant water (H(2)O)/tetraethyl-orthosilicate (TEOS) ratio (R=4). The fluorescence microscopic and spectroscopic measurements on fluorescent probe, Hoechst 33258 (H258) entrapped in these compositions were carried out at different days of storage to monitor the effects of concentration of ethanol on the internal environment of sol-gel materials. Fluorescence microscopic observations on sol-gel thin films, prepared by dip coating technique depicted uniform and cracked surface at withdrawal speed 1cm/min (high speed) and 0.1cm/min (low speed) respectively, which did not change during aging. Fluorescence spectral measurements showed emission maximum of H258 at approximately 535 nm in fresh sols at all concentrations of ethanol which depicted slight blue shift to 512 nm during aging in bulk. No such spectral shift has been observed in sol-gel thin films coated at high speed whereas thin films coated at low speed clearly showed an additional band at approximately 404 nm at 45 and 60% concentration of ethanol after about one month of storage. Analysis of the fluorescence lifetime data indicated single exponential decay (1.6-1.8 ns) in fresh sol and from third day onwards, invariably double exponential decay with a short (tau(1)) and a long (tau(2)) component were observed in sol-gel bulk with a dominant tau(1) at approximately 1.2 ns at all concentrations of ethanol. A double exponential decay consisting of a short component (tau(1)) at approximately 0.2 ns and a long component (tau(2)) at approximately 3.5 ns were observed at all ethanol concentrations in both fresh and aged sol-gel thin films. Further, distribution analysis of lifetimes of H258 showed two mean lifetimes with increased width in aged bulk and thin films. These results are likely to have strong implications in designing the internal environment for applications in biosensors.
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Affiliation(s)
- R Gupta
- Division of Biocybernetics, Institute of Nuclear Medicine and Allied Sciences, Delhi 110 054, India
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Dogra S. Excited state intramolecular proton transfer in anionic and cationic species of 2-(2′-amino-3-pyridyl)benzimidazole. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Gupta R, Mozumdar S, Chaudhury NK. Fluorescence spectroscopic studies to characterize the internal environment of tetraethyl-orthosilicate derived sol–gel bulk and thin films with aging. Biosens Bioelectron 2005; 20:1358-65. [PMID: 15590290 DOI: 10.1016/j.bios.2004.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Revised: 04/28/2004] [Accepted: 05/21/2004] [Indexed: 11/20/2022]
Abstract
Characterization of the internal environment of a sol-gel matrix is an important area of investigation in optical biosensors. In the present study, different sol-gel compositions were prepared by varying the water (H2O) to tetraethyl-orthosilicate (TEOS) ratio (R) from 1 to 16 and the changes in the internal environment of the sol-gel both in bulk and thin films as a function of aging (storage) were investigated using fluorescence spectroscopy. We focussed on the fluorescence characteristics , viz. emission and excited state lifetime of Hoechst 33258 (H258), a bisbenzimidazole derivative, which was used as fluorescence probe entrapped in the TEOS derived sol-gel bulk and thin films. These sols were prepared at a low pH (approximately 2.0) and the thin films were coated by dip coating technique at withdrawal speeds of 1 cm/min and 0.1cm/min. Usually, uniform thin films were obtained at a high speed (1 cm/min) and partially cracked film at a low speed (0.1 cm/min) as observed by fluorescence microscope. These observations did not change during aging. On the contrary, three months long observations on steady-state fluorescence emission measurements on H258 depicted a blue shift from 535 nm to 508 nm at R = 1 in the sol-gel bulk, whereas at higher ratios this was not prominent. At all ratios, dual emission bands were observed in thin films. This may be due to faster sol-gel to xerogel transition during aging depending on the ratio (R). Analysis of the excited state decay profiles of H258 revealed a double exponential fitting having a short (tau1) and a long (tau2) component in both fresh and during aging, in the sol-gel bulk and thin films, indicating heterogeneity in the internal environment. The value of tau1 increased from 0.4 ns to 1.2 ns whereas tau2 attained a value from 3.0 ns to 3.6 ns at R = 1 upon aging in the sol-gel bulk. The corresponding values of tau1 and tau2 in thin films were 0.3 ns and 3.5 ns, respectively. The values of these decay components in thin films did not alter much due to storage, but their relative contributions showed more systematic changes in the thin films. The observed changes could be correlated to rigidification in the bulk depending on the ratio (R). This process was very slow at R > or = 4. The heterogeneity in the internal environment of bulk and thin films upon aging appeared to be different as revealed from analysis of excited-state lifetime. Thus, the bisbenzimidazole derivative H258 appears to be very useful probe for characterizing the internal environment of both the sol-gel bulk and thin films.
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Affiliation(s)
- R Gupta
- Division of Biocybernetics, Institute of Nuclear Medicine and Allied Sciences, Delhi 110054, India
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Nayak MK, Dogra S. Photophysics of 1-hydroxy-9-fluorenone: absence of excited state intramolecular proton transfer reaction. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.05.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Excited state intramolecular proton transfer in 2-(2′-amino-3-pyridyl)-benzimidazole: effect of solvents. Chem Phys 2004. [DOI: 10.1016/j.chemphys.2004.06.037] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Effects of micelles on excited state intramolecular proton transfer activities of 2-hydroxy 1-naphthaldehyde. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.07.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Umeto H, Abe K, Kawasaki C, Igarashi T, Sakurai T. Cationic micellar effects on the proton transfer reactions of N-substituted 2-(7-hydroxycoumarin-4-yl)acetamides and related compound in the ground and excited singlet states. J Photochem Photobiol A Chem 2003. [DOI: 10.1016/s1010-6030(03)00010-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Panja S, Chowdhury P, Chakravorti S. Exploring the location and orientation of 4-(N,N-dimethylamino) cinnamaldehyde in anionic, cationic and non-ionic micelles. Chem Phys Lett 2003. [DOI: 10.1016/s0009-2614(02)01960-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Balamurali M, Dogra S. Excited state intramolecular proton transfer in 2-(2′-hydroxyphenyl)-1H-imidazo[4,5-c]pyridine: effects of solvents. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00308-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Santra S, Dogra SK. Effect of micelles on the spectral characteristics of the prototropic species of 2-(2'-aminophenyl)benzimidazole. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2000; 56:915-925. [PMID: 10809067 DOI: 10.1016/s1386-1425(99)00181-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The absorption and fluorescence spectra of 2-(2'-aminophenyl)benzimidazole (2-APBI) have been studied in anionic (sodium dodecylsulphate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and non-ionic micelles (Tween-80, TritonX-100) at different acid-base concentrations. Spectral characteristics of 2-APBI at various acid concentrations have established only one kind of monocation (MC) in Tween-80 and TritonX-100 (TX-100), whereas two kinds of MCs are present in SDS. Above study has further shown that there is a strong hydrogen bonding interaction between the polar polyoxyethylene groups of non-ionic micelles and the MCs of 2-APBI. This interaction is responsible for the stabilization of the MC III to MC III' which is more planar than either MC II or MC III, which is otherwise less stable in water. This is substantiated by the lifetime data, fluorescence excitation spectra and the pKa values of the monocation-neutral (MC-N) equilibrium.
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Affiliation(s)
- S Santra
- Department of Chemistry, Indian Institute of Technology, Kanpur
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Fluorescence quenching of 2-aminofluorene by cetylpyridinium chloride, iodide ion and acrylamide in non-ionic micelles: Tweens. J Photochem Photobiol A Chem 1999. [DOI: 10.1016/s1010-6030(98)00466-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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