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El-Khouly ME, Khatab HA, Abdel-Shafi AA, Hammad SF. Acridinedione-phthalimide conjugates: Intramolecular electron transfer and singlet oxygen generation studies for optical and photodynamic therapy applications. Photochem Photobiol Sci 2024; 23:1445-1455. [PMID: 38937393 DOI: 10.1007/s43630-024-00603-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Accepted: 06/10/2024] [Indexed: 06/29/2024]
Abstract
We reported herein the synthesis, characterization of hybrid conjugates composed of phthalimide (Phth) and acridine-1,8-diones (Acr) for optical and medical applications. For the synthetic procedure, a three-step synthetic strategy has been utilized. The optical properties of the examined 1,8-acridinedione-phthalimide connected molecules (AcrPhth 1-5) have been examined utilizing various spectroscopic techniques, e.g., steady-state absorption and fluorescence, and time-correlated single photon counting. The steady-state absorption studies showed that AcrPhth 1-5 absorbs the light in the UV and visible region. The fluorescence studies of AcrPhth 1-5 exhibited significant fluorescence quenching compared to the acridinedione control compounds (Acr 1-5) suggesting the occurrence of electron-transfer reactions from the electron donating acridinedione moiety (Acr) to the electron accepting phthalimide moiety (Phth). The rate and efficiency of the electron-transfer reactions were determined from the fluorescence lifetime measurements indicating the fast electron-transfer processes of the covalently connected AcrPhth 1-5 conjugates. Computational studies supported the intramolecular electron-transfer reaction of AcrPhth conjugates using ab initio B3LYP/6-311G methods. In the optimized structures, the HOMO was found to be entirely located on the Acr entity, while the LUMO was found to be entirely on the Phth entity. Further, the synthesized compounds were tested as photosensitizers for generating the singlet oxygen species, which is a key factor in the photodynamic therapy (PDT) applications. The nanosecond laser flash measurements enable us to detect the triplet-excited states of examined Acr and AcrPhth conjugates, determining the triplet quantum yields, and direct detecting the singlet oxygen in an accurate way. From this observation, the singlet quantum yields were found to be in the range of 0.12-0.27 (for Acr 1-5) and 0.07-0.19 (for AcrPhth 1-5 conjugates). The molecular docking studies revealed that compound AcrPhth 2 exhibited high binding affinity with for key genes (p53, TOP2B, p38, and EGFR) suggesting its potential as a targeted anticancer therapy.
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Affiliation(s)
- Mohamed E El-Khouly
- Nanoscience Program, Institute of Basic and Applied Sciences, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, Egypt.
| | - Hassan A Khatab
- Pharm D Program, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, Egypt
| | - Ayamn A Abdel-Shafi
- Department of Chemistry, Faculty of Science, Ain Shams University, 11566 Abbassia, Cairo, Egypt
| | - Sherif F Hammad
- Pharm D Program, Egypt-Japan University of Science and Technology (E-JUST), New Borg El-Arab City, Alexandria, Egypt
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Johnson KR, Vittardi SB, Gracia‐Nava MA, Rack JJ, Bettencourt‐Dias A. Wavelength‐Dependent Singlet Oxygen Generation in Luminescent Lanthanide Complexes with a Pyridine‐Bis(Carboxamide)‐Terthiophene Sensitizer. Chemistry 2020; 26:7274-7280. [DOI: 10.1002/chem.202000587] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/03/2020] [Indexed: 12/11/2022]
Affiliation(s)
| | - Sebastian B. Vittardi
- Department of Chemistry and Chemical Biology University of New Mexico Albuquerque NM 87131 USA
| | | | - Jeffrey J. Rack
- Department of Chemistry and Chemical Biology University of New Mexico Albuquerque NM 87131 USA
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Pina J, Queiroz MJRP, Seixas de Melo J. Effect of substitution on the ultrafast deactivation of the excited state of benzo[b]thiophene-arylamines. Photochem Photobiol Sci 2016; 15:1029-38. [PMID: 27417977 DOI: 10.1039/c6pp00140h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A complete and systematic study of the spectroscopic and photophysical properties of five novel diarylamines in the benzo[b]thiophene series (oligoanilines) was performed in solution at room (293 K) and low (77 K) temperature. The title compounds resulting from the link between one aniline unit with a benzo[b]thiophene unit (with two different methyl and methoxy substitution) were characterized using steady-state absorption, fluorescence and phosphorescence spectroscopy, as well as femto- to nano-second time resolved spectroscopies. The study involved the determination of the absorption, emission and triplet-triplet absorption together with all relevant quantum yields (fluorescence, phosphorescence, intersystem crossing, internal conversion and singlet oxygen yields), excited state lifetimes and the overall set of deactivation rate constants (kF, kIC and kISC). This study was further complemented with theoretical calculations, namely with the determination of the optimized ground-state molecular geometries for the diarylamines together with the prediction of the lowest vertical one-electron excitation energy and the relevant molecular orbital contours using DFT calculations. The DFT results were found to corroborate the observed charge-transfer character of the singlet excited state. The experimental results showed that the radiationless decay processes (internal conversion and intersystem-crossing) constitute the main excited state deactivation pathways and that substitution with methyl and methoxy groups induces significant changes in the spectroscopic and photophysical behaviour of these compounds. This was also corroborated by the femtosecond transient absorption study, where it was found that the ultrafast dynamics of the diarylamines was best described by a sequential model featuring fast solvent relaxation followed by conformational relaxation to a more planar excited state, from where singlet excited state deactivation occurs through internal conversion and competitive intersystem crossing (the latter giving rise to the formation of long lived triplet states). The high singlet oxygen quantum yield values obtained suggest that the triplet state is involved in the photodegradation processes of these compounds.
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Affiliation(s)
- J Pina
- Coimbra Chemistry Center, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
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Liu T, Zhao K, Liu K, Ding L, Yin S, Fang Y. Synthesis, optical properties and explosive sensing performances of a series of novel π-conjugated aromatic end-capped oligothiophenes. JOURNAL OF HAZARDOUS MATERIALS 2013; 246-247:52-60. [PMID: 23280053 DOI: 10.1016/j.jhazmat.2012.11.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2012] [Revised: 10/14/2012] [Accepted: 11/04/2012] [Indexed: 06/01/2023]
Abstract
Four novel terthiophene (3T) derivatives, have been synthesized by employing Grignard coupling reaction via end-capping of naphthyl (NA) or pyrenyl (Py) unit to the one or two ends of 3T. It has been shown that both increasing electron donating strength and extending conjugation are effective approaches to improve the photochemical stability of the oligothiophene. Fluorescence studies demonstrated that the emission of the 3T derivatives is sensitive to the presence of some important nitro-containing explosives in their ethanol solution, in particular, 2,4,6-trinitrophenol (PA) and 3,5-dinitro-2,6-bispicrylamino pyridine (PYX). As an example, the detection limits of 4 to PA and PYX were determined to be 6.21 × 10(-7)mol/L and 8.95 × 10(-7)mol/L, respectively. Based on the discovery, a colorimetric detection method has been developed. The sensitive and selective response of the modified 3T to the explosives have been tentatively attributed to the adsorptive affinity of the compounds to the explosives, and to the higher probability of the electron transfer from the electron-rich 3T derivatives to the electron-poor nitro-containing explosives. No doubt, present study broadens the family of fluorophores which may be employed for the development of fluorescent sensors.
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Affiliation(s)
- Taihong Liu
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, PR China
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Pina J, de Melo JS, Breusov D, Scherf U. Donor–acceptor–donor thienyl/bithienyl-benzothiadiazole/quinoxaline model oligomers: experimental and theoretical studies. Phys Chem Chem Phys 2013; 15:15204-13. [DOI: 10.1039/c3cp52056k] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sousa CM, Pina J, Seixas de Melo J, Berthet J, Delbaere S, Coelho PJ. Synthesis of a Photochromic Fused 2H-Chromene Capable of Generating a Single Coloured Species. European J Org Chem 2012. [DOI: 10.1002/ejoc.201101702] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Seixas de Melo JS, Cabral C, Lima JC, Maçanita AL. Characterization of the Singlet and Triplet Excited States of 3-Chloro-4-methylumbelliferone. J Phys Chem A 2011; 115:8392-8. [DOI: 10.1021/jp204354x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Sousa CM, Pina J, de Melo JS, Berthet J, Delbaere S, Coelho PJ. Preventing the Formation of the Long-Lived Colored Transoid-Trans Photoisomer in Photochromic Benzopyrans. Org Lett 2011; 13:4040-3. [DOI: 10.1021/ol201549v] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Céu M. Sousa
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
| | - João Pina
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
| | - João Seixas de Melo
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
| | - Jérôme Berthet
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
| | - Stéphanie Delbaere
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
| | - Paulo J. Coelho
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal, Departamento de Química, Universidade de Coimbra, Coimbra, Portugal, and Université Lille Nord de France, CNRS UMR 8516, UDSL, Faculté des Sciences Pharmaceutiques et Biologiques, F-59006, Lille, France
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Häussler M, King S, Eng M, Haque S, Bilic A, Watkins S, Wilson G, Chen M, Scully A. Photo-spectroscopic properties of benzothiadiazole-containing pendant polymers for photovoltaic applications. J Photochem Photobiol A Chem 2011. [DOI: 10.1016/j.jphotochem.2011.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Liu T, Ding L, He G, Yang Y, Wang W, Fang Y. Photochemical stabilization of terthiophene and its utilization as a new sensing element in the fabrication of monolayer-chemistry-based fluorescent sensing films. ACS APPLIED MATERIALS & INTERFACES 2011; 3:1245-1253. [PMID: 21449595 DOI: 10.1021/am2000592] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
To improve the photochemical stability of α-terthiophene (3T) in air, we purposely introduced a naphthalene unit into its conjugated backbone, resulting in a fluorescent compound, 5-(1-naphthyl)-2,2':5',2''-terthiophene (NA-3T). The compound was further employed as a sensing element for the fabrication of a monolayer-chemistry based fluorescent sensing film. It was demonstrated that the fabricated film is highly sensitive and selective to the presence of picric acid (PA). The detection limit was found to be 3.2 × 10(-7) mol/L. The high sensitivity of the film to PA has been attributed to the specific binding of the film to the analyte because of proton transfer from PA to the amino group in the spacer, which is in accordance with the static nature of the quenching as revealed by fluorescence lifetime measurements. Further experiments demonstrated that the sensing process is fully reversible and free of interference from common organic solvents, acids and bases, etc. In addition, the film is stable, at least, within half a year provided it is properly preserved. More importantly, the present work makes it possible to use oligothiophenes as a new class of sensing elements, which may combine the advantages of conjugated polymers or oligomers and those of fluorescent compounds of low-molecular masses. This effort enlarges, definitely, the applications of oligothiophenes and the space for creating monolayer-chemistry based fluorescent sensing films.
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Affiliation(s)
- Taihong Liu
- Key Laboratory of Applied Surface and Colloid Chemistry of Ministry of Education, School of Chemistry and Materials Science, Shaanxi Normal University, Xi'an 710062, PR China
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Prostota Y, Coelho PJ, Pina J, de Melo JS. Photochromic and photophysical properties of new benzo- and naphtho[1,3]oxazine switches. Photochem Photobiol Sci 2011; 10:1346-54. [PMID: 21706110 DOI: 10.1039/c1pp05067b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Yaroslav Prostota
- Centro de Química - Vila Real, Universidade de Trás-os-Montes e Alto Douro, 5001-801, Vila Real, Portugal
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Rondão R, Seixas de Melo JS, Voss G. Characterization of the excited states of indigo derivatives in their reduced forms. Chemphyschem 2010; 11:1903-8. [PMID: 20401897 DOI: 10.1002/cphc.201000082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A comprehensive characterization of the electronic spectral and photophysical properties of the leuco (reduced) form of several indigo derivatives, including indigo and Tyrian Purple, with di-, tetra-, and hexa-substitution, was obtained in solution. The characterization involves absorption, fluorescence, and triplet-triplet absorption spectra, together with quantitative measurements of quantum yields of fluorescence, phi(F) (0.46-0.04), intersystem crossing, phi(Tau) (0.013-0.034), internal conversion, phi(IC), and the corresponding lifetimes. The position and degree of substitution promote differences in the spectral and photophysical properties displayed by the investigated leuco derivatives. The phi(F) values are about two orders of magnitude higher than those previously obtained for the corresponding keto forms. Also in contrast with the behavior found for the keto forms, the S(1) approximately approximately -->T(1) intersystem crossing is an efficient route for the excited-state deactivation channel. These findings strengthen the fact that, in contrast to keto indigo where the internal conversion dominates the deactivation of the excited-state, with leuco indigo (and derivatives), the excited state deactivation involves competition between internal conversion, triplet state formation, and fluorescence. A time-resolved investigation of one of the compounds in glycerol showed the presence of a photoisomerization process.
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Affiliation(s)
- Raquel Rondão
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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Oliva MM, Pappenfus T, Melby J, Schwaderer K, Johnson J, McGee K, da Silva Filho D, Bredas JL, Casado J, López Navarrete J. Comparison of Thiophene-Pyrrole Oligomers with Oligothiophenes: A Joint Experimental and Theoretical Investigation of Their Structural and Spectroscopic Properties. Chemistry 2010; 16:6866-76. [DOI: 10.1002/chem.201000143] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rondão R, Seixas de Melo JS, Bonifácio VDB, Melo MJ. Dehydroindigo, the forgotten indigo and its contribution to the color of Maya Blue. J Phys Chem A 2010; 114:1699-708. [PMID: 20055403 DOI: 10.1021/jp907718k] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A comprehensive investigation of the electronic spectral and photophysical properties of the oxidized form of indigo, dehydroindigo (DHI), has been carried out in solution at 293 K. It is shown that dehydroindigo readily converts into its neutral keto form, the blue indigo, in a process which depends on the solvent and water content of the medium. DHI was investigated in toluene, in benzene, and in methanol and it was found that both the oxidized and the keto indigo forms are present in solution. In marked contrast to what has been found for keto-indigo, where the internal conversion channel dominates >99% of the excited state deactivation, or with the fully reduced leuco-indigo, where fluorescence, internal conversion, and singlet-to-triplet intersystem crossing coexist, in the case of DHI in toluene and benzene, the dominant excited state deactivation channel involves the triplet state. Triplet state yields (phi(T)) of 70-80%, with negligible fluorescence (< or = 0.01%) are observed in these solvents. In methanol the phi(T) value decreases to approximately 15%, with an increase of the fluorescence quantum yield to 2%, which makes these processes competitive with the S(1) --> S(0) internal conversion deactivation process. The data are experimentally compatible with the existence of a lowest lying singlet excited state of n,pi* origin in toluene and of pi,pi* origin in methanol. A time-resolved investigation in the picosecond time domain suggests that the emission of DHI involves three interconnected species (involving rotational isomerism), with relative contributions depending on the emission wavelength. DFT calculations (B3LYP 6-31G** level) were performed in order to characterize the electronic ground (S(0)) and excited singlet (S(1)) and triplet (T(1)) states of DHI. The HOMO-LUMO transition was found to accompany an n --> pi* transition of the oxygen nonbonding orbitals to the central CC and adjacent C-N bonds. Calculations also revealed that in S(0) the two indole-like moieties deviate from planarity from ca. 20 degrees, whereas in S(1) and T(1) the predicted structure is basically planar; a gradual decrease of the carbon-carbon central bond distance is seen in the order S(0), S(1), T(1). An additional study on the blue pigment Maya Blue was made, and the comparison between the solid-state spectra of indigo, DHI, and Maya Blue suggests that, in line with recent investigations, DHI is present together with indigo in Maya Blue. These results are relevant to the discussion of the involvement of dehydroindigo in the palette of colors of the ancient Maya Blue pigment.
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Affiliation(s)
- Raquel Rondão
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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Oliva MM, Casado J, Navarrete JTL, Patchkovskii S, Goodson T, Harpham MR, Seixas de Melo JS, Amir E, Rozen S. Do [all]-S,S′-Dioxide Oligothiophenes Show Electronic and Optical Properties of Oligoenes and/or of Oligothiophenes? J Am Chem Soc 2010; 132:6231-42. [DOI: 10.1021/ja101015q] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- María Moreno Oliva
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Juan Casado
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Juan T. López Navarrete
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Serguei Patchkovskii
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Theodore Goodson
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michael R. Harpham
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - J. Sérgio Seixas de Melo
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Elizabeta Amir
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shlomo Rozen
- Department of Physical Chemistry, University of Málaga, Campus de Teatinos s/n, Málaga 29071, Spain, Steacie Institute for Molecular Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, K1A 0R6 Canada, Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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Dos Santos CMG, Glynn M, Mccabe T, Seixas de Melo JS, Burrows HD, Gunnlaugsson T. Synthesis, Structural and Photophysical Evaluations of Urea Based Fluorescent PET Sensors for Anions. Supramol Chem 2009. [DOI: 10.1080/10610270701288045] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Cidália M. G. Dos Santos
- a School of Chemistry, Trinity College Dublin, Centre for Synthesis and Chemical Biology , Dublin 2, Ireland
| | - Mark Glynn
- a School of Chemistry, Trinity College Dublin, Centre for Synthesis and Chemical Biology , Dublin 2, Ireland
| | - Tomas Mccabe
- a School of Chemistry, Trinity College Dublin, Centre for Synthesis and Chemical Biology , Dublin 2, Ireland
| | - J. Sérgio Seixas de Melo
- b Departamento de Química , Faculdade de Ciências e Tecnologia, Universidade de Coimbra , Coimbra, Portugal
| | - Hugh D. Burrows
- b Departamento de Química , Faculdade de Ciências e Tecnologia, Universidade de Coimbra , Coimbra, Portugal
| | - Thorfinnur Gunnlaugsson
- a School of Chemistry, Trinity College Dublin, Centre for Synthesis and Chemical Biology , Dublin 2, Ireland
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Pina J, Seixas de Melo J, Burrows HD, Maçanita AL, Galbrecht F, Bünnagel T, Scherf U. Alternating Binaphthyl−Thiophene Copolymers: Synthesis, Spectroscopy, and Photophysics and Their Relevance to the Question of Energy Migration versus Conformational Relaxation. Macromolecules 2009. [DOI: 10.1021/ma802395c] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Pina
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - J. Seixas de Melo
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - H. D. Burrows
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - A. L. Maçanita
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - F. Galbrecht
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - T. Bünnagel
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
| | - U. Scherf
- Department of Chemistry, University of Coimbra, Rua Larga, 3004-535 Coimbra, Portugal, Departamento de Engenharia Química e Biológica, Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, s/n. Lisboa, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gaussstr. 20, 42097 Wuppertal, Germany
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Pina J, Seixas de Melo JS. A comprehensive investigation of the electronic spectral and photophysical properties of conjugated naphthalene–thiophene oligomers. Phys Chem Chem Phys 2009; 11:8706-13. [DOI: 10.1039/b909113k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Gigante B, Esteves MA, Pires N, Davies ML, Douglas P, Fonseca SM, Burrows HD, Castro RAE, Pina J, Seixas de Melo J. Synthesis, spectroscopy, photophysics and thermal behaviour of stilbene-based triarylamines with dehydroabietic acid methyl ester moieties. NEW J CHEM 2009. [DOI: 10.1039/b815711a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Seixas de Melo J, Pina J, Rodrigues L, Becker R. A comprehensive study of the spectral and photophysical properties of arylthiophenes. J Photochem Photobiol A Chem 2008. [DOI: 10.1016/j.jphotochem.2007.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Pina J, Seixas de Melo J, Burrows HD, Galbrecht F, Bilge A, Kudla CJ, Scherf U. Excited State Properties of Oligophenyl and Oligothienyl Swivel Cruciforms. J Phys Chem B 2008; 112:1104-11. [DOI: 10.1021/jp0773280] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Pina
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - J. Seixas de Melo
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - H. D. Burrows
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - F. Galbrecht
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - A. Bilge
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - C. J. Kudla
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
| | - U. Scherf
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal, and Makromolekulare Chemie, Bergische Universität Wuppertal, Gauβstr. 20, 42097 Wuppertal, Germany
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Pina J, Seixas de Melo J, Burrows HD, Bilge A, Farrell T, Forster M, Scherf U. Spectral and photophysical studies on cruciform oligothiophenes in solution and the solid state. J Phys Chem B 2007; 110:15100-6. [PMID: 16884222 DOI: 10.1021/jp060707t] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photophysical and spectroscopic properties of a new class of oligothiophene derivatives, designated as cruciform oligomers, have been investigated in solution (room and low temperature) and in the solid state (as thin films in Zeonex matrixes). The study comprises absorption, emission, and triplet-triplet absorption spectra, together with quantitative measurements of quantum yields (fluorescence, intersystem crossing, internal conversion, and singlet oxygen formation) and lifetimes. The overall data allow the determination of the rate constants for all decay processes. From these, several conclusions are drawn. First, in solution, the main deactivation channels for the compounds are the radiationless processes: S(1) --> S(0) internal conversion and S(1) --> T(1) intersystem crossing. Second, in general, in the solid state, the fluorescence quantum yields decrease relative to solution. A comparison is made with the analogous linear alpha-oligothiophenes, revealing a lower fluorescence quantum efficiency and, in contrast to the normal oligothiophenes, that internal conversion is an important channel for the deactivation of the singlet excited state. Replacement of thiophene by 1,4-phenylene units in the longer-sized cruciform oligomer increases the fluorescence efficiency. The highly efficient generation of singlet oxygen through energy transfer from the triplet state (S(Delta) approximately 1) provides support for the measured intersystem crossing quantum yields and suggests that reaction with this may be an important pathway to consider for degradation of devices produced with these compounds.
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Affiliation(s)
- J Pina
- Departamento de Química, Universidade de Coimbra, Rua Larga, 3004-535 Coimbra, Portugal
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Burrows HD, Chattopadhyay N, Esteves MA, Fernandes M, Gigante B. Fluorescence Characteristics of Some Dehydroabietic Acid-Based Arylamines. J Fluoresc 2007; 17:701-6. [PMID: 17665290 DOI: 10.1007/s10895-007-0221-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Accepted: 07/02/2007] [Indexed: 11/25/2022]
Abstract
Absorption spectra and fluorescence data in nonpolar solvents are reported for seven novel dehydroabietic acid-based diarylamines, which have potential as components of hole transport layers for molecular electronic devices. This bulky group has been found to improve the possibilities for film formation of these compounds, and in this study we show that this does not significantly affect their fluorescence characteristics, which are similar to diphenylamine.
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Affiliation(s)
- H D Burrows
- Departamento de Química, Universidade de Coimbra, Coimbra, Portugal.
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26
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Seixas de Melo J, Rodrigues LM, Serpa C, Arnaut LG, Ferreira ICFR, Queiroz MJRP. Photochemistry and Photophysics of Thienocarbazoles¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0770121papot2.0.co2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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27
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de Melo JSS, Costa T, Oliveira N, Schillén K. Fluorescence studies on the interaction between pyrene-labelled poly(acrylic acid) and cyclodextrins. POLYM INT 2007. [DOI: 10.1002/pi.2219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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28
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O'Neill L, Lynch P, McNamara M, Byrne HJ. Spectroscopic Characterization of Novel Polycyclic Aromatic Polymers. J Phys Chem A 2006; 111:299-305. [PMID: 17214468 DOI: 10.1021/jp0662754] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of novel polyphenylenevinylene (PPV) derivative polymers were studied by absorption and photoluminescence spectroscopies. The effect of the sequential introduction of polycyclic aromatic ring substituents into the delocalized backbone was examined with relation to hypsochromatic and bathochromatic shifting. While the replacement of the phenyl units by naphthyl units results in a substantial hypsochromic shift of both the absorption and emission spectra, their subsequent substitution by anthryl units results in a bathochromic shift. The system is modeled according to, and is found to be consistent with, a previous study of donor-acceptor polyenes of varying length. The electronic structure of the backbone is found to be a balance between that of the high electron affinity polycyclic ring system and the contribution to conjugation across the linking vinyl unit. The model is adapted based on electron affinities of the constituent units, and a clear structure-property relationship for the absorption and emission properties of the system is elucidated. The Stokes shift is examined and is seen to be well-correlated with the vinyl contribution to the electron affinity total (EAtotal). The trends observed in the optical properties of the polymeric system are supported by Raman spectroscopy, whereby the spectral signature of the connecting vinyl bond is seen to soften in a fashion which is correlated with the modeled electron affinity parameters.
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Affiliation(s)
- Luke O'Neill
- School of Physics and School of Chemical and Pharmaceutical Sciences, FOCAS Institute, Dublin Institute of Technology, Kevin Street, Dublin 8, Ireland.
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Seixas de Melo J, Rondão R, Burrows HD, Melo MJ, Navaratnam S, Edge R, Voss G. Photophysics of an Indigo Derivative (Keto and Leuco Structures) with Singular Properties. J Phys Chem A 2006; 110:13653-61. [PMID: 17181317 DOI: 10.1021/jp057451w] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spectral and photophysical properties of the indigo derivative Cibalackrot in keto and reduced (leuco) forms were studied by absorption spectra, fluorescence and pulse radiolysis and compared with the structurally similar indigo. With the keto form of this dye, fluorescence (phiF = 0.76) and intersystem crossing (phiT = 0.11) are dominant, whereas with indigo, efficient internal conversion (phiIC = 0.99) is observed, probably involving proton transfer through intramolecular hydrogen bonds. With Cibalackrot, this pathway is blocked, supporting the above model for indigo. With the reduced form of Cibalackrot, more than 98% of the absorbed quanta are dissipated through S1 approximately --> S0 internal conversion, which contrasts with leuco-indigo, where fluorescence (phiF = 0.35), internal conversion (phiIC = 0.53) and intersystem crossing (phiT = 0.125) are found to be competitive. In addition, a synthetic precursor of Cibalackrot (preCiba) was also investigated. This has a rigid molecular structure (with a moiety identical to Cibalackrot and the other to indigo), but intra- or intermolecular proton transfer is allowed between adjacent carbonyl and N-H groups. With this precursor in its keto structure the photophysical parameters are generally very close to those of the keto form of indigo, and different from those of Cibalackrot. A more detailed investigation of the time-decay profiles of preCiba in dioxane (and with added water and D2O) has shown that these follow biexponential laws with a shorter component of 14-25 ps, which appears associated with a risetime at longer wavelength emissions (and to a positive preexponential at shorter emission wavelengths) and a longer lived (decay) component of 104-130 ps. In the steady-state spectra of preCiba, the variation with temperature reveals a blue shift of the emission maxima, which is interpreted as the presence (simultaneous emission) of two species (keto and enol) in the excited state. Indigo and deuterated indigo are also found to present a similar behavior. The overall data are interpreted as to be due to an excited-state process involving the proton transfer between keto and enol forms. Rate constants with values of 7 x 10(10) s-1 for preCiba and 1.6 x 10(11) s-1 for deuterated indigo were obtained. This inverse isotope effect is justified on the basis of the proposed model for proton-transfer excited-state deactivation.
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Affiliation(s)
- J Seixas de Melo
- Departamento de Química, Universidade de Coimbra, P3004-535 Coimbra, Portugal.
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Seixas de Melo J, Pina J, Burrows H, Di Paolo R, Maçanita A. Electronic spectral and photophysical properties of some p-phenylenevinylene oligomers in solution and thin films. Chem Phys 2006. [DOI: 10.1016/j.chemphys.2006.09.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Pina J, Burrows HD, Becker RS, Dias FB, Maçanita AL, Seixas de Melo J. Photophysical Studies of α,ω-Dicyano-oligothiophenes NC(C4H2S)nCN (n = 1−6). J Phys Chem B 2006; 110:6499-505. [PMID: 16570947 DOI: 10.1021/jp055455v] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The photophysics of six oligothiophenes end-capped with cyano groups (CNalphan) was investigated in solution at room and low temperature. The study comprises singlet-singlet and triplet-triplet absorption and emission spectra together with lifetimes and quantum yields for all the radiative and nonradiative processes. From the lifetimes and quantum yields, it was possible to extract the rate constants for all the processes. Singlet oxygen yields were also determined, revealing an efficient sensitization (SDelta approximately 1) of its formation by the triplet state of the CNalphan. The introduction of the cyano groups is found to decrease the energetic separation between the highest occupied molecular orbital and the lowest unoccupied molecular orbital, leading to a red shift of the absorption and the emission when compared with the unsubstituted counterparts, the alpha-oligothiophenes. Phosphorescence is only observed for the first member of the series, CNalpha1.
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Affiliation(s)
- J Pina
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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32
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Costa T, Miguel MDG, Lindman B, Schillén K, Seixas de Melo JS. Dynamics and Energetics of the Self-Assembly of a Hydrophobically Modified Polyelectrolyte: Naphthalene-Labeled Poly(Acrylic Acid). J Phys Chem B 2005; 109:11478-92. [PMID: 16852406 DOI: 10.1021/jp050236v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Steady-state and time-resolved fluorescence studies were performed on aqueous solutions of poly(acrylic acid) hydrophobically modified with two very different levels of naphthalene (Np). It is demonstrated that unique information on association phenomena involving hydrophobe-modifed polymers can be obtained from an extended fluorescence study by using data for a less-modified polymer as a reference. For the more highly modified polymer, the presence of excited-state (as well as ground-state) dimers in addition to monomer emission due to locally excited naphthalene gives evidence for hydrophobic association between naphthalene groups. This association becomes, as expected, much less important at higher pH due to the electrostatic repulsion between different chain segments. However, it is noted that even at high pH there is a significant self-association. The coexistence of static and dynamic quenching phenomena of the Np monomer label was also revealed in the time-resolved fluorescence data. The data are compatible with the existence of two types of monomers and one excimer and suggest that the essential contribution to the monomer emission comes from isolated chromophores, whereas excimer formation arises from both a dynamic route (excited Np chromophores able to produce a dynamic excimer) and a static route (excitation of ground-state Np dimers). At room temperature, the dissociative reaction, excimer-to-monomer, can be neglected, and thus the rate constant for excimer formation and decay could be obtained with and without considering the influence of preformed dimers. Temperature has shown to induce different behavior in the polymer photophysics. In the case of the less-labeled polymer, the decays were found to be single-exponential with the fluorescence lifetime decreasing with increasing temperature. From the temperature dependence of the steady-state fluorescence data, the activation energy for excimer formation and the binding energy of the excimer were evaluated at different pH values, through the Stevens-Ban-type plots of the excimer-to-monomer intensity ratio. With the time-resolved data, measured in the temperature range of 5-60 degrees C, it was possible to extract the intrinsic activation energies for excimer formation. The thermodynamic driving force for the intrapolymeric association was found to be dependent on a balance between hydrophobic and electrostatic interactions, which are dependent on the pH, temperature, and hydrophobic content of the polymer.
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Affiliation(s)
- Telma Costa
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal
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33
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Singlet and triplet energy transfer in a bichromophoric system with anthracene covalently linked through sulfonamide to a meso-tetraphenylporphyrin. J Photochem Photobiol A Chem 2005. [DOI: 10.1016/j.jphotochem.2004.12.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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34
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Anni M, Della Sala F, Raganato MF, Fabiano E, Lattante S, Cingolani R, Gigli G, Barbarella G, Favaretto L, Görling A. Nonradiative Relaxation in Thiophene-S,S-dioxide Derivatives: The Role of the Environment. J Phys Chem B 2005; 109:6004-11. [PMID: 16851655 DOI: 10.1021/jp046465j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The intramolecular radiative and nonradiative relaxation processes of three thiophene-S,S-dioxide derivatives with different molecular rigidity are investigated in different solutions and in inert matrix. We show that the fluorescence quantum efficiency and the relaxation dynamics are strongly dependent on the environment viscosity, whereas they are almost independent of the environment polarity. We demonstrate that this strong dependence is due to an environment dependent nonradiative decay rate, whereas no relevant variations of the radiative decay rate are observed. We demonstrate that the dipole coupling with the solvent does not provide an efficient nonradiative decay channel and that the S(n) - S(1) vibrational relaxation is very efficient in all of the molecules and for all of the investigated environments. Moreover first-principles time-dependent density-functional theory calculations in the correct, i.e., excited-state, molecular conformation, suggest that significant contributions of intersystem crossing to the triplet manifold can be excluded. We then conclude that the main nonradiative process determining the fluorescence quantum efficiency of this class of molecules is S(1) - S(0) internal conversion (IC). An explanation for the IC rate dependence in terms of the environment viscosity, molecular rigidity, S(1) - S(0) energy-gap, and molecular volume is presented.
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Affiliation(s)
- M Anni
- National Nanotechnology Laboratory (NNL) of INFM, Dipartimento di Ingegneria dell'Innovazione, Università degli Studi di Lecce, Via per Arnesano, 73100 Lecce, Italy
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35
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Costa T, Miguel MG, Lindman B, Schillén K, Lima JC, Seixas de Melo J. Self-Assembly of a Hydrophobically Modified Naphthalene-Labeled Poly(acrylic acid) Polyelectrolyte in Water:Organic Solvent Mixtures Followed by Steady-State and Time-Resolved Fluorescence. J Phys Chem B 2005; 109:3243-51. [PMID: 16851348 DOI: 10.1021/jp046589w] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solution properties of two water-soluble polymers, poly(acrylic acid) (PAA), covalently labeled with the fluorescent hydrophobic dye naphthalene (Np), have been investigated in water:organic solvent mixtures. The naphthalene chromophores have been randomly attached, onto the polymer, with two different degrees of labeling. Fluorescence measurements (steady-state and time-resolved) have been used to follow the photophysical behavior of the polymers and consequently report on the self-association of the polymers in the mixed organic (methanol or dioxane):aqueous solutions. The emission spectra of the high-labeled Np PAA reveal the presence of monomer and excimer bands whereas with the low-labeled polymer only monomer emission is observed. The excitation spectra collected at the monomer and excimer emission bands show significant differences, depending on the water content of the mixture, which indicate the simultaneous presence of preformed and dynamic dimers as routes to excimer formation. The time-resolved data decay profiles of the high-labeled polymer in the mixtures were always triple exponential whereas in pure methanol and dioxane they follow biexponential laws. The data in the mixtures are consistent with two types of monomers and one excimer. Both monomers are able to give rise to excimer in the excited state, one type involving the movement of long distant Np chromophores and the other involving a local reorientation of adjacent Np chromophores. These correspond to different decay times: (1) a long which corresponds to the long distant approach of non-neighboring Np chromophores forming an excimer and (2) a short corresponding to the fast adjustment of two neighboring Np chromophores in order to have the adequate parallel geometry. An additional decay time corresponding to the excimer decay was found to be present at all wavelengths. All the decay times were dependent on the water content of the mixture. An estimation of the two excimer forming rate constants values is made for the mixed media considered in this work. On the whole, using both steady-state and time-resolved fluorescence parameters, and by comparing data for a polymer with a small number of hydrophobes with a more highly modified one, it is possible in great detail to demonstrate how association is controlled by solvent quality for the hydrophobes and by the distance between hydrophobes.
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Affiliation(s)
- Telma Costa
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal
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Seixas de Melo J, Moura AP, Melo MJ. Photophysical and Spectroscopic Studies of Indigo Derivatives in Their Keto and Leuco Forms. J Phys Chem A 2004. [DOI: 10.1021/jp049076y] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Seixas de Melo
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Departamento de Conservação e Restauro and ReQuimte, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica, Portugal
| | - A. P. Moura
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Departamento de Conservação e Restauro and ReQuimte, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica, Portugal
| | - M. J. Melo
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Departamento de Conservação e Restauro and ReQuimte, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Quinta da Torre, 2829-516 Monte de Caparica, Portugal
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Seixas de Melo J, Pina J, Burrows H, Brocke S, Herzog O, Thorn-Csányi E. The effect of substitution and isomeric imperfection on the photophysical behaviour of p-phenylenevinylene trimers. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.02.093] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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38
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Seixas de Melo J, Pina J, Pina F, Lodeiro C, Parola AJ, Lima JC, Albelda MT, Clares MP, Garcia-España E, Soriano C. Energetics and Dynamics of Naphthalene Polyaminic Derivatives. Influence of Structural Design in the Balance Static vs Dynamic Excimer Formation. J Phys Chem A 2003. [DOI: 10.1021/jp036149p] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Conxa Soriano
- Departament de Química Orgànica, Facultat de Farmàcia, Universitat de València, Burjassot, Spain
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Seixas de Melo J, Costa T, Miguel MDG, Lindman B, Schillén K. Time-Resolved and Steady-State Fluorescence Studies of Hydrophobically Modified Water-Soluble Polymers. J Phys Chem B 2003. [DOI: 10.1021/jp0346054] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. Seixas de Melo
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Telma Costa
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Maria da G. Miguel
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Björn Lindman
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Karin Schillén
- Chemistry Department, University of Coimbra, 3004-535 Coimbra, Portugal, and Physical Chemistry 1, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Ferrer M, Rodrı́guez L, Rossell O, Pina F, Lima JC, Bardia MF, Solans X. Linear ditopic acetylide gold or mercury complexes: synthesis and photophysic studies. J Organomet Chem 2003. [DOI: 10.1016/s0022-328x(03)00442-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dias FB, Maçanita AL, Seixas de Melo J, Burrows HD, Güntner R, Scherf U, Monkman AP. Picosecond conformational relaxation of singlet excited polyfluorene in solution. J Chem Phys 2003. [DOI: 10.1063/1.1560939] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Seixas de Melo J, Burrows HD, Svensson M, Andersson MR, Monkman AP. Photophysics of thiophene based polymers in solution: The role of nonradiative decay processes. J Chem Phys 2003. [DOI: 10.1063/1.1528604] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Guyard L, Dumas C, Miomandre F, Pansu R, Renault-Méallet R, Audebert P. Synthesis and the electrochemical and fluorescence properties of new cyclophane-derivatized oligothiophenes. NEW J CHEM 2003. [DOI: 10.1039/b210729p] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Seixas de Melo J, Elisei F, Becker RS. Photophysical studies of mixed furan, pyrrole, and thiophene-containing oligomers with three and five rings. J Chem Phys 2002. [DOI: 10.1063/1.1498115] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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