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Sakr AR, Georgiev NI, Bojinov VB. Design, synthesis, and biological activity of perylene tetracarboxydiimide dendrimer. SYNTHETIC COMMUN 2022. [DOI: 10.1080/00397911.2022.2134798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- Alaa R. Sakr
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, 8 Kliment Ohridsky Str., Sofia, Bulgaria
| | - Nikolai I. Georgiev
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, 8 Kliment Ohridsky Str., Sofia, Bulgaria
| | - Vladimir B. Bojinov
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, 8 Kliment Ohridsky Str., Sofia, Bulgaria
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Sakr AR, Georgiev NI, Bojinov VB. Design, photochemistry and antibacterial evaluation of novel light-harvesting antenna. SYNTHETIC COMMUN 2020. [DOI: 10.1080/00397911.2020.1788601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Alaa R. Sakr
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
- Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt
| | - Nikolai I. Georgiev
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
| | - Vladimir B. Bojinov
- Department of Organic Synthesis, University of Chemical Technology and Metallurgy, Sofia, Bulgaria
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Militello MP, Hernández-Ramírez RE, Lijanova IV, Previtali CM, Bertolotti SG, Arbeloa EM. Novel PAMAM dendrimers with porphyrin core as potential photosensitizers for PDT applications. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.10.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Elkin I, Banquy X, Barrett CJ, Hildgen P. Non-covalent formulation of active principles with dendrimers: Current state-of-the-art and prospects for further development. J Control Release 2017; 264:288-305. [PMID: 28887136 DOI: 10.1016/j.jconrel.2017.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/28/2017] [Accepted: 09/01/2017] [Indexed: 12/18/2022]
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An organic jelly made fractal logic gate with an infinite truth table. Sci Rep 2015; 5:11265. [PMID: 26086417 PMCID: PMC4471884 DOI: 10.1038/srep11265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/15/2015] [Indexed: 11/18/2022] Open
Abstract
Widely varying logic gates invented over a century are all finite. As data deluge problem looms large on the information processing and communication industry, the thrust to explore radical concepts is increasing rapidly. Here, we design and synthesis a molecule, wherein, the input energy transmits in a cycle inside the molecular system, just like an oscillator, then, we use the molecule to make a jelly that acts as chain of oscillators with a fractal like resonance band. Hence, with the increasing detection resolution, in the vacant space between two energy levels of a given resonance band, a new band appears, due to fractal nature, generation of newer energy levels never stops. This is natural property of a linear chain oscillator. As we correlate each energy level of the resonance band of organic jelly, as a function of pH and density of the jelly, we realize a logic gate, whose truth table is finite, but if we zoom any small part, a new truth table appears. In principle, zooming of truth table would continue forever. Thus, we invent a new class of infinite logic gate for the first time.
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El-Sayed MY, Refat MS. Structural and spectroscopic characterizations on the charge-transfer interactions of the second generation poly(propylene amine) dendrimers with iodine and picric acid acceptors. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2015; 137:1270-1279. [PMID: 25305621 DOI: 10.1016/j.saa.2014.09.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/24/2014] [Accepted: 09/11/2014] [Indexed: 06/04/2023]
Abstract
Herein, this study was focused to get a knowledge about the intermolecular charge transfer complexes between the second generation of poly(propylene amine) dendrimer (PPD2) with picric acid (PA) and iodine (I2) as π and σ-acceptors. The charge-transfer interaction of the PPD2 electron donor and the PA acceptor has been studied in CHCl3. The resulted data refereed to the formation of the new CT-complex with the general formula [(PPD2)(PA)4]. The 1:4 stoichiometry of the reaction was discussed upon the on elemental analysis and photometric titration. On the other hand, the 1:3½ iodine-PPD2 heptaiodide (I7(-)) charge-transfer complex has been studied spectrophotometrically in chloroform at room temperature with general formula [(PPD2)](+)I7(-). The electronic absorption bands of 2I2·I3(-) (I7(-)) are observed at 358 and 294 nm. Raman laser spectrum of the brown solid heptaiodide complex has two clearly vibration bands at 155 and 110 cm(-1) due to symmetric stretching νs(II) outer and inner bonds, respectively. The (1)H NMR spectra and differential scanning calorimetry (DSC) data of PPD2 charge-transfer complexes were discussed.
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Affiliation(s)
- Mohamed Y El-Sayed
- Department of Chemistry, Faculty of Science, Zagazig University, Egypt; Faculty of Applied Medical Science, Al Jouf University-Al Qurayate, Saudi Arabia
| | - Moamen S Refat
- Chemistry Department, Faculty of Science, Taif University, P.O. Box 888, Al-Hawiah, Taif 21974, Saudi Arabia; Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt.
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Excited state dynamics of PPI dendrimers functionalized with 4-(4′-ethoxybenzoyloxy)salicylaldehyde chromophores. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2012.12.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Franckevičius M, Vaišnoras R, Marcos M, Serrano J, Gruodis A, Galikova N, Gulbinas V. Tautomeric forms of PPI dendrimers functionalized with 4-(4′-ethoxybenzoyloxy)salicylaldehyde chromophores. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Trastoy B, Pérez-Ojeda ME, Sastre R, Chiara JL. Octakis(3-azidopropyl)octasilsesquioxane: a versatile nanobuilding block for the efficient preparation of highly functionalized cube-octameric polyhedral oligosilsesquioxane frameworks through click assembly. Chemistry 2010; 16:3833-41. [PMID: 20162645 DOI: 10.1002/chem.200902422] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A one-step synthesis of octakis(3-azidopropyl)octasilsesquioxane from commercially available octakis(3-aminopropyl)octasilsesquioxane has been developed through a highly efficient diazo-transfer reaction under very mild conditions. Nonaflyl azide is shown to be a safer, cheaper, and more efficient reagent for this transformation than the better known and generally used diazo-transfer reagent triflyl azide. Octakis(3-azidopropyl)octasilsesquioxane is an excellent nanobuilding block that can be readily octafunctionalized with a range of terminal alkynes by copper(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition to provide new functional nanocages, maintaining a perfect 3D cubic symmetry. The mildness, simplicity, and efficiency of this approach have been demonstrated in the preparation of a glyco-polyhedral oligosilsesquioxane (POSS) conjugate and a BODIPY-POSS cluster (BODIPY = boron dipyrromethene).
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Affiliation(s)
- Beatriz Trastoy
- Instituto de Química Orgánica General, CSIC, Juan de La Cierva, 3, 28006 Madrid, Spain
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Zhang KY, Liu HW, Fong TTH, Chen XG, Lo KKW. Luminescent Dendritic Cyclometalated Iridium(III) Polypyridine Complexes: Synthesis, Emission Behavior, and Biological Properties. Inorg Chem 2010; 49:5432-43. [DOI: 10.1021/ic902443e] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Kenneth Yin Zhang
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Hua-Wei Liu
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Tommy Tsz-Him Fong
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Xian-Guang Chen
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People’s Republic of China
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Galán H, Hennrich G, de Mendoza J, Prados P. Synthesis and Photoisomerization of Azocalixarenes with Dendritic Structures. European J Org Chem 2010. [DOI: 10.1002/ejoc.200901394] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Refat MS, El-Deen IM, Grabchev I, Anwer ZM, El-Ghol S. Spectroscopic characterizations and biological studies on newly synthesized Cu(2+) and Zn(2+) complexes of first and second generation dendrimers. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2009; 72:772-782. [PMID: 19119062 DOI: 10.1016/j.saa.2008.11.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2008] [Accepted: 11/15/2008] [Indexed: 05/27/2023]
Abstract
The novel Cu(II) and Zn(II) complexes of first and second generation poly(propylene amine) dendrimers (PPA), comprising 1,8-naphthalimde units on periphery have been synthesized. These new complexes were characterized by elemental analysis, molar conductivity, spectral methods (IR, (1)H NMR and UV-vis spectra) and thermal analysis (TG and DTG) techniques. From elemental analysis as well as thermal studies it has found that the first generation dendrimer behaves as bidentate ligand and forming chelates with 1:2 (ligand:metal) and 1:4 (ligand:metal) stoichiometry for second generation dendrimer. Different kinetic parameters namely activation energy (DeltaE*), enthalpy of activation (DeltaH*), entropy of activation (DeltaS*) and free energy change of activation (DeltaG*) are calculated using Coats-Redfern equation. The antibacterial activity of dendrimers and their complexes was evaluated against some Gram positive and negative bacteria.
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Affiliation(s)
- Moamen S Refat
- Department of Chemistry, Suez Canal University, Port Said, Egypt.
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Nantalaksakul A, Mueller A, Klaikherd A, Bardeen CJ, Thayumanavan S. Dendritic and Linear Macromolecular Architectures for Photovoltaics: A Photoinduced Charge Transfer Investigation. J Am Chem Soc 2009; 131:2727-38. [DOI: 10.1021/ja809194u] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Arpornrat Nantalaksakul
- Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, and University of California, Riverside, California 92521
| | - Astrid Mueller
- Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, and University of California, Riverside, California 92521
| | - Akamol Klaikherd
- Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, and University of California, Riverside, California 92521
| | - Christopher J. Bardeen
- Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, and University of California, Riverside, California 92521
| | - S. Thayumanavan
- Departments of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, and University of California, Riverside, California 92521
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Fischer MKR, Kaiser TE, Würthner F, Bäuerle P. Dendritic oligothiophene-perylene bisimide hybrids: synthesis, optical and electrochemical properties. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b817158k] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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McHedlov-Petrossyan NO, Bryleva EY, Vodolazkaya NA, Dissanayake AA, Ford WT. Nature of cationic poly(propylenimine) dendrimers in aqueous solutions as studied using versatile indicator dyes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:5689-5699. [PMID: 18452320 DOI: 10.1021/la800443q] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Aqueous solutions of four cationic poly(propylenimine) low-generation dendrimers of different architecture and hydrophobicity have been examined as media for acid-base reactions of indicator dyes. The cationic dendrimers in solution can be considered as oligomers of cationic polyelectrolytes, or surfactant-like species, able to form micelles through self-association or sometimes even as unimolecular micelles. The dendrimers influence the ionization constants, tautomeric equilibria, and absorption/emission/excitation spectra of indicator dyes. The p K a values of the majority of the indicator dyes decrease in dendrimer solutions, often by 1-2 p K a units, similar to effects registered in micellar solutions of cationic surfactants. Analogously, the shifts of absorption band maxima indicate that the microenvironments of the dyes bound to the dendrimers are less polar than in water. However, some spectral effects denote the specificity of the dendrimers. The greatest difference between the dendrimers and spherical surfactant micelles is revealed by kinetic processes, especially of bromophenol blue alkaline fading in a dendrimer solution but not in a micellar surfactant solution. Within the dendrimer series, the most significant differences were observed for substances possessing n-dodecyl tails on the one hand and those without such hydrophobic portions on the other. For the last-named, the decrease in p K a's of indicators, band shifts of their anions, and in particular displacement of tautomeric equilibria compared with aqueous solutions are much smaller than for more hydrophobic dendrimers.
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Newkome GR, Shreiner CD. Poly(amidoamine), polypropylenimine, and related dendrimers and dendrons possessing different 1→2 branching motifs: An overview of the divergent procedures. POLYMER 2008. [DOI: 10.1016/j.polymer.2007.10.021] [Citation(s) in RCA: 257] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Dendritic Host Molecules with a Polycationic Core and an Outer Shell of Dodecyl Groups. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600727] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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He Z, Ishizuka T, Jiang D. Dendritic Architectures for Design of Photo– and Spin–Functional Nanomaterials. Polym J 2007. [DOI: 10.1295/polymj.pj2007006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Melnikov SM, Yeow EKL, Uji-i H, Cotlet M, Müllen K, De Schryver FC, Enderlein J, Hofkens J. Origin of Simultaneous Donor−Acceptor Emission in Single Molecules of Peryleneimide−Terrylenediimide Labeled Polyphenylene Dendrimers. J Phys Chem B 2007; 111:708-19. [PMID: 17249814 DOI: 10.1021/jp0655625] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Förster type resonance energy transfer (FRET) in donor-acceptor peryleneimide-terrylenediimide dendrimers has been examined at the single molecule level. Very efficient energy transfer between the donor and the acceptor prevent the detection of donor emission before photobleaching of the acceptor. Indeed, in solution, on exciting the donor, only acceptor emission is detected. However, at the single molecule level, an important fraction of the investigated individual molecules (about 10-15%) show simultaneous emission from both donor and acceptor chromophores. The effect becomes apparent mostly after photobleaching of the majority of donors. Single molecule photon flux correlation measurements in combination with computer simulations and a variety of excitation conditions were used to determine the contribution of an exciton blockade to this two-color emission. Two-color defocused wide-field imaging showed that the two-color emission goes hand in hand with an unfavorable orientation between one of the donors and the acceptor chromophore.
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Affiliation(s)
- Sergey M Melnikov
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium
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Chen J, Zhang L, Li S, Li YY, Chen J, Yang G, Li Y. Valence isomerization in dendrimers by photo-induced electron transfer and energy transfer from the dendrimer backbone to the core. J Photochem Photobiol A Chem 2007. [DOI: 10.1016/j.jphotochem.2006.05.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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You CC, Hippius C, Grüne M, Würthner F. Light-Harvesting Metallosupramolecular Squares Composed of Perylene Bisimide Walls and Fluorescent Antenna Dyes. Chemistry 2006; 12:7510-9. [PMID: 16865755 DOI: 10.1002/chem.200600413] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The fluorescent dye 4-dimethylamino-1,8-naphthalimide was incorporated at the bay area of N,N'-bispyridyl perylene bisimide to afford a fourfold-functionalized perylene bisimide ligand. Through self-assembly directed by metal-ion coordination, a multichromophore supramolecular entity composed of sixteen dimethylaminonaphthalimide antennas and a perylene bisimide-walled square core was subsequently constructed from this linear ditopic ligand and 90 degrees metal corner [Pd(dppp)](OTf)2 (dppp=1,3-bis(diphenylphosphino)propane; OTf=trifluoromethanesulfonate) in good yield. The isolated metallosupramolecular square was characterized by elemental analysis and 1H, 13C, and 31P{1H} NMR and UV/Vis spectroscopy. Furthermore, by means of 1H NMR diffusion-ordered spectroscopy (DOSY) the dimension of this assembly was evaluated by employing a previously reported perylene bisimide ligand and its square assembly as references. The results obtained confirm the square framework of the current assembly. The optical properties of this multichromophore dye assembly were investigated by UV/Vis and steady-state and time-resolved fluorescence spectroscopy. It was revealed that light captured by dimethylaminonaphthalimide antennas could be efficiently transported to the perylene bisimide core by a fluorescence resonance mechanism (energy-transfer efficiency E=95%), and this resulted in almost exclusive detection of intense perylene bisimide emission, irrespective of the excitation wavelength applied. The present square scaffold containing aminonaphthalimide antenna dyes exhibits more than seven times higher fluorescence quantum yield (Phifl=0.37) than a previously reported pyrene-bearing perylene bisimide-walled square (Phifl=0.05). Thus, this multichromophore square assembly with aminonaphthalimide antenna dyes is an artificial model for the cyclic light-harvesting complexes in purple bacteria.
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Affiliation(s)
- Chang-Cheng You
- Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
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Yanagimoto Y, Takaguchi Y, Tsuboi S, Ichihara M, Ohta K. Photoreactivity of Tetra-Substituted Anthracene Derivatives and Their Mesophases. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2006. [DOI: 10.1246/bcsj.79.1265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Petrella A, Cremer J, De Cola L, Bäuerle P, Williams RM. Charge transfer processes in conjugated triarylamine-oligothiophene-perylenemonoimide dendrimers. J Phys Chem A 2006; 109:11687-95. [PMID: 16366618 DOI: 10.1021/jp0510995] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis and charge transfer properties of triarylamine-oligothiophene-perylenemonoimide dendrimers, TPA(T2-PMI)3 and TPA(T4-PMI)3, are described. The fluorescence quantum yields indicate strong emission quenching by electron transfer [phi(THF) = 0.004 for TPA(T2-PMI)3, phi(THF) = 0.003 for TPA(T4-PMI)3, and phi(THF) = 0.8 for PMI]. Moreover, with the increase of the solvent polarity, the quantum yields decrease indicating that the A+* D-* (acceptor/donor) couple is more stabilized. The femtosecond transient absorption spectra show a very fast charge separation process (approximately 2 ps; k(cs) approximately 5 x 10(11) s(-1)) and a charge recombination of more than 1 order of magnitude slower (approximately 50 ps; k(cr) approximately 2 x 10(10) s(-1)), as observed from the rise time and decay of the radical anion and radical cation absorption bands. The analysis of the transient absorption spectroscopy and of the energetics of the process using Marcus theory indicates that in the electron transfer process the thiophene unit is the first electron donor. The triarylamine is not functioning as a second electron donor, as also substantiated by the absence of an effect of the addition of acid on the emission intensity of the dendrimers. The presence of the triarylamine and/or the proximity of the oligothiophenes does improve the donor capabilities of the oligothiophene unit slightly and enhances its conjugation as seen in the absorption spectra and the transients of the radial cations. These results can be used for a better design of molecular materials for, e.g., photovoltaic applications.
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Affiliation(s)
- Andrea Petrella
- Molecular Photonic Materials, van 't Hoff Institute for Molecular Sciences, Universiteit van Amsterdam, Nieuwe Achtergracht 166, 1018 WS Amsterdam, The Netherlands
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Szaciłowski K, Macyk W, Drzewiecka-Matuszek A, Brindell M, Stochel G. Bioinorganic photochemistry: frontiers and mechanisms. Chem Rev 2005; 105:2647-94. [PMID: 15941225 DOI: 10.1021/cr030707e] [Citation(s) in RCA: 570] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Justin Thomas KR, Thompson AL, Sivakumar AV, Bardeen CJ, Thayumanavan S. Energy and Electron Transfer in Bifunctional Non-Conjugated Dendrimers. J Am Chem Soc 2004; 127:373-83. [PMID: 15631488 DOI: 10.1021/ja044778m] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Nonconjugated dendrimers, which are capable of funneling energy from the periphery to the core followed by a charge-transfer process from the core to the periphery, have been synthesized. The energy and electron donors involve a diarylaminopyrene unit and are incorporated at the periphery of these dendrimers. The energy and electron acceptor is at the core of the dendrimer, which involves a chromophore based on a benzthiadiazole moiety. The backbone of the dendrimers is benzyl ether based. A direct electron-transfer quenching of the excited state of the periphery or a sequential energy transfer-electron-transfer pathway are the two limiting mechanisms of the observed photophysical properties. We find that the latter mechanism is prevalent in these dendrimers. The energy transfer occurs on a picosecond time scale, while the charge-transfer process occurs on a nanosecond time scale. The lifetime of the charge separated species was found to be in the range of microseconds. Energy transfer efficiencies ranging from 80% to 90% were determined using both steady-state and time-resolved measurements, while charge-transfer efficiencies ranging from 70% to 80% were deduced from fluorescence quenching of the core chromophore. The dependence of the energy and charge-transfer processes on dendrimer generation is analyzed in terms of the backfolding of the flexible benzyl ether backbone, which leads to a weaker dependence of the energy and charge-transfer efficiencies on dendrimer size than would be expected for a rigid system.
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Affiliation(s)
- K R Justin Thomas
- Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA
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Andrews DL, Bradshaw DS. Optically nonlinear energy transfer in light-harvesting dendrimers. J Chem Phys 2004; 121:2445-54. [PMID: 15260800 DOI: 10.1063/1.1769354] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dendrimeric polymers are the subject of intense research activity geared towards their implementation in nanodevice applications such as energy harvesting systems, organic light-emitting diodes, photosensitizers, low-threshold lasers, and quantum logic elements, etc. A recent development in this area has been the construction of dendrimers specifically designed to exhibit novel forms of optical nonlinearity, exploiting the unique properties of these materials at high levels of photon flux. Starting from a thorough treatment of the underlying theory based on the principles of molecular quantum electrodynamics, it is possible to identify and characterize several optically nonlinear mechanisms for directed energy transfer and energy pooling in multichromophore dendrimers. Such mechanisms fall into two classes: first, those where two-photon absorption by individual donors is followed by transfer of the net energy to an acceptor; second, those where the excitation of two electronically distinct but neighboring donor groups is followed by a collective migration of their energy to a suitable acceptor. Each transfer process is subject to minor dissipative losses. In this paper we describe in detail the balance of factors and the constraints that determines the favored mechanism, which include the excitation statistics, structure of the energy levels, laser coherence factors, chromophore selection rules and architecture, possibilities for the formation of delocalized excitons, spectral overlap, and the overall distribution of donors and acceptors. Furthermore, it transpires that quantum interference between different mechanisms can play an important role. Thus, as the relative importance of each mechanism determines the relevant nanophotonic characteristics, the results reported here afford the means for optimizing highly efficient light-harvesting dendrimer devices.
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Affiliation(s)
- David L Andrews
- Nanostructures and Photomolecular Systems, School of Chemical Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
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Newkome GR, Kim HJ, Choi KH, Moorefield CN. Synthesis of Neutral Metallodendrimers Possessing Adamantane Termini: Supramolecular Assembly with β-Cyclodextrin. Macromolecules 2004. [DOI: 10.1021/ma048996b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- George R. Newkome
- Departments of Polymer Science and Chemistry and Maurice Morton Institute of Polymer Science, The University of Akron, Akron, Ohio 44325-4717, and Department of Applied Chemistry, Chonnam National University, Kwangju 500-757, Korea
| | - Hyung Jin Kim
- Departments of Polymer Science and Chemistry and Maurice Morton Institute of Polymer Science, The University of Akron, Akron, Ohio 44325-4717, and Department of Applied Chemistry, Chonnam National University, Kwangju 500-757, Korea
| | - Kyung Ho Choi
- Departments of Polymer Science and Chemistry and Maurice Morton Institute of Polymer Science, The University of Akron, Akron, Ohio 44325-4717, and Department of Applied Chemistry, Chonnam National University, Kwangju 500-757, Korea
| | - Charles N. Moorefield
- Departments of Polymer Science and Chemistry and Maurice Morton Institute of Polymer Science, The University of Akron, Akron, Ohio 44325-4717, and Department of Applied Chemistry, Chonnam National University, Kwangju 500-757, Korea
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