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Schulze B, Friebe C, Jäger M, Görls H, Birckner E, Winter A, Schubert US. PtII Phosphors with Click-Derived 1,2,3-Triazole-Containing Tridentate Chelates. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00777] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- B. Schulze
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - C. Friebe
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - M. Jäger
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - H. Görls
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - E. Birckner
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - A. Winter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - U. S. Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), ‡Center for Energy
and Environmental Chemistry Jena (CEEC Jena), §Laboratory of Inorganic and Analytical
Chemistry, and ∥Institute of Physical Chemistry, Friedrich Schiller University Jena, 07743 Jena, Germany
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Schweitzer D, Schenke S, Hammer M, Schweitzer F, Jentsch S, Birckner E, Becker W, Bergmann A. Towards metabolic mapping of the human retina. Microsc Res Tech 2007; 70:410-9. [PMID: 17393496 DOI: 10.1002/jemt.20427] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Functional alterations are first signs of a starting pathological process. A device that measures parameter for the characterization of the metabolism at the human eye-ground would be a helpful tool for early diagnostics in stages when alterations are yet reversible. Measurements of blood flow and of oxygen saturation are necessary but not sufficient. The new technique of auto-fluorescence lifetime measurement (FLIM) opens in combination with selected excitation and emission ranges the possibility for metabolic mapping. FLIM not only adds an additional discrimination parameter to distinguish different fluorophores but also resolves different quenching states of the same fluorophore. Because of its high sensitivity and high temporal resolution, its capability to resolve multi-exponential decay functions, and its easy combination with laser scanner ophthalmoscopy, multi-dimensional time-correlated single photon counting was used for fundus imaging. An optimized set up for in vivo lifetime measurements at the human eye-ground will be explained. In this, the fundus fluorescence is excited at 446 or 468 nm and the time-resolved autofluorescence is detected in two spectral ranges between 510 and 560 nm as well as between 560 and 700 nm simultaneously. Exciting the fundus at 446 nm, several fluorescence maxima of lifetime t1 were detected between 100 and 220 ps in lifetime histograms of 40 degrees fundus images. In contrast, excitation at 468 nm results in a single maximum of lifetime t1 = 190 +/- 16 ps. Several fundus layers contribute to the fluorescence intensity in the short-wave emission range 510-560 nm. In contrast, the fluorescence intensity in the long-wave emission range between 560 and 700 nm is dominated by the fluorescence of lipofuscin in the retinal pigment epithelium. Comparing the lateral distribution of parameters of a tri-exponential model function in lifetime images of the fundus with the layered anatomical fundus structure, the shortest component (t1 = 190 ps) originates from the retinal pigment epithelium and the second lifetime (t2 = 1,000 ps) from the neural retina. The lifetime t3 approximately 5.5 ns might be influenced by the long decay of the fluorescence in the crystalline lens. In vitro analysis of the spectral properties of expected fluorophores under the condition of the living eye lightens the interpretation of in vivo measurements. Taking into account the transmission of the ocular media, the excitation of NADH is unlikely at the fundus.
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Affiliation(s)
- D Schweitzer
- Department of Experimental Ophthalmology, University of Jena, Germany.
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Abstract
The rotational relaxation times of rod like molecules like poly[arylene-ethynylene]s and their low molecular weight model compounds calculated from a simple model agree well with the experimental ones as long as the axial ratio of the corresponding rotational ellipsoid is less than 8. For the polymer (axial ratio > 10) the fluorescence depolarization cannot be described by rotational motion perpendicularly to the long molecular axis. One has to take into consideration bending motions in connection with energy transfer along the bent backbone.
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Affiliation(s)
- E Birckner
- Institut für Physikalische Chemie, Friedrich-Schiller-Universitiät Jena, Lessingstrasse 10, D-07743 Jena, Germany.
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Dietzek B, Maksimenka R, Siebert T, Birckner E, Kiefer W, Popp J, Hermann G, Schmitt M. Excited-state processes in protochlorophyllide a – a femtosecond time-resolved absorption study. Chem Phys Lett 2004. [DOI: 10.1016/j.cplett.2004.08.075] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kühn C, Beckert R, Grummt UW, Käpplinger C, Birckner E. 1,4,5,8-Tetraazafulvalene – Darstellung schwefelhaltiger Derivate und Zuordnung des Chromophors / 1,4,5,8-Tetraazafulvalenes – Synthesis of Sulfur-Containing Derivatives and Classification of the Chromophor. Zeitschrift für Naturforschung B 2004. [DOI: 10.1515/znb-2004-0408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In order to obtain sulfur-containing tetraazafulvalenes the derivatives 1 - 3 were cross-coupled with different types of acetylenes via palladium-catalyzed reactions. Starting from the tetrabromoaryl derivative 3a, four bromine atoms could be replaced by 2-ethynylthiophene. Under analogous conditions, the methylsulfanyl esters 7 -11 could be obtained by employing 4-ethynylbenzoic acid 4-(methylsulfanyl)butylester 6. Lipoic acid could be integrated into tetraazafulvalenes successfully in a two step reaction. First, the Sonogashira coupling method yielded the compound 12 possessing two (4-anilino)ethynyl residues which were then condensed with lipoic acid to give derivative 13.
Whereas the NMR data suggest the predominance of prototropic form A, UV/vis spectra of the deeply colored tetraazafulvalenes are in favor with structure B rather than with structure A. DFT calculations at the B3LYP/6-31G(d) level showed that tautomeric form B is about 60 kJ/mol more stable than A. In addition, time-dependent density functional theory calculations support the substructure of two crossed diazaheptamethinemerocyanines.
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Affiliation(s)
- Christiane Kühn
- Institut für Organische und Makromolekulare Chemie, Friedrich-Schiller-Universität, Lessingstr. 8, D-07743 Jena
| | - R. Beckert
- Institut für Organische und Makromolekulare Chemie, Friedrich-Schiller-Universität, Lessingstr. 8, D-07743 Jena
| | - U.-W. Grummt
- Institut für Physikalische Chemie, Friedrich-Schiller-Universität, Lessingstr. 10, D-07743 Jena
| | - C. Käpplinger
- Institut für Organische und Makromolekulare Chemie, Friedrich-Schiller-Universität, Lessingstr. 8, D-07743 Jena
| | - E. Birckner
- Institut für Physikalische Chemie, Friedrich-Schiller-Universität, Lessingstr. 10, D-07743 Jena
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Grummt UW, Pautzsch T, Birckner E, Utterodt A, Neugebauer U, Klemm E. Photophysics of Poly{2,2′-bipyridine-5,5′-diylethynylene [2,5-di(2-ethylhexyl)oxy-1,4-phenylene[ethynylene}: a comparison with monomer and dimer model compounds. J PHYS ORG CHEM 2004. [DOI: 10.1002/poc.714] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Affiliation(s)
- E. Birckner
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - U.-W. Grummt
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - A. H. Göller
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - T. Pautzsch
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - D. A. M. Egbe
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - M. Al-Higari
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
| | - E. Klemm
- Institut für Physikalische Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany, and Institut für Organische und Makromolekulare Chemie der Friedrich-Schiller-Universität Jena, Jena, Germany
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Helbig M, Ruseckas A, Grage ML, Birckner E, Rentsch S, Sundström V. Resolving the radical cation formation from the lowest-excited singlet (S1) state of terthiophene in a TiO2–SiO2 hybrid polymer matrix. Chem Phys Lett 1999. [DOI: 10.1016/s0009-2614(99)00114-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rentsch S, Yang JP, Paa W, Birckner E, Schiedt J, Weinkauf R. Size dependence of triplet and singlet states of α-oligothiophenes. Phys Chem Chem Phys 1999. [DOI: 10.1039/a808617f] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Birckner E, Grummt UW, Rost H, Hartmann A, Pfeiffer S, Tillmann H, Hörhold HH. Fluorescence spectroscopy of potential electroluminescent materials: Substituent effects on DSB and segmented PPV derivatives. J Fluoresc 1998. [DOI: 10.1007/bf02758240] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Hagen C, Braune W, Birckner E, Nuske J. Functional aspects of secondary carotenoids in Haematococcus lacustris (Girod) Rostafinski (Volvocales): I. The accumulation period as an active metabolic process. New Phytol 1993; 125:625-633. [PMID: 33874597 DOI: 10.1111/j.1469-8137.1993.tb03912.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Alterations of photosynthetic activity were investigated during accumulation of secondary carotenoids in Haematococcus lacustris (Girod) Rostafinski. Using several methods regarding (i) pigment pattern and pigment content (cytophotometry, computer-aided microscopic image analysis, in vivo absorption spectroscopy, high-performance liquid chromatrography) and (ii) photosynthesis (microfluorometry, modulated chlorophyll fluorescence and luminescence detection, O2 evolution and consumption measurement, 77 K fluorescence spectroscopy) we examined single cells and cell suspensions of the green alga. The results indicate decrease of both the photosystem II activity and the linear electron transport accompanying synthesis of secondary carotenoids. On the other hand, activation of those processes leading to an increased transthylakoid proton gradient could be established during early accumulation period. This is assumed to be an active adaptation of the photosynthetic apparatus to energetic requirements given by secondary carotenoid biosynthesis in H. lacustris.
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Affiliation(s)
- C Hagen
- Institute of General Botany, Friedrich Schiller University Jena, von Hase-Weg 3, D-07743 Jena, Germany
| | - W Braune
- Institute of General Botany, Friedrich Schiller University Jena, von Hase-Weg 3, D-07743 Jena, Germany
| | - E Birckner
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Steiger 3, D-07743 Jena, Germany
| | - J Nuske
- Institute of Microbiology, Friedrich Schiller University Jena, Philosophenweg 12, D-07743 Jena, Germany
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Appenroth K, Birckner E, Reichenbächer M. Thermochromism and photochromism of aryl-substituted acylic azines X: Relationship between molecular geometry and fluorescence of anthranyl-substituted compounds. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0047-2670(87)85033-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ilge HD, Birckner E, Fassler D, Kozmenko M, Kuz'min M, Hartmann H. Spectroscopy, photophysics and photochemistry of 1,3-diketoboronates. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0047-2670(86)87007-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Birckner E, Paetzold R, Kozmenko M, Kuzmin M. The exciplexes of thioindigo with durene and hexamethylbenzene and their influence on photoisomerization. Chem Phys Lett 1983. [DOI: 10.1016/0009-2614(83)80113-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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