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You searched for subject:(bacteriochlorins). Showing records 1 – 2 of 2 total matches.

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North Carolina State University

1. Kim, Han-Je. De Novo Synthesis of Stable Bacteriochlorins.

Degree: PhD, Chemistry, 2005, North Carolina State University

Hydroporphyrins perform a wide variety of essential functions in living systems. Hydroporphyrins differ from porphyrins in having fewer pi bonds along the perimeter of the macrocycle. Efficient routes for the preparation of stable, dehydrogenation-resistant analogues of naturally occurring hydroporphyrins (e.g., chlorins, bacteriochlorins, isobacteriochlorins, corrins) are essential for fundamental studies and diverse applications. To develop such routes, a collection of 24 hydrodipyrrins has been prepared wherein each hydrodipyrrin contains a pyrrole ring and a pyrroline ring. The pyrroline ring bears a geminal-dimethyl group to lock-in the hydrogenation level. The alpha-substituents on the pyrrole and pyrroline rings provide different reactivity combinations (Nu/E⁺, E⁺/E⁺, or E⁺/Nu). Selected hydrodipyrrins have been employed in six exploratory routes to stable bacteriochlorins. The availability of straightforward routes to various hydrodipyrrins should facilitate development of syntheses of diverse hydroporphyrins (Chapter III). Bacteriochlorins are attractive for diverse photochemical applications owing to their strong absorption in the near-infrared spectral region, as exemplified by the bacterial photosynthetic pigment bacteriochlorophyll a, yet often are labile toward dehydrogenation to give the chlorin. An eight-step synthesis for preparing stable bacteriochlorins begins with p-tolualdehyde and proceeds to a dihydrodipyrrin-acetal (IV-1) bearing a geminal-dimethyl group and a p-tolyl substituent. Self-condensation of IV-1 in CH₃CN containing BF₃.OEt₂ at room temperature afforded a readily separable mixture of two free base bacteriochlorins and a ring-contracted, B,D-tetradehydrocorrin. Each bacteriochlorin contains two geminal-dimethyl groups to lock-in the bacteriochlorin (tetrahydroporphyrin) hydrogenation level, p-tolyl substituents at opposite (2,12) beta positions, and the absence (H-BC) or presence (MeO-BC) of a methoxy group at the 5- (meso) position. The B,D-tetradehydrocorrin (TDC) lies equidistant between the hydrogenation levels of corrin and corrole, is enantiomeric, and contains two geminal-dimethyl groups, 2,12-di-p-tolyl substituents, and an acetal group at the pyrroline-pyrrole junction. Examination of the effect of the concentrations of IV-1 (2.5 - 50 mM) and BF₃.OEt₂ (10 - 500 mM) revealed a different response surface for each of H-BC, MeO-BC, and TDC. The highest isolated yield of each was 49%, 30%, and 67%, respectively. The hydroporphyrins are stable to routine handling in light and air. The spectral features of H-BC are exemplary, including strong near-IR absorption (lambda[subscript Qy] = 737 nm, epsilon[subscript Qy] = 130,000 M⁻¹cm⁻¹) and emission (lambda[subscript em] = 744 nm, phi[subscript f] = 0.14). A crystal structure was obtained for MeO-BC. In summary, the ease of preparation of stable bacteriochlorins having characteristic spectral features should facilitate a wide variety of… Advisors/Committee Members: Jonathan S. Lindsey, Committee Member (advisor), David A. Shultz, Committee Member (advisor), Daniel L. Comins, Committee Member (advisor), Christopher B. Gorman, Committee Member (advisor).

Subjects/Keywords: hydrodipyrrins; porphyrins; chlorins; hydroporphyrins; bacteriochlorins

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APA (6th Edition):

Kim, H. (2005). De Novo Synthesis of Stable Bacteriochlorins. (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/4732

Chicago Manual of Style (16th Edition):

Kim, Han-Je. “De Novo Synthesis of Stable Bacteriochlorins.” 2005. Doctoral Dissertation, North Carolina State University. Accessed September 28, 2020. http://www.lib.ncsu.edu/resolver/1840.16/4732.

MLA Handbook (7th Edition):

Kim, Han-Je. “De Novo Synthesis of Stable Bacteriochlorins.” 2005. Web. 28 Sep 2020.

Vancouver:

Kim H. De Novo Synthesis of Stable Bacteriochlorins. [Internet] [Doctoral dissertation]. North Carolina State University; 2005. [cited 2020 Sep 28]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4732.

Council of Science Editors:

Kim H. De Novo Synthesis of Stable Bacteriochlorins. [Doctoral Dissertation]. North Carolina State University; 2005. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4732


Freie Universität Berlin

2. Mößler, Johann. Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis.

Degree: 1999, Freie Universität Berlin

This dissertation describes the synthesis and electron transfer properties of covalently linked biomimetic diads, containing a chlorin or a bacteriochlorin as electron donor and p-benzoquinone as electron aceptor. Two meso-substituted chlorin-quinones, linked via the chlorin-positions 5 and 10, and a bacteriochlorin-quinone were obtained by reduction of a porphyrin- hydroquinone with diimine, followed by selective oxidation of the hydroquinone moiety with p – benzoquinone. Semiempirical calculations of the LCAO-pz-coefficients, based on the results from EPR/ENDOR experiments on cation and anion radicals of (bacterio)chlorins and diads, predict a high efficient charge separation in a chlorin-quinone linked via the chlorin-position 10. Time-resolved fluorescence spectroscopy in dichloromethane and toluene on 1,4 -trans-cyclohexylene-linked diads show a strong dependency of the singulet electron transfer rate on the free enthalpy of electron transfer, while the LCAO-pz-coefficients at the linking positions seem to have only little influence on kET. It is assumed that the electron transfer takes place mainly through the solvent. The electron transfer in the free bases of these chlorin- and bacteriochlorin-quinones ist about five times faster than in the corresponding porphyrin-quinone. The charge-separated state tends to be more long-lived in chlorin-quinones linked via chlorin-position 10, confirming the predictions from the semiempirical calculations in part. Time-resolved triplet EPR spectra show spin polarization patterns similar to natural chlorophylls. The kinetics of the triplet electron transfer were studied on a cyclohexylene-linked Zn(II)-chlorin-quinone in ethanol glass matrix at 130 K. Advisors/Committee Members: n (gender), Prof. Dr. Harry Kurreck (firstReferee), Prof. Dr. Jürgen-Hinrich Fuhrhop (furtherReferee), Prof. Dr. Hans-Heinrich Limbach, Prof. Dr. Klaus Christmann (furtherReferee).

Subjects/Keywords: Porphyrins; Bacteriochlorins; Quinones; Photosynthesis; Electron Transfer; Biomimetic; 500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Mößler, J. (1999). Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis. (Thesis). Freie Universität Berlin. Retrieved from http://dx.doi.org/10.17169/refubium-8451

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Mößler, Johann. “Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis.” 1999. Thesis, Freie Universität Berlin. Accessed September 28, 2020. http://dx.doi.org/10.17169/refubium-8451.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Mößler, Johann. “Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis.” 1999. Web. 28 Sep 2020.

Vancouver:

Mößler J. Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis. [Internet] [Thesis]. Freie Universität Berlin; 1999. [cited 2020 Sep 28]. Available from: http://dx.doi.org/10.17169/refubium-8451.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mößler J. Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis. [Thesis]. Freie Universität Berlin; 1999. Available from: http://dx.doi.org/10.17169/refubium-8451

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.