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Title: Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures

Abstract

The long-term objective of the Bocian/Holten/Lindsey research program is to design, synthesize, and characterize tetrapyrrole-based molecular architectures that absorb sunlight, funnel energy, and separate charge with high efficiency and in a manner compatible with current and future solar-energy conversion schemes. The synthetic tetrapyrroles include porphyrins and hydroporphyrins; the latter classes of molecules encompass analogues of the naturally occurring chlorophylls and bacteriochlorophylls (e.g., chlorins, bacteriochlorins, and their derivatives). The attainment of the goals of the research program requires the close interplay of molecular design and synthesis (Lindsey group), static and time-resolved optical spectroscopic measurements (Holten group), and electrochemical, electron paramagnetic resonance, and resonance Raman studies, as well as density functional theory calculations (Bocian Group). The proposed research encompasses four interrelated themes: (1) Determination of the rates of ground-state hole/electron transfer between (hydro)porphyrins in multipigment arrays as a function of array size, distance between components, linker type, site of linker connection, and frontier molecular orbital composition. (2) Examination of excited-state energy transfer among hydroporphyrins in multipigment arrrays, including both pairwise and non-adjacent transfer, with a chief aim to identify the relative contributions of through-space (Förster) and through-bond (Dexter) mechanisms of energy transfer, including the roles of site of linker connection and frontiermore » molecular orbital composition. (3) Elucidation of the role of substituents in tuning the spectral and electronic properties of bacteriochlorins, with a primary aim of learning how to shift the long-wavelength absorption band deeper into the near-infrared region. (4) Continued development of the software package PhotochemCAD for spectral manipulations and calculations through the compilation of a database of spectra for naturally occurring and synthetic hydroporphyrins. The availability of such data should augment efforts in the design of light-harvesting systems where spectral coverage in the red and near-infrared regions is desired. Collectively, the proposed studies will provide fundamental insights into molecular properties, interactions, and processes relevant to the design of molecular architectures for solar-energy conversion. The accomplishment of these goals is only possible through a highly synergistic program that encompasses molecular design, synthesis, and characterization.« less

Authors:
 [1]
  1. University of California, Riverside, CA (United States)
Publication Date:
Research Org.:
University of California, Riverside, CA (United States).The Regents of the University of California,
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1150022
Report Number(s):
DOE UC RIVERSIDE 15660
DOE Contract Number:
FG02-05ER15660
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; Solar energy; energy transfer; hole/electron transfer; hydroporphyrin

Citation Formats

Bocian, David F. Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures. United States: N. p., 2014. Web. doi:10.2172/1150022.
Bocian, David F. Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures. United States. doi:10.2172/1150022.
Bocian, David F. Wed . "Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures". United States. doi:10.2172/1150022. https://www.osti.gov/servlets/purl/1150022.
@article{osti_1150022,
title = {Fundamental studies of energy-and hole/electron- transfer in hydroporphyrin architectures},
author = {Bocian, David F.},
abstractNote = {The long-term objective of the Bocian/Holten/Lindsey research program is to design, synthesize, and characterize tetrapyrrole-based molecular architectures that absorb sunlight, funnel energy, and separate charge with high efficiency and in a manner compatible with current and future solar-energy conversion schemes. The synthetic tetrapyrroles include porphyrins and hydroporphyrins; the latter classes of molecules encompass analogues of the naturally occurring chlorophylls and bacteriochlorophylls (e.g., chlorins, bacteriochlorins, and their derivatives). The attainment of the goals of the research program requires the close interplay of molecular design and synthesis (Lindsey group), static and time-resolved optical spectroscopic measurements (Holten group), and electrochemical, electron paramagnetic resonance, and resonance Raman studies, as well as density functional theory calculations (Bocian Group). The proposed research encompasses four interrelated themes: (1) Determination of the rates of ground-state hole/electron transfer between (hydro)porphyrins in multipigment arrays as a function of array size, distance between components, linker type, site of linker connection, and frontier molecular orbital composition. (2) Examination of excited-state energy transfer among hydroporphyrins in multipigment arrrays, including both pairwise and non-adjacent transfer, with a chief aim to identify the relative contributions of through-space (Förster) and through-bond (Dexter) mechanisms of energy transfer, including the roles of site of linker connection and frontier molecular orbital composition. (3) Elucidation of the role of substituents in tuning the spectral and electronic properties of bacteriochlorins, with a primary aim of learning how to shift the long-wavelength absorption band deeper into the near-infrared region. (4) Continued development of the software package PhotochemCAD for spectral manipulations and calculations through the compilation of a database of spectra for naturally occurring and synthetic hydroporphyrins. The availability of such data should augment efforts in the design of light-harvesting systems where spectral coverage in the red and near-infrared regions is desired. Collectively, the proposed studies will provide fundamental insights into molecular properties, interactions, and processes relevant to the design of molecular architectures for solar-energy conversion. The accomplishment of these goals is only possible through a highly synergistic program that encompasses molecular design, synthesis, and characterization.},
doi = {10.2172/1150022},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Aug 20 00:00:00 EDT 2014},
month = {Wed Aug 20 00:00:00 EDT 2014}
}

Technical Report:

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  • The long-term objective of the Bocian/Holten&Kirmaier/Lindsey research program is to design, synthesize, and characterize tetrapyrrole-based molecular architectures that absorb sunlight, funnel energy, and separate charge with high efficiency and in a manner compatible with current and future solar-energy conversion schemes. The synthetic tetrapyrroles include porphyrins and hydroporphyrins; the latter classes of molecules encompass analogues of the naturally occurring chlorophylls and bacteriochlorophylls (e.g., chlorins, bacteriochlorins, and their derivatives). The attainment of the goals of the research program requires the close interplay of molecular design and synthesis (Lindsey group), static and time-resolved optical spectroscopic measurements (Holten&Kirmaier group), and electrochemical, electron paramagnetic resonance,more » resonance Raman, and infrared studies, as well as density functional theory calculations (Bocian Group). The proposed research encompasses four interrelated themes: (i) Gain a deeper understanding of the spectral and electronic properties of bacteriochlorins, with a subsidiary aim of learning how to shift the long-wavelength absorption band deeper into the NIR region. Bacteriochlorins bearing diverse substituents, including annulated rings, will be prepared and examined. A set of bacteriochlorins with site-specific isotopic (13C, 2H) substitution patterns about the macrocycle perimeter will be prepared for studies of vibrational and electronic properties. (ii) Examine the underlying electronic origin of panchromatic absorption and excited-state behavior of strongly coupled rylene–tetrapyrrole arrays. The rylene constituents include a perylene-monoimide and a terrylene-monoimide. The tetrapyrroles include porphyrins (meso- or β-linked) and bacteriochlorins (β-linked). The objective is to achieve panchromatic absorption while preserving a viable, long-lived excited singlet state. (iii) Determine the rates of ground-state hole/electron transfer between (hydro)porphyrins as a function of array size, distance between components, linker type, site of linker connection, and frontier molecular orbital composition. (iv) Build upon the results of the aforementioned studies to design, synthesize, and characterize integrated architectures that incorporate a panchromatic absorber and other molecular components that that afford efficient hole/electron migration and long-lived charge separation. Such architectures will be examined on solid substrates to explore the viability of the component parts and processes under application-oriented conditions. Such architectures or successors may prove directly useful for solar-energy conversion systems. An equally important attribute is to serve as a test-bed for successful integration of the requisite properties and processes, some of which require rather weak coupling between constituents, some of which require very strong electronic interactions to elicit the desired behavior, and all of which should be tunable under molecular design control to the extent possible. Collectively, the proposed studies will provide fundamental insights into molecular properties, interactions, and processes relevant to the design of molecular architectures for solar-energy conversion. The accomplishment of these goals is only possible through a highly synergistic program that encompasses molecular design, synthesis, and in-depth characterization.« less
  • Research is summarized for flow in porous media, finite amplitude waves in viscous shear flow, vortex induced lift, vortex dynamics, curvilinear grids, Taylor vortex flows, and the Dean problem of steady viscous flow in a uniformly curved tube. (GHT)
  • This report concerning the CALTECH-DOE program presents information on: vortex dynamics, turbulence and separated flows; flow in porous media and Hele-Shaw fingering; steady viscous flows with and without bifurcations; continuation methods; and boundary conditions on artificial boundaries. 33 refs.
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  • In this project we studied both natural photosynthetic antenna complexes and various artificial systems (e.g. chlorophyll (Chl) trefoils) using high resolution hole-burning (HB) spectroscopy and excitonic calculations. Results obtained provided more insight into the electronic (excitonic) structure, inhomogeneity, electron-phonon coupling strength, vibrational frequencies, and excitation energy (or electron) transfer (EET) processes in several antennas and reaction centers. For example, our recent work provided important constraints and parameters for more advanced excitonic calculations of CP43, CP47, and PSII core complexes. Improved theoretical description of HB spectra for various model systems offers new insight into the excitonic structure and composition of low-energymore » absorption traps in very several antenna protein complexes and reaction centers. We anticipate that better understanding of HB spectra obtained for various photosynthetic complexes and their simultaneous fits with other optical spectra (i.e. absorption, emission, and circular dichroism spectra) provides more insight into the underlying electronic structures of these important biological systems. Our recent progress provides a necessary framework for probing the electronic structure of these systems via Hole Burning Spectroscopy. For example, we have shown that the theoretical description of non-resonant holes is more restrictive (in terms of possible site energies) than those of absorption and emission spectra. We have demonstrated that simultaneous description of linear optical spectra along with HB spectra provides more realistic site energies. We have also developed new algorithms to describe both nonresonant and resonant hole-burn spectra using more advanced Redfield theory. Simultaneous description of various optical spectra for complex biological system, e.g. artificial antenna systems, FMO protein complexes, water soluble protein complexes, and various mutants of reaction centers continues; this work is supported by the new DOE BES grant.« less