Detailed Information on Publication Record
2015
Searching for Improved Photoreleasing Abilities of Organic Molecules
ŠOLOMEK, Tomáš, Hans Jakob WIRZ and Petr KLÁNBasic information
Original name
Searching for Improved Photoreleasing Abilities of Organic Molecules
Authors
ŠOLOMEK, Tomáš (703 Slovakia, belonging to the institution), Hans Jakob WIRZ (756 Switzerland) and Petr KLÁN (203 Czech Republic, guarantor, belonging to the institution)
Edition
Accounts of chemical research, American Chemical Society, 2015, 0001-4842
Other information
Language
English
Type of outcome
Článek v odborném periodiku
Field of Study
10401 Organic chemistry
Country of publisher
United States of America
Confidentiality degree
není předmětem státního či obchodního tajemství
References:
Impact factor
Impact factor: 22.003
RIV identification code
RIV/00216224:14310/15:00081563
Organization unit
Faculty of Science
UT WoS
000366871400009
Keywords in English
photochemistry; photoremovable protecting groups; DFT calculations
Změněno: 11/2/2016 14:07, prof. RNDr. Petr Klán, Ph.D.
Abstract
V originále
Photoremovable protecting groups (PPGs) are chemical auxiliaries that provide spatial and temporal control over the release of various molecules: bioagents (neurotransmitters and cell-signaling molecules, Ca2+ ions), acids, bases, oxidants, insecticides, pheromones, fragrances, etc. A major challenge for the improvement of PPGs lies in the development of organic chromophores that release the desired bioagents upon continuous irradiation at wavelengths above 650 nm, that is, in the tissue-transparent window. Understanding of the photorelease reaction mechanisms, investigated by laser flash photolysis and rationalized with the aid of quantum chemical calculations, allows for achieving this goal. In particular, simple Hiickel calculations provide useful guidelines for designing new PPGs, because both the lowest excited singlet and triplet states of conjugated systems can be reasonably well described by a single electronic configuration formed by promotion of a single electron from the highest occupied molecular orbital (HOMO) to the lowest unoccupied MO (LUMO) of the ground state configuration. Here we show that Hiickel calculations permit rapid identification of common features in the nodal properties of the frontier orbitals of various chromophores that can be classified into distinct chromophore families. If the electronic excitation involves a substantial electron density transfer to an sp(2) carbon atom at which HOMO and LUMO are nearly disjoint, for example, by virtue of symmetry, favorable photoheterolysis can be expected when the corresponding atom carries a leaving group at the alpha-position. We show examples of photoheterolytic reactions that indicate that the efficiency of photoheterolysis diminishes for chromophores absorbing in the NIR region. We provide a rationale for more efficient photoheterolytic reactions occurring via the triplet state, and we demonstrate the advantages of this mechanistic pathway. Analogies in the structure reactivity relationships of PPGs can therefore lead to new strategies for the development of more efficient NIR-absorbing photoremovable protecting groups.
Links
GA13-25775S, research and development project |
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LM2011028, research and development project |
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LO1214, research and development project |
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