The dynamics of photoinduced charge separation and recombination processes in synthetic DNA hairpins have been investigated by means femtosecond transient absorption spectroscopy. driving force distance dependence charge-transfer involving singlet acceptors nucleobase donors are consistent with a single-step superexchange mechanism which the electronic coupling between donor acceptor is strongly dependent. reversible hole transport primary guanine nearby GG or GGG sequences has also...

The distance dependence of photoinduced electron transfer in duplex DNA was determined for a family synthetic hairpins which stilbene dicarboxamide forms bridge connecting two oligonucleotide arms. Investigation the fluorescence and transient absorption spectra these established that no occurs hairpin has six deoxyadenosine-deoxythymidine base pairs. However, introduction single deoxyguanosine-deoxycytidine pair resulted distance-dependent quenching formation anion radical. Kinetic analysis...

Absolute rates of hole transfer between guanine nucleobases separated by one or two A:T base pairs in stilbenedicarboxamide-linked DNA hairpins were obtained improved kinetic analysis experimental data. The charge-transfer four different sequences calculated using a density-functional-based tight-binding model and semiclassical superexchange model. Site energies integrals directly as the diagonal off-diagonal matrix elements Kohn-Sham Hamiltonian, respectively, for all possible combinations...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis acid catalysis of photochemical reactions. 8. Photodimerization and cross-cycloaddition coumarinFrederick D. Lewis Steven V. BarancykCite this: J. Am. Chem. Soc. 1989, 111, 23, 8653–8661Publication Date (Print):November 1, 1989Publication History Published online1 May 2002Published inissue 1 November 1989https://pubs.acs.org/doi/10.1021/ja00205a015https://doi.org/10.1021/ja00205a015research-articleACS PublicationsRequest reuse...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProton-transfer reactions of photogenerated radical ion pairsFrederick D. LewisCite this: Acc. Chem. Res. 1986, 19, 12, 401–405Publication Date (Print):December 1, 1986Publication History Published online1 May 2002Published inissue 1 December 1986https://pubs.acs.org/doi/10.1021/ar00132a004https://doi.org/10.1021/ar00132a004research-articleACS PublicationsRequest reuse permissionsArticle Views837Altmetric-Citations155LEARN ABOUT THESE...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical .alpha. cleavage of benzoin derivatives. Polar transition states for free-radical formationF. D. Lewis, R. T. Lauterbach, H. G. Heine, W. Hartmann, and RudolphCite this: J. Am. Chem. Soc. 1975, 97, 6, 1519–1525Publication Date (Print):March 1, 1975Publication History Published online1 May 2002Published inissue 1 March 1975https://pubs.acs.org/doi/10.1021/ja00839a041https://doi.org/10.1021/ja00839a041research-articleACS...

We developed a model for hole migration along relatively short DNA hairpins with fewer that seven adenine (A):thymine (T) base pairs. The was used to simulate poly(A)-poly(T) sequences particular emphasis on the impact of partial localization different rate processes. simulations, performed within framework stochastic surrogate Hamiltonian approach, give values arrival in good agreement experimental data. Theoretical results obtained than three A:T pairs suggest transfer occurs via...

The mechanism and dynamics of photoinduced charge separation recombination have been investigated in synthetic DNA hairpins possessing donor acceptor stilbenes separated by one to seven A:T base pairs. application femtosecond broadband pump−probe spectroscopy, nanosecond transient absorption picosecond fluorescence decay measurements permits detailed analysis the formation stilbene singlet state charge-separated intermediates. When are a single pair, occurs via single-step superexchange...

The driving force dependence of photoinduced electron-transfer dynamics in duplex DNA has been investigated for 16 synthetic hairpins which an acceptor chromophore serves as a linker connecting two complementary oligonucleotide arms containing single donor nucleobase located either adjacent to the or separated from by unreactive base pairs. rate constants both charge separation and recombination processes have determined means subpicosecond time-resolved transient absorption spectroscopy...

Electron transfer (ET) processes in DNA are of current interest because their involvement oxidative strand cleavage reactions and relevance to the development molecular electronics. Two mechanisms have been identified for ET DNA, a single-step tunneling process multistep charge-hopping process. The dynamics depend on both distance between electron donor acceptor nature bridge separating acceptor. In case protein alkane bridges, dependence is not strongly dependent properties contrast, we...

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTBispyrenyl Excimer Fluorescence: A Sensitive Oligonucleotide ProbeFrederick D. Lewis, Yifan Zhang, and Robert L. LetsingerView Author Information Department of Chemistry, Northwestern University 2145 Sheridan Road, Evanston, Illinois 60208 Cite this: J. Am. Chem. Soc. 1997, 119, 23, 5451–5452Publication Date (Web):June 11, 1997Publication History Received2 December 1996Published online11 June 1997Published inissue 1...

The dynamics of photoinduced charge separation and recombination in synthetic DNA hairpins have been investigated by means femtosecond nanosecond transient spectroscopy. consist a stilbene linker connecting two complementary 6-mer or 7-mer oligonucleotide strands. Base pairing between these strands results formation which the is approximately parallel to adjacent base pair. singlet selectively quenched guanine, but not other nucleobases, via an electron-transfer mechanism state electron...

The effects of aromatic stabilization on the rates [1,5]-hydrogen shifts in a series carbo- and heterocyclic dihydroaromatic compounds were estimated by B3LYP/6-31G computations. energy product is directly translated into increased exothermicity these reactions. Relative trends for significant range endothermic exothermic [1,5]-shifts with different intrinsic activation energies are reliably described Marcus theory. aromaticity or antiaromaticity very large can lead to dramatic acceleration...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical generation, isomerization, and oxygenation of stilbene cation radicalsFrederick D. Lewis, Ann M. Bedell, Ruth E. Dykstra, Jeffrey Elbert, Ian R. Gould, Samir FaridCite this: J. Am. Chem. Soc. 1990, 112, 22, 8055–8064Publication Date (Print):October 1, 1990Publication History Published online1 May 2002Published inissue 1 October 1990https://pubs.acs.org/doi/10.1021/ja00178a031https://doi.org/10.1021/ja00178a031research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleFormation and reactions of stilbene exciplexesFrederick D. LewisCite this: Acc. Chem. Res. 1979, 12, 4, 152–158Publication Date (Print):April 1, 1979Publication History Published online1 May 2002Published inissue 1 April 1979https://pubs.acs.org/doi/10.1021/ar50136a007https://doi.org/10.1021/ar50136a007research-articleACS PublicationsRequest reuse permissionsArticle Views549Altmetric-Citations112LEARN ABOUT THESE METRICSArticle Views are the...

Solution state x-ray diffraction fingerprinting is demonstrated as a method for experimentally assessing the accuracy of molecular dynamics (MD) simulations. Fourier transforms coordinate data from MD simulations are used to produce reciprocal space "fingerprints" atomic pair distance correlations that characteristic ensemble and direct numerical analogues experimental solution (SXD). SXD experiments were carried out test ability experiment simulation resolve sequence-dependent modifications...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis acid catalysis of photochemical reactions. 7. Photodimerization and cross-cycloaddition cinnamic estersFrederick D. Lewis, Suzanne L. Quillen, Paul Hale, Joe OxmanCite this: J. Am. Chem. Soc. 1988, 110, 4, 1261–1267Publication Date (Print):February 17, 1988Publication History Published online1 May 2002Published inissue 17 February 1988https://pubs.acs.org/doi/10.1021/ja00212a039https://doi.org/10.1021/ja00212a039research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLewis acid catalysis of coumarin photodimerizationFrederick D. Lewis, Daniel K. Howard, and Joe OxmanCite this: J. Am. Chem. Soc. 1983, 105, 10, 3344–3345Publication Date (Print):May 1, 1983Publication History Published online1 May 2002Published inissue 1 1983https://doi.org/10.1021/ja00348a069RIGHTS & PERMISSIONSArticle Views1098Altmetric-Citations76LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum full text article downloads...

The structure and properties of oligonucleotide conjugates possessing stilbenedicarboxamide chromophores at both ends a poly(dA):poly(dT) base-pair domain variable length have been investigated using combination spectroscopic computational methods. These form capped hairpin structures in which one stilbene serves as linker the other hydrophobic end-cap. capping stabilizes by ca. 2 kcal/mol, making possible formation stable folded containing single A:T base pair. Exciton coupling between has...

The dynamics of single-step hole transport processes have been investigated in a number DNA conjugates possessing stilbenedicarboxamide electron acceptor, guanine primary donor, and several secondary donors. Rate constants for both forward return between the donor are obtained from kinetic modeling nanosecond transient absorption decay profiles stilbene anion radical. model requires that be localized on either or not delocalized over donor. found to dependent upon identity intervening bases,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTtrans-Stilbene-amine exciplexes. Stereoelectronic control of amine dimer cation radical formationWalter Hub, Siegfried Schneider, Friedrich Doerr, Joe D. Oxman, and Frederick LewisCite this: J. Am. Chem. Soc. 1984, 106, 3, 701–708Publication Date (Print):February 1, 1984Publication History Published online1 May 2002Published inissue 1 February 1984https://pubs.acs.org/doi/10.1021/ja00315a040https://doi.org/10.1021/ja00315a040research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOne-way photoisomerization of cis-stilbene via a cation radical chain mechanismFrederick D. Lewis, James R. Petisce, Joe Oxman, and Marshall J. NeprasCite this: Am. Chem. Soc. 1985, 107, 1, 203–207Publication Date (Print):January 1985Publication History Published online1 May 2002Published inissue 1 January 1985https://doi.org/10.1021/ja00287a037RIGHTS & PERMISSIONSArticle Views510Altmetric-Citations84LEARN ABOUT THESE METRICSArticle Views are the...

A perylenediimide chromophore (P) was incorporated into DNA hairpins as a base-pair surrogate to prevent the self-aggregation of P that is typical when it used hairpin linker. The photoinduced charge-transfer and spin dynamics these were studied using femtosecond transient absorption spectroscopy time-resolved EPR (TREPR). photooxidant sufficiently powerful quantitatively inject holes adjacent adenine (A) guanine (G) nucleobases. observed following hole injection from A-tract consistent with...