Synthesis, Photophysical Behavior, and Electronic Structure of Push−Pull Purines

Butler, Roslyn S.; Cohn, Pamela; Tenzel, Phillip A; Abboud, Khalil A.; Castellano, Ronald K.

doi:10.1021/ja806348z

Cited by 67 publications

(64 citation statements)

References 159 publications

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“…6). 22,23 In agreement with the observations by Tor, Castellano, and others, 24,25 the linearities of the two correlations, as determined by the correlation coefficients of the least-squares fits, are slightly better than those of the typical Lippert plots (Fig. S7†).…”

Section: Resultssupporting

confidence: 90%

Electronic structural dependence of the photophysical properties of fluorescent heteroditopic ligands – implications in designing molecular fluorescent indicators

et al. 2010

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Two fluorescent heteroditopic ligands (2a and 2b) for zinc ion were synthesized and studied. The efficiencies of two photophysical processes, intramolecular charge transfer (ICT) and photoinduced electron transfer (PET), determine the magnitudes of emission bathochromic shift and enhancement, respectively, when a heteroditopic ligand forms mono- or dizinc complexes. The electron-rich 2b is characterized by a high degree of ICT in the excited state with little propensity for PET, which is manifested in a large bathochromic shift of emission upon Zn2+ coordination without enhancement in fluorescence quantum yield. The electron-poor 2a displays the opposite photophysical consequence where Zn2+ binding results in greatly enhanced emission without significant spectral shift. The electronic structural effects on the relative efficiencies of ICT and PET in 2a and 2b as well as the impact of Zn2+-coordination are probed using experimental and computational approaches. This study reveals that the delicate balance between various photophysical pathways (e.g. ICT and PET) engineered in a heteroditopic ligand is sensitively dependent on the electronic structure of the ligand, i.e. whether the fluorophore is electron-rich or poor, whether it possesses a donor–acceptor type of structure, and where the metal binding occurs.

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Section: Resultssupporting

confidence: 90%

Electronic structural dependence of the photophysical properties of fluorescent heteroditopic ligands – implications in designing molecular fluorescent indicators

et al. 2010

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“…These trends suggest solvent-mediated stabilization of a chargeseparated emissive state that has a larger dipole moment than the ground state. [53,54] The Stokes shifts measured in six solvents were therefore plotted against Reichardts normalized solvent-polarity parameter E T N -a polarity scale that takes microenvironment solvent-solute interactions into account. [55,56] The resulting plot exhibits an excellent linear correlation (R 2 = 0.98) and large positive solvatochromic response slope of 4094 cm À1 (Figure 2 B).…”

Section: Resultsmentioning

confidence: 99%

Site‐Specific Control of N7–Metal Coordination in DNA by a Fluorescent Purine Derivative

Dumas

Luedtke

2011

Chemistry A European J

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A synthetic strategy that utilizes O6-protected 8-bromoguanosine gives broad access to C8-guanine derivatives with phenyl, pyridine, thiophene, and furan substituents. The resulting 8-substituted 2'-deoxyguanosines are push-pull fluorophores that can exhibit environmentally sensitive quantum yields (Φ=0.001-0.72) due to excited-state proton-transfer reactions with bulk solvent. Changes in nucleoside fluorescence were used to characterize metal-binding affinity and specificity of 8-substituted 2'-deoxyguanosines. One derivative, 8-(2-pyridyl)-2'-deoxyguanosine (2PyG), exhibits selective binding of Cu(II), Ni(II), Cd(II), and Zn(II) through a bidentate effect provided by the N7 position of guanine and the 2-pyridyl nitrogen atom. Upon incorporation into DNA, 2-pyridine-modified guanine residues selectively bind to Cu(II) and Ni(II) with equilibrium dissociation constants (K(d)) that range from 25 to 850 nM; the affinities depend on the folded state of the oligonucleotide (duplex>G-quadruplex) as well as the identity of the metal ion (Cu>Ni≫Cd). These binding affinities are approximately 10 to 1 000 times higher than for unmodified metal binding sites in DNA, thereby providing site-specific control of metal localization in alternatively folded nucleic acids. Temperature-dependent circular-dichroism studies reveal metal-dependent stabilization of duplexes, but destabilization of G-quadruplex structures upon adding Cu(II) to 2PyG-modified oligonucleotides. These results demonstrate how the addition of a single pyridine group to the C8 position of guanine provides a powerful new tool for studying the effects of N7 metalation on the structure, stability, and electronic properties of nucleic acids.

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“…A very similar spectral behavior has been observed for pushpull purines upon the introduction of suitable electron donor and acceptor groups that also exhibited enhanced luminescence. 17,61,62 However, in our case the situation is more complex.…”

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confidence: 79%

Three-Dimensional Uracil Network with Sodium as a Linker

et al. 2016

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Here we show that uracil and sodium form a three-dimensional metal-mediated nucleic acid network; it is grown in atomic/molecular layer-by-layer manner using the atomic/molecular layer deposition (ALD/MLD) thin-film technique. The long-range ordered Na-uracil crystalline structure is evidenced as sharp Bragg reflections. Based on density functional theory (DFT) calculations, a tetrameric-like crystal structure is proposed. Na-uracil thin films are fluorescent with a lifetime three orders of magnitude higher than commonly seen for nucleic acid molecules. Our method provides a new approach to designing 3D nucleic acid-metal nanostructures.

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Synthesis, Photophysical Behavior, and Electronic Structure of Push−Pull Purines

Cited by 67 publications

References 159 publications

Electronic structural dependence of the photophysical properties of fluorescent heteroditopic ligands – implications in designing molecular fluorescent indicators

Electronic structural dependence of the photophysical properties of fluorescent heteroditopic ligands – implications in designing molecular fluorescent indicators

Site‐Specific Control of N7–Metal Coordination in DNA by a Fluorescent Purine Derivative

Three-Dimensional Uracil Network with Sodium as a Linker

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