scholarly journals Thionation of a Fluorescent Thieno[3,4-d]pyrimidine Derivative for the Development of a Heavy-Atom-Free Photosensitizer

2021 ◽  
Author(s):  
Luis A. Ortiz-Rodríguez ◽  
Ye-Guang Fang ◽  
Germain Niogret ◽  
Kaivin Hadidi ◽  
Yitzhak Tor ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Heavy Atom ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Yield ◽  
Pyrimidine Derivative ◽  
Transient Absorption Spectroscopy ◽  
Acetonitrile Solution ◽  
Visible Radiation ◽  
Dna And Rna

All-organic, heavy-atom-free photosensitizers based on thionation of nucleobases are receiving increased attention because they are easy to make, noncytotoxic, work both in the presence and absence of molecular oxygen and can be readily incorporated into DNA and RNA. In this contribution, the DNA and RNA fluorescent probe, thieno[3,4-d]pyrimidin-4(1H)-one, has been thionated to develop thieno[3,4-d]pyrimidin-4(1H)-thione, which is nonfluorescent and absorbs near-visible radiation with about 60% higher efficiency. Steady-state absorption and emission spectra are combined with transient absorption spectroscopy and CASPT2 calculations to delineate the electronic relaxation mechanisms of both pyrimidine derivatives in aqueous and acetonitrile solutions and to explain the origin of the remarkable fluorescence quenching in the thionated compound. It is demonstrated that thieno[3,4-d]pyrimidin-4(1H)-thione efficiently populates the long-lived and reactive triplet state in hundreds of femtoseconds independent of solvent. Conversely, fluorescence emission in thieno[3,4-d]pyrimidin-4(1H)-one is highly sensitive to solvent, with an order of magnitude decrease in fluorescence yield in going from aqueous to acetonitrile solution. Collectively, the experimental and computational results demonstrate that thieno[3,4-d]pyrimidine-4(1H)-thione stands out as the most promising thiopyrimidine photosensitizer developed to this date, which can be readily incorporated as a photodynamic agent into sequence-specific DNA and RNA sequences for the treatment of skin cancer cells.

scholarly journals Thionation of a Fluorescent Thieno[3,4-d]pyrimidine Derivative for the Development of a Heavy-Atom-Free Photosensitizer

2021 ◽  
Author(s):  
Luis A. Ortiz-Rodríguez ◽  
Ye-Guang Fang ◽  
Germain Niogret ◽  
Kaivin Hadidi ◽  
Yitzhak Tor ◽  
...  
Keyword(s):  
Transient Absorption ◽  
Heavy Atom ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Fluorescence Yield ◽  
Pyrimidine Derivative ◽  
Transient Absorption Spectroscopy ◽  
Acetonitrile Solution ◽  
Visible Radiation ◽  
Dna And Rna

All-organic, heavy-atom-free photosensitizers based on thionation of nucleobases are receiving increased attention because they are easy to make, noncytotoxic, work both in the presence and absence of molecular oxygen and can be readily incorporated into DNA and RNA. In this contribution, the DNA and RNA fluorescent probe, thieno[3,4-d]pyrimidin-4(1H)-one, has been thionated to develop thieno[3,4-d]pyrimidin-4(1H)-thione, which is nonfluorescent and absorbs near-visible radiation with about 60% higher efficiency. Steady-state absorption and emission spectra are combined with transient absorption spectroscopy and CASPT2 calculations to delineate the electronic relaxation mechanisms of both pyrimidine derivatives in aqueous and acetonitrile solutions and to explain the origin of the remarkable fluorescence quenching in the thionated compound. It is demonstrated that thieno[3,4-d]pyrimidin-4(1H)-thione efficiently populates the long-lived and reactive triplet state in hundreds of femtoseconds independent of solvent. Conversely, fluorescence emission in thieno[3,4-d]pyrimidin-4(1H)-one is highly sensitive to solvent, with an order of magnitude decrease in fluorescence yield in going from aqueous to acetonitrile solution. Collectively, the experimental and computational results demonstrate that thieno[3,4-d]pyrimidine-4(1H)-thione stands out as the most promising thiopyrimidine photosensitizer developed to this date, which can be readily incorporated as a photodynamic agent into sequence-specific DNA and RNA sequences for the treatment of skin cancer cells.

Synthesis, characterization and photophysical properties of ferrocenyl and mixed sandwich cobaltocenyl ester linked meso-triaryl corrole dyads

2017 ◽  
Vol 21 (10) ◽  
pp. 646-657 ◽  
Author(s):  
B. Shivaprasad Achary ◽  
A. R. Ramya ◽  
Rajiv Trivedi ◽  
P. R. Bangal ◽  
L. Giribabu
Keyword(s):  
Transient Absorption ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
Parent Compound ◽  
Fluorescence Emission ◽  
Soret Band ◽  
Transient Absorption Spectroscopy ◽  
Ferrocene Derivatives ◽  
Time Resolved ◽  
Design And Synthesis

We report here the design and synthesis of corrole-metallocene dyads consisting of a metallocene (either ferrocene (Dyad 1) or mixed sandwich [Formula: see text]-[C[Formula: see text]H[Formula: see text](COOH)]Co([Formula: see text]-C[Formula: see text]Ph[Formula: see text] (Dyad 2)) connected via an ester linkage at meso phenyl position. Both the dyads were characterized by [Formula: see text]H NMR, MALDI-TOF, UV-visible, fluorescence spectroscopies (steady-state, picosecond time-resolved), femtosecond transient absorption spectroscopy (fs-TA) and electrochemical methods. The absorption spectra of these dyads showed slight broadening and splitting of the Soret band that indicates a weak ground state interaction between the corrole macrocycle and metallocene part of the present donor–acceptor (D–A) system. However, in both the dyad systems, fluorescence emission of the corrole was quenched in polar solvents as compared to its parent compound 10-(4-hydroxyphenyl)-5,15-bis-(pentafluorophenyl ) corrole (Ph-Corr). The quenching was more pronounced in ferrocene derivatives than in cobaltocenyl derivatives. Transient absorption studies confirm the absence of photoinduced electron transfer from metallocene to correl for these dyad systems and the quenching of singlet state of corrole is found to enhance intersystem crossing due to heavy atom effect.

The internal heavy-atom effect on 3-phenylselanyl and 3-phenyltellanyl BODIPY derivatives studied by transient absorption spectroscopy

2016 ◽  
Vol 15 (2) ◽  
pp. 250-259 ◽  
Author(s):  
Jamaludin Al Anshori ◽  
Tomáš Slanina ◽  
Eduardo Palao ◽  
Petr Klán
Keyword(s):  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Heavy Atom ◽  
Transient Absorption Spectroscopy ◽  
Intersystem Crossing ◽  
Heavy Atom Effect ◽  
Atom Effect

The extent of intersystem crossing related to the heavy-atom effect of Se and Te atoms was investigated on monosubstituted 3-phenylselanyl and 3-phenyltellanyl BODIPY derivatives.

scholarly journals Interactions of nucleic acids with fluorescent dyes: spectral properties of condensed complexes.

1990 ◽  
Vol 38 (9) ◽  
pp. 1323-1329 ◽  
Author(s):  
J Kapuscinski
Keyword(s):  
Nucleic Acids ◽  
Spectral Properties ◽  
Fluorescent Dyes ◽  
Fluorescence Emission ◽  
Emission Spectra ◽  
Binding Mode ◽  
Fluorescence Yield ◽  
Cooperative Interaction ◽  
Fluorescence Emission Spectra ◽  
Yield Information

Interaction of cations with nucleic acids (NA) often results in condensation of the product. The driving force of aromatic cation-induced condensation is the cooperative interaction between ligand and single-stranded (ss) NA. This type of reaction is highly specific with regard to the primary and secondary structure of NA, and results in destabilization of the latter. The spectral properties of fluorescent intercalating and non-intercalating ligands [acridine orange, pyronin Y(G), DAPI, Hoechst 33258, and Hoechst 33342]-NA complexes were studied in both the relaxed and condensed form. The changes in absorption, excitation, and fluorescence emission spectra and fluorescence yield that followed the condensation were examined. Although some of these effects can be explained by changes in solvation of the fluorophore and its interaction with NA bases and the solvent, the overall effect of condensation on spectral properties of the complex is unpredictable. In particular, no correlation was found between these effects and the ds DNA binding mode of these ligands. Nevertheless, the spectral data associated with polymer condensation can yield information about the composition and structure of NA and can explain some nonspecific interactions of these probes.

Thymine Dimerization Induced by Oxidative DNA Lesions and Epigenetic Intermediates via Triplet-Triplet Energy Transfer

2020 ◽  
Author(s):  
Mauricio Lineros-Rosa ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Miguel Angél Miranda ◽  
Virginie Lhiaubet-Vallet
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Transient Absorption ◽  
Theoretical Calculations ◽  
Dna Lesions ◽  
Transient Absorption Spectroscopy ◽  
Triplet Energy ◽  
Pyrimidine Dimers ◽  
Triplet Energy Transfer ◽  
Dna Nucleobases

Interaction of nucleic acids with light is a scientific question of paramount relevance not only in the understanding of life functioning and evolution, but also in the insurgence of diseases such as malignant skin cancer and in the development of biomarkers and novel light-assisted therapeutic tools. This work shows that the UVA portion of sunlight, not absorbed by canonical DNA nucleobases, can be absorbed by 5-formyluracil (ForU) and 5-formylcytosine (ForC), two ubiquitous oxidative lesions and epigenetic intermediates present in living beings in natural conditions. We measure the strong propensity of these molecules to populate triplet excited states able to transfer the excitation energy to thymine-thymine dyads, inducing the formation of the highly toxic and mutagenic cyclobutane pyrimidine dimers (CPDs). By using steady-state and transient absorption spectroscopy, NMR, HPLC, and theoretical calculations, we quantify the differences in the triplet-triplet energy transfer mediated by ForU and ForC, revealing that the former is much more efficient in delivering the excitation energy and producing the CPD photoproduct. Although significantly slower than ForU, ForC is also able to harm DNA nucleobases and therefore this process has to be taken into account as a viable photosensitization mechanism. The present findings evidence a rich photochemistry crucial to understand DNA photodamage and of potential use in the development of biomarkers and non-conventional photodynamic therapy agents.

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

Charge-Transfer Dynamics at Ag/Ni-MOF/Cu2O heterostructure in Photoelectrochemical NH3 production

2021 ◽  
Author(s):  
Ying Liu ◽  
Jianmin Lu ◽  
Qianxiao Zhang ◽  
Yajie Bai ◽  
Xuliang Pang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Yield Rate ◽  
Ultrafast Transient Absorption ◽  
Charge Transfer Dynamics ◽  
Ultrafast Transient Absorption Spectroscopy

Decoration of Ag-ultrathin Ni-MOF onside Cu2O was firstly fabricated. The charge-transfer dynamics at heterostructure was in-depth revealed by ultrafast transient absorption spectroscopy. NH3 yield rate (4.63 μg h-1 cm-2) with...

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