Theory of Triplet Excitation Transfer in the Donor-Oxygen-Acceptor System: Application to Cytochrome b 6 f

Петров, Е. С.; Robert, Bruno; Lin, Sheng Hsien; Valkūnas, Leonas

doi:10.1016/j.bpj.2015.08.026

Cited by 5 publications

(4 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In line with the experimental observations, this theoretically verifies that the bridging state, available through the presence of oxygen, has an accelerating effect on the electron transfer step between the two starting materials. A related involvement of an oxygen mediated bridging state for a triplet excitation energy transfer process was reported by Valkunas group [22] . This theory is also in line with GC kinetic results: at the early stage, under dioxygen the reaction is faster than under dinitrogen atmosphere, and under air (open flask) faster than under dinitrogen; the final yields according to GC are the essentially the same (Figure 6 and Figure S22, S23).…”

Section: Resultssupporting

confidence: 84%

A Metal‐Free Direct Arene C−H Amination

et al. 2021

View full text Add to dashboard Cite

The synthesis of aryl amines via the formation of a C−N bond is an essential tool for the preparation of functional materials, active pharmaceutical ingredients and bioactive products. Usually, this chemical connection is only possible by transition metal‐catalyzed reactions, photochemistry or electrochemistry. Here, we report a metal‐free arene C−H amination using hydroxylamine derivatives under benign conditions. A charge transfer interaction between the aminating reagents TsONHR and the arene substrates enables the chemoselective amination of the arene, even in the presence of various functional groups. Oxygen was crucial for an effective conversion and its accelerating role for the electron transfer step was proven experimentally. In addition, this was rationalized by a theoretical study which indicated the involvement of a dioxygen‐bridged complex with a “Sandwich‐like” arrangement of the aromatic starting materials and the aminating agents at the dioxygen molecule.

show abstract

Section: Resultssupporting

confidence: 84%

A Metal‐Free Direct Arene C−H Amination

et al. 2021

View full text Add to dashboard Cite

show abstract

“…However, transmitted electron from excited chlorophyll to molecular oxygen (O 2 ) produces singlet oxygen. 6 Plants develop defense systems consist of an inhibitor to protect themselves against ROS damages and cope with totally different environmental constraints. 7 The inhibitor system opposed ROS injury and limits ROS physiological damage in plant cells.…”

Section: Introductionmentioning

confidence: 99%

Foliar Applied Acetylsalicylic Acid Induced Growth and Key-Biochemical Changes in Chickpea (Cicer arietinum L.) Under Drought Stress

et al. 2020

View full text Add to dashboard Cite

The exogenous application of acetylsalicylic acid (ASA) is stated to increase tolerance of plants against different environmental stresses. Therefore, the present study was planned to get insight into ASA-mediated regulation of growth, secondary metabolism, and oxidative defense in 2 chickpea varieties. Ten seeds of 2 chickpea varieties (DG-89 and Bittle-98) were sown in plastic pots containing sandy loam soil with 3 drought stress levels, i.e. wet conditions or flooded water (100% FC) as recommended control, 75% FC, 50% FC and 25% FC for chickpea. The moisture contents were maintained and regularly monitored through the addition of normal irrigation water. The design of experimental was completely randomized with 3 replicates per treatment. Penultimate leaves were harvested with knife after 20 days of foliar spray to observe the effect of exogenously applied ASA (100 mg/L) on growth, and key-biochemical attributes of chickpea plants (DG-89 and Bittle-98) under drought stress regimes. Drought stress regimes caused a substantial decline in shoot (37% and 35%) and root length (67% and 78%), shoot (80% and 76%) and root (62% and 68%) fresh masses, shoot (71% and 63%) and root (77% and 74%) dry masses, leaf area per plant (77% and 80%), chlorophyll a (7% and 45%), chlorophyll b (57% and 42%), total chlorophyll (30% and 39%), total carotenoids (76% and 54%), total anthocyanins (38%), reducing sugar (10% and 57%), total soluble proteins (77% and 44%), total flavonoids (61% and 59%) and total phenolics (58% and 31%) contents in both DG-89 and Bittle-98, respectively. A significant increase in MDA (25%), H2O2 contents (100% and 62%), proline (145% and 131%), and ascorbic acid (133% and 203%) contents was documented in stressed plants of both varieties, respectively. Additionally, drought stress significantly improved the activities of POD (154% and 76%), CAT (87% and 45%) and SOD (248% and 143%) in both varieties. Exogenous application of ASA reduced drought-mediated oxidative stress by reducing MDA (53% and 14%), and H2O2 (84% and 56%) contents, proline contents (50% and 17%) and enhanced the shoot (6% and 25%) and root (43% and 33%) dry masses, leaf area (9% and 10%), chlorophyll a (7% and 32%), b (82% and 81%), and carotenoids (53% and 33%) in both barley cultivars. When plants of chickpea was treated with ASA had greater total anthocyanins (26% and 35%), free amino acids (48% and 28%), ascorbic acid contents (135% and 179%), total soluble proteins (34% and 23%), total flavonoids (58% and 35%) and phenolic (50% and 69%)contents besides the POD (41% and 64%), CAT (23% and 56%) and SOD (73% and 72%) enzymes activities. Plants of DG-89 showed more tolerance to drought stress than that of Bittle-98 as a manifest from higher plant biomasses. Thus, our results showed that foliar-applied ASA is an effective strategy that can be used to improve the tolerance of chickpea plants to drought stress.

show abstract

“…Solvent molecules have been implicated in the control of electronic coupling in systems containing solvent-separated ion pairs and in linked D-A pairs in favorable geometries to host solvent molecules [64][65][66]. Recently, an investigation into TTET in cytochrome b6f has proposed a non-covalent path for TTET [67]. A number of studies have provided convincing evidence that water molecules located in proximity to the D and A pairs can mediate the electronic coupling [68][69][70].…”

Section: Discussionmentioning

confidence: 99%

The fine tuning of carotenoid–chlorophyll interactions in light-harvesting complexes: an important requisite to guarantee efficient photoprotection via triplet–triplet energy transfer in the complex balance of the energy transfer processes

Valentin

Carbonera

2017

J. Phys. B: At. Mol. Opt. Phys.

View full text Add to dashboard Cite

Triplet-triplet energy transfer (TTET) from the chlorophyll to the carotenoid triplet state is the process exploited by photosynthetic systems to protect themselves from singlet oxygen formation under light-stress conditions. A deep comprehension of the molecular strategies adopted to guarantee TTET efficiency, while at the same time maintaining minimal energy loss and efficient light-harvesting capability, is still lacking. The paramagnetic nature of the triplet state makes electron paramagnetic resonance (EPR) the method of choice when investigating TTET. In this review, we focus on our extended comparative study of two photosynthetic antenna complexes, the Peridinin-chlorophyll a-protein of dinoflagellates and the lightharvesting complex II of higher plants, in order to point out important aspects of the molecular design adopted in the photoprotection strategy. We have demonstrated that a proper analysis of the EPR data allows one to identify the pigments involved in TTET and, consequently, gain an insight into the structure of the photoprotective sites. The structural information has been complemented by a detailed description of the electronic structure provided by hyperfine spectroscopy. All these elements represent the fundamental building blocks toward a deeper understanding of the requirements for efficient photoprotection, which is fundamental to guarantee the prolonged energy conversion action of photosynthesis.

show abstract

Theory of Triplet Excitation Transfer in the Donor-Oxygen-Acceptor System: Application to Cytochrome b 6 f

Cited by 5 publications

References 69 publications

A Metal‐Free Direct Arene C−H Amination

A Metal‐Free Direct Arene C−H Amination

Foliar Applied Acetylsalicylic Acid Induced Growth and Key-Biochemical Changes in Chickpea (Cicer arietinum L.) Under Drought Stress

The fine tuning of carotenoid–chlorophyll interactions in light-harvesting complexes: an important requisite to guarantee efficient photoprotection via triplet–triplet energy transfer in the complex balance of the energy transfer processes

Contact Info

Product

Resources

About