A5029930768- Photosynthetic Processes and Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Quantum Chemical Studies
- Metal-Catalyzed Oxygenation Mechanisms
- Free Radicals and Antioxidants
- Advanced Photocatalysis Techniques
- TiO2 Photocatalysis and Solar Cells
- Crystallization and Solubility Studies
- Electrocatalysts for Energy Conversion
- Organic Chemistry Cycloaddition Reactions
- Analytical Chemistry and Chromatography
- Thermal and Kinetic Analysis
- Computational Drug Discovery Methods
- Photoreceptor and optogenetics research
- Synthesis and Reactivity of Heterocycles
- X-ray Diffraction in Crystallography
- Molecular Junctions and Nanostructures
- Inorganic and Organometallic Chemistry
- Advanced Chemical Physics Studies
- Synthesis and Characterization of Heterocyclic Compounds
- Advanced battery technologies research
- Perovskite Materials and Applications
- Synthesis and Biological Evaluation
- Fullerene Chemistry and Applications
University of Puerto Rico at Cayey
2017-2021
University of Puerto Rico System
2017-2019
Arizona State University
2012-2017
Yale University
2015-2017
Tempe Union High School District
2017
Significance The capture and conversion of sunlight into a useful chemical fuel (H 2 , CH 4 3 OH, etc.) is central goal the field artificial photosynthesis. Water oxidation to generate O protons stands as major bottleneck in these processes. Relatively few stable photosensitizers can sufficient oxidizing power drive water oxidation, those that do contain rare elements such ruthenium. In this paper, we show metal-free organic are capable driving photoelectrochemical oxidation. Significantly,...
Understanding the effect of vibronic coupling on electron transfer (ET) rates is a challenge common to wide range applications, from electrochemical synthesis and catalysis biochemical reactions solar energy conversion. The Marcus-Jortner-Levich (MJL) theory offers model ET based simple analytic expression with few adjustable parameters. However, MJL equation in conjunction density functional (DFT) has yet be established as predictive first-principles methodology. A framework presented for...
We describe and evaluate a method for computationally predicting reduction potentials of diverse group organic molecules by linearly correlating calculated lowest unoccupied molecular orbital energies with ground state measured in acetonitrile. The approach is shown to provide unique combination extreme computational simplicity excellent accuracy across range structures wide window potentials. A disparate set (74 compounds belonging six distinct structural families, comprised containing C,...
Significance Rapid chlorophyll-to-carotenoid triplet–triplet energy transfer (T-TET) in photosynthetic organisms is crucial to photoprotection from singlet oxygen. Photosynthesis reengineered for increased efficiency will result oxygen levels the cells, and need ensure adequately rapid T-TET arise. Using a combination of theoretical experimental studies on artificial natural carotenoid–chlorophyll complexes, we have identified spectroscopic markers indicative specific pigment–pigment...
We report on the photosensitization of titanium dioxide nanoparticles (TiO2 NPs) synthesized inside AOT (bis(2-ethylhexyl) sulfosuccinate sodium salt) reverse micelles following photoexcitation perylene derivatives with dicarboxylate anchoring groups. The dyes, 1,7-dibromoperylene-3,4,9,10-tetracarboxy dianhydride (1), 1,7-dipyrrolidinylperylene-3,4,9,10-tetracarboxy (2), and 1,7-bis(4-tert-butylphenyloxy)perylene-3,4,9,10-tetracarboxy (3), have considerably different driving forces for...
A short, convenient, and scalable protocol for the one-pot synthesis of a series fluorescent 7,8-dihalo-2,3-diaminophenazines is introduced. The synthetic route based on oxidative condensation 4,5-dihalo-1,2-diaminobenzenes in aqueous conditions. resulting diaminophenazines could be attractive intermediates preparation polyfunctional phenazines extended polyheteroacenes. We find that undesired hydroxylation byproducts, typically obtained conditions, are completely suppressed by addition...
Iridium oxide (IrOx) is one of the best water splitting electrocatalysts, but its active site details are not well known. As with all heterogeneous catalysts, a strategy for counting number sites clear, and understanding their nature structure remarkably difficult. In this work, we performed combined study using optical spectroscopy, magnetic resonance electrochemistry to characterize interaction IrOx nanoparticles (NPs) probe molecule, catechol. The catalyst given that substrate in...
Using natural photosynthesis as a model, bio-inspired constructs for fuel generation from sunlight are being developed. Here we report the synthesis and time-resolved spectroscopic analysis of molecular triad in which porphyrin electron donor is covalently linked to both cyanoporphyrin acceptor benzimidazole-phenol model TyrZ-D1His190 pair PSII. A dual-laser setup enabled us record ultrafast kinetics long-living species single experiment. From this data, photophysical relaxation pathways...
A zinc and a free base phthalocyanine-fulleropyrrolidine dyad in which the chromophores are linked by phenylethynyl group have been prepared using new synthetic route, their photoelectrochemical properties investigated. The is readily soluble variety of solvents, its spectroscopic determined toluene benzonitrile. In toluene, excitation phthalocyanine followed rapid establishment an equilibrium between fullerene excited states. These states decay mainly to ground state respective triplet then...
The photosynthetic water-oxidation reaction is catalyzed by the oxygen-evolving complex in photosystem II (PSII) that comprises Mn
Under excess illumination, photosystem II of plants dissipates energy through the quenching chlorophyll fluorescence in light harvesting antenna. Various models involving by carotenoids have been proposed, including (i) direct transfer from to low-lying optically forbidden carotenoid S1 state, (ii) formation a collective quenched chlorophyll-carotenoid excitonic (iii) charge separation and recombination, (iv) chlorophyll-chlorophyll recombination. In previous work, first three processes were...
In this study we use the molecular orbital energy approximation (MOEA) and difference (EDA) to build linear correlation models for redox potentials of 53 organic compounds in aqueous solutions. The molecules evaluated include nitroxides, phenols amines. Both MOEA EDA methods yield similar models, however method is less computationally expensive. Correlation coefficients (R2) below 0.3 mean absolute errors above 0.25 V were found built without solvent effects. When explicit water a continuum...
<p>In this study we use the molecular orbital energy approximation (MOEA) and difference (EDA) to build linear correlation models for redox potentials of 53 organic compounds in aqueous solutions. The molecules evaluated include nitroxides, phenols amines. Both MOEA EDA methods yield similar models, however method is less computationally expensive. Correlation coefficients (R2) below 0.3 mean absolute errors above 0.25 V were found built without solvent effects. When explicit water a...
Light-driven water oxidation in algae, cyanobacteria, and higher plants generates dioxygen that supports life on Earth. The water-oxidation reaction is catalyzed by the oxygen-evolving complex (OEC) photosystem II (PSII) comprised of tetranuclear manganese calcium-oxo (Mn 4 CaO 5 ) cluster, with participation redox-active tyrosine residue (Y Z a hydrogen-bonded network amino acids molecules. Y mediates successive proton-coupled electron transfer (PCET) reactions are essential for to at Mn...
<p>Light-driven water oxidation in algae, cyanobacteria, and higher plants generates dioxygen that supports life on Earth. The water-oxidation reaction is catalyzed by the oxygen-evolving complex (OEC) photosystem II (PSII) comprised of tetranuclear manganese calcium-oxo (Mn<sub>4</sub>CaO<sub>5</sub>) cluster, with participation redox-active tyrosine residue (Y<sub>Z</sub>) a hydrogen-bonded network amino acids molecules. Y<sub>Z</sub>...
In the discovery process of new drugs and development novel therapies in medicine, computational modeling is a complementary tool for design molecules by predicting example their solubility different solvents. Here, we benchmarked several methods to calculate partition coefficients diverse set 161 organic with experimental logP values obtained from literature. general, density functional theory yielded best correlations lower average deviations. Although results are faster semiempirical...