A5083662167- Photochromic and Fluorescence Chemistry
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Machine Learning in Materials Science
- Radical Photochemical Reactions
- Organic Chemistry Cycloaddition Reactions
- Photochemistry and Electron Transfer Studies
- Synthesis and Properties of Aromatic Compounds
- Organic Electronics and Photovoltaics
- Advanced Chemical Physics Studies
- Click Chemistry and Applications
- Fluorine in Organic Chemistry
- Photoreceptor and optogenetics research
- Advanced Physical and Chemical Molecular Interactions
- Surface Chemistry and Catalysis
- Computational Drug Discovery Methods
- Electrochemical Analysis and Applications
- Perovskite Materials and Applications
- Career Development and Diversity
- Cyclopropane Reaction Mechanisms
- Advanced biosensing and bioanalysis techniques
- Molecular Junctions and Nanostructures
- Fuel Cells and Related Materials
- Chemistry and Chemical Engineering
- Conducting polymers and applications
Northeastern University
2018-2025
Universidad del Noreste
2019-2024
University of New Mexico Hospital
2022
University of New Mexico
2020-2021
Eastern University
2020
University of California, Los Angeles
2012-2018
Los Angeles City College
2016-2018
Harvard University
2016-2018
Science Oxford
2016
Harvard University Press
2016
The azide-dibenzocyclooctyne and trans-cyclooctene-tetrazine cycloadditions are both bioorthogonal mutually orthogonal: trans-cyclooctene derivatives greatly prefer to react with tetrazines rather than azides, while dibenzocyclooctyne azides but not under physiological conditions. DFT calculations used identify the origins of this extraordinary selectivity reported, design principles guide discovery new orthogonal proposed. Two reagents, methylcyclopropene...
Bioorthogonal chemistries have provided tremendous insight into biomolecule structure and function. However, many popular bioorthogonal transformations are incompatible with one another, limiting their utility for studies of multiple biomolecules in tandem. We identified two reactions that can be used concurrently to tag complex environments: the inverse electron-demand Diels-Alder reaction tetrazines 1,3-disubstituted cyclopropenes, 1,3-dipolar cycloaddition nitrile imines 3,3-disubstituted...
Abstract The Harvard Organic Photovoltaic Dataset (HOPV15) presented in this work is a collation of experimental photovoltaic data from the literature, and corresponding quantum-chemical calculations performed over range conformers, each with quantum chemical results using variety density functionals basis sets. It anticipated that dataset will be use both relating electronic structure to observations through generation calibration schemes, as well for creation new semi-empirical methods...
The reactivities of enamines and predistorted (strained) dipolarophiles toward perfluoroaryl azides (PFAAs) were explored experimentally computationally. Kinetic analyses indicate that PFAAs undergo (3 + 2) cycloadditions with up to 4 orders magnitude faster than phenyl azide reacts these dipolarophiles. DFT calculations used identify the origin this rate acceleration. Orbital interactions between cycloaddends are larger due relatively low-lying LUMO PFAAs. triazolines resulting from...
Photochemical reactions are widely used by academia and industry to construct complex molecular architectures<italic>via</italic>mechanisms that often inaccessible other means.
The transition structures for 1,3-dipolar cycloadditions of phenyl azide to norbornene derivatives were located with quantum mechanical methods. Calculations carried out M06-2X/6-311G(d,p) and SCS-MP2/6-311G(d,p)//M06-2X/6-311G(d,p) calculated activation barriers strongly correlate state distortion energies (ΔE(d‡)) but not the reaction energies. Strain-promoted reactions are accelerated because it is easy distort strained reactants a pyramidalized geometry; correlation cycloaddition rates...
ConspectusPhotochemical reactions are of great importance in chemistry, biology, and materials science because they take advantage a renewable energy source, mild reaction conditions, high atom economy. Light absorption can excite molecules to higher electronic state the same spin multiplicity. The following nonadiabatic processes induce molecular transformations that afford exotic architectures high-energy-isomers inaccessible by thermal means. Computational simulations now complement...
This study describes the design and implementation of remote Summer undergraduate research programs during COVID-19 pandemic, including program strengths recommendations for improvement from perspectives researchers.
Photochemical [2 + 2]-cycloadditions store solar energy in chemical bonds and efficiently access strained organic molecular architectures. Functionalized [3]-ladderdienes undergo 2]-photocycloadditions to afford cubanes, a class of molecules. The substituents (e.g., methyl, trifluoromethyl, cyclopropyl) affect the overall reactivities these cubane precursors; yields range from 1 48%. However, origin substituent effects on chemoselectivities is not understood. We now integrate single...
Machine learning (ML) continues to revolutionize computational chemistry for accelerating predictions and simulations by training on experimental or accurate but expensive quantum mechanical (QM) calculations. Photodynamics require hundreds of trajectories coupled with multiconfigurational QM calculations excited-state potential energies surfaces that contribute the prohibitive cost at long timescales complex organic molecules. ML accelerates photodynamics combining nonadiabatic an model...
Abstract Crystalline pentacene is a model solid-state light-harvesting material because its quantum efficiencies exceed 100% via ultrafast singlet fission. The fission mechanism in crystals disputed due to insufficient electronic information time-resolved experiments and intractable mechanical calculations for simulating realistic crystal dynamics. Here we combine multiscale multiconfigurational approach machine learning photodynamics understand competing mechanisms crystalline pentacene....
The transition structures for the 1,3-dipolar cycloadditions of phenyl azide to enamines derived from acetophenone or phenylacetaldehyde and piperidine, morpholine, pyrrolidine were located using quantum mechanical methods. These studied experimentally in 1975 by Meilahn, Cox, Munk (J. Org. Chem. 1975, 40, 819-823). Calculations carried out with M06-2X/6-311+G(d,p), SCS-MP2/6-311+G(d,p)//M06-2X/6-311+G(d,p), B97D/6-311+G(d,p) methods IEF-PCM solvation model chloroform ethanol....
In order to understand the conformational behavior of organic components in electronic devices, we have computed torsional potentials for a library thiophene-based heterodimers. The accuracy and efficiencies computational methods these materials were benchmarked 11 common density functionals with three Pople basis sets against Focal Point Analysis (FPA) on model oligothiophene 2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]-thiophene (BTTT) system. This study establishes set general trends...
We systematically varied the degree of fluorination along backbone a series highly regioregular 3-hexylthiophene-based polymers, P3HT-50F, P3HT-33F, and P3HT-25F, in which 50%, 33%, 25% thiophene units within polymer chain contain fluorine atoms available 4-position, respectively. These materials were homopolymerized using Kumada catalyst transfer polycondensation method from set mono-fluorinated bi-, ter-, quarterthiophenes to ensure high regioregularity evenly spaced conjugated backbone....
This work addresses the need for chemical tools that can selectively form cross-links. Contemporary thiol-selective cross-linkers, example, modify all accessible thiols, but only cross-links between a subset. The resulting terminal "dead-end" modifications of lone thiols are toxic, confound cross-linking-based studies macromolecular structure, and an undesired, currently unavoidable, byproduct in polymer synthesis. Using thiol pair Cu/Zn-superoxide dismutase (SOD1), we demonstrated cyclic...
Optical imaging in the shortwave infrared region (SWIR, 1000–2000 nm) provides high-resolution images complex systems. Here we explore substituent placement on dimethylamino flavylium polymethine dyes, a class of SWIR fluorophores. We find that position significantly affects λmax and fluorescence quantum yield. Quantum-mechanical calculations suggest steric clashes control extent π-conjugation. These insights provide design principles for development fluorophores enhanced imaging.
This letter announces the Virtual Excited State Reference for Discovery of Electronic Materials Database (VERDE materials DB), first database to include downloadable excited-state structures (S0, S1, T1) and photophysical properties. VERDE DB is searchable, open-access via www.verdedb.org , focused on light-responsive π-conjugated organic molecules with applications in green chemistry, solar cells, redox flow batteries. It includes results our active past virtual screening studies; date,...
The morphologies and electron mobilities for 20 single-crystal 21 thin-film organic n-type semiconductors are predicted using a multi-mode methodology previously applied by our group p-type materials [I. Yavuz, <italic>et al.</italic>, <italic>J. Am. Chem. Soc.</italic>, 2015, <bold>137</bold>, 2856–2866].
Storing solar energy is a vital component of using renewable sources to meet the growing demands global economy. Molecular thermal (MOST) storage promising means store with on-demand release. The light-induced isomerization reaction norbornadiene (NBD) quadricyclane (QC) great interest because generally high density (0.97 MJ kg-1) and long reversion lifetime (t1/2,300K = 8346 years). However, mechanistic details ultrafast excited-state [2 + 2]-cycloaddition are largely unknown due...
The reactivities and torquoselectivities of electrocyclic ring opening reactions fluoromethyl-substituted cyclobutenes oxetenes were studied with M06-2X density functional theory. a series mono-, di-, trifluoromethylcyclobutenes result from the interplay favorable orbital interactions closed-shell repulsions. When substituent rotates inward, there can be interaction between breaking σ(CO) bond σ(CF)* (σ(CO) → σ(CF)*) fluoromethyl group in fluoromethyloxetenes. preference for rotation is...