A5064263858- Photochemistry and Electron Transfer Studies
- Metal-Catalyzed Oxygenation Mechanisms
- Advanced Chemical Physics Studies
- Electron Spin Resonance Studies
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photosynthetic Processes and Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Organometallic Complex Synthesis and Catalysis
- Machine Learning in Materials Science
- Catalysis and Oxidation Reactions
- Spectroscopy and Quantum Chemical Studies
- Quantum, superfluid, helium dynamics
- Radical Photochemical Reactions
- CO2 Reduction Techniques and Catalysts
- Inorganic and Organometallic Chemistry
- Asymmetric Hydrogenation and Catalysis
- Advanced NMR Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Magnetism in coordination complexes
- Boron and Carbon Nanomaterials Research
- Atomic and Subatomic Physics Research
- Photochromic and Fluorescence Chemistry
- Catalytic Cross-Coupling Reactions
- Synthesis and Properties of Aromatic Compounds
Pennsylvania State University
2023-2025
Yale University
2018-2022
Princeton University
2016-2018
California Institute of Technology
2017-2018
Lomonosov Moscow State University
2011-2013
Python‐based simulations of chemistry framework (P y SCF) is a general‐purpose electronic structure platform designed from the ground up to emphasize code simplicity, so as facilitate new method development and enable flexible computational workflows. The package provides wide range tools support finite‐size systems, extended systems with periodic boundary conditions, low‐dimensional custom Hamiltonians, using mean‐field post‐mean‐field methods standard Gaussian basis functions. To ensure...
PySCF is a Python-based general-purpose electronic structure platform that supports first-principles simulations of molecules and solids as well accelerates the development new methodology complex computational workflows. This paper explains design philosophy behind enables it to meet these twin objectives. With several case studies, we show how users can easily implement their own methods using environment. We then summarize capabilities for molecular solid-state simulations. Finally,...
We introduce the atomic valence active space (AVAS), a simple and well-defined automated technique for constructing orbital spaces use in multiconfiguration multireference (MR) electronic structure calculations. Concretely, constructs molecular orbitals capable of describing all relevant configurations emerging from targeted set (e.g., metal d coordination complex). This is achieved via linear transformation occupied unoccupied an easily obtainable single-reference wave function (such as...
We describe a state interaction spin-orbit (SISO) coupling method using density matrix renormalization group (DMRG) wavefunctions and the mean-field (SOMF) operator. implement our DMRG-SISO scheme spin-adapted algorithm that computes transition matrices between arbitrary product states. To demonstrate potential of we present accurate benchmark calculations for zero-field splitting copper gold atoms, comparing to earlier complete active space self-consistent-field second-order perturbation...
Molecules with conjugated π systems often feature strong electron correlation and therefore require multireference methods for a reliable computational description. A key prerequisite the successful application of such is choice suitable active space. Herein automated π-orbital space (PiOS) method selecting spaces calculations presented. This approach allows construction small but effective based on Hückel theory. To demonstrate its performance, → π* excitations benzene, octatetraene,...
Ethylene-forming enzyme (EFE) is a non-heme iron (II)- and 2-oxoglutarate-(Fe(II)/2OG)-dependent oxygenase that exhibits distinct catalytic activity. While most Fe(II)/2OG-dependent oxygenases catalyze the substrate hydroxylation accompanied by decarboxylation of 2OG cosubstrate to succinate, EFE primarily converts into CO2 ethylene. Experimental studies suggest reaction mechanism does not involve Fe(IV)=O (ferryl) intermediate central in consensus for oxygenases, ethylene-forming pathway...
Charge-transfer cold Yb${}^{+}$$+$ Rb collision dynamics is investigated theoretically using high-level ab initio potential energy curves, dipole moment functions, and nonadiabatic coupling matrix elements. Within the scalar-relativistic approximation, radiative transitions from entrance $A{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Sigma}}^{+}$ to ground $X{\phantom{\rule{0.16em}{0ex}}}^{1}{\ensuremath{\Sigma}}^{+}$ state are found be only efficient charge-transfer pathway. The...
Developing new strategies to activate and cleave C–H bonds is important for a broad range of applications. Recently approach bond activation using multi-site concerted proton-coupled electron transfer (PCET) involving intermolecular an oxidant coupled intramolecular proton was reported. For series oxidants reacting with 2-(9H-fluoren-9-yl)benzoate, experimental studies revealed atypical Brønsted α, defined as the slope logarithm PCET rate constant versus equilibrium or scaled driving force....
Photoreceptor proteins control vital cellular responses to light. The photocycle of the Slr1694 blue light using flavin photoreceptor is initiated by photoexcitation a locally excited state within flavin, followed electron transfer from Tyr8 and proton relay via an intervening glutamine. Herein, two-dimensional potential energy surfaces associated with this double proton-transfer reaction are computed complete active space self-consistent-field method multiconfigurational perturbation...
PySCF is a general-purpose electronic structure platform designed from the ground up to emphasize code simplicity, both aid new method development, as well for flexibility in computational workflow. The package provides wide range of tools support simulations finite size systems, extended systems with periodic boundary conditions, low dimensional and custom Hamiltonians, using mean-field post-mean-field methods standard Gaussian basis functions. To ensure easy extensibility, uses Python...
Recently selective C-H bond cleavage under mild conditions with weak oxidants was reported for fluorenyl-benzoates. This mechanism is based on multi-site concerted proton-coupled electron transfer (PCET) involving intermolecular to an outer-sphere oxidant coupled intramolecular proton a well-positioned acceptor. The driving force depends predominantly the oxidant, and mainly basicity of carboxylate, which influenced by substituent benzoate fragment. Experiments showed that rate constants are...
Ribonucleotide reductase (RNR) is an essential enzyme in DNA synthesis for all living organisms. It reduces ribonucleotides to the corresponding deoxyribonucleotides by a reversible radical transfer mechanism. The active form of E. coli Ia RNR composed two subunits, α and β, which asymmetric α2β2 complex. pathway involves series proton-coupled electron (PCET) reactions spanning β over ∼32 Å. Herein, quantum mechanical/molecular mechanical free energy simulations PCET between tyrosine...
Ethylene-forming enzyme (EFE) is a non-heme iron (II)- and 2-oxoglutarate-(Fe(II)/2OG)-dependent oxygenase that exhibits distinct catalytic activity. While most Fe(II)/2OG-dependent oxygenases catalyze the substrate hydroxylation accompanied by decarboxylation of 2OG cosubstrate to succinate, EFE primarily converts into CO2 ethylene. Experimental studies suggest reaction mechanism does not involve Fe(IV)=O (ferryl) intermediate central in consensus for oxygenases, ethylene-forming pathway...
We present a state interaction spin-orbit coupling method to calculate electron paramagnetic resonance (EPR) $g$-tensors from density matrix renormalization group wavefunctions. apply the technique compute for \ce{TiF3} and \ce{CuCl4^2-} complexes, [2Fe-2S] model of active center ferredoxins, \ce{Mn4CaO5} S2 oxygen evolving complex. These calculations raise prospects determining in multireference with large number open shells.
Inverted region behavior for concerted proton-coupled electron transfer (PCET) was recently demonstrated biomimetic anthracene–phenol–pyridine molecular triads. Photoexcitation of the anthracene to a locally excited state (LES) is followed by from phenol and proton pyridine, forming relatively long-lived charge separated (CSS). The CSS inverted associated with decay ground through recombination were experimentally observed only triads certain substituents on pyridine. To explain this...
Supporting ligands reduce the Lewis acidity of transition metal ions, limiting degree electrophilic activation for any substrate. Here, we demonstrate that L1 and L2 mask dicationic Pd(II) via a reversible C–N bond formation. These shapeshifting complexes catalyze olefin isomerization, even in presence polar functional group. The equilibrium between two coor-dination modes allows system to access an state is comparable “naked” acid. However, because these systems are not sub-ject same rate...
Supporting ligands limit the degree of electrophilic ac-tivation for any substrate because they also reduce Lewis acidity transition metal ion. Here, we tem-porarily mask dicationic Pd(II) by using “shapeshifting” bidentate pyrimidine/olefin lig-ands L1 and L2. These delocalize/relocalize charge via reversible C–N bond formation. So, although ligated Pd compounds [1]2+ [2]2+ appear separated (distributed across ligand), react comparably to a solvated dication. We observe properties that are...
Photoinduced proton-coupled electron transfer (PCET) in anthracene–phenol–pyridine triads exhibits inverted region behavior, where the more thermodynamically favorable process is slower. The long-lived transient charge-separated state (CSS) associated with from phenol to anthracene and behavior were only observed experimentally for certain triads. Herein, excited molecular dynamics simulations performed on four different simulate nonequilibrium following photoexcitation locally (LES) of...
We present an ab initio study of cold (4)He + ThO((1)Σ(+)) collisions based on accurate potential energy surface (PES) evaluated by the coupled cluster method with single, double, and noniterative triple excitations using extended basis set augmented bond functions. Variational calculations rovibrational levels show that (4)He-ThO van der Waals complex has a binding 10.9 cm(-1) in its ground J = 0 rotational state. The calculated are used to obtain temperature dependence chemical equilibrium...
We extend the π-orbital space (PiOS) method introduced for planar π-conjugated molecular systems [J. Chem. Theory Comput. 2019, 15, 1679] to also allow constructing efficient active spaces non-planar systems. demonstrate performance of this with multiconfigurational and multireference calculations on prototypical π-systems: cycloacenes, short carbon nanotubes, various conformations 2,2-bipyridine anion, C20 fullerenes.
Our recent experimental and theoretical investigations have shown that fluorene C–H bonds can be activated through a mechanism in which the proton electron are transferred from bond to separate base oxidant concerted, elementary step. This multisite proton-coupled transfer (MS-PCET) for activation was facilitated by shorter donor–acceptor distances. With goal of intentionally modulating this distance, we now studied MS-PCET 3-methyl-substituted fluorenyl benzoate (2-Flr-3-Me-BzO–)....
Supporting ligands limit the degree of electrophilic activation for any substrate because they also reduce Lewis acidity transition metal ion. Here, we temporarily mask dicationic Pd(II) by using "shapeshifting" bidentate pyrimidine/olefin L1 and L2. These delocalize/relocalize charge via reversible C–N bond formation. So, although ligated Pd compounds [1]2+ [2]2+ appear separated (distributed across ligand), react comparably to a solvated dication. Despite reacting like strong acids,...