Ground and excited state CASPT2 geometry optimizations of small organic molecules

2003 ◽  
Vol 24 (3) ◽  
pp. 298-309 ◽  
Author(s):  
Christopher S. Page ◽  
Massimo Olivucci
Keyword(s):  
Excited State ◽  
Organic Molecules ◽  
Small Organic Molecules

scholarly journals Hole-Mediated PhotoRedox Catalysis: Tris(p-Substituted)biarylaminium Radical Cations as Tunable, Precomplexing and Potent Photooxidants

2020 ◽  
Author(s):  
Shangze Wu ◽  
Jonas Zurauskas ◽  
Michal Domanski ◽  
Patrick Hitzfeld ◽  
Valeria Butera ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Excited State ◽  
Excited States ◽  
Organic Molecules ◽  
Radical Cations ◽  
Single Electron Transfer ◽  
Photoredox Catalysis ◽  
Small Organic Molecules ◽  
Fundamental Limitations ◽  
Ion Species

<p>Electrochemically-mediated Photoredox Catalysis emerged as a powerful synthetic technique in recent years, overcoming fundamental limitations of electrochemistry and photoredox catalysis in the single electron transfer activation of small organic molecules. However, the mechanism of how photoexcited radical ion species with ultrashort (picosecond-order) lifetimes could ever undergo productive photochemistry has eluded synthetic chemists. We report tri(<i>para</i>-substituted)biarylamines as a tunable class of electroactivated photocatalysts that become superoxidants in their photoexcited states, even able to oxidize molecules (such as dichlorobenzene and trifluorotoluene) beyond the solvent window limits of cyclic voltammetry. Furthermore, we demonstrate that precomplexation not only permits the excited state photochemistry of tris(<i>para</i>-substituted)biarylaminium cations, but enables and rationalizes the surprising photochemistry of their <i>higher-order</i> doublet (D<i><sub>n</sub></i>) excited states.</p>

scholarly journals Hole-Mediated PhotoRedox Catalysis: Tris(p-Substituted)biarylaminium Radical Cations as Tunable, Precomplexing and Potent Photooxidants

2020 ◽  
Author(s):  
Shangze Wu ◽  
Jonas Zurauskas ◽  
Michal Domanski ◽  
Patrick Hitzfeld ◽  
Valeria Butera ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Excited State ◽  
Excited States ◽  
Organic Molecules ◽  
Radical Cations ◽  
Single Electron Transfer ◽  
Photoredox Catalysis ◽  
Small Organic Molecules ◽  
Fundamental Limitations ◽  
Ion Species

<p>Electrochemically-mediated Photoredox Catalysis emerged as a powerful synthetic technique in recent years, overcoming fundamental limitations of electrochemistry and photoredox catalysis in the single electron transfer activation of small organic molecules. However, the mechanism of how photoexcited radical ion species with ultrashort (picosecond-order) lifetimes could ever undergo productive photochemistry has eluded synthetic chemists. We report tri(<i>para</i>-substituted)biarylamines as a tunable class of electroactivated photocatalysts that become superoxidants in their photoexcited states, even able to oxidize molecules (such as dichlorobenzene and trifluorotoluene) beyond the solvent window limits of cyclic voltammetry. Furthermore, we demonstrate that precomplexation not only permits the excited state photochemistry of tris(<i>para</i>-substituted)biarylaminium cations, but enables and rationalizes the surprising photochemistry of their <i>higher-order</i> doublet (D<i><sub>n</sub></i>) excited states.</p>

QUBEKit: Automating the Derivation of Force Field Parameters from Quantum Mechanics

2019 ◽  
Author(s):  
Joshua Horton ◽  
Alice Allen ◽  
Leela Dodda ◽  
Daniel Cole
Keyword(s):  
Quantum Mechanics ◽  
Force Field ◽  
Organic Molecules ◽  
Force Fields ◽  
Liquid Density ◽  
Small Organic Molecules ◽  
Automated Generation ◽  
Energy Of Hydration ◽  
Novel Method ◽  
Force Field Parameters

<div><div><div><p>Modern molecular mechanics force fields are widely used for modelling the dynamics and interactions of small organic molecules using libraries of transferable force field parameters. For molecules outside the training set, parameters may be missing or inaccurate, and in these cases, it may be preferable to derive molecule-specific parameters. Here we present an intuitive parameter derivation toolkit, QUBEKit (QUantum mechanical BEspoke Kit), which enables the automated generation of system-specific small molecule force field parameters directly from quantum mechanics. QUBEKit is written in python and combines the latest QM parameter derivation methodologies with a novel method for deriving the positions and charges of off-center virtual sites. As a proof of concept, we have re-derived a complete set of parameters for 109 small organic molecules, and assessed the accuracy by comparing computed liquid properties with experiment. QUBEKit gives highly competitive results when compared to standard transferable force fields, with mean unsigned errors of 0.024 g/cm3, 0.79 kcal/mol and 1.17 kcal/mol for the liquid density, heat of vaporization and free energy of hydration respectively. This indicates that the derived parameters are suitable for molecular modelling applications, including computer-aided drug design.</p></div></div></div>

QUBEKit: Automating the Derivation of Force Field Parameters from Quantum Mechanics

2019 ◽  
Author(s):  
Joshua Horton ◽  
Alice Allen ◽  
Leela Dodda ◽  
Daniel Cole
Keyword(s):  
Quantum Mechanics ◽  
Force Field ◽  
Organic Molecules ◽  
Force Fields ◽  
Liquid Density ◽  
Small Organic Molecules ◽  
Automated Generation ◽  
Energy Of Hydration ◽  
Novel Method ◽  
Force Field Parameters

<div><div><div><p>Modern molecular mechanics force fields are widely used for modelling the dynamics and interactions of small organic molecules using libraries of transferable force field parameters. For molecules outside the training set, parameters may be missing or inaccurate, and in these cases, it may be preferable to derive molecule-specific parameters. Here we present an intuitive parameter derivation toolkit, QUBEKit (QUantum mechanical BEspoke Kit), which enables the automated generation of system-specific small molecule force field parameters directly from quantum mechanics. QUBEKit is written in python and combines the latest QM parameter derivation methodologies with a novel method for deriving the positions and charges of off-center virtual sites. As a proof of concept, we have re-derived a complete set of parameters for 109 small organic molecules, and assessed the accuracy by comparing computed liquid properties with experiment. QUBEKit gives highly competitive results when compared to standard transferable force fields, with mean unsigned errors of 0.024 g/cm3, 0.79 kcal/mol and 1.17 kcal/mol for the liquid density, heat of vaporization and free energy of hydration respectively. This indicates that the derived parameters are suitable for molecular modelling applications, including computer-aided drug design.</p></div></div></div>

scholarly journals Interaction Mechanisms between Lithium Polysulfides/Sulfide and Small Organic Molecules

ACS Omega ◽  
2021 ◽  
Vol 6 (7) ◽  
pp. 4995-5000 ◽  
Author(s):  
Jiaxiang Zhang ◽  
Junwen Yang ◽  
Ziyue Liu ◽  
Bin Zheng
Keyword(s):  
Organic Molecules ◽  
Small Organic Molecules ◽  
Interaction Mechanisms

Dual functioning porous catalysts: Robust electro-oxidation of small organic molecules and water electrolysis at bimetallic Ni/Cu foam

2021 ◽  
Author(s):  
Mohamed R. Rizk ◽  
Muhammad G. Gamal ◽  
Amina Mazhar ◽  
Mohamed El-Deab ◽  
Bahgat El-Anadouli
Keyword(s):  
Thin Layer ◽  
Organic Molecules ◽  
Water Electrolysis ◽  
Single Step ◽  
Hydrogen Bubble ◽  
Small Organic Molecules ◽  
Porous Catalysts ◽  
Electro Oxidation ◽  
Bubble Template ◽  
Cu Foam

In this work, we report a single-step preparation of porous Ni-based foams thin layer atop Cu substrate via a facile dynamic hydrogen bubble template technique (DHBT). The prepared porous Ni-based...

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