Insight into 6-aminopenicillanic acid structure and study of the quantum mechanical calculations of the acid–base site on γ-Fe2O3@SiO2 core–shell nanocomposites and as efficient catalysts in multicomponent reactions

2020 ◽  
Vol 44 (47) ◽  
pp. 20688-20696
Author(s):  
Farveh Saberi ◽  
Somayeh Ostovar ◽  
Roya Behazin ◽  
Alireza Rezvani ◽  
Ali Ebrahimi ◽  
...  
Keyword(s):  
Multicomponent Reactions ◽  
Quantum Mechanical ◽  
Core Shell ◽  
Quantum Mechanical Calculations ◽  
Acid Base ◽  
Base Site ◽  
Insight Into ◽  
Acid Structure

Magnetic 6-APA/γ-Fe2O3@Sio2 nanocomposites have been developed by exploiting the potential of the acid–base bifunctional system to study the quantum mechanistic calculations.

The acidity of β-phosphoglucomutase monofluoromethylenephosphonate ligands probed by NMR spectroscopy and quantum mechanical methods

2016 ◽  
Vol 94 (11) ◽  
pp. 902-908 ◽  
Author(s):  
Stephanie M. Forget ◽  
Eric A.C. Bushnell ◽  
Russell J. Boyd ◽  
David L. Jakeman
Keyword(s):  
Nmr Spectroscopy ◽  
Transition State ◽  
Quantum Mechanical ◽  
Phosphoryl Transfer ◽  
Quantum Mechanical Calculations ◽  
Transition State Analogues ◽  
Mechanical Methods ◽  
Insight Into ◽  
Computational Quantum

We recently described the binding of 1-β-phosphonomethylene-1-deoxy-d-glucopyranose, (S)-1-β-phosphonofluoromethylene-1-deoxy-D-glucopyranose (βG1CFSP), and (R)-1-β-phosphonofluoromethylene-1-deoxy-d-glucopyranose (βG1CFRP) to the enzyme β-phosphoglucomutase as transition state analogues of phosphoryl transfer through formation of stable MgF3− and AlF4− complexes (Proc. Natl. Acad. Sci. U.S.A. 2014, 111, 12384). Herein, we describe in detail the five-fold difference in acidity (pKa2) for the (S)- and (R)-configured diastereomeric fluorophosphonates through a series of NMR spectroscopy experiments. The differences in acidity were corroborated using computational quantum mechanical calculations to determine structures of lowest energy conformers and provide insight into why the (S) isomer is substantially more acidic.

scholarly journals Substituent and structural effects on the kinetics of the reaction of N-(substituted phenylmethylene)-m- and -p-aminobenzoic acids with diazodiphenylmethane

2007 ◽  
Vol 72 (12) ◽  
pp. 1191-1200 ◽  
Author(s):  
Bratislav Jovanovic ◽  
Aleksandar Marinkovic ◽  
Zeljko Vitnik ◽  
Ivan Juranic
Keyword(s):  
Molecular Structure ◽  
Rate Constants ◽  
Experimental Results ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Structural Effects ◽  
Electronic Effects ◽  
Aminobenzoic Acids ◽  
Kinetics Of ◽  
Insight Into

The rate constants for the reaction of twenty-two N-(substituted phenylmethylene)- m- and -p-aminobenzoic acids with diazodiphenylmethane were determined in absolute ethanol at 30 ?C. The effects of substituents on the reactivity of the investigated compounds were interpreted by correlation of the rate constants with LFER equations. The results of quantum mechanical calculations of the molecular structure together with experimental results gave a better insight into the effects of structure on the transmission of electronic effects of the substituents. New ? constants for substituted benzylideneamino group were calculated.

Insight into conformationally-dependent binding of 1-n-alkyl-3-methylimidazolium cations to porphyrin molecules using quantum mechanical calculations

2019 ◽  
Vol 21 (19) ◽  
pp. 10095-10104 ◽  
Author(s):  
Atiya Banerjee ◽  
Jindal K. Shah
Keyword(s):  
Ionic Liquid ◽  
Cytochrome P450 ◽  
Ionic Liquids ◽  
Binding Energies ◽  
Side Chain ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Alkyl Side Chain ◽  
Catalytic Center ◽  
Insight Into

The first step in the biodegradation of imidazolium-based ionic liquids involves the insertion of the –OH group into the alkyl side chain, and it is believed to be triggered by cytochrome P450. In this work, we investigate the effect of conformations on binding energies of ionic liquid cations to the catalytic center of P450.

scholarly journals Structure and Function of NzeB, a Versatile C–C and C–N Bond Forming Diketopiperazine Dimerase

2020 ◽  
Author(s):  
Vikram V. Shende ◽  
Yogan Khatri ◽  
Sean A. Newmister ◽  
Jacob N. Sanders ◽  
Petra Lindovska ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cytochrome P450 ◽  
Active Site ◽  
Structure And Function ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Bond Forming ◽  
And Function ◽  
Insight Into

This report details the discovery and characterization of a versatile bacterial cytochrome P450, NzeB, which catalyzes the dimerization of diketopiperazines via enzymatic C–H functionalization. This includes the first high-resolution crystal structure of a diketopiperazine dimerase, which along with active site via mutagenesis and quantum mechanical calculations, provides insight into the selectivity and mechanism of these enzymes.

Structure and Function of NzeB, a Versatile C–C and C–N Bond Forming Diketopiperazine Dimerase

2020 ◽  
Author(s):  
Vikram V. Shende ◽  
Yogan Khatri ◽  
Sean A. Newmister ◽  
Jacob N. Sanders ◽  
Petra Lindovska ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cytochrome P450 ◽  
Active Site ◽  
Structure And Function ◽  
Quantum Mechanical ◽  
Quantum Mechanical Calculations ◽  
Bond Forming ◽  
And Function ◽  
Insight Into

This report details the discovery and characterization of a versatile bacterial cytochrome P450, NzeB, which catalyzes the dimerization of diketopiperazines via enzymatic C–H functionalization. This includes the first high-resolution crystal structure of a diketopiperazine dimerase, which along with active site via mutagenesis and quantum mechanical calculations, provides insight into the selectivity and mechanism of these enzymes.

Quantum mechanical calculations of the interactions between diazacrowns and the sodium cation: an insight into Na+ complexation in diazacrown-based synthetic ion channels

RSC Advances ◽  
2015 ◽  
Vol 5 (68) ◽  
pp. 55033-55047 ◽  
Author(s):  
A. A. Skelton ◽  
N. Agrawal ◽  
J. R. Fried
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Sodium Cation ◽  
Quantum Mechanical ◽  
Conformational Behavior ◽  
Quantum Mechanical Calculations ◽  
Functional Theory ◽  
Synthetic Ion Channels ◽  
Moller Plesset ◽  
Insight Into

Quantum mechanical calculations were performed to study the conformational behavior and complexation between a sodium cation and a diazacrown (diaza-18-crown-6) using density functional theory (DFT), Møller–Plesset (MP2) and molecular mechanics methods.

Quantum Mechanical Interpretation of the Ultra-Low Energy Methyl-Rotation Dynamics in Porous Metal-Organic Frameworks Probed by Low-Frequency Vibrational Spectroscopy and ab initio Simulations

2018 ◽  
Author(s):  
Qi Li ◽  
Adam J. Zaczek ◽  
Timothy M. Korter ◽  
J. Axel Zeitler ◽  
Michael T. Ruggiero
Keyword(s):  
Ab Initio ◽  
Metal Organic Frameworks ◽  
Low Frequency ◽  
Rotor Dynamics ◽  
Quantum Mechanical ◽  
Valuable Insight ◽  
Void Space ◽  
Ab Initio Simulations ◽  
Metal Organic ◽  
Insight Into

<div>Understanding the nature of the interatomic interactions present within the pores of metal-organic frameworks</div><div>is critical in order to design and utilize advanced materials</div><div>with desirable applications. In ZIF-8 and its cobalt analogue</div><div>ZIF-67, the imidazolate methyl-groups, which point directly</div><div>into the void space, have been shown to freely rotate - even</div><div>down to cryogenic temperatures. Using a combination of ex-</div><div>perimental terahertz time-domain spectroscopy, low-frequency</div><div>Raman spectroscopy, and state-of-the-art ab initio simulations,</div><div>the methyl-rotor dynamics in ZIF-8 and ZIF-67 are fully charac-</div><div>terized within the context of a quantum-mechanical hindered-</div><div>rotor model. The results lend insight into the fundamental</div><div>origins of the experimentally observed methyl-rotor dynamics,</div><div>and provide valuable insight into the nature of the weak inter-</div><div>actions present within this important class of materials.</div>

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