PMMA – C60 composite: thermal decomposition experiments in mass spectrometer and quantum chemical modeling

Mass-spectrometric thermal decomposition experiments with submicron films of neat polymethylmethacrylate (PMMA), and PMMA-fullerene composite (PMMA-C60) after UV irradiation are discussed. The experiment registers thermal desorption mass spectra (TDMS), that is the monomer desorption rate versus time upon gradual heating the PMMA films in a given heating regime. The spectra provide information on the amount of the monomer desorbed at different decomposition stages upon heating the given amount of film material as well as on the spectral shape changes. It is shown that both amount of monomer and the TDMS spectral shape are sensitive to the presence of fullerene and UV irradiation. The experimental results are discussed in terms of quantum chemical models of binding. The DFT/B3LYP-D3/def2/J RIJCOSX level of theory was used. The MMA-C60 structures which can yield different amounts of monomer have been compared.

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Thermal decomposition mechanism of dimethyl(acetylacetonato)gold(III): Quantum chemical modeling

Kinetics and Catalysis ◽

10.1134/s0023158414030100 ◽

2014 ◽

Vol 55 (4) ◽

pp. 401-408 ◽

Cited By ~ 1

Author(s):

N. G. Nikitenko ◽

A. F. Shestakov

Keyword(s):

Thermal Decomposition ◽

Quantum Chemical ◽

Decomposition Mechanism ◽

Quantum Chemical Modeling ◽

Thermal Decomposition Mechanism ◽

Chemical Modeling

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Quantum chemical modeling of the olefin oxidation in the triplet state

10.3390/ecsoc-19-e006 ◽

2015 ◽

Author(s):

Sergey Plehovitch ◽

Yuri Minasyan ◽

Sergei Zelentsov

Keyword(s):

Triplet State ◽

Quantum Chemical ◽

Quantum Chemical Modeling ◽

Chemical Modeling ◽

Olefin Oxidation

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Prebiotic Route to Thymine from Formamide—A Combined Experimental–Theoretical Study

Molecules ◽

10.3390/molecules26082248 ◽

2021 ◽

Vol 26 (8) ◽

pp. 2248

Author(s):

Lukáš Petera ◽

Klaudia Mrazikova ◽

Lukas Nejdl ◽

Kristyna Zemankova ◽

Marketa Vaculovicova ◽

...

Keyword(s):

Formic Acid ◽

Quantum Chemical ◽

Prebiotic Chemistry ◽

Theoretical Study ◽

Reaction Pathway ◽

Hydrolysis Product ◽

Current Paper ◽

Reaction Conditions ◽

Chemical Modeling ◽

Chemistry Research

Synthesis of RNA nucleobases from formamide is one of the recurring topics of prebiotic chemistry research. Earlier reports suggest that thymine, the substitute for uracil in DNA, may also be synthesized from formamide in the presence of catalysts enabling conversion of formamide to formaldehyde. In the current paper, we show that to a lesser extent conversion of uracil to thymine may occur even in the absence of catalysts. This is enabled by the presence of formic acid in the reaction mixture that forms as the hydrolysis product of formamide. Under the reaction conditions of our study, the disproportionation of formic acid may produce formaldehyde that hydroxymethylates uracil in the first step of the conversion process. The experiments are supplemented by quantum chemical modeling of the reaction pathway, supporting the plausibility of the mechanism suggested by Saladino and coworkers.

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Quantum Chemical Studies and Electrochemical Investigations of Polymerized Brilliant Blue-Modified Carbon Paste Electrode for In Vitro Sensing of Pharmaceutical Samples

Chemosensors ◽

10.3390/chemosensors9060135 ◽

2021 ◽

Vol 9 (6) ◽

pp. 135

Author(s):

Pattan-Siddappa Ganesh ◽

Sang-Youn Kim ◽

Savas Kaya ◽

Rajae Salim ◽

Ganesh Shimoga ◽

...

Keyword(s):

Electrochemical Sensor ◽

Carbon Paste Electrode ◽

Quantum Chemical ◽

Electrochemical Sensing ◽

Quantum Chemical Modeling ◽

Brilliant Blue ◽

Carbon Paste ◽

Chemical Modeling ◽

The Real ◽

Paste Electrode

To develop an electrochemical sensor for electroactive molecules, the choice and prediction of redox reactive sites of the modifier play a critical role in establishing the sensing mediating mechanism. Therefore, to understand the mediating mechanism of the modifier, we used advanced density functional theory (DFT)-based quantum chemical modeling. A carbon paste electrode (CPE) was modified with electropolymerization of brilliant blue, later employed for the detection of paracetamol (PA) and folic acid (FA). PA is an analgesic, anti-inflammatory and antipyretic prescription commonly used in medical fields, and overdose or prolonged use may harm the liver and kidney. The deficiency of FA associated with neural tube defects (NTDs) and therefore the quantification of FA are very essential to prevent the problems associated with congenital deformities of the spinal column, skull and brain of the fetus in pregnant women. Hence, an electrochemical sensor based on a polymerized brilliant blue-modified carbon paste working electrode (BRB/CPE) was fabricated for the quantification of PA and FA in physiological pH. The real analytical applicability of the proposed sensor was judged by employing it in analysis of a pharmaceutical sample, and good recovery results were obtained. The potential excipients do not have a significant contribution to the electro-oxidation of PA at BRB/CPE, which makes it a promising electrochemical sensing platform. The real analytical applicability of the proposed method is valid for pharmaceutical analysis in the presence of possible excipients. The prediction of redox reactive sites of the modifier by advanced quantum chemical modeling-based DFT may lay a new foundation for researchers to establish the modifier–analyte interaction mechanisms.

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