Chemistry Journal of Moldova

Physical chemistry and chemical physics

OXAZIRIDINE (C-CH3NO), C-CH2NO RADICALS AND CL, NH2 AND METHYL DERIVATIVES OF OXAZIRIDINE; STRUCTURES AND QUANTUM CHEMICAL PARAMETERS (Supplementary material)

Author(s):

Mohammad Taghi Taghizadeh, Morteza Vatanparast, Saeed Nasirianfar


Field: Physical chemistry and chemical physics
Type:
Issue: 2015 Volume 10, no.2
Pages: 99-108
Keywords: oxaziridine, DFT, Fukui function, vertical ionization energy, adiabatic ionization energy.
Full Text (PDF): Download
Graphical Abstract: Supplementary material contains Tables S1 to S9 and Figures S1 to S4.

Downloads: 38

AN INVESTIGATION OF THE PROTONATION STATES OF HUMAN LACTOFERRIN IRON-BINDING PROTEIN

Author(s):

Lilia Anghel


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 71-75
Keywords: lactoferrin, ionizable residues, protonation, continuum electrostatics.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).10

Graphical Abstract:
 In this study, the protonation states of ionizable groups of human lactoferrin in various conformations were investigated theoretically, at physiological pH (7.365). These calculations show that the transition of the protein from a conformation to another one is accompanied by changes in the protonation state of specific amino acid residues. 

Downloads: 59

OXIDATION AND CHARACTERIZATION OF ACTIVE CARBON AG-5

Author(s):

Tatiana Goreacioc


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 76-83
Keywords: active carbon, oxidation, surface properties, thermal analysis, infrared spectroscopy.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).11

Graphical Abstract:  
The surface chemistry of the commercial active carbon AG-5 has been modified by oxidation with concentrated nitric acid. The structural changes caused by oxidative treatment were estimated on the basis of nitrogen adsorption-desorption isotherms and thermal analysis. Boehm titration method and infrared spectral analysis have been used in order to evaluate surface chemistry characteristics of active carbon samples.

Downloads: 48

TEMPERATURE DEPENDENCE OF 57Fe-MÖSSBAUER SPECTRA FOR A TRINUCLEAR SYSTEM

Author(s):

Dumitru Sirbu


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 84-88
Keywords: ferrocene, terpyridine, Mӧssbauer, Debye temperature.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).12

Graphical Abstract:
 57Fe Mӧssbauer spectra were recorded for 1'-terpyridine ferrocenecarboxylic acid and [bis(1'-terpyridine ferrocenecarboxylic acid) Fe(II)]2+ in the temperature range 7 – 293 K. The temperature dependence of the Quadrupole Splitting, Isomer Shift and Debye-Waller factor are discussed. The Debye temperature, θD, for the iron nuclei in the investigated compounds was determined.

Downloads: 68

ANTIOXIDANT PROPERTIES OF DIHYDROXYFUMARIC ACID AND ITS DIMETHYL ETHER: A COMPARATIVE DFT STUDY OF THEIR REACTIONS WITH THE STABLE RADICAL DPPH*

Author(s):

Mikhail Gorbachev, Natalia Gorinchoy, Ion Arsene


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 89-94
Keywords: antioxidant activity, DPPH*, dihydroxyfumaric acid, dimethyl ether of dihydroxyfumaric acid, DFT calculations.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).13

Graphical Abstract:
 The preferred mechanism of the reaction of dihydroxyfumaric acid and its dimethyl ether with the free stable radical 1,1-diphenyl-2-picrylhydrazyl (DPPH*) was revealed by means of Density Functional Theory (DFT) calculations. The proposed mechanism has an ionic character and includes the formation of charge-transfer complexes as the main stage. It is also shown that the lower antioxidant activity of dimethyl ether of dihydroxyfumaric acid is caused by both its lower acidity (as compared with its precursor acid) and formation of more stable intermediates during its reaction with DPPH*. Our results allow one to rationalize the available experimental data.

Downloads: 44

APPLICATION OF TAGUCHI OPTIMIZATION METHOD IN THE PREPARATION OF ACTIVATED CARBON BY MICROWAVE TREATMENT

Author(s):

Oleg Petuhov


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 95-103
Keywords: activated carbon, walnut shells, microwave radiation, experimental design, analysis of variance.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).14

Graphical Abstract: 
This paper reports on the preparation of activated carbon from walnut shell. Orthogonal array experimental design method was used to optimize the preparation of activated carbon with phosphoric acid by using microwave treatment. The optimization parameters were: microwave power, activation time, phosphoric acid concentration and particle sizes of nut shells. Thermal analysis of the intact and impregnated with phosphoric acid walnut shells was used for the simulation of activation process. Activated carbon with the optimal parameters was obtained, being characterized by gas adsorption method and scanning electron microscopy.

 

Downloads: 46

TOWARDS SCREENING THE ENHANCE OF LUMINESCENCE PROPERTIES OF MODIFIED TANNINS IN ALKALINE SOLUTION BY A FENTON-LIKE REACTION

Author(s):

Alexandru Gonta


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2015 Volume 10, no.1
Pages: 104-112
Keywords: oxidation, tannins, free radical, chemiluminescence.
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2015.10(1).15

Graphical Abstract:
 After modification of enotannins, flavonols monomer units could be obtained with polyfunctional properties. Moreover, polyphenols are known to generate H2O2 and other ROS under alkaline conditions. ROS generation and catalytic influence of ferrous ions enhance the chemiluminescence light. Therefore in this work, Tox/Tris-Edta/Fe2+ ions have been used for screening luminescent properties of oxidized tannins.


Downloads: 58

POLYMER NANOCOMPOSITE BASED ON STYRENE WITH BUTYL METHACRYLATE AND INORGANIC SEMICONDUCTOR CdS

Author(s):

Mihail Iovu, Marius Enachescu, Ion Culeac, Victor Verlan, Stefan Robu, Dionezie Bojin, Iurie Nistor, Ion Cojocaru


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 74-79
Keywords: nanocomposite, polymer matrix, photoluminescence, exciton
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2014.09(2).11

Graphical Abstract:
 We present experimental results on copolymer-based nanocomposite made of styrene with butyl methacrylate (1:1) and inorganic semiconductor CdS. Thin film composite samples have been characterized by UV-Vis absorption and photoluminescent spectroscopy, as well as by transmission electron microscopy.

Downloads: 48

ELECTRONIC CONTROL OF MOLECULAR CONFIGURATION INSTABILITY VIA VIBRONIC COUPLING. PSEUDO JAHN-TELLER STABILIZATION OF VERTICALLY EXCITED STATES OF F2CO, N2H2 AND H2C2O MOLECULES

Author(s):

Natalia Gorinchoy


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 80-89
Keywords: Pseudo Jahn-Teller effect, stereochemistry, excited states, carbonyl fluoride, diazene, ketene
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2014.09(2).12

Graphical Abstract:
 The pseudo Jahn-Teller effect is employed to explane the origin of structural distortions of carbonyl fluoride, diazene and ketene molecules in the lowest singlet and triplet excited states. It was shown that in all the cases the distortions of the molecules in the excited states are due to the vibronic mixing of considered states with the appropriate by symmetry higher-lying excited states.



Downloads: 30

IODIDE IONS SORPTION ON POLYMER AV-17(Cl) AND SORBENT AV-17(Bi)

Author(s):

Vasile Gutsanu


Field: Physical chemistry and chemical physics
Type: Research paper
Issue: 2014 Volume 9, no.2
Pages: 90-98
Keywords: strongly basic anion exchanger, iodide ions, sorption, Bi(III) compounds
Full Text (PDF): Download
Abstract (PDF)

DOI:
dx.doi.org/10.19261/cjm.2014.09(2).13

Graphical Abstract:
 The iodide ions sorption from solutions of KI and KI in excess of KCl has been investigated. The strongly basic anion exchangers AV-17 in Cl- form and Varion AD in NO3- form were used as sorbents. Also AV-17 polymer modified with Bi(III)-containing compounds were used. The sorption was performed in static and dynamic conditions. Isotherms are approximated with BET sorption model. The sorption value of iodide ions in the KI solutions with KCl in excess is quite high. It was established that sorption of iodide ions in the form of polyiodide occurs both as a result of anion exchange and as a result of chemisorption.


Downloads: 28