Publications

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Volume 6, Issue 1, (January – February 2017)

Quantitative Structure-Activity Relationship Analysis of the Anti-tyrosine Activity of Some Tetraketone and Benzyl-benzoate Derivatives Based on Genetic Algorithm-Multiple Linear Regression

Original Research

Journal of Chemistry and Materials Research Vol. 6 (1), 2017, 2–12

Emmanuel Israel Edache*, David Ebuka Arthur and Usman Abdulfatai

 

Abstract

A QSAR study is performed on the seriestetraketone and benzyl benzoate derivatives in order to analyze the physicochemical requirements of tyrosinase inhibitors and to provide structural insight into the binding mode of the molecules to the enzyme. All the derivatives in the series were sketched using ChemDraw ultra v12.0.2 module of ChemOffice 2010 and the sketched structures were consequently used for the calculation of molecular descriptors available in QSAR software Spartan’14 and PaDEL-Descriptors software. Quantum, constitutional and topological descriptors for all molecules were calculated using Spartan’14 v1.1.2, 2013 and PaDEL-Descriptors software v2.20, 2011 and correlation between the biological activity and molecular descriptors was found through genetic function approximation adopted by statistical program material studio v7.0. The generated QSAR models revealed that ATS0s, AATS6p, ATSC1i, SpMAD_Dzv and VR1_Dze descriptors have good correlation to the anti-tyrosinase activity. The results obtained by regression analysis indicated that ATSC1i and SpMAD_Dzv is negatively contributing to inhibitory activity thus; enhancement of anti-tyrosinase activity can be achieved by decreasing the respective descriptors. Positive contribution of ATS0s, AATS6p, and VR1_Dze specifies that increase of Average Broto-Moreau autocorrelation - lag 6 / weighted by polarizabilities, Average Broto-Moreau autocorrelation - lag 6 / weighted by polarizabilities and Randic-like eigenvector-based index from Barysz matrix / weighted by Sanderson electronegativities will impart positive influence on the activity.

 

Keywords: Tyrosinase; Tetraketone and benzyl benzoate; Semi-empirical (PM6); GFA-MLR; QSAR; Applicability Domain

Received

Received in revised
  Accepted
02 October 2016
  19 October 2016
10 January 2017
 

Quantum chemical sustainability assessment of Oxygen-containing Carbon Cluster Compounds with Alkali Metals Cations

Original Research

Journal of Chemistry and Materials Research Vol. 6 (1), 2017, 13–15

Sagim Suleymanov*, Jannet Sveshnikova, Ahmed Amirov, Rashid Dallaev

 

Abstract

In this paper, the authors presented first results on the theoretically studying of adsorption of alkali metal cations on the surface of activated carbons with approximation of a cluster model. The evaluation of oxygen-containing carbon cluster compounds stability with cations of alkali metals has been carried out according to quantum chemical calculations of semi-empirical MNDO.

 

Keywords: Activated carbon; Oxygen-containing carbon cluster; Quantum-chemical calculation.

Received
Accepted
18 January 2017
22 February 2017
 

Study of Quenching Gases effect in the environmental scanning electron microscope (ESEM)

Original Research

Journal of Chemistry and Materials Research Vol. 6 (1), 2017, 16–21

Souhila Zebbar*, Abd-Ed-Daim Kadoun, Djallel Zebbar, Omar Mansour

 

 

Abstract

The gaseous secondary electron detector operates mainly due to the gas composition and evenly to detector's geometry. Nevertheless, the detector efficiency optimization is subjected to many inherent constraints. The most significant one is related to the use of the same gas in ESEM as gas environment inside the specimen chamber and for the signal detection (amplification). To overcome the above-mentioned constraint, a proposal is made in this paper to use argon and carbon dioxide as quenchers with helium to prevent secondary effects and get a stable gas gain.  For this purpose, a Monte Carlo code was elaborated and used to calculate the electron beam skirt. It shows that electronic amplification in the (95%He-5%Ar) mixture is better than in case of pure helium and (95% He-5%CO2) mixture. Moreover, the skirt effect is reduced in (95%He-5%CO2) mixture under pressure of 1 to 3 Torr. Finally, an observed increase of ionization process gives a good contrast in imaging since the signal to noise remains high.

 

Keywords: Quenching; GSED; ESEM ;gas mixture.

Received
 Accepted
17 December 2016
22 February 2017
 

Ground state lithium cation affinities (LCA) and associate parameters of a series of α,β-unsaturated carbonyl compounds of type-2-alkene chemical class: A DFT study

Original Research

Journal of Chemistry and Materials Research Vol. 6 (1), 2017, 22–30

Biswarup Mandal*, Umasankar Senapati, Bhudeb Ranjan De

 

 

Abstract

A DFT [B3LYP] /6-311G(d, p) calculations were performed to evaluate the lithium cation affinities (LCA) for a set of  α, β-unsaturated carbonyl derivatives of type-2-alkene chemical class (acrolien, 4-hydroxy-2-nonenal, methyl vinyl ketone, acrylamide, methyl acrylate and ethylmethacryalate). The interaction energies were calculated to quantify the affinity of the bases for the Li+ cation. LCA values are influenced by the electronic nature of the alkyl chain adjacent to the carbonyl carbon and also different substituent at functional carbon. Lithium cation basicitiy (LCB = –∆GLi+), change of entropy (∆S) during complexation in each compound has been analysed systematically. Acrylamide exhibit the highest LCA value in gas phase as well as in aqueous phase relative to other bases in the series.  Complete geometry optimization both before and after Li+ complex formation were performed in both phases. Geometric and electronic parameters were correlated with the strength of the metal-ligand interaction. Net charges on the atoms of free bases and their O-Li+ complexes are evaluated by natural population analysis (NPA) and Mulliken population analysis. The energetic, structural and electronic properties of the complexes indicate that the interaction between the Li+ ion and a carbonyl base is preferably an electrostatic interaction as well rather than a covalent interaction. The overall reactivity is explained by entire molecular contribution in addition to the contribution from the carbonyl group.

 

Keywords: DFT, Gas phase, aqueous phase, LCA, LCB.

Received
 Accepted
18 December 2017
28 February 2017