scholarly journals THEORETICAL STUDY OF THE EFFECT OF WATER MOLECULE ADDITION ON THE CONFORMATION OF SUBSTITUTED DIBENZO-18-CROWN-6 ETHER IN ITS COMPLEXATION WITH Na+ CATION USING SEMI EMPIRICAL METHOD MNDO/d

2010 ◽  
Vol 3 (2) ◽  
pp. 111-117
Author(s):  
Harno Dwi Pranowo ◽  
Tuti Hartati Siregar ◽  
Mudasir Mudasir
Keyword(s):  
Binding Energy ◽  
Water Molecule ◽  
Metal Ion ◽  
Geometry Optimization ◽  
Semiempirical Method ◽  
Empirical Method ◽  
Trial And Error ◽  
Effect Of Water ◽  
The Stability ◽  
Semi Empirical

The effect of water molecule addition into modeling structure of complex of substituted dibenzo-18-crown-6 ether with metal ion Na+ was studied. The aim of this research is to find information about geometrical conformation of substituted DB18C6 and its selectivity to complex/coordinate metal ion Na+ in the presence of water molecule. In this research semi empirical method was used for calculation. To find the best conformation, trial and error experiments were conducted using semi empirical method available in HyperChem 6.0, finally MNDO/d method was selected. The result of geometry optimization showed that addition of water molecule improve the stability of the conformation of substituted DB18C6 and increase the selectivity of this compound to complex metal ion Na+. The presence of electron-withdrawing substituents decreased the binding energy while that of electron-donating one increase the binding energy (value of DE more negative). Cavity radii of DB18C6 in the presence of water molecule extended from 2.3 Å to 2.6 Å. This figure is almost similar to that of experimental data.   Keywords: Crown ether, molecular modelling, semiempirical method

scholarly journals INTERACTION BETWEEN Li+ CATION WITH CROWN ETHERS OF Bz15C5, DBz16C5 AND DBz18C6: MOLECULAR MODELING BASE ON MNDO/d SEMIEMPIRICAL METHOD

2010 ◽  
Vol 3 (1) ◽  
pp. 55-66
Author(s):  
Harno Dwi Pranowo ◽  
Chairil Anwar
Keyword(s):  
Binding Energy ◽  
Crown Ether ◽  
Crown Ethers ◽  
Metal Cation ◽  
Geometry Optimization ◽  
Semiempirical Method ◽  
Ionic Radii ◽  
Cation Selectivity ◽  
Structural Match ◽  
Semi Empirical

The aim of this research is to find information about the substituent effect to the structure of crown ether benzo-15-crown-5 (Bz15C5), dibenzo-16-crown-5 (DBz16C5) and dibenzo-18-crown-6 (DBz18C6), and also crown ether selectivity to coordinate a Li+ metal cation. The presence of substituent could change the conformations flexibility of crown ether during interact with metal cation. In this research semi empirical MNDO/d method was used for calculations. Firstly, geometry optimization was conducted to crown ethers structure using MNDO/d methods. The next steps were running the geometry optimization of complexes between cation Li+ with crown ethers. Data were produced from these calculation are the parameter of crown ether structures, structures of the complexes, and the binding energy of the cation-crown ethers. The presence of electron-withdrawing substituents decreased the binding energy while that of electron-donating one increase the binding energy (value of ΔE more negative). The substituents which are increase the degree of symmetry of the cation-crown ether complexes could give the increase of crown ether selectivity to bind the cation. Selectivity of crown ether to bind the cation depends on the structural match between ionic radii of crown ether cavity (the ion-cavity size concept). Bz15C5 what has higher selectivity to bind Li+ than DBz16C5 and DBz18C6.   Keywords: selectivity, crown ether, MNDO/d.

The Investigation of Stability Analysis of Tube and Coupler Scaffold

2012 ◽  
Vol 594-597 ◽  
pp. 730-733 ◽  
Author(s):  
Hua Zhi Li ◽  
Zhe Liu ◽  
Jia Yong Miao
Keyword(s):  
Ultimate Load ◽  
Load Capacity ◽  
Empirical Method ◽  
Analysis Method ◽  
Ultimate Load Capacity ◽  
Calculation Results ◽  
Impacting Factors ◽  
The Stability ◽  
High Load Capacity ◽  
Semi Empirical

The tube and coupled scaffold is widely used in the construction of building, bridge, sports stadium etc, due to the advantage of easily assembling, high load capacity and good overall stiffness. However as a very important temporary structure in the construction, the semi-empirical method has been used for the calculation of ultimate load capacity (ULC), whether the calculation results are acceptable is not given too much attention. To ascertain the safety of using process, the FEM code-Midas is used to investigate and compare the stability and ultimate load analysis method of scaffold, and the impacting factors, such as the span, step distance, height, and width of scaffold, are discussed, the varying process and trend is described in this paper.

scholarly journals Seismic Hazard of the Uttarakhand Himalaya, India, from Deterministic Modeling of Possible Rupture Planes in the Area

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Anand Joshi ◽  
Ashvini Kumar ◽  
Heriberta Castanos ◽  
Cinna Lomnitz
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Strong Motion ◽  
Semiempirical Method ◽  
Empirical Method ◽  
Attenuation Relation ◽  
Ground Acceleration ◽  
Important Region ◽  
Semi Empirical ◽  
Uttarakhand Himalaya

This paper presents use of semiempirical method for seismic hazard zonation. The seismotectonically important region of Uttarakhand Himalaya has been considered in this work. Ruptures along the lineaments in the area identified from tectonic map are modeled deterministically using semi empirical approach given by Midorikawa (1993). This approach makes use of attenuation relation of peak ground acceleration for simulating strong ground motion at any site. Strong motion data collected over a span of three years in this region have been used to develop attenuation relation of peak ground acceleration of limited magnitude and distance applicability. The developed attenuation relation is used in the semi empirical method to predict peak ground acceleration from the modeled rupture planes in the area. A set of values of peak ground acceleration from possible ruptures in the area at the point of investigation is further used to compute probability of exceedance of peak ground acceleration of values 100 and 200 gals. The prepared map shows that regions like Tehri, Chamoli, Almora, Srinagar, Devprayag, Bageshwar, and Pauri fall in a zone of 10% probability of exceedence of peak ground acceleration of value 200 gals.

scholarly journals MOLECULAR MODELLING OF Mn+.[DBz16C5] COMPLEXES, M = Li+, Na+ AND Zn2+ BASED ON MNDO/d SEMIEMPIRICAL METHOD

2010 ◽  
Vol 6 (2) ◽  
pp. 144-149
Author(s):  
Harno Dwi Pranowo ◽  
Chairil Anwar
Keyword(s):  
Crown Ether ◽  
Computational Chemistry ◽  
Semiempirical Method ◽  
Empirical Method ◽  
Induction Effect ◽  
Cation Selectivity ◽  
Symmetrical Form ◽  
Chemistry Calculation ◽  
Semi Empirical ◽  
Cation Complexes

The effect of substituent on dibenzo-16-crown-5 (DBz16C5) and interaction between these crown ether with metal cations was evaluated using computational chemistry calculations. Substituens where are connected to the benzene ring on the DBz16C5 are -COOH, -Br, -COOC2H5, -CHO, -CH=CHCO2H, -CH=CHCO2C2H5 and -CH(OH)CH3. The analysis based on computational chemistry calculation using MNDO/d semi empirical method was done. The first step is structure optimization of crown ether followed by optimization of crown ether-metals cation complexes Mn+.[DBz16C5], where M is Li+, Na+ and Zn2+. Interactions of the crown ether and cation were discussed in term of the structure parameter of crown ether, atomic charges and energy interaction of the crown ether-metals cation. Electron donating groups increase the capability of crown ether to bind cation by means of induction effect, while electron withdrawing groups reduce the ability of crown ether to bind cation. Any substituent on the benzene in DBz16C5 which can be make the symmetrical form of the crown ether-metals cation complexes will increase the selectivity of the crown ether to bind the cation. Selectivity of the crown ether to bind cation also depends on the compatibility of the diameter of cation and cavity of crown ether. DBz16C5 has higher selectivity to bind the Na+ compare to the Li+ and Zn2+.   Keywords: selectivity, dibenzo-16-crown-5, MNDO/d

scholarly journals QSAR Analysis of Benzothiazole Derivatives of Antimalarial Compounds Based On AM1 Semi-Empirical Method

2015 ◽  
Vol 15 (1) ◽  
pp. 86-92 ◽  
Author(s):  
Ruslin Hadanu ◽  
Salim Idris ◽  
I Wayan Sutapa
Keyword(s):  
Antimalarial Activity ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Qsar Model ◽  
Empirical Method ◽  
Statistical Parameters ◽  
Qsar Analysis ◽  
Benzothiazole Derivatives ◽  
Semi Empirical ◽  
Antimalarial Compounds

Quantitative Structure and Activity Relationship (QSAR) analysis of 13 benzothiazoles derivatives compound as antimalarial compounds have been performed using electronic descriptor of the atomic net charges (q), dipole moment (μ), ELUMO, EHOMO and polarizability (α). The electronic structures as descriptors were calculated through HyperChem for Windows 7.0 using AM1 semi-empirical method. The descriptors were obtained through molecules modeling to get the most stable structure after geometry optimization step. The antimalarial activity (IC50) were taken from literature. The best model of QSAR model was determined by multiple linear regression approach and giving equation of QSAR: Log IC50 = 23.527 + 4.024 (qC4) + 273.416 (qC5) + 141.663 (qC6) – 0.567 (ELUMO) – 3.878 (EHOMO)– 2.096 (α). The equation was significant on the 95% level with statistical parameters: n = 13, r = 0.994, r2 = 0.987, SE = 0.094, Fcalc/Ftable = 11.212, and gave the PRESS = 0.348. Its means that there were only a relatively few deviations between the experimental and theoretical data of antimalarial activity.

scholarly journals 1H NMR and spectrophotometric study of alkaline metal ion complexes with N-dansyl aza-18-crown-6

2006 ◽  
Vol 4 (1) ◽  
pp. 13-28 ◽  
Author(s):  
Tadeusz Ossowski ◽  
Hanna Sulowska ◽  
Tomasz Karbowiak ◽  
Dorota Zarzeczanska ◽  
Błażej Gierczyk ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Stability Constants ◽  
Metal Ion ◽  
Spectrophotometric Study ◽  
Alkaline Metal ◽  
Empirical Methods ◽  
Absorption And Fluorescence Spectroscopy ◽  
The Stability ◽  
Semi Empirical ◽  
Formation Of Complexes

AbstractFormation of complexes of A18C6-Dns and metal cations (Ca2+, Sr2+, Ba2+ and Mg2+) in acetonitrile has been studied by NMR, absorption and fluorescence spectroscopy and PM5 semi-empirical methods. A18C6-Dns forms stable complexes with Ca2+, Sr2+ and Ba2+ cations. The stability constants of various complexes are determined by different methods and their structures are visualised by the PM5 semi-empirical calculations.

scholarly journals Molecular Modelling, Docking and Pharmacokinetic Studies of N-Arylidenequinoline-3-Carbohydrazides Analogs as Novel β-Glucuronidase Inhibitors

2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Muhammad Tukur Ibrahim ◽  
Adamu Uzairu ◽  
Abdullahi Bello Umar ◽  
Abubakar Sadiq Bello ◽  
Yusuf Isyaku
Keyword(s):  
Geometry Optimization ◽  
Docking Study ◽  
Empirical Method ◽  
Basis Set ◽  
Pharmacokinetic Studies ◽  
Amino Acid Residues ◽  
Molecular Docking Study ◽  
Data Set ◽  
New Compounds ◽  
Semi Empirical

Quantitative structure-activity relationships (QSAR) modelling on 30 N-Arylidenequinoline-3-carbohydrazides analogs was performed using Multi-Linear Regression (MLR) analysis adopting Genetic Function Algorithm (GFA) method. Semi empirical method using PM6 basis set was used for complete geometry optimization of the data set. The best model was chosen based on its statistical fit due to it good internal and external validations. From the Williams plot, it can be inferred that the reported model can make prediction of new compounds that are not within the data set. The molecular docking study showed that, the most active chemical in the data set was better than the standard β-glucuronidase inhibitor both in terms of binding scores and the amino acid residues that interacted with the drug and β-glucuronidase enzyme. The Pharmacokinetic studies indicated that none of the chemicals violated any of the condition set by the Lipinski′s Rule of five which confirm the bioavailability of these chemicals. The results these findings give room for designing novel β-glucuronidase inhibitors that are highly effective.                                                Resumen. Se llevó a cabo la técnica de QSAR en 30 analogos de N-arilidenequinolina-3-carbohidrazidas mediante el analisis de regresesión lineal múltiple (MLS) adopatando el método del algoritmo de función genética (GFA). Para la optimización completa de la geometría del conjunto de datos se utilizó un método semiémpirico del conjunto de bases PM6. El mejor modelo fue elegido basado en función de su ajuste estadístico debido a su validación interna y externa. A partir de la gráfica de Williams, se puede inferir que el modelo reportado puede predecir nuevos compuestos que no se encuentran en el conjunto de datos. Este estudio de acomplamiento molecular mostró que, el químico más activo del conjunto de datos fue mejor que el inhibidor estándar β-glucuronidasa, tanto en términos de unión y en términos de  interacción de los residuos con el fármaco y la enzima β-glucuronidasa. Los estudios farmacocinéticos que indicaron que ninguno de los fármacos incumple ninguna de las condiciones establecidas por la regla de cinco de Lipinski, en donde se confirma la biodisponibilidad de estos químicos. Los resultados de los hallazgos computacionales permiten diseñar nuevos inhibidores de la β-glucuronidasa que son altamente efectivos.

scholarly journals MIXED-LIGAND ACETYLACETONATE COMPLEXES OF LANTANUM (III) AND GADOLINIUM (III) WITH CARBOXYLIC ACIDS AND ACETONITRILE OR DIMETHYLFORMAMIDE

2019 ◽  
Vol 85 (1) ◽  
pp. 3-12
Author(s):  
Lyudmila Sliusarchuk ◽  
Lidia Zheleznova ◽  
Artem Mishchenko
Keyword(s):  
Thermal Analysis ◽  
Empirical Method ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Ionic Radii ◽  
Chemical Modeling ◽  
Computational Data ◽  
The Stability ◽  
Semi Empirical ◽  
Volatile Precursors

This paper presents the study of mixed-ligand complexes of Ln(III), which are used as volatile precursors in CVD processes for the preparation of lanthanide-containing films and coatings. New mixed-ligand acetylacetonate complexes of lanthanides (III) with acetic (propionic) acid and acetonitrile or dimethylformamide were synthesized and investigated by physic-chemical methods of analysis (elemental analysis, differential thermal analysis, IR spectroscopy, powder X-ray diffraction). Using mixed-ligand complexation, the properties of the initial lanthanide β-diketonates (in particular, chemical and thermal stability) can be changed significantly. To assess the stability of the synthesized mixed-ligand complexes, their quantum-chemical modeling was performed using the semi-empirical method Sparkle/PM7. Standard changes of the Gibbs energy ∆G0298 were calculated for the solution reaction of (1) synthesis of mixed-ligand complexes and (2) substitution of one of the β-diketonate ligands in the Ln(III) tris-acetylacetonates dihydrates by an acetate ion or propionate ion. The ∆G0298 values for the syntesis reaction mainly increases with increasing donor basicity and decreasing ionic radii Ln(III) in the La>Gd>Lu series. For all mixed ligand complexes of Ln(III), the heats of formation are negative, which indicates their thermodynamic stability in solution. It was established that the obtained complexes have the same composition of the general formula [Ln(AA)2·L·2D], where Ln (III) = La, Gd; НАА- acetylacetonе; L - anion of acetic (HAc) or propionic (HРrop) acids, D- acetonitrile (AN), dimethylformamide (DMFA). The results of the thermal analysis confirm the computational data: in the case of the lanthanum mixed-ligand complexes, the carboxylic acid is coordinated to the central ion through bridging carboxylate-ions, which contributes to the formation of oligomers. The lanthanum mixed-ligand complexes are not volatile due to their oligomeric structure. On the other hand, similar gadolinium complexes are monomeric and sublimate at 180 - 350 °C.

Theoretical Study of the Complexation of Lidocaine by α- and β-Cyclodextrins

2021 ◽  
Vol 43 (4) ◽  
pp. 429-429
Author(s):  
Nourredine Meddah Araibi Nourredine Meddah Araibi ◽  
Teffaha Fergoug Teffaha Fergoug ◽  
Mansour Azayez Mansour Azayez ◽  
Cherifa Zelmat Cherifa Zelmat ◽  
Jendara Ali Cherif and Youcef Bouhadda Jendara Ali Cherif and Youcef Bouhadda
Keyword(s):  
Inclusion Complex ◽  
Quantum Chemical ◽  
Driving Forces ◽  
Minimum Energy ◽  
Geometry Optimization ◽  
Empirical Method ◽  
Van Der Waals Interactions ◽  
Basis Set ◽  
The Stability ◽  
Complexation Reactions

Structure and stability of an eventual inclusion complex formed by Lidocaine and two cyclodextrins (α- and β-CD) were investigated using molecular mechanics and quantum-chemical methods in the gas phase and in water. The molecular docking and quantum chemical calculations results show that no inclusion complex is formed between α-CD and Lidocaine molecule, while the conformational research allowed observing two minimum-energy structures between this molecule and β-CD. From a potential energy scan, a partial inclusion of the two ends of Lidocaine by the secondary face of the cavity of β-CD is observed with a better stability for the complex including the ((-N(C2H5)2) group in it. The minimum energy conformers, obtained by semi empirical method (PM3), have been exposed to fully geometry optimization employing ONIOM2 calculations by combining PM3 method with B3LYP, M06-HF and WB97XD functionals at 6-311G (d,p) basis set. The results show that complexation reactions are thermodynamically favored (Gand#176; ˂ 0) and the inclusion complexes are energetically stables and well structured (Sand#176; ˂ 0). According to the analysis of natural bond orbitals, the Van der Waals interactions are the sole driving forces that ensure the stability of the formed complexes.

Monoatomic Chains Deposited onto Silicon Steps Studied by Density Functional and Scattering Theories

2006 ◽  
Vol 959 ◽  
Author(s):  
Anna Mazzone
Keyword(s):  
Binding Energy ◽  
Density Functional ◽  
Free Standing ◽  
Linear Chains ◽  
Chain Composition ◽  
Atomic Chains ◽  
Central Result ◽  
The Stability ◽  
The One ◽  
Semi Empirical

ABSTRACTThe purpose of this study is the assessment of the properties of deposited atomic chains. Therefore linear chains of covalent and metallic atoms, i.e. As and Ag,deposited onto monolayer SA steps onto Si(100) have been considered. Their study is based on a semi-empirical Hamiltonian, used for the evaluation of both the electronic structure and the conductance, and the calaculations analyze the binding energy of chains of variable length deposited onto steps in the light of the analogous energy of free-standing chains and of chains deposited onto the Si(100) surface. This comparison shows that the stability of the chains has a primary dependence on the type of the substrate, rather than on the chain length and composition, and increases in the order: free standing,deposited onto SA,deposited onto Si(100). The central result of the calculations of the conductance is that the dependence on the type of the substrate and on the chain composition parallels the one of the binding energy.

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