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 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.

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 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

Modeling the Effects of O-sulfonation on the CID of Serine

2020 ◽  
Author(s):  
Kenneth Lucas ◽  
George Barnes
Keyword(s):  
Sulfo Group ◽  
High Energy ◽  
Empirical Method ◽  
Side Chain ◽  
Energy Structure ◽  
Direct Dynamics ◽  
Theoretical Mass ◽  
Intermolecular Proton Transfer ◽  
Dynamics Simulations ◽  
Semi Empirical

We present the results of direct dynamics simulations and DFT calculations aimed at elucidating the effect of \textit{O}-sulfonation on the collision induced dissociation for serine. Towards this end, direct dynamics simulations of both serine and sulfoserine were performed at multiple collision energies and theoretical mass spectra obtained. Comparisons to experimental results are favorable for both systems. Peaks related to the sulfo group are identified and the reaction dynamics explored. In particular, three significant peaks (m\z 106, 88, and 81) seen in the theoretical mass spectrum directly related to the sulfo group are analyzed as well as major peaks shared by both systems. Our analysis shows that the m\z 106 peaks result from intramolecular rearrangements, intermolecular proton transfer among complexes composed of initial fragmentation products, and at high energy side-chain fragmentation. The \mz 88 peak was found to contain multiple constitutional isomers, including a previously unconsidered, low energy structure. It was also seen that the RM1 semi empirical method was not able to obtain all of the major peaks seen in experiment for sulfoserine. In contrast, PM6 did obtain all major experimental peaks.

Theoretical investigation of Ramachandran plot of N-formyl-L-alanine-amide

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Genetic Algorithm ◽  
Theoretical Investigation ◽  
Energy Analysis ◽  
Empirical Method ◽  
Conformational Space ◽  
Ramachandran Plot ◽  
Global Minima ◽  
Reasonable Time ◽  
Semi Empirical

The full conformational space of N-formyl-L-alanine-amide was explored by the semi-empirical method AM1 coupled to the Multi Niche Crowding (MNC) genetic algorithm implemented in a package of programs developed in our laboratory. The structural and energy analysis of the resulting conformational space E(,ψ) exhibits 5 regions or minima ɣL, ɣD, ɛL, D and αD. The technique provides better detection of local and global minima within a reasonable time.

scholarly journals How Good Is the STW Sensor? An Account from a Larger Shipping Company

2021 ◽  
Vol 9 (5) ◽  
pp. 465
Author(s):  
Angelos Ikonomakis ◽  
Ulrik Dam Nielsen ◽  
Klaus Kähler Holst ◽  
Jesper Dietz ◽  
Roberto Galeazzi
Keyword(s):  
High Frequency ◽  
Additional Data ◽  
Empirical Method ◽  
Influential Factor ◽  
Sensor Data ◽  
Sea State ◽  
Shipping Company ◽  
Frequency Sensor ◽  
Semi Empirical

This paper examines the statistical properties and the quality of the speed through water (STW) measurement based on data extracted from almost 200 container ships of Maersk Line’s fleet for 3 years of operation. The analysis uses high-frequency sensor data along with additional data sources derived from external providers. The interest of the study has its background in the accuracy of STW measurement as the most important parameter in the assessment of a ship’s performance analysis. The paper contains a thorough analysis of the measurements assumed to be related with the STW error, along with a descriptive decomposition of the main variables by sea region including sea state, vessel class, vessel IMO number and manufacturer of the speed-log installed in each ship. The paper suggests a semi-empirical method using a threshold to identify potential error in a ship’s STW measurement. The study revealed that the sea region is the most influential factor for the STW accuracy and that 26% of the ships of the dataset’s fleet warrant further investigation.

scholarly journals A semi-empirical method for predicting GOC in oil reservoirs with limited PVT dataset

2020 ◽  
Vol 2 (7) ◽  
Author(s):  
Oluchukwu M. Okoh ◽  
Kazeem A. Lawal ◽  
Asekhame U. Yadua ◽  
Mathilda I. Ovuru ◽  
Stella I. Eyitayo ◽  
...  
Keyword(s):  
Empirical Method ◽  
Oil Reservoirs ◽  
Semi Empirical
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