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Journal articles on the topic 'AM1 and PM3 semiempirical methods'

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Published: 4 June 2025

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1

Fabian, Walter M. F. "Tautomerism in Five-membered Nitrogen Heterocycles. A Test of the Reliability of Semiempirical (AMI, PM3, MNDO) Quantum Chemical Methods." Zeitschrift für Naturforschung A 45, no. 11-12 (1990): 1328–34. http://dx.doi.org/10.1515/zna-1990-11-1216.

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AbstractThe reliability of three popular semiempirical quantum chemical methods (AM1, PM3, MNDO) for the treatment of tautomeric equilibria is tested in a series of five-membered nitrogen heterocycles. The known flaw of MNDO to overestimate the stability of compounds with two or more adjacent pyridine-like lone pairs is also present in AM1 and to a somewhat lesser extent in PM3. Tautomeric species differing in the number of adjacent pyridine-like lone pairs, thus, cannot be adequately treated by these semiempirical methods. Both AM1 as well as PM3, however, represent major improvements over MN

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2

Mahboub, Radia. "Structural Conformational Study of Eugenol Derivatives Using Semiempirical Methods." Advances in Chemistry 2014 (October 20, 2014): 1–5. http://dx.doi.org/10.1155/2014/490358.

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We investigated the conformational structure of eugenol and eugenyl acetate under torsional angle effect by performing semiempirical calculations using AM1 and PM3 methods. From these calculations, we have evaluated the strain energy of conformational interconversion. To provide a better estimate of stable conformations, we have plotted the strain energy versus dihedral angle. So, we have determined five geometries of eugenol (three energy minima and two transition states) and three geometries of eugenyl acetate (two energy minima and one transition state). From the molecular orbital calculati

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3

Bureš, Michal, and Jaroslav Bezus. "Study of Hydrogen Bonding in Carboxylic Acids by the MNDO/M Method." Collection of Czechoslovak Chemical Communications 59, no. 6 (1994): 1251–60. http://dx.doi.org/10.1135/cccc19941251.

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The semiempirical methods MNDO/M, AM1 and PM3 were applied to the study of hydrogen bonds in carboxylic acids. The calculated hydrogen bond lengths and enthalpies of dimerization were compared with experimental data. The AM1 method fails to properly describe systems with strong hydrogen bonds. The PM3 method predicts the hydrogen bond lengths correctly but underestimates systematically the enthalpies of dimerization. MNDO/M appears to be a promising method for the treatment of association of carboxylic acids.

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4

Shephard, MJ, and MN Paddonrow. "A Caveat Concerning the Use of the AM1 and PM3 Semiempirical Methods in Calculating Conformational Preferences in Acyclic Amines and Saturated Azaheterocycles." Australian Journal of Chemistry 46, no. 4 (1993): 547. http://dx.doi.org/10.1071/ch9930547.

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A theoretical investigation of the conformational analysis of several acyclic amines, N- alkylated saturated azaheterocycles and alkylcyclohexanes (alkyl = Me, Et, isopropyl, t-butyl) has been carried out by using the MNDO, AM1 and PM3 semiempirical methods. It is found that all three methods correctly predict, qualitatively, the conformational preferences in alkylcyclohexanes, although the PM3 method underestimates the conformational energy for the t-butyl group by as much as 13 kJ/mol. Both AM1 and PM3 overestimate the conformational energy of the nitrogen lone pair to the extent that it exc

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5

Straßner, Thomas. "Diphenylmethane and diphenyl ether — experimental conformations and torsional surfaces calculated with AM1, MNDO, PM3, and density functional theory (Becke3LYP)." Canadian Journal of Chemistry 75, no. 7 (1997): 1011–22. http://dx.doi.org/10.1139/v97-121.

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The complete energy surfaces of the torsion around the central C—O or C—CH2 bonds in diphenyl ether (DPE) and diphenylmethane (DPM) are calculated with semiempirical methods (AM1, MNDO, PM3) and density functional theory (Becke3LYP/3-21G). Stationary points are optimized at the Becke3LYP/6-31G(d) level of theory. The geometry of a very recently published X-ray structure of 4,4′-bis[N-(2,4,6-trimethyl)benzenesulfonamide]diphenylmethane (1), as well as the solid state structures of many other diphenyl ethers and diphenylmethanes, is found in the low-energy regions of the AM1 surfaces of the pare

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6

Chen, Zhongfang, Keqin Ma, Yinming Pan, Xuezhuang Zhao, and Auchin Tang. "Theoretical studies of heterofullerenes C68X2 (X = N, B)." Canadian Journal of Chemistry 77, no. 3 (1999): 291–98. http://dx.doi.org/10.1139/v99-016.

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A systematic investigation on the molecular structures of the possible energetically favored isomers of C68X2 (X = N, B) has been performed using the semiempirical MNDO, AM1, and PM3 methods. The most stable isomer of C68X2 was computed, and the static properties such as heats of atomization, ionization potentials, electron affinities, absolute electronegativities, and global hardness have been predicted theoretically. The proposition that the changes of hybridization from sp2 to sp3 are the predominant factors of the regiochemistry for both C60X2 and C58X2 are supported by the calculations, a

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7

Jalali-Heravi, M., S. P. McManus, S. E. Zutaut, and J. K. McDonald. "Semiempirical SCF-MO modeling of polysilanes using AM1 and PM3 methods." Chemistry of Materials 3, no. 6 (1991): 1024–30. http://dx.doi.org/10.1021/cm00018a016.

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8

Rak, Janusz, Piotr Skurski, Ludwika Jozwiak, and Jerzy Blazejowski. "Theoretical Studies on the Effect of the Medium on Tautomeric Phenomena in Neutral and Protonated Acridin-9-amine. Mechanism of Tautomerization in Neutral Entities." Australian Journal of Chemistry 50, no. 2 (1997): 97. http://dx.doi.org/10.1071/c96184.

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Semiempirical AM1 and PM3 (gaseous phase) and AM1-COSMO, PM3-COSMO and PM3-AQ (liquid phase) methods were used to examine the structure, as well as the thermodynamic and physicochemical features (dipole moments and LUMO and HOMO energies), of tautomeric forms of neutral, mono- and di-protonated acridin-9-amine. The energy gaps between possible tautomers are only insignificantly influenced by the medium and reveal the coexistence of neutral and diprotonated entities in two forms, and the monoprotonated entity in one form. Entropy and thermal energy, which can be evaluated only for gaseous syste

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9

Pankratov, Alexei. "Use of semiempirical quantum chemical approaches in computation of molecular dipole moments of tropones and tropolones." Journal of the Serbian Chemical Society 65, no. 1 (2000): 1–13. http://dx.doi.org/10.2298/jsc0001001p.

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Using the MNDO, AM1 and PM3 methods, the dipole moments (m) of 28 tropones and 34 tropolones molecules have been computed. The potentials of the above approaches for the evaluation of m have been revealed. The correlations mexper = bmtheor have been established.

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10

Dinadayalane, T. C., and G. Narahari Sastry. "An assessment of semiempirical (MNDO, AM1 and PM3) methods to model buckybowls." Journal of Molecular Structure: THEOCHEM 579, no. 1-3 (2002): 63–72. http://dx.doi.org/10.1016/s0166-1280(01)00716-3.

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11

Gajanan, Pandey, Shrivastava Snehika, and K. Sharma Harendra. "Theoretical investigations of synthesized Schiff base ligand derived from S-alkyldithiocarbazate." Journal of Indian Chemical Society Vol. 91, Nov 2014 (2014): 2009–18. https://doi.org/10.5281/zenodo.5734240.

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Department of Applied Chemistry, Babasaheb Bhimrao Ambedkar University, Lucknow-226 025, Uttar Pradesh, India <em>E-mail</em> : pandeygajanan@rediffmail.com Department of Chemistry, I.P.S. College of Technology and Management, Gwalior-474 001, Madhya Pradesh, India Indira Gandhi Academy of Environmental Education, Research and Ecoplanning, Jiwaji University, Gwalior-474 011, Madhya Pradesh, India <em>E-mail</em> : drsharmahk@yahoo.com <em>Manuscript received online 26 March 2014, accepted 03 June 2014</em> 4-Hydroxy-3-methoxy Schiff base derived from S-methyldithiocarbazate was prepared adopti

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12

Posokhov, Yevgen, Sule Erten, Ömer Koz, H. AnIl, Süheyla KIrmIzIgül, and SIddIk Içli. "UV/VIS spectral properties of novel natural products from Turkish lichens." International Journal of Photoenergy 7, no. 1 (2005): 27–35. http://dx.doi.org/10.1155/s1110662x0500005x.

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UV/VIS spectral characteristics of three new biologically active natural products, isolated from Turkish lichens, have been investigated in solvents of various polarity and proton donating ability. The effect of the solvent on spectral characteristics has been estimated. Quantum chemical calculations with the optimization of molecular geometry were done with the full-valent semiempirical methods AM1 and PM3 for conformational analysis and in order to discuss the charge distributions and dipole moments in the ground and in the excited states.

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Iswanto, Ponco, Irvan Maulana Firdaus, Ahmad Fawwaz Dafaulhaq, Ahmad Ghifari Ramadhani, Maylani Permata Saputri, and Heny Ekowati. "Quantitative Structure-Activity Relationship of 3-Thiocyanate-1H-Indoles Derived Compounds as Antileukemia by AM1, PM3, and RM1 Methods." Jurnal Kimia Sains dan Aplikasi 26, no. 3 (2023): 109–17. http://dx.doi.org/10.14710/jksa.26.3.109-117.

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Cancer is a disease with fatal consequences; thus, searching for innovative compounds with anticancer properties remains an active pursuit. One of the highly promising candidates is a compound derived from 3-thiocyanato-1H-indoles. However, the number of derivative compounds is currently limited. A quantitative structure and activity relationship (QSAR) study was conducted on derivate compounds 3-thiocyanato-1H-indoles to establish equations that predict the anticancer activity of more effective derivatives. This study aims to compare the effectiveness of the AM1 (Austin Model 1), PM3 (Paramet

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14

Jorge, N. L., L. C. A. Leiva, M. G. Castellanos, M. E. Gomez Vara, L. F. R. Cafferata, and E. A. Castro. "Experimental and Theoretical Study of the Enthalpy of Formation of 3,6-Diphenyl-1,2,4,5-Tetroxane Molecule." Scientific World JOURNAL 2 (2002): 455–60. http://dx.doi.org/10.1100/tsw.2002.126.

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We report the results obtained for the experimental determination and the theoretical calculation of the enthalpy of formation of 3,6-diphenyl-1,2,4,5-tetroxane molecule. The experimental work was performed using a macrocalorimeter to measure the combustion heat, and the sublimation enthalpy was determined via the measurement of the vapor pressure at equilibrium with the vapor phase at different temperatures resorting to the Clapeyron-Claussius equation. Theoretical calculations were performed using semiempirical AM1 and PM3 methods as well asab initiotechniques at the 3-21, 6-31G(d,p), and 6-

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15

El-Shamy, Omnia A. A. "Semiempirical Theoretical Studies of 1,3-Benzodioxole Derivatives as Corrosion Inhibitors." International Journal of Corrosion 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/8915967.

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The efficiency of 1,3-benzodioxole derivatives as corrosion inhibitors is theoretically studied using quantum chemical calculation and Quantitative Structure Activity Relationship (QSAR). Different semiempirical methods (AM1, PM3, MNDO, MINDO/3, and INDO) are applied in order to determine the relationship between molecular structure and their corrosion protection efficiencies. Different quantum parameters are obtained as the energy of highest occupied molecular orbitalEHOMO, the energy of the lowest unoccupied molecular orbitalELUMO, energy gapΔEg, dipole momentμ, and Mulliken charge on the at

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16

Al-Dabbagh, A. B., R. Z. Al-Khayat, and A. Y. Al-Hamdany. "Thermodynamic Study on Ionization Constant (Ka) Values for Some Imines derived from p,o-Aminobenzaldehydes and Cinnaldehyde by Conductance Method supported by Theoretical Studies." Research Journal of Chemistry and Environment 26, no. 12 (2022): 44–56. http://dx.doi.org/10.25303/2612rjce044056.

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The synthesis of three imines derivatives from various aliphatic and aromatic aldehydes was achieved by standard methods. The main objective of the study was the estimation of Ka values for these imines using conductivity method in a range (293-333) K and to deal with thermodynamic parameters namely ΔG, ΔH, ΔS. The values of ionization constant of these imines under study were calculated. Based on AM1 and PM3 semiempirical methods, εHOMO, εLUMO, band gap Eg, hardeness η, chemical potential μ, softness S, electronegativity χ, elechtrophilicity ω and amount of charge transfer ΔN in electron volt

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17

Luque, F. J., N. Reuter, A. Cartier, and M. F. Ruiz-López. "Calibration of the Quantum/Classical Hamiltonian in Semiempirical QM/MM AM1 and PM3 Methods." Journal of Physical Chemistry A 104, no. 46 (2000): 10923–31. http://dx.doi.org/10.1021/jp001974g.

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18

Tóth, Jaroslav, Milan Remko, and Milan Nagy. "Structural Study of Flavonoids and Their Protonated Forms." Zeitschrift für Naturforschung C 51, no. 11-12 (1996): 784–90. http://dx.doi.org/10.1515/znc-1996-11-1204.

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The highly successful semiempirical quantum chemical methods AM1 (Austin Model 1) and PM3 (a reparametrization of AM1) were applied to an investigation of the conformational properties of flavone, 3-hydroxyflavone, isoflavone and 2-hydroxyisoflavone. The most stable structures correspond to the non-planar forms with an angle of phenyl ring rotation out of the chromone moiety from a relatively narrow interval (28° - 38°). The mono- and diprotonation of these compounds was also investigated. The prominent site of protonation is the oxygen of the carbonyl group with a protonation enthalpy from th

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19

Ibrahim, Medhat Ahmed, Mousa Allam, Hanan El-Haes, Abraham F. Jalbout, and Aned De Leon. "Analysis of the structure and vibrational spectra of glucose and fructose." Ecletica Quimica 31, no. 3 (2006): 15–21. http://dx.doi.org/10.26850/1678-4618eqj.v31.3.2006.p15-21.

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Molecular modelling using semiempirical methods AM1, PM3, PM5 and, MINDO as wellas the Density Functional Theory method BLYP/DZVP respectively were used to calculate the struc-ture and vibrational spectra of d-glucose and d-fructose in their open chain, α-anomer and β-anomermonohydrate forms. The calculated data show that both molecules are not linear; ground state and thenumber for the point-group C is equal to 1. Generally, the results indicate that there are similarities inbond lengths and vibrational modes of both molecules. It is concluded that DFT could be used to studyboth the structura

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20

Fausto, Rui. "Calculation of vibrational frequencies of sulphur compounds using semiempirical molecular orbital methods (AM1, PM3, MNDO)." Journal of Molecular Structure 323 (July 1994): 267–77. http://dx.doi.org/10.1016/0022-2860(94)07989-7.

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21

Hariharan, Sivaram, and William H. Shelver. "Conformational studies of imiloxan and imiloxan cation using AM1 and PM3 semiempirical molecular orbital methods." Journal of Molecular Structure: THEOCHEM 285, no. 3 (1993): 235–50. http://dx.doi.org/10.1016/0166-1280(93)87039-g.

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22

Fabian, Walter M. F. "Tautomeric equilibria of heterocyclic molecules. A test of the semiempirical AM1 and MNDO-PM3 methods." Journal of Computational Chemistry 12, no. 1 (1991): 17–35. http://dx.doi.org/10.1002/jcc.540120104.

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23

Nelly, L. Jorge, E. Gomez-Vara Manuel, F. R. Cafferata Lazaro, and A. Castro Eduardo. "Conformational study of 1,2-dioxane molecule and its halogenated derivatives from the semiempirical AM1 and PM3 molecular orbital methods - a comparative analysis." Journal of Indian Chemical Society Vol. 80, Jan 2003 (2003): 14–20. https://doi.org/10.5281/zenodo.5835454.

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Area de Fisicoquimica, FACENA, Campus Universitario, Avda. Libertad 5600, Facultad de Ciencias Exactas, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina Laboratorio LADECOR, Departamento de Quimica, Facultad de Ciencias Exactas, UNLP, Calles 47 y 115, 1900 La Pima, Argentina Departamento de Quimica, Facultad de Ciencias Exactas, UNLP, CC 962, La Plata 1900, Argentina <em>E-mail :</em> castro@dalton.quimica.unlp.edu.ar. jubert@arnet.com.ar <em>Manuscript received 26 June 2001. revised 17 May 2002. accepted 27 August 2002</em> A conformational study of 1,2-dioxane and several haloge

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24

Raabe, Gerhard. "The Use of Quantum-Chemical Semiempirical Methods to Calculate the Lattice Energies of Organic Molecular Crystals. Part III: The Lattice Energy of Borazine (B3N3H6) and its Packing in the Solid State*." Zeitschrift für Naturforschung A 59, no. 9 (2004): 609–14. http://dx.doi.org/10.1515/zna-2004-0911.

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A previously presented quantum-chemical scheme has been used to calculate the lattice energies of borazine (B3N3H6), the low pressure polymorph of benzene (C6H6), and of borazine in the lowpressure benzene lattice utilizing some frequently used semiempirical methods (CNDO/2, INDO, MINDO/3, MNDO, AM1, PM3, MSINDO). With all methods the lattice energy of the title compound was found to be less favourable than that of isoelectronic benzene, which offers an explanation of the significantly lower melting point of B3N3H6. Calculation of the lattice energy of borazine in the crystal lattice of the lo

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Sigmundová, Ivica, Pavol Zahradník, and Dušan Loos. "Synthesis and Study of Novel Benzothiazole Derivatives with Potential Nonlinear Optical Properties." Collection of Czechoslovak Chemical Communications 72, no. 8 (2007): 1069–93. http://dx.doi.org/10.1135/cccc20071069.

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The synthesis of new benzothiazole push-pull systems as candidates for NLO-phores is described. Spectral (UV/VIS and solvatochromic) and theoretical studies (electronic properties based on semiempirical AM1 and PM3 methods) of the prepared compounds were carried out. The structure and physico-chemical parameters affecting the push-pull character and intramolecular charge transfer (ICT) of the studied compounds have been investigated and compounds with enhanced hyperpolarizability β have been predicted. The benzothiazolium salts were found to be much more effective NLO-phores in comparison with

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Stewart, James J. P. "Optimization of parameters for semiempirical methods IV: extension of MNDO, AM1, and PM3 to more main group elements." Journal of Molecular Modeling 10, no. 2 (2004): 155–64. http://dx.doi.org/10.1007/s00894-004-0183-z.

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Tupper, Kenneth J., Joseph J. Gajewski, and Richard W. Counts. "Semiempirical computation of homolytic O-H bond dissociation energies of alcohols: comparison of the AM1 and PM3 methods." Journal of Molecular Structure: THEOCHEM 236, no. 3-4 (1991): 211–17. http://dx.doi.org/10.1016/0166-1280(91)80013-x.

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Milena, Jankulovska-Petkovska, S. Jankulovska Mirjana, and Dimova Vesna. "Protonation of citraconic and glutaconic acid in perchloric acid media." Technologica Acta 12, no. 1 (2019): 1–8. https://doi.org/10.5281/zenodo.3267263.

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The protonation process of citraconic and glutaconic acid in perchloric acid media was followed using the method of UV spectroscopy. The observed changes in the UV spectra of investigated acids confirmed that the protonation process in perchloric acid with concentration from 5 to 10 mol/dm<sup>3</sup> occurred. Glutaconic acid behaved as weak organic base in perchloric acid media and existed in its monoprotonated form. On the other hand, citraconic acid existed in its protonated form and as protonated anhydride at higher perchloric acid concentration. Using the absorbance data the thermodynami

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29

Rak, Janusz, Karol Krzyminski, Piotr Skurski, et al. "X-Ray, Quantum Mechanics and Density Functional Methods in the Examination of Structure and Tautomerism of N-Methyl-Substituted Acridin-9-amine Derivatives." Australian Journal of Chemistry 51, no. 8 (1998): 643. http://dx.doi.org/10.1071/c97205.

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X-Ray diffraction has shown that N,N-dimethylacridin-9-amine (4) and N ,10-dimethylacridin-9-imine (5) both crystallize in the monoclinic space group P21/c (No. 14) with four molecules in the unit cell. The dimethylamino group in (4) is twisted through an angle of 58·6° relative to a nearly planar acridine moiety. On the other hand, the central ring in (5) is folded along the C(9) · · · N(10) axis through an angle of 26·3° and the exocyclic nitrogen atom with the methyl group attached to it is directed away from the concave side of the acridine nucleus. Theoretical ab initio Hartree–Fock (HF)

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Silva-Junior, Mario R., and Walter Thiel. "Benchmark of Electronically Excited States for Semiempirical Methods: MNDO, AM1, PM3, OM1, OM2, OM3, INDO/S, and INDO/S2." Journal of Chemical Theory and Computation 6, no. 5 (2010): 1546–64. http://dx.doi.org/10.1021/ct100030j.

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Shapovalov, Serghey, Vadim Ponomariov, Oryna Mosharenkova, and Sophia Butenko. "Studies of the Association of Dyes with Surfactants in Aqueous Solutions: Spectrophotometry and Computer Simulation." French-Ukrainian Journal of Chemistry 7, no. 2 (2019): 9–19. http://dx.doi.org/10.17721/fujcv7i2p9-19.

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The association of cationic dye (pinacyanol, PC) with anionic dyes (ethyleosin, EE, or rhodamine 200 C, R200C), and also the interaction “dye+surfactant” has been investigated in aqueous solutions by visible spectroscopy and computer simulation. Cetylpyridinium bromide (CPB), sodium dodecylsulfate (SDS) and triton X-100 (TX) were used as cationic, anionic and non-ionic surfactants respectively. The formation of “dye+surfactant” associates takes place at low dye concentrations (≥10‑6 M) and concentrations of surfactant, which are much smaller than the critical micelle concentrations (CMC). In c

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Jankulovska, Mirjana Stojan, and Ilinka Spirevska. "Analysis of acid-base properties of some p-substituted aromatic hydrazones in aqueous perchloric acid by spectrophotometric and semiempirical methods." Macedonian Journal of Chemistry and Chemical Engineering 33, no. 1 (2014): 85. http://dx.doi.org/10.20450/mjcce.2014.370.

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<p>The acid-base properties of some <em>p</em>-substituted aromatic hydrazones were examined in aqueous perchloric acid medim by spectrophotometric methods. The possible site where the proton may take place and the stability of the protonated form was discussed using the values of the total energy, binding energy, heat of formation and proton affinity calculated according to the semiempirical methods AM1 and PM3. Furthermore, the stability of the protonated forms, as well as, the stability of the isomers (<em>E</em> and <em>Z</em>) was discussed. Elect

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Nural, Yahya, H. Ali Döndaş, Hayati Sarı, Hasan Atabey, Samet Belveren, and Müge Gemili. "Determination of Acid Dissociation Constants (pKa) of Bicyclic Thiohydantoin-Pyrrolidine Compounds in 20% Ethanol-Water Hydroorganic Solvent." International Journal of Analytical Chemistry 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/634194.

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The acid dissociation constants of potential bioactive fused ring thiohydantoin-pyrrolidine compounds were determined by potentiometric titration in 20% (v/v) ethanol-water mixed at25±0.1°C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Proton affinities of potential donor atoms of the ligands were calculated by AM1 and PM3 semiempiric methods. We found, potentiometrically, three different acid dissociation constants for1a–f. We suggest that these acid dissociation constants are related to the carboxyl, enol, and amino groups.

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Nomozov, A. K., Kh S. Beknazarov, Y. A. Geldiev, B. E. Babamurodov, N. Sh Muzaffarova, and S. G. Yuldashova. "SYNTHESIS OF PFG BRAND CORROSION INHIBITOR AND ITS QUANTUM CHEMICAL CALCULATION RESULTS." Chemical Problems 23, no. 3 (2025): 297–309. https://doi.org/10.32737/2221-8688-2025-3-297-309.

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This article examines the optimal conditions for synthesizing a new type of corrosion inhibitor based on p-paraphenylenediamine, formalin, and glycine. It was determined that the ideal mole ratio of the initial substances is 1:2:2 mol, and the optimal temperature range is between 40 and 65 degrees Celsius. The reaction efficiency under these optimal conditions was found to be 89.4%. The structure of the synthesized corrosion inhibitor was analyzed using IR spectra. Additionally, the Avogadro, Hyper Chem 8.01, Asselrys MS Modeling 3.0.1 software was used to perform quantum chemical calculations

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35

Al-Swaidan, Ibrahim A., Adel S. El-Azab, Amer M. Alanazi, and Alaa A. M. Abdel-Aziz. "Synthesis and Conformational Analysis of Sterically Congested (4R)-(−)-1-(2,4,6-Trimethylbenzenesulfonyl)-3-n-butyryl-4-tert-butyl-2-imidazolidinone: X-Ray Crystallography and Semiempirical Calculations." Journal of Chemistry 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/173902.

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The crystal structure of (4R)-(−)-1-(2,4,6-trimethylbenzenesulfonyl)-3-n-butyryl-4-tert-butyl-2-imidazolidinone(3)was determined by single-crystal X-ray diffraction. Compound3crystallizes in triclinic system in space groupP1 (≠1). The crystal data area=10.62165 Å,b=16.5321 Å,c=8.95729 Å,∝=91.1936∘,β=93.8496∘,γ=88.0974∘,V=1568.22 Å3,Z=3,Dcalc=1.253 g/cm3,μCuKα=15.98 cm−1,F000=636.00,T=20.0°C, andR=0.037. The crystal structure confirmed the occurrence of three molecules of3A,3B, and3Cin which then-butyryl moiety adopted thes-transoidconformation. Crystal structure also revealed that the conforma

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Maksić, Z. B., D. Kovaček, K. Kovačević, and Ž. Medven. "Semiempirical calculations of the ESCA chemical shifts of nitrogen atoms in a chemical environment: failure of the PM3 and AM1 methods." Journal of Molecular Structure: THEOCHEM 304, no. 2 (1994): 151–61. http://dx.doi.org/10.1016/s0166-1280(96)80007-8.

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37

Xu, Lei, Wensheng Cai, and Xueguang Shao. "Performance of the semiempirical AM1, PM3, MNDO, and tight-binding methods in comparison with DFT method for the large fullerenes C116–C120." Journal of Molecular Structure: THEOCHEM 817, no. 1-3 (2007): 35–41. http://dx.doi.org/10.1016/j.theochem.2007.04.020.

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38

Öǧretir, Cemil, and N. Funda (Kaypak) Tay. "Investigation of the structure and properties of some indazole derivatives using the AM1, PM3 and MNDO semiempirical methods. 2. An aqueous phase study." Journal of Molecular Structure: THEOCHEM 588, no. 1-3 (2002): 145–53. http://dx.doi.org/10.1016/s0166-1280(02)00167-7.

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39

Jursic, Branko S., and Zoran Zdravkovski. "Comparison of AM1 and PM3 semiempirical to ab initio methods in the study of Diels-Alder reactions of butadiene and cyclopentadiene with cyanoethylenes." Journal of Molecular Structure: THEOCHEM 309, no. 3 (1994): 249–57. http://dx.doi.org/10.1016/0166-1280(94)80077-4.

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40

Gundertofte, Klaus, Jonas Palm, Ingrid Pettersson, and Anders Stamvik. "A comparison of conformational energies calculated by molecular mechanics (MM2(85), Sybyl 5.1, Sybyl 5.21, and ChemX) and semiempirical (AM1 and PM3) methods." Journal of Computational Chemistry 12, no. 2 (1991): 200–208. http://dx.doi.org/10.1002/jcc.540120209.

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41

Alcolea Palafox, M., and F. J. Meléndez. "A comparative study of the scaled vibrational frequencies in the local anesthetics procaine, tetracaine and propoxycaine by means of semiempirical methods: AM1, PM3 and SAM1." Journal of Molecular Structure: THEOCHEM 459, no. 1-3 (1999): 239–71. http://dx.doi.org/10.1016/s0166-1280(98)00304-2.

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42

Hobza, Pavel, Martin Kabel�?, Ji?� ?poner, Petr Mejzl�k, and Ji?� Vondr�?ek. "Performance of empirical potentials (AMBER, CFF95, CVFF, CHARMM, OPLS, POLTEV), semiempirical quantum chemical methods (AM1, MNDO/M, PM3), andab initio Hartree-Fock method for interaction of DNA bases: Comparison with nonempirical beyond Hartree-Fock results." Journal of Computational Chemistry 18, no. 9 (1997): 1136–50. http://dx.doi.org/10.1002/(sici)1096-987x(19970715)18:9<1136::aid-jcc3>3.0.co;2-s.

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43

Przybylski, Piotr, Adam Huczyński, and Bogumil Brzezinski. "The structures of monensin A derivatives and its complexes with some monovalent cations studied by the AM1d, PM3 as well as PM5 semiempirical methods." Journal of Molecular Structure 826, no. 2-3 (2007): 156–64. http://dx.doi.org/10.1016/j.molstruc.2006.04.043.

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44

Csonka, G. I., and P. Hencsei. "AM1 and PM3 semiempirical molecular orbital study of silatranes." Journal of Molecular Structure: THEOCHEM 283 (July 1993): 251–59. http://dx.doi.org/10.1016/0166-1280(93)87135-z.

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45

Istyastono, Enade Perdana, Sudibyo Martono, Harno Dwi Pranowo, and Iqmal Tahir. "QUANTITATIVE STRUCTURE-ACTIVITY RELATIONSHIP ANALYSIS OF CURCUMIN AND ITS DERIVATIVES AS GST INHIBITORS BASED ON COMPUTATIONAL CHEMISTRY CALCULATION." Indonesian Journal of Chemistry 3, no. 3 (2010): 179–86. http://dx.doi.org/10.22146/ijc.21886.

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The Quantitative Structure-Activity Relationship (QSAR) study was established on curcumin and its derivatives as glutathione S-transferase(s) (GSTs) inhibitors using atomic net charges as the descriptors. The charges were resulted by semiempirical AM1 and PM3 quantum-chemical calculations using computational chemistry approach. The inhibition activity was expressed as the concentration that gave 50% inhibition of GSTs activity (IC50). The selection of the best QSAR equation models was determined by multiple linear regression analysis. This research was related to the nature of GSTs as multifun

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46

Böhm, Stanislav, Pavel Šebek, Stanislav Nešpůrek, and Josef Kuthan. "Photocolouration of 2,4,4,6-Tetraaryl-4H-thiopyrans: A Semiempirical Quantum Chemical Study." Collection of Czechoslovak Chemical Communications 59, no. 5 (1994): 1115–25. http://dx.doi.org/10.1135/cccc19941115.

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Molecular geometries of 4H-thiopyrans Ia, Ib and their possible photoisomers IVa - VIIa and IVb - VIIb were optimized by the AM1 and PM3 method and used for the calculation of electronic absorption spectra by the CNDO/S-CI procedure. Comparison of the theoretical data with experimental UV-VIS absorption spectra made it possible to postulate two probable mechanisms of the photocolouration of Ia, Ib caused by sunlight or UV-illumination.

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47

Csonka, G. I., and P. Hencsei. "MNDO, AM1 and PM3 semiempirical molecular orbital study of 1-fluorosilatrane." Journal of Organometallic Chemistry 446, no. 1-2 (1993): 99–106. http://dx.doi.org/10.1016/0022-328x(93)80040-i.

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48

Csonka, G. I., and P. Hencsei. "AM1 and PM3 semiempirical molecular orbital study of silatranes III. 1-Chlorosilatrane." Journal of Organometallic Chemistry 454, no. 1-2 (1993): 15–23. http://dx.doi.org/10.1016/0022-328x(93)83218-k.

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Janoschek, Rudolf, Walter M. F. Fabian, Gert Kollenz, and C. Oliver Kappe. "Conformation and reactivity of ?-oxo-ketenes:Ab initio and semiempirical (AM1, PM3) calculations." Journal of Computational Chemistry 15, no. 2 (1994): 132–43. http://dx.doi.org/10.1002/jcc.540150203.

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50

Hüseyin, Ünver. "Conformation analyses of N-(3-pyridyl)-2-oxo-1-naphthylidenemethylamine." Journal of Indian Chemical Society Vol. 79, Jul 2002 (2002): 590–92. https://doi.org/10.5281/zenodo.5844800.

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Ankara University, Faculty of Sciences, Department of Physics, TR-06100 Tandogan, Ankara, Turkey E-mail : unver@science.ankara.edu.tr <em>Manuscript received 27 August 2001, revised 15 January 2002, accepted 12 February 2002</em> <em>N</em>-(3-Pyridyl)-2-oxo-1-naphthylidenemethylamine (1) has been studied by AM1 and PM3 semi-empirical quantum mechanical methods. Minimum energy conformation from AM1 and PM3 are calculated as a function of <em>0 </em>(C10-C11-N1-C12). Tautomerism and tautomer conformations of the compound (I) have also been investigated by AM1 and PM3 semi-empirical quantum mech

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