Log in

Relevant bibliographies by topics / GIAO-NMR / Journal articles

To see the other types of publications on this topic, follow the link: GIAO-NMR.

Journal articles on the topic 'GIAO-NMR'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'GIAO-NMR.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

RAMALHO, TEODORICO C., ELAINE F. F. DA CUNHA, FERNANDO C. PEIXOTO, and JOSÉ DANIEL FIGUEROA-VILLAR. "COMPUTATIONAL NMR INVESTIGATION OF RADIOSENSITIZER IN SOLUTION." Journal of Theoretical and Computational Chemistry 07, no. 01 (2008): 37–52. http://dx.doi.org/10.1142/s0219633608003575.

Full text

Abstract:

15 N and 13 C NMR chemical shifts for four radiosensitizers have been calculated and compared with experimental data. The thermal and solvent effects on NMR spectra were simulated with the polarizable continuum model and an alternative molecular dynamics/quantum mechanics methodology. Magnetic shielding tensors were evaluated at the GIAO-B3LYP and GIAO-OPBE level using II' and 6-311+(2D,P) basis sets, showing that it is essential to incorporate the dynamics and solvent effects on NMR calculations in condensed phases.

APA, Harvard, Vancouver, ISO, and other styles

2

MacGregor, Callum I., Bing Yuan Han, Jonathan M. Goodman, and Ian Paterson. "Toward the stereochemical assignment and synthesis of hemicalide: DP4f GIAO-NMR analysis and synthesis of a reassigned C16–C28 subunit." Chemical Communications 52, no. 25 (2016): 4632–35. http://dx.doi.org/10.1039/c6cc01074a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Ji, Xiaozhou, Nina C. Gonnella, and Dongyue Xin. "Deconvolution of fast exchange equilibrium states in NMR spectroscopy using virtual reference standards and probability theory." Organic & Biomolecular Chemistry 18, no. 35 (2020): 6927–34. http://dx.doi.org/10.1039/d0ob01459a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Ananikov, Valentine. "Evaluation of 13C NMR spectra of cyclopropenyl and cyclopropyl acetylenes by theoretical calculations." Open Chemistry 2, no. 1 (2004): 196–213. http://dx.doi.org/10.2478/bf02476190.

Full text

Abstract:

AbstractA convenient methodology was developed for a very accurate calculation of 13C NMR chemical shifts of the title compounds. GIAO calculations with density functional methods (B3LYP, B3PW91, PBE1PBE) and 6-311+G(2d,p) basis set predict experimental chemical shifts of 3-ethynylcyclopropene (1), 1-ethynylcyclopropane (2) and 1,1-diethynylcyclopropane (3) with high accuracy of 1–2 ppm. The present article describes in detail the effect of geometry choice, density functional method, basis set and effect of solvent on the accuracy of GIAO calculations of 13C NMR chemical shifts. In addition, t

APA, Harvard, Vancouver, ISO, and other styles

5

Chianese, Giuseppina, Bin-Bin Gu, Fan Yang, et al. "Spiroplakortone, an unprecedented spiroketal lactone from the Chinese sponge Plakortis simplex." RSC Advances 5, no. 78 (2015): 63372–76. http://dx.doi.org/10.1039/c5ra09840h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Loghmani-Khouzani, Hossein, Teresa Rauckyte, Borys Ośmiałowski, Ryszard Gawinecki, and Erkki Kolehmainen. "GIAO/DFT 13C NMR Chemical Shifts of 1,3,4-Thiadiazoles." Phosphorus, Sulfur, and Silicon and the Related Elements 182, no. 9 (2007): 2217–25. http://dx.doi.org/10.1080/10426500701407755.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Meléndez-Rodríguez, Myriam, Willy Rendón, Galia Chávez, Gerardo Martínez-Guajardo, and Pedro Joseph-Nathan. "1H and13C NMR assignments of dihydropipataline, the main of four long-chain 1-(3,4-methylenedioxyphenyl)-alkanes fromPiper darienenceD.C." Spectroscopy 14, no. 4 (2000): 195–201. http://dx.doi.org/10.1155/2000/784518.

Full text

Abstract:

Four 1-(3,4-methylenedioxyphenyl)-alkanes having linear ten, eleven, twelve and fourteen carbon atom chains, found in the roots ofPiper darienenceD.C., were separated by HPLC and their structures determined by mass spectrometry and NMR spectroscopy. Conventional 1D NMR methods were used for1H chemical shifts assignment of the main compound dihydropipataline (3) [1-(3,4-methylenedioxyphenyl)‒dodecane]. The13C NMR assignment was carried out using conventional considerations and 2D NMR techniques (HETCOR and FLOCK) in combination with spectral13C NMR simulation andab initioDFT-GIAO NMR calculatio

APA, Harvard, Vancouver, ISO, and other styles

8

Alkorta, Ibon, José Elguero, María Ángeles García, et al. "A tris(pyrazol-1-yl)methane bearing carboxylic acid groups at position 4: {1-[bis(4-carboxy-3,5-dimethyl-1H-pyrazol-1-yl)methyl]-3,5-dimethyl-1H-pyrazole-4-carboxylato}sodium dihydrate." Acta Crystallographica Section C Crystal Structure Communications 69, no. 9 (2013): 972–76. http://dx.doi.org/10.1107/s0108270113018969.

Full text

Abstract:

A low-resolution X-ray molecular structure of the title hydrated salt, [Na(C19H21N6O6)]·2H2O, displays scorpionate character and resolves apparent ambiguities between solution and solid-state NMR spectroscopies. The13C NMR CPMAS spectrum is consistent with this structure showing some splittings, which have been rationalized using GIAO/B3LYP/6-311++G(d,p) theoretical calculations.

APA, Harvard, Vancouver, ISO, and other styles

9

García-Granados, Andrés, José Dueñas, Juan N. Moliz, et al. "Semi-Synthesis of Triterpene A-ring Derivatives from Oleanolic and Maslinic Acids. Theoretical and experimental 13C chemical shifts." Journal of Chemical Research 2000, no. 2 (2000): 56–57. http://dx.doi.org/10.3184/030823400103166535.

Full text

Abstract:

Oleanolic and maslinic acids were isolated from solid waste from olive oil and several derivatives were semi-synthesised using typical reaction procedures. Experimental and theoretical (GIAO, B3LYP/6-31G*//MM+) 13C NMR chemical shifts for 21 compounds are given.

APA, Harvard, Vancouver, ISO, and other styles

10

Żołek, Teresa, Katarzyna Paradowska, and Iwona Wawer. "13C CP MAS NMR and GIAO-CHF calculations of coumarins." Solid State Nuclear Magnetic Resonance 23, no. 1-2 (2003): 77–87. http://dx.doi.org/10.1016/s0926-2040(02)00018-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Fukaya, Haruhiko, and Taizo Ono. "DFT-GIAO calculations of19F NMR chemical shifts for perfluoro compounds." Journal of Computational Chemistry 25, no. 1 (2004): 51–60. http://dx.doi.org/10.1002/jcc.10339.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Bashiz, Roghieh Tarlani, Sara Shahriari, Neda Samiei Soofi, et al. "Basis Sets and Nuclear Magnetic Resonance Shielding Effects for Mixing of MWBN and CNTs." Journal of Computational and Theoretical Nanoscience 13, no. 10 (2016): 6440–45. http://dx.doi.org/10.1166/jctn.2016.5583.

Full text

Abstract:

Density functional theory calculations (DFT), as well as hybrid methods (B3LYP) and HF method for MWCNTs have been carried out to study structural stability. The geometry of the MWCNTs have been optimized at DFT and HF methods within CCPTZ-CCPVZ, EPR-II, EPR-II, 6-31G* and 6-31++G** basis sets. According to GIAO method, NMR parameters have been evaluated. The Gaussian quantum chemical package is used for all calculations. The gauge including atomic orbital (GIAO) approach was applied for chemical shielding calculations of (5, 5)@(10, 10), (3, 3)@(7, 7), (4, 4)@(8, 8) DWCNTs.

APA, Harvard, Vancouver, ISO, and other styles

13

Siskos, Michael G., M. Iqbal Choudhary, and Ioannis P. Gerothanassis. "Refinement of labile hydrogen positions based on DFT calculations of 1H NMR chemical shifts: comparison with X-ray and neutron diffraction methods." Organic & Biomolecular Chemistry 15, no. 21 (2017): 4655–66. http://dx.doi.org/10.1039/c7ob01019b.

Full text

Abstract:

High resolution structures of hydrogen bonds: experimental (δ<sub>exp</sub>) and GIAO calculated <sup>1</sup>H NMR chemical shifts, δ<sub>calc</sub>, in combination with DFT energy minimization, are an excellent means for obtaining high resolution structures of labile protons.

APA, Harvard, Vancouver, ISO, and other styles

14

Rivera, Augusto, and Jaime Rios-Motta. "Revised Structure by Computational Methods for a Coumarin Isolated from Zanthoxylum Rhoifolium (Rutaceae)." Natural Product Communications 3, no. 3 (2008): 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300306.

Full text

Abstract:

On the basis of theoretical methods using DFT/B3LYP/6-31G* geometries and HF/6-311+G** GIAO NMR predictions, the 13C NMR spectroscopic data of a coumarin from Zanthoxylum rhoifolium was reassigned. The structure was revised to be 4-methoxy-3-(3-methylbut-2-enyl)-2 H-chromen-2-one (4) and not 3-methoxy-4-(3-methylbut-2-enyl)-2 H-chromen-2-one (2), as assumed previously.

APA, Harvard, Vancouver, ISO, and other styles

15

Tsipis, Athanassios C., and Ioannis N. Karapetsas. "Accurate prediction of 195Pt NMR chemical shifts for a series of Pt(ii) and Pt(iv) antitumor agents by a non-relativistic DFT computational protocol." Dalton Trans. 43, no. 14 (2014): 5409–26. http://dx.doi.org/10.1039/c3dt53594k.

Full text

Abstract:

Exhaustive benchmark DFT calculations reveal that the non-relativistic GIAO-PBE0/SARC-ZORA(Pt)∪6-31+G(d)(E) computational protocol predicts accurate <sup>195</sup>Pt NMR chemical shifts for a wide range of square planar Pt(ii) and octahedral Pt(iv) anticancer agents.

APA, Harvard, Vancouver, ISO, and other styles

16

Wu, Wei-Xiong, Xiao-Zeng You, An-Bang Dai, and Shou-Ping Jing. "Indo/Giao calculations of the NMR shielding constant including d orbitals." Polyhedron 9, no. 15-16 (1990): 1849–54. http://dx.doi.org/10.1016/s0277-5387(00)83997-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Costa, Fabio Luiz Paranhos, Ana Carolina Ferreira de Albuquerque, Fernando Martins dos Santos, and Mauro Barbosa de Amorim. "GIAO-HDFT scaling factor for 13 C NMR chemical shifts calculation." Journal of Physical Organic Chemistry 23, no. 10 (2010): 972–77. http://dx.doi.org/10.1002/poc.1749.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Xiaozeng, You, and Wu Weixiong. "15N and17O NMR chemical shift calculations using the MNDO/GIAO method." Magnetic Resonance in Chemistry 25, no. 10 (1987): 860–63. http://dx.doi.org/10.1002/mrc.1260251006.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Kupka, Teobald, Grażyna Pasterna, Piotr Lodowski, and Wiesław Szeja. "GIAO-DFT prediction of accurate NMR parameters in selected glucose derivatives." Magnetic Resonance in Chemistry 37, no. 6 (1999): 421–26. http://dx.doi.org/10.1002/(sici)1097-458x(199906)37:6<421::aid-mrc479>3.0.co;2-w.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Vázquez, Santiago. "GIAO-DFT study of13C NMR chemical shifts of highly pyramidalized alkenes." J. Chem. Soc., Perkin Trans. 2, no. 12 (2002): 2100–2103. http://dx.doi.org/10.1039/b207060j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Liu, Yannan, Tina A. Holt, Andrei Kutateladze, and Timothy R. Newhouse. "Stereochemical revision of xylogranatin F by GIAO and DU8+ NMR calculations." Chirality 32, no. 5 (2020): 515–23. http://dx.doi.org/10.1002/chir.23189.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Nieto, Carla I., Pilar Cabildo, M. Ángeles García, Rosa M. Claramunt, Ibon Alkorta, and José Elguero. "An experimental and theoretical NMR study of NH-benzimidazoles in solution and in the solid state: proton transfer and tautomerism." Beilstein Journal of Organic Chemistry 10 (July 16, 2014): 1620–29. http://dx.doi.org/10.3762/bjoc.10.168.

Full text

Abstract:

This paper reports the 1H, 13C and 15N NMR experimental study of five benzimidazoles in solution and in the solid state (13C and 15N CPMAS NMR) as well as the theoretically calculated (GIAO/DFT) chemical shifts. We have assigned unambiguously the "tautomeric positions" (C3a/C7a, C4/C7 and C5/C6) of NH-benzimidazoles that, in some solvents and in the solid state, appear different (blocked tautomerism). In the case of 1H-benzimidazole itself we have measured the prototropic rate in HMPA-d 18.

APA, Harvard, Vancouver, ISO, and other styles

23

Puškárová, Ingrid, and Martin Breza. "Antioxidant effectiveness of dehydrogenated p-phenylene diamines through NMR calculations." Acta Chimica Slovaca 9, no. 2 (2016): 100–103. http://dx.doi.org/10.1515/acs-2016-0017.

Full text

Abstract:

Abstract NMR shifts of N-phenyl-N’-alkyl-p-phenylenediamines (PPD) in vacuum were evaluated by B3LYP calculations using GIAO method. According to our previous studies, the Molar Antioxidant Effectiveness (AEM) of PPD antioxidants correlates with NMR chemical shifts of the amine nitrogen between aromatic rings (NA), the side aliphatic chain nitrogen (NB) and its neighboring tertiary carbon atom (CT) as well as of the hydrogens bonded to them. Our results indicate that the above mentioned chemical shifts correlate with increasing reactivity of dehydrogenated PPD antioxidants at these sites as we

APA, Harvard, Vancouver, ISO, and other styles

24

Buehl, M., W. Thiel, U. Fleischer, and W. Kutzelnigg. "Ab Initio Computation of 77Se NMR Chemical Shifts with the IGLO-SCF, the GIAO-SCF, and the GIAO-MP2 Methods." Journal of Physical Chemistry 99, no. 12 (1995): 4000–4007. http://dx.doi.org/10.1021/j100012a021.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Barone, Giampaolo, Luigi Gomez-Paloma, Dario Duca, Arturo Silvestri, Raffaele Riccio, and Giuseppe Bifulco. "Structure Validation of Natural Products by Quantum-Mechanical GIAO Calculations of 13C NMR Chemical Shifts GIAO=gauge including atomic orbitals." Chemistry - A European Journal 8, no. 14 (2002): 3233. http://dx.doi.org/10.1002/1521-3765(20020715)8:14<3233::aid-chem3233>3.0.co;2-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Luber, Markus, Arafa Musa, Hazem A. Kadry, and Franz Bracher. "Isolation of the Pyrrolizidine Alkaloid Intermedine-N-oxide from Cerinthe glabra and ab initio Calculation of its 13C NMR Shifts." Zeitschrift für Naturforschung B 67, no. 5 (2012): 411–16. http://dx.doi.org/10.5560/znb.2012-0030.

Full text

Abstract:

The pyrrolizidine alkaloid intermedine-N-oxide was isolated from Cerinthe glabra for the first time. Due to the questionable assignments of NMR signals of this compound in previous literature reports ab initio calculations of the 13C NMR values based on the GIAO approach, using HF and B3LYP levels of theory and the four basis sets 6-31G(d), 6-311G(d), 6-31G(d,p), and 6-311G(d,p) were performed. The assignments obtained this way are in very good accordance with the experimental values.

APA, Harvard, Vancouver, ISO, and other styles

27

Afonin, Andrei V., Alexander V. Vashchenko, Tatsuya Takagi, Atsuomi Kimura, and Hideaki Fujiwara. "Specific intramolecular interactions C-H···N in heteroaryl vinyl ethers and heteroaryl vinyl sulfides studied by 1H, 13C, and 15N NMR spectroscopies and by ab initio calculations on molecular structures as well as on nuclear shieldings." Canadian Journal of Chemistry 77, no. 4 (1999): 416–24. http://dx.doi.org/10.1139/v99-038.

Full text

Abstract:

1H,13C, and 15N NMR spectra have been measured for a series of isostructural aryl (heteroaryl) vinyl sulfides and compared with analogues of vinyl ethers. It was found that "intramolecular interaction" of the α-hydrogen of the vinyl group with endocyclic nitrogen takes place in 2-vinylthiopyridines. This is in common with the findings for 2-vinyloxypyridine and the intramolecular interaction is shown to have a profile characteristic of hydrogen bonding. Also, the NMR spectral data show that this type of interaction is more intense (~1.5 times) in 2-vinyloxypyridine than in 2-vinylthiopyridine.

APA, Harvard, Vancouver, ISO, and other styles

28

Boratyński, Przemysław J. "A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data." Beilstein Journal of Organic Chemistry 13 (November 22, 2017): 2478–85. http://dx.doi.org/10.3762/bjoc.13.245.

Full text

Abstract:

Scoring permutations of experimental chemical shift deviations and DFT/GIAO calculated deviations of isotropic shieldings for sets of four diastereomers can help to assign their relative configurations. This method was exercised on a set of diastereomeric Cinchona alkaloid derivatives, where 13C NMR data always identified the proper configuration. The presented approach is also an attempt to quantify the assignment by exclusion.

APA, Harvard, Vancouver, ISO, and other styles

29

Bühl, Michael, Jürgen Gauss, and John F. Stanton. "Accurate computations of 77Se NMR chemical shifts with the GIAO-CCSD method." Chemical Physics Letters 241, no. 3 (1995): 248–52. http://dx.doi.org/10.1016/0009-2614(95)00635-h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Olah, George A., Golam Rasul, Ludger Heiliger, and G. K. Surya Prakash. "Preparation, NMR Spectroscopic, andab Initio/DFT/GIAO-MP2 Studies of Halomethyl Cations1." Journal of the American Chemical Society 118, no. 15 (1996): 3580–83. http://dx.doi.org/10.1021/ja9538905.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Smith, Steven G., and Jonathan M. Goodman. "Assigning Stereochemistry to Single Diastereoisomers by GIAO NMR Calculation: The DP4 Probability." Journal of the American Chemical Society 132, no. 37 (2010): 12946–59. http://dx.doi.org/10.1021/ja105035r.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Katritzky, Alan R., Novruz G. Akhmedov, Jacek Doskocz, Prabhu P. Mohapatra, C. Dennis Hall, and Alâattin Güven. "NMR spectra, GIAO and charge density calculations of five-membered aromatic heterocycles." Magnetic Resonance in Chemistry 45, no. 7 (2007): 532–43. http://dx.doi.org/10.1002/mrc.1967.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Jaroszewska-Manaj, Jolanta, Dorota Maciejewska, and Iwona Wawer. "1H,13C and15N NMR and GIAO CPHF calculations on two quinoacridinium salts." Magnetic Resonance in Chemistry 38, no. 6 (2000): 482–85. http://dx.doi.org/10.1002/1097-458x(200006)38:6<482::aid-mrc677>3.0.co;2-p.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Schleyer, Paul von R., Jürgen Gauss, Michael Bühl, Robert Greatrex, and Mark A. Fox. "Even more reliable NMR chemical shift computations by the GIAO-MP2 method." J. Chem. Soc., Chem. Commun., no. 23 (1993): 1766–68. http://dx.doi.org/10.1039/c39930001766.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Gauss, Jürgen, and Hans-Joachim Werner. "NMR chemical shift calculations within local correlation methods: the GIAO-LMP2 approach." Physical Chemistry Chemical Physics 2, no. 10 (2000): 2083–90. http://dx.doi.org/10.1039/b000024h.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Aridoss, Gopalakrishnan, Chunqing Zhao, Gabriela L. Borosky, and Kenneth K. Laali. "Experimental and GIAO 15N NMR Study of Substituent Effects in 1H-Tetrazoles." Journal of Organic Chemistry 77, no. 8 (2012): 4152–55. http://dx.doi.org/10.1021/jo300242s.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Smith, Steven G., and Jonathan M. Goodman. "Assigning the Stereochemistry of Pairs of Diastereoisomers Using GIAO NMR Shift Calculation." Journal of Organic Chemistry 74, no. 12 (2009): 4597–607. http://dx.doi.org/10.1021/jo900408d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Monajjemi, M., S. Afsharnezhad, M. R. Jaafari, S. Mirdamadi, H. Monajemi, and S. Mollaamin. "THEORETICAL STUDY OF SOLVENT EFFECTS AND NMR SHIELDING TENSORS OF DLPC." Indonesian Journal of Chemistry 8, no. 1 (2010): 58–64. http://dx.doi.org/10.22146/ijc.21649.

Full text

Abstract:

The effect of the polarity of the environment on the conformation zwitterionic membrane dilauroyl phosphatidylcholine (DLPC) has been investigated with calculation at the Hatree-Fock level using the 6-31G* basis set with Onsager continuum solvation model. The ‘Gauge Including Atomic Orbital' (GIAO) approach is used to investigate Ab initio GIAO calculations of NMR chemical shielding tensors carried out within SCF-Hartree-Fock approximation are described. In order to compare the calculated chemical shifts with experimental ones, it is important to use consistent nuclear shielding for NMR refere

APA, Harvard, Vancouver, ISO, and other styles

39

Ortiz, P. J., E. M. Evleth, and L. A. Montero. "Ab initio SCF GIAO/NMR study of 1H and 13C NMR spectra of furan-2-carboxaldehyde isomers." Journal of Molecular Structure: THEOCHEM 432, no. 2 (1998): 121–27. http://dx.doi.org/10.1016/s0166-1280(98)00041-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Czernek, Jiří, та Jiří Brus. "Parametrizing the Spatial Dependence of 1H NMR Chemical Shifts in π-Stacked Molecular Fragments". International Journal of Molecular Sciences 21, № 21 (2020): 7908. http://dx.doi.org/10.3390/ijms21217908.

Full text

Abstract:

Most recently a renewed interest in several areas has arisen in factors governing the 1H NMR chemical shift (1H CS) of protons in aromatic systems. Therefore, it is important to describe how 1H CS values are affected by π-stacking intermolecular interactions. The parametrization of radial and angular dependences of the 1H CS is proposed, which is based on conventional gauge-independent atomic orbital (GIAO) calculations of explicit molecular fragments. Such a parametrization is exemplified for a benzene dimer with intermonomer vertical and horizontal distances which are in the range of values

APA, Harvard, Vancouver, ISO, and other styles

41

MOEINPOUR, F., M. BAKAVOLI, A. DAVOODNIA, and A. MORSALI. "THEORETICAL AND EXPERIMENTAL STUDY ON THE REGIOSELECTIVITY OF ACRYLONITRILE AND METHYLMETHACRYLATE 1,3-DIPOLAR CYCLOADDITION TO SOME NITRILIMINES." Journal of Theoretical and Computational Chemistry 11, no. 01 (2012): 99–109. http://dx.doi.org/10.1142/s021963361250006x.

Full text

Abstract:

1,3-dipolar cycloaddition between acrylonitrile and methylmethacrylate with two N-(4-bromophenyl)-C-(4-substituted) nitrilimines which were generated in situ afforded the new pyrazoles. The regioselectivity and reactivity of these reactions has been investigated on the basis of density functional theory (DFT)-based reactivity indexes and activation energy calculations. The theoretical 13C NMR chemical shifts of the cycloadducts which were obtained by GIAO method were comparable with the observed values.

APA, Harvard, Vancouver, ISO, and other styles

42

Lampert, Heike, Werner Mikenda, Alfred Karpfen, and Hanspeter Kählig. "NMR Shieldings in Benzoyl and 2-Hydroxybenzoyl Compounds. Experimental versus GIAO Calculated Data." Journal of Physical Chemistry A 101, no. 50 (1997): 9610–17. http://dx.doi.org/10.1021/jp970280d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Dokalik, Albrecht, Hermann Kalchhauser, Werner Mikenda, and Gerhard Schweng. "NMR spectra of nitrogen-containing compounds. Correlations between experimental and GIAO calculated data." Magnetic Resonance in Chemistry 37, no. 12 (1999): 895–902. http://dx.doi.org/10.1002/(sici)1097-458x(199912)37:12<895::aid-mrc581>3.0.co;2-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Wrackmeyer, Bernd, Silke Gerstmann, Max Herberhold, Graham A. Webb, and Hiromichi Kurosu. "Nitrogen NMR of some sulphur diimide anions and calculated (GIAO) nitrogen shielding constants." Magnetic Resonance in Chemistry 32, no. 8 (1994): 492–95. http://dx.doi.org/10.1002/mrc.1260320811.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Wolff, S. K., and T. Ziegler. "Calculation of DFT-GIAO NMR shifts with the inclusion of spin-orbit coupling." Journal of Chemical Physics 109, no. 3 (1998): 895–905. http://dx.doi.org/10.1063/1.476630.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Belaykov, P. A., and V. P. Ananikov. "Modeling of NMR spectra and signal assignment using real-time DFT/GIAO calculations." Russian Chemical Bulletin 60, no. 5 (2011): 783–89. http://dx.doi.org/10.1007/s11172-011-0125-8.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Holzer, Wolfgang, Laura Castoldi, Viktoriya Kyselova, et al. "Multinuclear NMR spectra and GIAO/DFT calculations of N-benzylazoles and N-benzylbenzazoles." Structural Chemistry 30, no. 5 (2019): 1729–35. http://dx.doi.org/10.1007/s11224-019-01310-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Hu, Xue-Yi, Xiao-Ming Li, Sui-Qun Yang, Hui Liu, Ling-Hong Meng, and Bin-Gui Wang. "Three New Sesquiterpenoids from the Algal-Derived Fungus Penicillium chermesinum EN-480." Marine Drugs 18, no. 4 (2020): 194. http://dx.doi.org/10.3390/md18040194.

Full text

Abstract:

Secondary metabolites obtained from marine-derived fungi are rich sources of drug candidates. Three new sesquiterpenoids, chermesiterpenoids A–C (1–3), along with four known alkaloids (4–7), were isolated and identified from the marine red algal-derived fungus Penicillium chermesinum EN-480. The structures of these new sesquiterpenoids were elucidated using detailed analysis of the NMR data and their relative configurations were elucidated using nuclear overhauser effect spectroscopy (NOESY) spectra as well as gauge-independent atomic orbital (GIAO) NMR shift calculations and DP4+ probability

APA, Harvard, Vancouver, ISO, and other styles

49

Blagojević, Polina D., Marko S. Pešić, and Niko S. Radulović. "Methyl 3-(5-(prop-1-yn-1-yl)thiophen-2-yl)propanoate: A Rare Acetylene Derivative from Artemisia absinthium Root Essential Oil." Natural Product Communications 12, no. 4 (2017): 1934578X1701200. http://dx.doi.org/10.1177/1934578x1701200433.

Full text

Abstract:

Methyl 3-(5-(prop-1-yn-1-yl)thiophen-2-yl)propanoate (1), biosynthetically and structurally related to dehydromatricaria ester, was isolated from the root essential oil of Artemisia absinthium L. (0.7% of the total oil). This is the second record of this compound and the very first one regarding it as an essential-oil constituent. In this paper, we give details regarding its isolation, structural elucidation and gas chromatographic properties (RI on DB-5 MS column: 1694). The NMR-based identification of the compound was corroborated by simulation of its 1H- and 13C-NMR spectra using a GIAO met

APA, Harvard, Vancouver, ISO, and other styles

50

SHAABANZADEH, MASOUD, HAMID HASHEMIMOGHADDAM, MARYAM BIKHOF TORBATI, and TAHEREH SOLEYMANI AHOEE. "SYNTHESIS AND GIAO NMR CALCULATIONS FOR TWO DIASTEREOISOMERS OF 2′-ACETYLOXY-2′-PHENYLSPIRO[INDENO[1,2-b]QUINOXALIN-11,1′-CYCLOPROPANE]." Journal of Theoretical and Computational Chemistry 11, no. 06 (2012): 1227–36. http://dx.doi.org/10.1142/s0219633612500824.

Full text

Abstract:

Two diastereoisomers of 2′-acetyloxy-2′-phenylspiro[indeno[1,2-b]quinoxalin-11,1′-cyclopropane] were synthesized and their 1 H NMR spectra were recorded. Their chemical structures were fully optimized at B3LYP/6-311+G(d,p) level of theory using the Gaussian 03W program package. The 1 H NMR chemical shifts were calculated for geometry-optimized structures of the diastereoisomers with the gauge independent atomic orbital (GIAO) and B3LYP method with the 6-311+G(d,p), 6-311++G(d), 6-31++G(d,p) and 6-31+G(d) basis sets. The computational results were then compared with the experimental values and

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!