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Li F, Zhao Q, Sun C, Zhu L, Xia J, Huang B. Probing natural gas components with Raman integrating sphere technology. OPTICS LETTERS 2023; 48:187-190. [PMID: 36638414 DOI: 10.1364/ol.474494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Raman spectroscopy is a powerful method of probing natural gas components, but higher sensitivity, greater miniaturization, and lower cost techniques are required. Therefore, we designed a Raman integrating sphere-enhanced spectroscopy technology in a volume of 40 × 40 × 20 cm3 based on the principle of integrating sphere reflection. This technology consists of two parts: the first is an integrating sphere model to collect scattered signals, and the second is a right-angle light-boosting system to increase the optical path of the pump light in the sample. Raman integrating sphere technology has a detection limit of 0.5 ppm in the air with an exposure time of 600 s under room temperature and ambient pressure conditions. Experiments of natural gas detection display that the detection limits of ethane, propane, n-butane, isobutane, n-pentane, and isopentane are 28, 28, 95, 28, 189, and 95 ppm, respectively. In addition, there is a linear relationship between the relative Raman intensity and the concentration of each component in natural gas, which can be used as a probe for detecting unknown natural gas components in gas wells.
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Gassoumi B, Dlala NA, Echabaane M, Ghalla H, Zhou Y, Castro ME, Melendez FJ, Leila N, Madi F, Chaabane RB. Adsorption of toxic and non-toxic metals with new model of CX[4]: Experimental and computational investigation, Spectroscopic, QTAIM, and Antibacterial activity analyses. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Hernandes IS, Da Silva HC, Dos Santos HF, Pereira Ávila E, de almeida MV, Gomes MGR, Paschoal D, De Almeida WB. An Investigation of the Predominant Structure of Antibiotic Azithromycin in Chloroform Solution through NMR and Thermodynamic Analysis. Phys Chem Chem Phys 2022; 24:22845-22858. [DOI: 10.1039/d2cp02843c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Azithromycin (AZM) is a well-known macrolide-type antibiotic that has been used in the treatment of infections and inflammations. Knowledge of the predominant molecular structure in solution is a prerequisite for...
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Ávila EP, Mendes LA, De Almeida WB, Santos HFD, De Almeida MV. Conformational analysis and reactivity of naringenin. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.131027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hernandes IS, Da Silva HC, Dos Santos HF, De Almeida WB. Unveiling the Molecular Structure of Antimalarial Drugs Chloroquine and Hydroxychloroquine in Solution through Analysis of 1H NMR Chemical Shifts. J Phys Chem B 2021; 125:3321-3342. [PMID: 33760611 DOI: 10.1021/acs.jpcb.1c00609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chloroquine (CQ) and hydroxychloroquine (HCQ) have been standard antimalarial drugs since the early 1950s, and very recently, the possibility of their use for the treatment of COVID-19 patients has been considered. To understand the drug mode of action at the submicroscopic level (atoms and molecules), molecular modeling studies with the aid of computational chemistry methods have been of great help. A fundamental step in such theoretical investigations is the knowledge of the predominant drug molecular structure in solution, which is the real environment for the interaction with biological targets. Our strategy to access this valuable information is to perform density functional theory (DFT) calculations of 1H NMR chemical shifts for several plausible molecular conformers and then find the best match with experimental NMR profile in solution (since it is extremely sensitive to conformational changes). Through this procedure, after optimizing 30 trial distinct molecular structures (ωB97x-D/6-31G(d,p)-PCM level of calculation), which may be considered representative conformations, we concluded that the global minimum (named M24), stabilized by an intramolecular N-H hydrogen bond, is not likely to be observed in water, chloroform, and dimethyl sulfoxide (DMSO) solution. Among fully optimized conformations (named M1 to M30, and MD1 and MD2), we found M12 (having no intramolecular H-bond) as the most probable structure of CQ and HCQ in water solution, which is a good approximate starting geometry in drug-receptor interaction simulations. On the other hand, the preferred CQ and HCQ structure in chloroform (and CQ in DMSO-d6) solution was assigned as M8, showing the solvent effects on conformational preferences. We believe that the analysis of 1H NMR data in solution can establish the connection between the macro level (experimental) and the sub-micro level (theoretical), which is not so apparent to us and appears to be more appropriate than the thermodynamic stability criterion in conformational analysis studies.
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Affiliation(s)
- Isabel S Hernandes
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, Centro, Niterói 24020-141, Rio de Janeiro, Brazil
| | - Haroldo C Da Silva
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, Centro, Niterói 24020-141, Rio de Janeiro, Brazil
| | - Hélio F Dos Santos
- Núcleo de Estudos em Química Computacional (NEQC), Departamento de Química, ICE, Universidade Federal de Juiz de Fora (UFJF), Campus Universitário, Martelos, Juiz de Fora 36036-330, Minas Gerais, Brazil
| | - Wagner B De Almeida
- Laboratório de Química Computacional e Modelagem Molecular (LQC-MM), Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n, Campus do Valonguinho, Centro, Niterói 24020-141, Rio de Janeiro, Brazil
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The inclusion behavior of 8-Anilino-1-naphthalene sulfonate into Cucurbit[7]uril: A DFT approach. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2020.128390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Da Silva HC, De Almeida WB. Theoretical calculations of 1H NMR chemical shifts for nitrogenated compounds in chloroform solution. Chem Phys 2020. [DOI: 10.1016/j.chemphys.2019.110479] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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8
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Zhou Q, Du F, Chen Y, Fu Y, Sun W, Wu Y, Chen G. l -( -) -Quebrachitol as a Ligand for Selective Copper(0)-Catalyzed N-Arylation of Nitrogen-Containing Heterocycles. J Org Chem 2019; 84:8160-8167. [PMID: 31190531 DOI: 10.1021/acs.joc.9b00997] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
l-(-)-Quebrachitol (QCT) has been found as a ligand of copper powder for selective N-arylation of nitrogen-containing heterocycles with aryl halides. Furthermore, another potential catalytic system (copper powder/QCT/ t-BuOK) was successfully adapted to unactivated aryl chlorides.
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Affiliation(s)
- Qifan Zhou
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Fangyu Du
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Yuanguang Chen
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Yang Fu
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Wenjiao Sun
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
| | - Ying Wu
- Yunnan Institute of Tropical Crops , Jinghong 666100 , China
| | - Guoliang Chen
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education , Shenyang Pharmaceutical University , Shenyang 110016 , China
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Safia H, Ismahan L, Abdelkrim G, Mouna C, Leila N, Fatiha M. Density functional theories study of the interactions between host β-Cyclodextrin and guest 8-Anilinonaphthalene-1-sulfonate: Molecular structure, HOMO, LUMO, NBO, QTAIM and NMR analyses. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.01.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Aguiar AR, Alvarenga ES, Oliveira RP, Carneiro VMT, Moura LG. Syntheses of epoxides, and structural analysis of (E)N-hexyl-3-(trans-3-methyloxiran-2-yl)prop-2-enamide by spectroscopic techniques and DFT calculations. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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De Souza LA, Dos Santos HF, Costa LT, De Almeida WB. Inclusion complexes between cisplatin and oxidized carbon nanostructures: A theoretical approach. J Inorg Biochem 2018; 178:134-143. [DOI: 10.1016/j.jinorgbio.2017.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 10/05/2017] [Accepted: 10/30/2017] [Indexed: 11/26/2022]
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12
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De Souza LA, Tavares WM, Lopes APM, Soeiro MM, De Almeida WB. Structural analysis of flavonoids in solution through DFT 1H NMR chemical shift calculations: Epigallocatechin, Kaempferol and Quercetin. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.038] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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13
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Dos Santos HF, Chagas MA, De Souza LA, Rocha WR, De Almeida MV, Anconi CPA, De Almeida WB. Water Solvent Effect on Theoretical Evaluation of 1H NMR Chemical Shifts: o-Methyl-Inositol Isomer. J Phys Chem A 2017; 121:2839-2846. [DOI: 10.1021/acs.jpca.7b01067] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
| | - Marcelo A. Chagas
- Laboratório
de Química Computacional e Modelagem Molecular (LQC-MM), Departamento
de Química, ICEx, Universidade Federal de Minas Gerais, Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil
| | - Leonardo A. De Souza
- Laboratório
de Química Computacional (LQC), Departamento de Química
Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), 24020-150 Niterói, RJ, Brazil
| | - Willian R. Rocha
- Laboratório
de Química Computacional e Modelagem Molecular (LQC-MM), Departamento
de Química, ICEx, Universidade Federal de Minas Gerais, Campus Pampulha, 31270-901 Belo Horizonte, MG, Brazil
| | | | - Cleber P. A. Anconi
- Laboratório
de Química Fundamental (LQF), Departamento de Química, Universidade Federal de Lavras, 37200-000 Lavras, MG, Brazil
| | - Wagner B. De Almeida
- Laboratório
de Química Computacional (LQC), Departamento de Química
Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), 24020-150 Niterói, RJ, Brazil
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Maia PP, de Sousa SMR, De Almeida WB, Guimarães L, Nascimento CS. Computational investigation on the host-guest inclusion process of norfloxacin into β-cyclodextrin. J Mol Model 2016; 22:220. [PMID: 27558797 DOI: 10.1007/s00894-016-3098-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 08/08/2016] [Indexed: 11/24/2022]
Abstract
A theoretical (1)H NMR spectroscopy and thermodynamic analysis of the host-guest inclusion process involving the norfloxacin (NFX) into β-cyclodextrin (β-CD) was carried out. DFT structure and stabilization energies were obtained in both gas and aqueous phases. We could establish that the complex formation is enthalpy driven, and the hydrogen bonds established between NFX and β-CD play a major role in the complex stabilization. Besides, a theoretical (1)H NMR analysis has shown to be a supplementary proceeding to predict appropriately the inclusion mode of norfloxacin molecule into the β-CD. In this work, a theoretical study of the NFX@β-CD complex is reported for the first time, seeking a deep understanding of topology and thermodynamics of the inclusion complex formation. Graphical Abstract Topology, thermodynamic and (1)H NMR analysis of NFX@β-CD host-guest complexes.
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Affiliation(s)
- Pollyanna P Maia
- LQTC: Laboratório de Química Teórica e Computacional, Departamento de Ciências Naturais (DCNAT), Universidade Federal de São João Del-Rei (UFSJ), Campus Dom Bosco, 36301-160, São João Del Rei, MG, Brazil
| | - Sara Maria R de Sousa
- LQTC: Laboratório de Química Teórica e Computacional, Departamento de Ciências Naturais (DCNAT), Universidade Federal de São João Del-Rei (UFSJ), Campus Dom Bosco, 36301-160, São João Del Rei, MG, Brazil.,Grupo de Química Verde Coloidal e Macromolecular, Departamento de Química, Centro de Ciências Exatas e Tecnológicas, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil
| | - Wagner B De Almeida
- LQC: Laboratório de Química Computacional, Departamento de Química Inorgânica, Instituto de Química, Universidade Federal Fluminense (UFF), Outeiro de São João Batista s/n Centro, 24020-140, Niterói, RJ, Brazil
| | - Luciana Guimarães
- LQTC: Laboratório de Química Teórica e Computacional, Departamento de Ciências Naturais (DCNAT), Universidade Federal de São João Del-Rei (UFSJ), Campus Dom Bosco, 36301-160, São João Del Rei, MG, Brazil
| | - Clebio S Nascimento
- LQTC: Laboratório de Química Teórica e Computacional, Departamento de Ciências Naturais (DCNAT), Universidade Federal de São João Del-Rei (UFSJ), Campus Dom Bosco, 36301-160, São João Del Rei, MG, Brazil.
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15
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de Sousa SMR, Guimarães L, Ferrari JL, De Almeida WB, Nascimento CS. A DFT investigation on the host/guest inclusion process of prilocaine into β-cyclodextrin. Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.04.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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16
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Mancini DT, Souza EF, Caetano MS, Ramalho TC. 99Tc NMR as a promising technique for structural investigation of biomolecules: theoretical studies on the solvent and thermal effects of phenylbenzothiazole complex. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014; 52:129-137. [PMID: 24446055 DOI: 10.1002/mrc.4043] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 12/15/2013] [Accepted: 12/18/2013] [Indexed: 06/03/2023]
Abstract
The phenylbenzothiazole compounds show antitumor properties and are highly selective. In this paper, the (99)Tc chemical shifts based on the ((99m)Tc)(CO)3 (NNO) complex conjugated to the antitumor agent 2-(4'-aminophenyl)benzothiazole are reported. Thermal and solvent effects were studied computationally by quantum-chemical methods, using the density functional theory (DFT) (DFT level BPW91/aug-cc-pVTZ for the Tc and BPW91/IGLO-II for the other atoms) to compute the NMR parameters for the complex. We have calculated the (99)Tc NMR chemical shifts of the complex in gas phase and solution using different solvation models (polarizable continuum model and explicit solvation). To evaluate the thermal effect, molecular dynamics simulations were carried, using the atom-centered density matrix propagation method at the DFT level (BP86/LanL2dz). The results highlight that the (99)Tc NMR spectroscopy can be a promising technique for structural investigation of biomolecules, at the molecular level, in different environments.
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Affiliation(s)
- Daiana T Mancini
- Department of Chemistry, Federal University of Lavras, 37200-000, Lavras, Brazil
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18
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Teixeira MG, de Assis JV, Soares CGP, Venâncio MF, Lopes JF, Nascimento CS, Anconi CPA, Carvalho GSL, Lourenço CS, de Almeida MV, Fernandes SA, de Almeida WB. Theoretical and Experimental Study of Inclusion Complexes Formed by Isoniazid and Modified β-Cyclodextrins: 1H NMR Structural Determination and Antibacterial Activity Evaluation. J Phys Chem B 2013; 118:81-93. [DOI: 10.1021/jp409579m] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Milena G. Teixeira
- Grupo de Química Supramolecular
e Biomimética
(GQSB), Departamento de Química, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, Minas Gerais, Brazil
| | - João V. de Assis
- Núcleo Multifuncional de Pesquisas Químicas
(NUPEQ), Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), 36036-330, Juiz
de Fora, Minas Gerais, Brazil
| | - Cássia G. P. Soares
- Grupo de Química Supramolecular
e Biomimética
(GQSB), Departamento de Química, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, Minas Gerais, Brazil
| | - Mateus F. Venâncio
- Laboratório de Computacional e Modelagem Molecular
(LQC-MM), Departamento de Química, Universidade Federal de Minas Gerais (UFMG), 31270-901, Belo
Horizonte, Minas Gerais, Brazil
| | - Juliana F. Lopes
- Laboratório de Química Computacional (LaQC), Instituto de Física e Química, Universidade Federal de Itajubá (UNIFEI), 37500-903, Itajubá, Minas Gerais, Brazil
| | - Clebio S. Nascimento
- Departamento
de Ciências Naturais (DCNAT), Universidade Federal de São João Del Rei (UFSJ), Campus Dom Bosco, Praça Dom Helvécio,
74, 36301-160, São
João Del Rei, Minas Gerais, Brazil
| | - Cleber P. A. Anconi
- Laboratório de Química Fundamental
(LQF), Departamento de Química, Universidade Federal de Lavras (UFLA), Campus Universitário, 37200-000, Lavras, Minas Gerais, Brazil
| | - Guilherme S. L. Carvalho
- Laboratório
de Bacteriologia e Bioensaios em Micobactérias, Instituto de Pesquisa Clínica Evandro Chagas (IPEC) FIOCRUZ, 38659-508, Manguinhos, Rio de Janeiro, Brazil
| | - Cristina S. Lourenço
- Laboratório
de Bacteriologia e Bioensaios em Micobactérias, Instituto de Pesquisa Clínica Evandro Chagas (IPEC) FIOCRUZ, 38659-508, Manguinhos, Rio de Janeiro, Brazil
| | - Mauro V. de Almeida
- Núcleo Multifuncional de Pesquisas Químicas
(NUPEQ), Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora (UFJF), 36036-330, Juiz
de Fora, Minas Gerais, Brazil
| | - Sergio A. Fernandes
- Grupo de Química Supramolecular
e Biomimética
(GQSB), Departamento de Química, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, Minas Gerais, Brazil
| | - Wagner B. de Almeida
- Laboratório de Computacional e Modelagem Molecular
(LQC-MM), Departamento de Química, Universidade Federal de Minas Gerais (UFMG), 31270-901, Belo
Horizonte, Minas Gerais, Brazil
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19
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De Souza LA, Nogueira CA, Lopes JF, Dos Santos HF, De Almeida WB. DFT study of cisplatin@carbon nanohorns complexes. J Inorg Biochem 2013; 129:71-83. [DOI: 10.1016/j.jinorgbio.2013.09.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 09/08/2013] [Accepted: 09/10/2013] [Indexed: 11/26/2022]
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de Assis JV, Couri MRC, Porto RS, de Almeida WB, dos Santos LHR, Diniz R, de Almeida MV. Synthesis of Mercaptobenzothiazole and Mercaptobenzimidazole Condensed with Inositol Derivatives. J Heterocycl Chem 2013. [DOI: 10.1002/jhet.1096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- João Vitor de Assis
- Departamento de Química, ICE; Universidade Federal de Juiz de Fora, Campus Universitário, Martelos; 36036-330; Juiz de Fora; MG; Brazil
| | - Mara Rubia C. Couri
- Departamento de Química, ICE; Universidade Federal de Juiz de Fora, Campus Universitário, Martelos; 36036-330; Juiz de Fora; MG; Brazil
| | - Ricardo Silva Porto
- Instituto de Química e Biotecnologia; IQB, Universidade Federal de Alagoas; Campus A. C. Simões, Tabuleiro do Martins; 57072-970; Maceió; AL; Brazil
| | - Wagner B. de Almeida
- Departamento de Química, ICEx; Universidade Federal de Minas Gerais, Campus Universitário; Pampulha; 31270-901; Belo Horizonte; MG; Brazil
| | - Leonardo H. R. dos Santos
- Departamento de Química, ICE; Universidade Federal de Juiz de Fora, Campus Universitário, Martelos; 36036-330; Juiz de Fora; MG; Brazil
| | - Renata Diniz
- Departamento de Química, ICE; Universidade Federal de Juiz de Fora, Campus Universitário, Martelos; 36036-330; Juiz de Fora; MG; Brazil
| | - Mauro V. de Almeida
- Departamento de Química, ICE; Universidade Federal de Juiz de Fora, Campus Universitário, Martelos; 36036-330; Juiz de Fora; MG; Brazil
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De Almeida MV, Couri MRC, De Assis JV, Anconi CPA, Dos Santos HF, De Almeida WB. (1) H NMR analysis of O-methyl-inositol isomers: a joint experimental and theoretical study. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2012; 50:608-614. [PMID: 22865668 DOI: 10.1002/mrc.3848] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 06/11/2012] [Accepted: 06/26/2012] [Indexed: 06/01/2023]
Abstract
Density functional theory (DFT) calculations of (1) H NMR chemical shifts for l-quebrachitol isomers were performed using the B3LYP functional employing the 6-31G(d,p) and 6-311 + G(2d,p) basis sets. The effect of the solvent on the B3LYP-calculated NMR spectrum was accounted for using the polarizable continuum model. Comparison is made with experimental (1) H NMR spectroscopic data, which shed light on the average uncertainty present in DFT calculations of chemical shifts and showed that the best match between experimental and theoretical B3LYP (1) H NMR profiles is a good strategy to assign the molecular structure present in the sample handled in the experimental measurements. Among four plausible O-methyl-inositol isomers, the l-quebrachitol 2a structure was unambiguously assigned based only on the comparative analysis of experimental and theoretical (1) H NMR chemical shift data. The B3LYP infrared (IR) spectrum was also calculated for the four isomers and compared with the experimental data, with analysis of the theoretical IR profiles corroborating assignment of the 2a structure. Therefore, it is confirmed in this study that a combined experimental/DFT spectroscopic investigation is a powerful tool in structural/conformational analysis studies.
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Affiliation(s)
- Mauro V De Almeida
- Departamento de Química, ICE, Universidade Federal de Juiz de Fora, Campus Martelos, 36036-330, Juiz de Fora, MG, Brazil.
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de Assis JV, Teixeira MG, Soares CGP, Lopes JF, Carvalho GSL, Lourenço MCS, de Almeida MV, de Almeida WB, Fernandes SA. Experimental and theoretical NMR determination of isoniazid and sodium p-sulfonatocalix[n]arenes inclusion complexes. Eur J Pharm Sci 2012; 47:539-48. [PMID: 22841846 DOI: 10.1016/j.ejps.2012.07.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 07/13/2012] [Accepted: 07/17/2012] [Indexed: 11/20/2022]
Abstract
In this work the inclusion complex formation of isoniazid with sodium p-sulfonatocalix[n]arenes is reported aiming to improve the physicochemical and biopharmaceutical properties of isoniazid a first line antibuberculosis drug. The architectures of the complexes were proposed according to NMR data Job plot indicating details on the insertion of the isoniazid in the calix[n]arenes cavities. DFT theoretical NMR calculations were also performed for sodium p-sulfonatocalix[4]arene complex with isoniazid, with various modes of complexation being considered, to provide support for the experimental proposal. A comparison between experimental and theoretical ¹H NMR chemical shifts profiles allowed for the inclusion complex characterization confirming the isoniazid inclusion mode which is preferentially through the hydrazide moiety. The remarkable agreement between experimental and theoretical NMR profiles adds support to their use in the structural characterization of inclusion compounds. Antibacterial activity was evaluated and the results indicated the inclusion complexes as a potential strategy for tuberculosis treatment.
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Affiliation(s)
- João V de Assis
- Núcleo Multifuncional de Pesquisas Químicas-NUPEQ, Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora-UFJF, 36033-900 Juiz de Fora, MG, Brazil
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Oliveira BG, Araújo RCMU. Theoretical aspects of binary and ternary complexes of aziridine···ammonia ruled by hydrogen bond strength. J Mol Model 2011; 18:2845-54. [PMID: 22127607 DOI: 10.1007/s00894-011-1300-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 11/02/2011] [Indexed: 11/27/2022]
Abstract
B3LYP calculations, ChelpG atomic charges, and quantum theory of atoms in molecules (QTAIM) integrations were used to investigate the binary (1:1) and ternary (1:2) hydrogen-bonded complexes formed by aziridine (1) and ammonia (2). In a series of analysis, geometry data, electronic parameters, vibrational oscillators, and topological descriptors were used to evaluate hydrogen bond strength, and additionally to determine the more prominent molecular deformations upon the formation of C(2)H(5)N···NH(3) (1:1) and C(2)H(5)N···2NH(3) (1:2) systems. Taking a spectroscopic viewpoint, results obtained from analysis of the harmonic infrared spectrum were examined. From these, new vibrational modes and red- and blue-shifts related to the stretch frequencies of either donors or acceptors of protons were identified. Furthermore, the molecular topology of the electronic density modeled in accord with QTAIM was absolutely critical in defining bond critical points (BCP) and ring critical points (RCP) on the heterocyclic structures. Taking all the results together allowed us to identify and characterize all the N···H hydrogen bonds, as well as the strain ring of the aziridine and its stability.
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Affiliation(s)
- Boaz G Oliveira
- Instituto de Ciências Ambientais e Desenvolvimento Sustentável, Universidade Federal da Bahia, Barreiras, Brazil.
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