Estudio de las Propiedades Moleculares y Reactivas del eucaliptol usando la Teoría Funcional de la Densidad DFT B3LYP/6-31G* / Reactive and Molecular properties of eucaliptol using Density Functional Theory DFT B3LYP/6-31G*

Introducción: El eucalipto fue utilizado el 2020 para tratar síntomas del coronavirus, en un intento de comprender el comportamiento reactivo del componente principal el eucaliptol, y con la finalidad de disponer de información preliminar para estudios posteriores, es que se escogió a esta molécula en el presente estudio. Se realizó un estudio químico teórico computacional, se calcularon propiedades moleculares, valores de longitudes de enlace y ángulos, así como propiedades químicas y descriptores químicos de interés en estudios QSAR, de energías y de reactividad. Objetivo: Determinar las propiedades moleculares, y descriptores de reactividad del eucaliptol con el fin de comprender el comportamiento reactivo mediante la Teoría Funcional de la Densidad (DFT). Método: Este estudio computacional utilizo los métodos Hartree Fock y la Teoría Funcional de densidad DFT, las propiedades químicas y descriptores moleculares para el eucaliptol, simulado en condiciones de vacío y en medio etanólico, fueron comparadas con los datos de referencia del Banco de Datos Europeo. Los descriptores ADME se calcularon con la estructura optimizada, usando los servidores en línea SwissADME y ADMETlab. Resultados: En cuanto se refiere a las longitudes de enlace intramolecular se encontró que no hay diferencia estadística significativa entre las longitudes de enlace en los cuatro tratamientos cuánticos. En los orbitales frontera, un band gap de 8,1 eV entre los orbitales HOMO LUMO muestra que la molécula es muy estable, los orbitales HOMO-1 y LUMO+1 de 9,8eV indica que se necesitaría mucha energía para que ocurra una transición electrónica. Conclusión: La teoría DFT B3LYP/6-31G fue aplicada sobre la estructura del eucaliptol, se investigaron algunas propiedades geométricas, electrónicas, de reactividad química y descriptores ADME intentando comprender el comportamiento reactivo de esta molécula, la energía de los orbitales HOMO-LUMO mostraron que la molécula tiene estabilidad energética, y los descriptores ADME sugieren una buena absorción a través de las membranas, finalmente el eucaliptol no es mutagénico desde el punto de vista de la química teórica.

Introduction: Eucalyptol was used in 2020 to treat coronavirus symptoms, in an attempt to understand the reactive behavior of the eucalyptol, a main molecule, and in order to have preliminary information for subsequent studies, this molecule was chosen in this study. A computational theoretical chemical study was carried out, molecular properties, values ​​of bond lengths and angles, as well as chemical properties and chemical descriptors of interest in QSAR, energy and reactivity studies were calculated. Objective: To determine the molecular properties and reactivity descriptors of eucalyptol in order to understand the reactive behavior through the Density Functional Theory (DFT). Method: This computational study used the Hartree Fock methods and the DFT Density Functional Theory, the chemical properties and molecular descriptors for eucalyptol, simulated under vacuum conditions and in ethanolic medium, were compared with the reference data from the Data Bank. European. The ADME descriptors were calculated with the optimized structure, using the online servers SwissADME and ADMETlab. Results: Regarding the intramolecular bond lengths, it was found that there is no statistically significant difference between the bond lengths in the four quantum treatments. In the frontier orbitals, a band gap of 8.1 eV between the HOMO LUMO orbitals shows that the molecule is very stable, the HOMO-1 and LUMO+1 orbitals of 9.8eV indicate that a lot of energy would be needed for a transition to occur. electronics. Conclusion: The DFT B3LYP/6-31G theory was applied to the structure of eucalyptol, some geometric, electronic, chemical reactivity properties and ADME descriptors were investigated trying to understand the reactive behavior of this molecule, the energy of the HOMO-LUMO orbitals showed that the molecule has energetic stability, and the ADME descriptors suggest a good absorption through the membranes, finally eucalyptol is not mutagenic from the point of view of theoretical chemistry.

Síntesis de tioureas con isoniacida y niacida estructural: test frente a bacterias Gram + y Gram -

Se sintetizaron los compuestos N-(2-ni-cotinoilhidrazina-1-carbonotioil)benzamida (H3L1) y su isómero N-(2-isonicoti-noilhidrazina-1-carbonotioil)benzamida (H3L2) tipo N, S, O dadores, por reacción del isotiocianato de benzoilo con la hidracida nicotínica y la isoniacida, respectivamente. Los compuestos H3L1 y H3L2 fueron caracterizados por 1H-RM-N,13C-RMN, FT-IR y análisis elemental. Se realizó el análisis computacional utilizando las funciones de Fukui para determinar las razones por las cuales no se formaron los 1,2,4-triazoles. Se hicieron pruebas preliminares de los compuestos sintetizados frente a Staphylococcus aureus (Gram+) y Escherichia coli (Gram-). Se demostró importante actividad frente a las bacterias mencionadas.

The compounds N-(2-nicotinoylhydra-zine-1-carbonothioyl)benzamide (H3L1) and its isomer N-(2-isonicotinoylhydra-zine-1-carbonothioyl)benzamide (H3L2) type N, S, O donors, by reaction of benzoyl isothiocyanate with nicotinic hydrazide and isoniazid respectively were synthesized. The H3L1 and H3L2 compounds were characterized by 1H-NMR, 13C-NMR, FT-IR and elemental analysis. Computational analysis using the Fukui functions were performed to determine the reasons why the 1,2,4-triazoles were not formed. Preliminary tests of the synthesized compounds were carried out against Staphylo-coccus aureus (Gram+) and Escherichia coli (Gram-), having demonstrated significant activity against such bacteria.

Os compostos N-(2-nicotinoilhidrazina-1-carbonotioil)benzamida (H3L1) e seu isòmero N-(2-isonicotinoilhidrazina-1-carbonotioil)benzamida foram sintetizados. (H3L2) doadores tipo N, S, O, por reação de isotiocianato de benzoíla com hidrazida nicotínica e isoniazida, respectivamente. Os compostos H3L1 e H3L2 foram caracterizados por 1H-NMR, 13C-NMR, FT-IR e análise elementar. A análise computacional usando as funções de Fukui foi realizada para determinar as razões pelas quais os 1,2,4-triazóis não foram formados. Testes preliminares dos compostos sintetizados foram realizados contra Staphylococcus aureus (Gram+) e Escherichia coli (Gram-), tendo demonstrado atividade significativa contra as referidas bactérias.

Desenvolvimento de rota sintética da Rosiglitazona em processo batelada e microrreator capilar / Rosiglitazone synthetic route development in batch process and capillary microreactor

Para que os fármacos possam ser comercializados economicamente, a sua escala de produção deve ser aumentada para atender à demanda do mercado. Atualmente, a maior parte dos fármacos são sintetizados em processos batelada que possuem limitações quanto à eficiência de mistura, temperatura e pressão. O uso de microrreatores surge como alternativa na indústria químico-farmacêutica, aumentando a eficiência dos processos de maneira segura. Ferramentas utilizadas no segmento computacional multidisciplinar teórico, como o DFT (Density Functional Theory), podem prever e compreender o comportamento das reações químicas, podendo ter grande utilidade na síntese de novos fármacos economizando tempo, investimento e reduzindo a geração de resíduos. A diabetes mellitus é uma doença de caráter epidêmico, que a cada ano vem aumentando o número de casos. O emprego de fármacos derivados das glitazonas no tratamento de diabetes mellitus tipo 2 é recomendado devido ao excelente controle glicêmico que esta classe de fármacos oferece. Neste trabalho, foi sintetizada a Rosiglitazona, um fármaco derivado das glitazonas, que auxilia no tratamento da diabetes mellitus tipo 2, sendo estudadas duas rotas de síntese distintas, que foram otimizadas com o intuito de maximizar o rendimento de seus intermediários, obtendo a Rosiglitazona com pureza de cerca de 94%. Foi realizada, para os intermediários, aqui denominados, 1R, 2R2 e 3R2 a síntese one-pot e para os intermediários 1R, 2R1 e 3R2 foi realizada a transposição do processo usual em batelada para fluxo contínuo no microrreator, com rendimentos de até 93%. Com o auxílio da química quântica computacional, a reação de síntese do intermediário 1R, foi elucidada teoricamente e determinadas as grandezas termodinâmicas (ΔH‡, ΔG‡ e ΔS‡) no estado de transição, que foram comparadas com os valores experimentais, sendo constatada uma boa concordância, com desvio máximo de 14%

In order for drugs to be commercialized economically, their production scale must be increased to meet market demand. Currently, most drugs are synthesized in batch processes that have limitations in terms of mixing efficiency, temperature and pressure. The use of microreactors appears as an alternative in the chemical-pharmaceutical industry, increasing the efficiency of the synthesis processes in a safe way. Tools used in the theoretical multidisciplinary computational segment, such as DFT (Density Functional Theory), can predict and understand the behavior of chemical reactions, and can be very useful in the synthesis of new drugs, saving time, investment and reducing waste generation. Diabetes mellitus is an epidemic disease that has been increasing the number of cases every year. The use of drugs derived from glitazones in the treatment of type 2 diabetes mellitus is recommended due to the excellent glycemic control that this class of drugs offers. In this work, Rosiglitazone, a drug derived from glitazones, which helps in the treatment of type 2 diabetes mellitus, was synthesized. Two different synthetic routes were studied and optimized in order to maximize the yield of its intermediates, obtaining Rosiglitazone with purity of about 94%. One-pot synthesis was performed to 1R, 2R2 and 3R2 intermediates, and the transposition from the usual batch process to continuous flow in microreactor was performed to 1R, 2R1 and 3R2 intermediates, with yields of up to 93%. With the aid of computational quantum chemistry, the intermediate 1R synthesis reaction was theoretically elucidated and the thermodynamic properties were determined (ΔH‡, ΔG‡ and ΔS‡) in the transition state, which were compared with the experimental results, obtaining good agreement, with a maximum deviation of 14%

Modelagem Molecular (TD-DFT) aplicada na predição do fator de proteção solar de compostos naturais / Molecular Modeling (TD-DFT) applied to predict the sun protection factor of natural compounds

Na área da saúde pública, as doenças provocadas pela radiação solar têm ganho grande destaque, por serem cada vez mais comuns. Dentre as principais formas de prevenção a utilização de filtros solares são as mais comuns e de fácil acesso. Os filtros utilizados atuam por sua capacidade de refletir, absorver ou dispersar os raios solares ultravioletas (UV). A aplicação de métodos teóricos tornou-se indispensável no auxílio do planejamento de novos compostos com função terapêutica, em estudos de suas diferentes propriedades, buscando gerar, manipular e analisar representações realistas de estruturas moleculares obtidas a partir de cálculos de propriedades físico-químicas por meio da química computacional. Neste estudo, foram selecionados compostos naturais de origem vegetal (3-O-metilquercetina, ácido gálico, aloína, catequina, quercetina e resveratrol), os quais são descritos com propriedades fotoprotetoras, para os quais se aplicou métodos computacionais para predição dos espectros de absorção, por meio do método TD-DFT (Teoria funcional da densidade dependente do tempo). Foram avaliadas as principais transições eletrônicas dos compostos estudados e se as diferenças de energia HOMO e LUMO para os compostos que absorvem na faixa UV compreendem na UVA (320400 nm, 3.103.87 eV), UVB (290320 nm, 3.874.27 eV) ou na UVC (100290 nm, 4.2712.4 eV). Realizou-se a validação experimental para o método aplicado para o EMC, quercetina e resveratrol, demonstrando a eficácia. Após os estudos realizados concluímos que o resveratrol, teoricamente é um ótimo candidato a fotoprotetor. O estudo ofereceu informações relevantes sobre o poder de predição in silico para fotoprotetores, e se utilizado pode contribuir diminuindo de tempo e custos em pesquisas para desenvolver fármacos

In the area of public health, diseases caused by solar radiation have gained great prominence, as they are increasingly common. Among the main ways to prevent the use of sunscreens are the most common and easily accessible. The filters used act by their ability to reflect, absorb or scatter the sun's ultraviolet (UV) rays. The application of theoretical methods has become indispensable in helping to plan new compounds with therapeutic function, in studies of their different properties, seeking to generate, manipulate and analyze realistic representations of molecular structures obtained from calculations of physicochemical properties through computational chemistry. In this study, natural compounds of plant origin (3-O-methylquercetin, gallic acid, aloin, catechin, quercetin, and resveratrol) were selected, which are described with photoprotective properties, for which computational methods were applied to predict the absorption spectra, using the TD-DFT (Time-Dependent Density Functional Theory) method. The main electronic transitions of the studied compounds were evaluated and whether the differences in HOMO and LUMO energy for compounds that absorb in the UV range comprise UVA (320400 nm, 3.103.87 eV), UVB (290 320 nm, 3.87 4.27 eV) or UVC (100290 nm, 4.2712.4 eV). Experimental validation was carried out for the method applied for CME, quercetin, and resveratrol, demonstrating its effectiveness. After the studies carried out, we concluded that resveratrol, theoretically, is an excellent candidate for sunscreen. The study provided relevant information about the in silico predictive power for photoprotectors, and if used, it can contribute to reducing time and costs in research to develop drugs

Desenvolvimento de rota sintética da Rosiglitazona em processo batelada e microrreator capilar / Rosiglitazone synthetic route development in batch process and capillary microreactor

Para que os fármacos possam ser comercializados economicamente, a sua escala de produção deve ser aumentada para atender à demanda do mercado. Atualmente, a maior parte dos fármacos são sintetizados em processos batelada que possuem limitações quanto à eficiência de mistura, temperatura e pressão. O uso de microrreatores surge como alternativa na indústria químico-farmacêutica, aumentando a eficiência dos processos de maneira segura. Ferramentas utilizadas no segmento computacional multidisciplinar teórico, como o DFT (Density Functional Theory), podem prever e compreender o comportamento das reações químicas, podendo ter grande utilidade na síntese de novos fármacos economizando tempo, investimento e reduzindo a geração de resíduos. A diabetes mellitus é uma doença de caráter epidêmico, que a cada ano vem aumentando o número de casos. O emprego de fármacos derivados das glitazonas no tratamento de diabetes mellitus tipo 2 é recomendado devido ao excelente controle glicêmico que esta classe de fármacos oferece. Neste trabalho, foi sintetizada a Rosiglitazona, um fármaco derivado das glitazonas, que auxilia no tratamento da diabetes mellitus tipo 2, sendo estudadas duas rotas de síntese distintas, que foram otimizadas com o intuito de maximizar o rendimento de seus intermediários, obtendo a Rosiglitazona com pureza de cerca de 94%. Foi realizada, para os intermediários, aqui denominados, 1R, 2R2 e 3R2 a síntese one-pot e para os intermediários 1R, 2R1 e 3R2 foi realizada a transposição do processo usual em batelada para fluxo contínuo no microrreator, com rendimentos de até 93%. Com o auxílio da química quântica computacional, a reação de síntese do intermediário 1R, foi elucidada teoricamente e determinadas as grandezas termodinâmicas (ΔH‡, ΔG‡ e ΔS‡) no estado de transição, que foram comparadas com os valores experimentais, sendo constatada uma boa concordância, com desvio máximo de 14%

In order for drugs to be commercialized economically, their production scale must be increased to meet market demand. Currently, most drugs are synthesized in batch processes that have limitations in terms of mixing efficiency, temperature and pressure. The use of microreactors appears as an alternative in the chemical-pharmaceutical industry, increasing the efficiency of the synthesis processes in a safe way. Tools used in the theoretical multidisciplinary computational segment, such as DFT (Density Functional Theory), can predict and understand the behavior of chemical reactions, and can be very useful in the synthesis of new drugs, saving time, investment and reducing waste generation. Diabetes mellitus is an epidemic disease that has been increasing the number of cases every year. The use of drugs derived from glitazones in the treatment of type 2 diabetes mellitus is recommended due to the excellent glycemic control that this class of drugs offers. In this work, Rosiglitazone, a drug derived from glitazones, which helps in the treatment of type 2 diabetes mellitus, was synthesized. Two different synthetic routes were studied and optimized in order to maximize the yield of its intermediates, obtaining Rosiglitazone with purity of about 94%. One-pot synthesis was performed to 1R, 2R2 and 3R2 intermediates, and the transposition from the usual batch process to continuous flow in microreactor was performed to 1R, 2R1 and 3R2 intermediates, with yields of up to 93%. With the aid of computational quantum chemistry, the intermediate 1R synthesis reaction was theoretically elucidated and the thermodynamic properties were determined (ΔH‡, ΔG‡ and ΔS‡) in the transition state, which were compared with the experimental results, obtaining good agreement, with a maximum deviation of 14%.

3, 4-seco-Isopimarane and 3, 4-seco-pimarane diterpenoids from Callicarpa nudiflora / 中国天然药物

A phytochemical investigation was carried out on the extract of a medicinal plant Callicarpa nudiflora, resulting in the characterization of five new 3, 4-seco-isopimarane (1-5) and one new 3, 4-seco-pimarane diterpenoid (6), together with four known compounds. The structures of the new compounds were fully elucidated by extensive analysis of MS, 1D and 2D NMR spectroscopic data, and time-dependent density functional theory (TDDFT) calculation of electronic circular dichroism (ECD) spectra, and DFT calculations for NMR chemical shifts and optical rotations.

A Schiff base of 2-((E)-(2-amino-5-methylphenylimino)methyl)- 5-(difluoromethoxy)phenol and its applications on fluorescent chemosensor for selection of Mg2+ ion, molecular docking, and anticancer activity

A novel Schiff base of 2-((E)-(2-amino-5-methylphenylimino)methyl)-5-(difluoromethoxy)phenol (R) wassynthesized and characterized by FTIR, 1H&13C-NMR, and mass spectrometry. The receptor turned yellow and thengreen in the presence of Mg2+ molecules, with the intervention of different metal ions. The selectivity and sensitivityof Mg2+ ion caused the maximum fluorescence emission intensity at 524 nm, with an excitation wavelength at 378nm. Further experiments confirmed that receptor R binds with Mg2+. Job’s plot conforms to a 1:1 stoichiometrycomplex formation. The strong fluorescence is owing to the photoinduced electron/energy transfer effect. The receptorwas recovered by an ethylenediaminetetraacetic acid titration and the emission intensity also returned to a valueequivalent to the unbound ligand. protein data bank: 4J96 was used for the molecular docking of receptor R. Thecytotoxicity effect treatment was carried out by increasing the concentration of HeLa cells to predict IC50 value. Thehighest occupied molecular orbital/lowest unoccupied molecular orbita energy gap calculated and compared betweenR results as 3.48 eV and R-Mg2+ alpha and the beta value calculated a low energy value at 2.27 eV.

Estudio de las propiedades moleculares y reactivas del antibiótico Ciprofloxacina a nivel de teoría de funcional de densidad DFT B3LYP/6- 31G* / Study of the molecular and reactive properties of the antibiotic Ciprofloxacin at the level of functional density theory DFT B3LYP / 6-31G*

INTRODUCCIÓN: se realizó un estudio teórico computacional de la ciprofloxacina calculando detalladamente las propiedades moleculares del mismo. Se caracterizó este antibiótico, presentado valores de longitudes de enlace y ángulos, así como de propiedades químicas de interés en estudios QSAR, de energías y de reactividad, obtenidos por métodos mecano cuánticos utilizando la teoría funcional de densidad DFT B3LYP/6-31G*. OBJETIVO: determinar las propiedades moleculares, de QSAR y de reactividad de la Ciprofloxacina usando el método teórico de cálculo denominado: Teoría del Funcional de la Densidad (DFT) MÉTODO: la estructura de la ciprofloxacina fue trazada usando la interfaz de SPARTAN; esta fue sometida a cálculos de optimización geométrica inicialmente de Mecánica Molecular para obtener la estructura más estable, posteriormente todas las estructuras fueron analizadas utilizando la teoría de Hartree-Fock para obtener valores más confiables de energía y geometría. Posteriormente sobre estas estructuras se aplica la Teoría de Funcional de Densidad DFT usándose la base 6-31G*. Con esta estructura se realizaron cálculos de energía en conjunto con un análisis de población natural (NPA) para la molécula neutra e ionizada (positiva y negativa) para determinar los centros nucleofílicos, electrofílicos y radicalarios, y obtener posteriormente los descriptores de la reactividad local y las funciones de Fukui nucleofílica y electrofílica. RESULTADOS: Los valores experimentales de longitud de enlace para los enlaces C=C aromático del fenilo de 1.400 Å, respecto a longitudes de enlace C(10q)-C(5)=1.401 Å y C(8)- C(9q)=1.406 Å mostraron diferencias de 0.001 y 0.006. El enlace característico con el flúor F-C aromático reportado de 1.363Å, respecto al calculado en este estudio de 1.353Å muestra una diferencia de 0.01 del valor experimental. La longitud de enlace N1 de la quinolina y el C9 del ciclopropil reportado con 1.465Å y el calculado 1.450Å muestra una diferencia de 0.015. La longitud de enlace experimental C=O aromático de 1.230Å respecto al encontrado O(3)-C(4) de 1.227Å, muestra una diferencia de 0.003. Finalmente, en el anillo piperazina la longitud experimental C-N reportado de 1.465 Å, la calculada 1.463 Å diferencia de 0.002 De acuerdo con los datos calculados y reportados experimentalmente, se puede concluir que existe una buena correlación en los valores de las longitudes de enlace a nivel DFT B3LYP/6-31G*. Los ángulos entre átomos de carbono del sistema aromático encontrados en la ciprofloxacina oscilan entre 120.02° a 122.27°, en relación al valor teórico de este tipo de átomos de carbono con hibridación sp2 cuentan con un ángulo de 120°. En cuanto a la reactividad química, los índices descriptores de reactividad química global y local, el orbital HOMO es el dador y el orbital LUMO el aceptor. Un band-gap de 4.65 ev indica claramente que la molécula es muy estable. CONCLUSIÓN: se establecieron valores de las propiedades moleculares y así como de propiedades químicas de interés en estudios de estructura actividad QSAR, de energías y de reactividad del antibiótico ciprofloxacina.

INTRODUCTION: a theoretical computational study of ciprofloxacin was performed, calculating in detail the molecular properties of it. This antibiotic was characterized, presenting values of link lengths and angles as well as chemical properties of interest in QSAR, energy and reactivity studies, obtained by quantum mechanic methods using the Functional Density Theory DFT B3LYP / 6-31G *. OBJECTIVE: to determine the molecular, QSAR and reactivity properties of Ciprofloxacin using the theoretical calculation method called: Density Functional Theory (DFT). METHOD: the structure of ciprofloxacin was mapped using the SPARTAN interface; This was initially subjected to calculations of geometric optimization of Molecular Mechanics to obtain the most stable structure, later all the structures were analyzed using the Hartree-Fock theory to obtain more reliable values of energy and geometry. Subsequently on these structures the DFT Density Functional Theory is applied using the 6-31G * base. With this structure, energy calculations were performed in conjunction with a natural population analysis (NPA) for the neutral and ionized molecule (positive and negative) to determine the nucleophilic, electrophilic and radical centers, and subsequently obtain the descriptors of the local reactivity and the nucleophilic and electrophilic Fukui functions. RESULTS: The experimental values of bond length for the aromatic C = C bonds of the phenyl of 1,400 Å, with respect to link lengths C (10q) -C (5) = 1,401 Å and C (8) -C (9q) = 1,406 Å showed differences of 0.001 and 0.006. The characteristic link with the reported aromatic F-C fluorine of 1,363Å, compared to that calculated in this study of 1,353Å shows a difference of 0.01 of the experimental value. The linkage length N1 of the quinoline and the C9 of the cyclopropyl reported with 1,465Å and the calculated 1,450Å shows a difference of 0.015. The experimental aromatic C = O link length of 1,230Å with respect to the found O (3) -C (4) of 1,227Å, shows a difference of 0.003. Finally, in the piperazine ring, the reported CN experimental length of 1,465 Å, the calculated 1,463 Å difference of 0.002 According to the data calculated and reported experimentally, it can be concluded that there is a good correlation in the values of the link lengths at the DFT level B3LYP / 6-31G *. The angles between carbon atoms of the aromatic system found in ciprofloxacin range from 120.02 ° to 122.27 °, in relation to the theoretical value of this type of carbon atoms with sp2 hybridization have an angle of 120 °. Regarding chemical reactivity, the indexes describing global and local chemical reactivity [2], the HOMO orbital is the donor and the LUMO orbital is the acceptor. A band-gap of 4.65 ev clearly indicates that the molecule is very stable. The chemical potential obtained for the neutral ciprofloxacin of (-3,715ev) indicates that the electronic density of the system can vary spontaneously, since it has a negative value. The hardness gave the value of 2,325ev, indicates that ciprofloxacin will have little tendency to give or receive electrons, that is, the hardness has been associated with the stability of the chemical system. CONCLUSION: molecular and chemical properties values of interest were established in QSAR activity structure studies, energies and reactivity of the antibiotic ciprofloxacin.

Structural, spectroscopic, and theoretical analysis of a molecular system based on 2-((2-(4-chlorophenylhydrazone) methyl)quinolone / Análisis estructural, espectroscópico y teórico de un sistema molecular basado en la 2-((2-(4-clorofenilhidrazono) metil)quinolina / Análise estrutural, espectroscópico, e teórico de um sistema molecular com base na 2-((2-(4-Clorofenilhidrazona) metil)quinolina

Abstract A novel molecular system based on 2-((2-(4-chlorophenylhydrazone)methyl)quinoline (1-E ) was synthesized. Interconversion of 1-E to its configurational isomer 1-Z was achieved using UV radiation (250 W Hg lamp). Such isomerization was monitored by ¹H-NMR. The results suggest that the hydrazone derivative can act as a chemical brake in solution. This molecular system was structurally (Single Crystal X-Ray diffraction and DFT calculations) and spectroscopically (NMR, UV, and IR) characterized. Electrochemical measurements showed that configurational changes induce differential redox behavior. In this regard, the reported quinoline system exhibits different dynamic absorption and electrochemical properties that are modulated by UV-light. Therefore, 1-E can be regarded as a potential photo-electrochemical switch.

Resumen Se sintetizó un nuevo sistema molecular basado en 2-((2-(4-chlorofenilhidrazona)metil)quinolina. Del mismo modo, se evaluó la respuesta dinámica de este compuesto a radiación ultravioleta y formación de un enlace de hidrógeno intramolecular. Los resultados muestran que este derivado de hidrazona puede actuar como freno en solución. El sistema en mención es descrito estructural (Cristalografía de Rayos X y cálculos DFT) y espectroscópicamente (RMN, UV e IR). La interconversión de este sistema entre las configuraciones 1-E y 1-Z fue mediada por radiación UV y monitoreada a través de RMN-¹H. El estudio electroquímico mostró un comportamiento diferencial en función de su configuración, aspecto fundamental en el desarrollo de sistemas foto- y electroquímicamente modulados.

Resumo Neste trabalho é apresentado um novo sistema molecular baseado na 2-((2-(4-clorofenilhidrazona)metil)quinolina, capaz de responder dinamicamente à radiação ultravioleta formando uma ligação de hidrogénio intramolecular que atua como um freio na solução. Este sistema é descrito estruturalmente (cristalografia de raios-X e DFT) e por diferentes técnicas espectroscópicas (RMN, de UV e de IV). Radiação UV foi usada para fazer a interconversão da hidrazona 1-E no seu isômero configuracional 1-Z . Este processo foi monitorado pelo RMN. As medidas eletroquímicas mostraram que as mudanças configuracionais entre os isômeros induzem a comportamentos redox diferentes, o que é uma caraterística chave no desenvolvimento de interruptores fotoelectroquímicos.

Synthesis, characterization and theoretical calculations of Cu(I) complex of trithiocyanuric acid [Cu(ttc)3] / Síntesis, caracterización y cálculos teóricos del complejo Cu(I) de ácido cianúrico [Cu(ttc)3] / Síntese, caracterização e cálculos teóricos do complexo Cu(I) de ácido cianúrico [Cu(ttc)3]

Abstract A new Cu(I) complex constructed by reaction of trithiocyanuric acid (ttc) and copper(II) perchlorate hexahydrate has been successfully synthesized by a slow sedimentation method in a DMF solvent at room temperature. The molecular structure of the compound was elucidated by MALDI-TOF MS, UV-Vis and FTIR spectroscopy, DSC-TGA analysis and magnetic susceptibility measurement. The proposed structure was corroborated by a computational study carried out with the Gaussian09® and AIMAII® programs using the RB3LYP hybrid DFT functional with both 6-31G and Alhrich-TZV basis sets. The calculated vibrational frequencies values were compared with experimental FTIR values. Photophysical properties of the synthesized complex were evaluated by UV-Visible spectroscopy and compared with computed vertical excitation obtained from TDDFT. The theoretical vibrational frequencies and the UV-Vis spectra are in good agreement with the experimental values. Additionally, the Frontier Molecular Orbitals (HOMO - LUMO) and the Molecular Electrostatic Potential of the complex was calculated using same theoretical approximation. The results showed the interaction between three coordinated ligand atoms and the Cu(I) ion.

Resumen Un nuevo complejo de Cu(I) elaborado por la reacción de ácido cianúrico (ttc) y perclorato de cobre(II) hexahidrato se sintetizó exitosamente por medio de un método lento de sedimentación en un solvente de DMF a temperatura ambiente. La estructura molecular del compuesto se determinó utilizando MS de MALDI-TOF, la espectroscopia de UV-VIS y de FTIR, el análisis de DSC-TGA y el análisis magnético de susceptibilidad. La estructura propuesta se corroboró por medio de un estudio computacional usando los programas Gaussian09® y AIMAII®, utilizando el híbrido RB3LYP DFT con los equipos 6-31G y Alhrich-TZV. Se compararon los valores calculados de las frecuencias vibracionales con los valores experimentales de FTIR. Se evaluaron las características fotofísicas del complejo sintetizado usando espectroscopia UV-visible y se compararon con la vibración vertical obtenida de TDDFT. Las frecuencias teóricas vibracionales y los espectros UV-VIS coinciden con los valores experimentales. Además, se calcularon las órbitas moleculares (HOMO - LUMO) y el potencial electrostático molecular del complejo usando la misma aproximación teórica. Los resultados demostraron la interacción entre tres receptores de átomos coordinados y el ion del Cu(I).

Resumo Um novo complexo de Cu(I) elaborado pela reação de ácido cianúrico (ttc) e perclorato de cobre (II) hexahidratado foi sintetizado de maneira exitosa por meio de um método lento de sedimentação em um solvente de DMF a temperatura ambiente. A estrutura molecular do composto se determinou utilizando MALDI-TOF, espectroscopia de UV-VIS e FTIR, DSC-TGA e análise magnético de susceptibilidade. A estrutura proposta se corroborou por meio de um estudo computacional usando os programas Gaussian09® e AIMAII®, utilizando o híbrido RB3LYP DFT com os equipamentos 6-31G e Alhirich-TZV. Se compararam os valores calculados das frequências vibracionais com os valores experimentais de FTIR. Se avaliaram as características fotofísicas do complexo sintetizado utilizando espectroscopia UV-VIS e se compararam com a vibração vertical obtida de TDDFT. As frequências teóricas vibracionais e os espectros UV-VIS coincidem com os valores experimentais. Além disso, se calcularam as órbitas moleculares (HOMO - LUMO) e o potencial eletrostático molecular do complexo utilizando a mesma aproximação teórica. Os resultados demonstraram a interação entre três receptores de átomos coordenados e o íon de Cu(I).

Efecto de la estructura molecular sobre el espectro electrónico vertical de la oxoglaucina / Effects of the molecular structure on the electronic vertical spectrum of oxoglaucine / Efeito da estrutura molecular no espectro eletrônico vertical da oxoglaucina

Resumen Se investigó el espectro electrónico vertical de la oxoglaucina utilizando el método de interacción de configuraciones multi-referencial (DFT/MRCI). Se analizó el efecto de los grupos metilo y metoxilo sobre la geometría y la distribución energética de los estados excitados de baja energía utilizando la base TZVP. Se encontró que, en los mínimos del estado fundamental de oxoglaucina, oxoglaucina sin grupos metilo y sin grupos metoxilo, los estados excitados singulete de más baja energía son de tipo nП* (S1) y ПП* (S2) y que los estados triplete ПП* (T1) y nП* (T2) son energéticamente accesibles desde S1 Desde el punto de vista energético, se encontró que el canal más eficiente para el entrecruzamiento de sistemas singulete-triplete es 1(nП*)3(ПП*). Aunque la presencia de los grupos metilo y metoxilo distorsionan la planaridad del sistema de anillos, su efecto en la distribución (vertical) de los estados singulete y triplete de más baja energía es mínimo.

Abstract The vertical electronic spectrum of oxoglaucine by means of a multireference configuration interaction method (DFT/ MRCI) was studied. The effect of both methyl and methoxy groups on the geometries and energetic distribution of the low-lying excited states was analyzed. The results show that, by means of the TZVP basis set, at the ground state minima of oxoglaucine, oxoglaucine without methyl and methoxy groups, the lowest excited singlet states are of nП* (S1) and ПП* (S2) type. Triplet states of ПП* (T1) and nП* (T2) type are energetically accessible from S1. From the energetic point of view, it can be proposed that the channel for an efficient intersystem crossing 1(nП*)3(ПП*) is plausible. Although the presence of the methyl and methoxyl groups distort the planarity of the rings system, the effect in the vertical distribution of the lowest lying singlet and triplet states can be considered as negligible.

Resumo O espectro eletrônico vertical da oxoglaucina foi investigado por meio do método de interação de configurações multi referência (DFT/MRCI). Foi estudado o efeito dos grupos metilo e metoxi nas geometrias e na distribuição energética dos estados excitados de baixa energia utilizando a base TZVP. Os resultados mostram que nos mínimos do estado fundamental da oxoglaucina, a oxoglaucina sem grupos metilo e metoxi os estados excitados singletos de mais baixa energia são de tipo nП* (S1) y ПП* (S2) e que os estados tripletos do tipo ПП* (T1) e nП* (T2) são energeticamente acessíveis a partir de S1 Do ponto de vista energético, pode-se propor que o canal para um cruzamento intersistema eficiente 1(nП*)3(ПП*) seja plausível. Embora a presença dos grupos metilo e metoxilo distorçam a planaridade do sistema de anéis, o efeito na distribuição vertical dos estados de singleto e de tripleto de mais baixa energía pode ser considerado negligenciável.

Synthesis, characterization, X-ray crystal structure and DFT calculations of 4-([2,2':6',2 '' -terpyridin]-4'-yl)phenol / Síntesis, caracterización, estructura cristalina y cálculos DFT para el 4-([2,2':6',2 '' -terpiridin]-4'-il)fenol / Síntese, caracterização, estrutura de cristal e cálculos DFT para o 4-([2,2':6',2 '' -terpiridina]-4'-il)fenol

Abstract The synthesis of new terpyridine (Tpy) derivatives has been subject of extensive research due to its potential as functional materials for solar energy conversion, among other applications. In this contribution, the 4-([2,2':6',2"-terpyndm]-4'-yl)phenol (TpyOH) was synthesized, characterized and studied through several methods, including X-ray crystallography and computational approaches. Single crystal X-ray structure analysis shows that TpyOH is essentially planar, with dihedral angles of about 5.03° between the central pyridinyl and the phenolic ring, and also 6.05 and 12.2° in the terpyridine moiety. In the crystal, molecules are linked by intermolecular hydrogen bonds and through П- П stacking interactions. Using a time dependent density functional theory approach and taking into account bulk solvent effects, the absorption and fluorescence spectra of TpyOH were investigated and compared. The TD-DFT S0→Sn and S1 →S0 transition energies are in good agreement with experimental results. The frontier molecular orbitals analysis showed that the low-energy absorption band has an intraligand charge transfer character (ICT), while the high-energy band is a common feature of П- П* transitions of the Tpy moiety. The S1→S0 emission transition also has an ICT character, with a 90% contribution from the HOMO→LUMO transitions.

Resumen La síntesis de derivados terpiridinicos (Tpy) se ha investigado ampliamente debido a su potencial para la conversión de energía solar En este artículo se sintetizó y caracterizó el 4-([2,2':6',2"-terpiridin]-4'-il)fenol (TpyOH), a través de varias metodologías como la cristalografía de rayos X y herramientas computacionales. El análisis de rayos X de monocristal mostró que el TpyOH es plano, con ángulos diedros de 5,03° entre el piridinilo central y el anillo fenólico, con presencia de ángulos de 6,05 y 12,2° en la porción terpiridínica. En el cristal, las moléculas están unidas por enlaces de hidrógeno intermoleculares y mediante interacciones de apilamiento n-n. Utilizando cálculos DFT dependientes del tiempo (TD-DFT) y teniendo en cuenta el efecto de los disolventes, se investigaron y compararon los espectros de absorción y fluorescencia de TpyOH. Las energías de transición TD-DFT de S0→Sn y S1→S0 concuerdan con los resultados experimentales. El análisis de orbitales moleculares de frontera mostró que la banda de absorción de baja energía corresponde a transferencia de carga intraligando (ICT); mientras que la banda de alta energía es común en las transiciones П-П* del resto Tpy. La emisión debido a la transición S1→S0 corresponde a ICT, con una contribución del 90% proveniente de transiciones HOMO→LUMO.

Resumo A síntese de derivados de terpiridina (Tpy) tem sido estudada devido ao seu potencial para a conversão de energia solar. Nesta contribuição, o 4-([2,2':6',2"- terpindina]-4'-il) fenol (TpyOH) foi sintetizado, caracterizado e estudado por vários métodos A análise de estrutura de raios X de cristal único mostra que o TpyOH é plano, com Ångulos diedros de 5,03 ° entre o piridinilo central e o anel fenólico, e também 6,05 e 12,2 ° na porção de terpiridina No cristal, as moléculas são ligadas por ligações intermoleculares de hidrogênio e através de interações de empilhamento n-n. Usando uma abordagem da teoria funcional da densidade dependente do tempo e levando em consideração os efeitos do solvente em massa, foram investigados e comparados os espectros de absorção e fluorescência do TpyOH As energias de transição TD-DFT S0→Sn e S1→S0 estão de acordo com os resultados experimentais A análise de orbitários moleculares de fronteira mostrou que a banda de absorção de baixa energia possui um caráter de transferência de carga intraligando (TIC), enquanto a banda de alta energia é uma característica comum das transições П-П* da fração Tpy. A transição de emissão S1→S0 também tem um caráter TIC, com uma contribuição de 90% das transições HOMO→LUMO.

Probing the Pharmacological Parameters, Molecular Docking and Quantum Computations of Plant Derived Compounds Exhibiting Strong Inhibitory Potential Against NS5 from Zika Virus

ABSTRACT Zika virus (ZIKV) is known for microcephaly and neurological disease in humans and the nonstructural proteins of ZIKV play a fundamental role in the viral replication. Among the seven nonstructural proteins, NS5 is the most conserved and largest protein. Two major functional domains of NS5 i.e. methyltransferase (MTase) and RNA-dependent RNA polymerase (RdRp) are imperative for the virus life cycle and survival. The present study explicates the inhibitory action of phytochemicals from medicinal plants against NS5 from ZIKV, leading to the identification of potential inhibitors. The crystal structure of the protein is retrieved from RCSB protein data bank. A total of 2035 phytochemicals from 505 various medicinal plants are analysed for their pharmacological properties and pharmacokinetics. Compounds having effective drug-likeness are docked against the protein and further analysed using density functional theory approach. Among the 2035 phytochemicals, 13 are selected as potential inhibitors against MTase having high binding affinities and 17 compounds are selected for RdRp. HOMO and LUMO energies are calculated for the docked compounds within and outside binding pockets of MTase and RdRp, adapting the B3LYP hybrid exchange-correlation functional with def2-SV(P) basis set. Physicochemical properties such as ionization energy, electronic chemical potential, electronegativity, electron affinity, molecular softness, molecular hardness and electrophilicity index have also been analysed for selected phytochemicals. Based upon the results, it is concluded that the selected phytochemicals are highly competent to impede the replication of the virus by inhibiting the ZIKV-NS5.

Density functional theory investigation on antioxidant activity of five flavonoids from Hebei Xiangju / 中国中药杂志

Five main flavonoids of Hebei Xiangju were studied using the Density Functional Theory (DFT) B3LYP method with 6-311 G (d) basis set．Their activities were analyzed based on molecular structure,bond dissociation energy (BDE),natural orbital charge distribution (NBO),bond order and the energy gap between HOMO and LUMO. The results showed that the existing of intra molecular hydrogen bond in B ring can improve the antioxidant activity of the flavonoids, at the same time, the hydroxyl groups on the glycosides do not have the activity of eliminating free radicals, but decrease the total molecular antioxidant activity. As a result, the antioxidant ability order of the five flavonoids compounds is luteolin< luteolin-7-O-glucoside< apigenin < acacetin < acacetin-7-O-glucose, which is agreement with the experimental conclusion reported in literature. The results showed that the DFT method can provide theoretical guidance for the selection of natural flavonoid antioxidants.

A DFT study on Dichloro {(E)-4-dimethylamino-N'-[(pyridin-2-yl) methylideneK N] benzohydrazide-k0}M2+ (M = Zn, Cu, Ni, Fe, Mn, Ca and Co) complexes: Effect of the metal over association energy and complex geometry / Un estudio DFT en complejos Dicloro {(E)-4-dimetilamino-N'-[(piridin-2-il) metilideno-K N] benzohidrazida-K0} M2+ (M = Zn, Cu, Ni, Fe, Mn, Ca y Co): efecto del metal sobre la energía de asociación y la geometría del complejo / Um estudo DFT nos complexos Dicloro {(E)-4-dimetilamino-N'-[(piridin-2-il) metilideno -K N] benzohidrazida-K0} M2+ (M = Zn, Cu, Ni, Fe, Mn, Ca y Co): efeito do metal sobre a energia de associação e a geometria do complexo

The molecular geometry of (E)-4-dimethylamino-N'-[(pyridin-2yl)methylidene-kN]benzohydrazide (C15H16N4O) complexed with M²+ (M=Zn, Cu, Ni, Fe, Mn, Ca and Co) ions was calculated, using density functional theory (B3LYP) with 6-31G(d, p) basis set. Vibrational frequencies were computed in order to verify the absence of imaginary vibrational frequencies, fact that confirms the global minimum in geometry optimization. Molecular geometry parameters (bond lengths and angles) for Cu²+ and Zn²+ complexes were compared with crystallographic data previously reported, showing good correlation. Binding energies for all complexes were computed at the B3LYP/6-31G++(d, p) level of theory. These calculations indicate that Cu-L is the lowest favorable complex, Cu²+ corresponds to the smallest cation on the present study. On the other hand, Ca-L, one of the less favorable complex, corresponds to the largest cation analyzed in the present study. Molecular orbital analysis was carried out showing variations in ΔE HOMO-LUMO values as a function of the metallic ion employed.

La geometría molecular de la (E)-4-dimetilamino-N'-[(piridin-2-il) metilideno-kN] benzohidrazida (C15H16N4O) acomplejada con iones M²+ (M=Zn, Cu, Ni, Fe, Mn, Ca y Co) se calculó usando la teoría funcional de densidad (B3LYP) empleando un conjunto de bases 6-31G(d, p). Las frecuencias vibracionales fueron calculadas con el propósito de comprobar la ausencia de frecuencias vibracionales imaginarias, hecho que confirma el mínimo global en la optimización de la geometría. Los parámetros de la geometría molecular (longitudes de enlace y ángulos) para los complejos de Cu²+ y Zn²+ fueron comparados con datos cristalográficos previamente reportados, mostrando una buena correlación. Las energías de asociación para todos los complejos fueron determinadas a un nivel de teoría B3LYP/6-31G++(d, p) mostrando que el complejo menos favorable es Cu-L, correspondiente al catión más pequeño del estudio. Por otro lado Ca-L, uno de los menos estables, corresponde al catión más grande analizado. Se llevó a cabo un análisis de orbitales moleculares en el cual los complejos exhibieron diferentes valores de ΔE HOMO-LUMO en función del metal empleado.

A geometria molecular da (E)-4-dimetilamino-N'-[(piridin-2-il) metilideno-kN] benzohidrazida (C15H16N4O) acomplexada com íons M²+ (M=Zn, Cu, Ni, Fe, Mn, Ca y Co) foi calculada usando a teoria funcional da densidade (B3LYP) utilizando um conjunto de bases 6-31G(d, p). As frequências vibracionais foram calculadas com o objetivo de comprovar a ausência de frequências vibracionais imaginárias, fato que confirma o mínimo global na otimização da geometria. Os parâmetros da geometria molecular (longitudes de enlace e ângulos) para os complexos de Cu²+ y Zn²+ foram comparados com dados cristalográficos previamente reportados e mostraram boa correlação. As energias de associação para todos os complexos foram determinadas ao nível de teoria B3LYP/6-31G++(d, p) mostrando que o complexo menos favorável é Cu-L, correspondente ao cátion mais pequeno do estudo. Por outro lado Ca-L, um dos menos estáveis, corresponde ao cátion mais grande analisado. Foi feita uma análise de orbitais moleculares no qual os complexos exibiram diferentes valores de ΔE HOMO-LUMO em função do metal utilizado.

A simple approach to calculate active power of electrosurgical units

Abstract Introduction: Despite of more than a hundred years of electrosurgery, only a few electrosurgical equipment manufacturers have developed methods to regulate the active power delivered to the patient, usually around an arbitrary setpoint. In fact, no manufacturer has a method to measure the active power actually delivered to the load. Measuring the delivered power and computing it fast enough so as to avoid injury to the organic tissue is challenging. If voltage and current signals can be sampled in time and discretized in the frequency domain, a simple and very fast multiplication process can be used to determine the active power. Methods This paper presents an approach for measuring active power at the output power stage of electrosurgical units with mathematical shortcuts based on a simple multiplication procedure of discretized variables – frequency domain vectors – obtained through Discrete Fourier Transform (DFT) applied on time-sampled voltage and current vectors. Results Comparative results between simulations and a practical experiment are presented – all being in accordance with the requirements of the applicable industry standards. Conclusion An analysis is presented comparing the active power analytically obtained through well-known voltage and current signals against a computational methodology based on vector manipulation using DFT only for time-to-frequency domain transformation. The greatest advantage of this method is to determine the active power of noisy and phased out signals with neither complex DFT or ordinary transform methodologies nor sophisticated computing techniques such as convolution. All results presented errors substantially lower than the thresholds defined by the applicable standards.

Oral Hygiene Practices and Bottle Feeding Pattern Among Children with Early Childhood Caries: A Preliminary Study

@#The purpose of this study was to assess the association of bottle feeding and oral hygiene practices with the severity of caries among 3 to 5-year-old children with Early Childhood Caries (ECC). This cross-sectional study was carried out on pediatric dental patients with ECC attending a public university hospital. The parents or guardians were interviewed for the bottle-feeding pattern and oral hygiene practices followed by a clinical dental examination of their children with ECC. Data analysis was done using Chi squared test. Out of 32 children, 69% had severe early childhood caries with mean dft of 8.88. In this study, 87.5% of the subjects had a history of bottle feeding, with 53.1% still being bottle fed at the time of study. Current bottle-feeding habit was found to be statistically significant with the severity of caries (p=0.021). Majority (69 %) of the children were introduced to tooth brushing only after 1 year of age. About 40% of the children consumed either pre-chewed rice and/or shared spoons or feeding utensils with their parents or siblings but there was no significant association with the severity of caries (p=1.00). Because of its association with ECC, prolonged bottle feeding is significantly associated with the severity of caries in our study population. Besides, vertical and horizontal transmission of bacteria was also a risk factor for ECC, but it did not show any significant association with severity of ECC.

Density functional theory investigation on antioxidation activity of four flavonoids from Rhododendri Daurici Folium / 中国中药杂志

Four main flavonoids of the Chinese medicine Rhododendri Daurici Folium were studied using the density functional theory (DFT) B3LYP method with 6-311 + + G (d, p) basis set．Their activities were analyzed based on molecular structure, bond dissociation energy (BDE) and the energy gap between HOMO and LUMO. As a result, the antioxidant ability order of the four flavonoids compounds is farrerol<kaempferol< quercetin <myricetin base on the work.

Thermodynamic study of asparagine and glycyl-asparagine using computational methods

This work aimed to develop an ab initio procedure for accurately calculating pKa values and applied it to study the acidity of asparagine and glycyl-asparagine. DFT methods with B3LYP composed by 6-31+G(d) basis set were applied for calculating the acidic dissociation constant of asparagine and glycyl-asparagine. The formation of intermolecular hydrogen bonds between the available species and water was analyzed using Tomasi,s method. Results showed that in alkaline solutions, the cation, anion and neutral species of asparagine and glycyl-asparagine were solvated with one, two, three and four molecules of water, respectively. There was an excellent similarity between the experimentally attained pKa values and the theoretically ones in this work.

Quantum chemical investigations of AlN-doped C60 for use as a nano-biosensor in detection of mispairing between DNA bases.

Quantum chemical calculations were carried out to study the electronic structure and stability of adenine–thymine and the rare tautomer of adenine–thymine base pairs along with their Cu2+ complexes and their interactions with AlNmodified fullerene (C58AlN) using Density Functional Theory (B3LYP method). Since, these two forms of base pairs and their Cu2+ complexes have almost similar electronic structures, their chemical differentiation is an extremely difficult task. In this investigation, we have observed that AlN-doped C60 could be used as a potentially viable nanoscale sensor to detect these two base pairs as well as their Cu2+ complexes.