Structural and vibrational study on the acid, hexa-hydrated and anhydrous trisodic salts of antiviral drug Foscarnet

The structural and vibrational properties of acid species, hexa-hydrated and anhydrous trisodic salts of antiviral drug foscarnetin gas phase and in aqueous solution have been studied in this work by using the hybrid B3LYP method with the 6-31G* and6-311++G** basis sets. The properties in solution were carried out with the self consistent reaction force (SCRF) method by usingthe integral equation formalism variant polarised continuum (IEFPCM) and SD models while the complete vibrational assignmentsfor those three species were performed in both media by using the experimental available infrared spectrum of hexa-hydratedtrisodic salt and the scaled quantum mechanical force field (SQMFF) methodology. The natural bond orbital (NBO) studies suggestthat the hexa-hydrated salt in solution is most stable than the anhydrous one in the same medium but in gas phases the anhydroussalt shows a higher stability in solution. The atoms in molecules (AIM) analyses have revealed the ionic characteristics of the O---Na bonds in both salts supporting the higher stability of the hexa-hydrated salt in solution. The evaluation of the frontier orbitalsshow that the anhydrous salt is the most reactive species in solution, as supported by its higher solvation energy and volumevariation. Apparently, the presences of phosphate group in foscarnet probably increase its activity when it is used as drug. Theexperimental infrared bands observed in the hexa-hydrated species at 1059 and 983 cm-1 are clearly attributed to the stretchingmodes of phosphate group while the strong bands at 1445 and 1333 cm-1 are associated to the stretching modes of carboxylategroup. In addition, the force constants for the carboxylate and phosphate groups are reported.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin

Vibrational assignments of two polymorphic forms of metaxolone by using DFT calculations and the SQM methodology

A theoretical study has been performed on the musclerelaxant 5-[(3, 5-dimethylphenoxy)methyl]-1,3-oxazolidin-2-one, of generic name metaxolone (MTX), by using the hybridB3LYP/6-31G calculations in the gas phase and theexperimental available infrared and Raman spectra in thesolid phase. Three C1, C2 and C3 isomers were found in thepotential energy surface (PES) but only two of them, C1 andC2 correspond to those experimentally reported polymorphicforms A and B, respectively. The absence of C3 isomer couldbe easily explained by the quite high values in the dihedralC5-C7-O2-C9 and O1-C5-C7-O2 angles different from thoseexperimental structures reported for the two polymorphicforms A and B of MTX. On the other hand, the higher bondorders values together with the high topological propertiesobserved for the oxazolidinone ring of C1 could possiblysupport their existence despite this isomer has highest energythan C2 and C3. The natural bond orbital (NBO) analysesreveal the high stabilities of C1 and C2 while the atoms inmolecules(AIM) study suggests that the ringdimethylphenoxy-methyl practically do not have influence onthe properties of MTX. The frontier orbitals show that theisomers of MTX have reactivities and electrophilicity indexessimilar to antiviral thymidine while their nucleophilicityindexes present values closer to antimicrobial thione. Inaddition, the complete vibrational assignments of those twostable isomers were performed by using the experimentalavailable FT-IR and FT-Raman spectra, their normal internalcoordinates,the scaled quantum mechanical force field(SQMFF) methodology and the Molvib program.Theharmonic force fields for the two isomers and theircorresponding force constants were also reported. The forceconstants values are in agreement with values reported in theliterature for species with similar groups.Fil: Iramain, Maximiliano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica; ArgentinaFil: Márquez, María J.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica; ArgentinaFil: Ledesma, Ana Estela. Universidad Nacional de Santiago del Estero. Facultad de Cs.exactas y Tecnologías. Departamento de Física y Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brandan, Silvia Antonia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica; Argentin

Analizando the effects of halogen on properties of a halogenated series of R and S enantiomers analogues alkaloid cocaine-X, X=F, Cl, Br, I.

The volumes and weight molecular of all members of both series are relationed with the Van der Waals radius X distances with the electronegativities and R of X suggesting that these two properties have influence on the positions of the CO CH groups of VdW 2 3 both series. The NBO calculations have evidenced that the F and Cl derivatives of both series present the higher variations in the total energies while the AIM analyses reveal that the presence of halogen X in the benzyl rings generate a new H bonds no observed in the free base of cocaine whose topological properties are strongly dependent from the electronegativity of the halogen. Hence, the properties for the F derivatives are higher than the observed for the other ones. The NBO calculations also show clearly that the presence of the halogen X generates variations in the bond orders related to the inter-rings C-C bonds formed between the piperidine and benzyl rings and, in the C atoms that contain the CO CH groups. The frontier orbitals 2 3 demonstrate that the effects of halogen X on the halogenated series are to increase the gaps values and, as consequence decrease the reactivities of all members of both series. Finally, the higher dipole moment values observed for the Cl derivatives of both R and S series could be clearly explained by the higher Merz-Kollman (MK) charges values observed on all C atoms belong to the benzyl rings that contain the halogen X.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ledesma, Ana Estela. Universidad Nacional de Santiago del Estero. Facultad de Cs.exactas y Tecnologías. Departamento de Física y Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effect of Media on the Properties of Monoterpene Cyclic Eucalyptol

Structural, electronic, topological and vibrational propertiesof Eucalyptol have been theoretically studied in the gas phaseand in acetone, chloroform, ethanol, and water solutions byusing the hybrid B3LYP/6-31G* level of theory. Theproperties were evaluated in function of the solvent´spermittivities. A higher dipole moment and lower volumevalues were observed for eucalyptol in water due probably tothe higher permittivity. Also, higher corrected solvationenergy is predicted for eucalyptol in water (-22.51 kJ/mol) inagreement with the higher volume contraction observed inthis medium (-0.4 Å3). Atomic charges reveal the mostnegative values on the O atoms and the most positive valueson the C3 and C4 atoms. MEP surfaces of eucalyptol in allmedia evidence clear nucleophilic sites on the O atoms. NBO analyses show two E→* and ELP→* transitions while theAIM studies reveal two new H---H interactions which supportvisibly the stabilities of eucalyptol in all studied media. Thegap values show a decreasing in the reactivity of eucalyptol ingas phase and mainly in chloroform and acetone solutionswhile in aqueous solution eucalyptol is slightly most reactive.Besides, the higher nucleophilic indexes of eucalyptol in allsolvents support the characteristic nucleophilic of eucalyptol,as compared with scopolamine and tropane alkaloids. Theharmonic force fields and their complete vibrationalassignments of 81 normal vibration modes were performed.The predicted IR, ATR, Raman, 1H- and 13C-NMR and UVvisiblespectra show reasonable concordance with thecorresponding experimental ones.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Ruiz Hidalgo, José. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin

Structural Studies and Spectroscopic properties of Quinolizidine Alkaloids (+) and (-)-Lupinine in different media

The quinolizidine alkaloids, as numerous species of lupine (Lupinus spp.), are toxic andhave biological effect on the nervous system. Hence, four (+) and (-)- molecular structuresof quinolizidine alkaloid lupinine, named C0, C1a, C1b and C1c have been theoreticallydetermined in gas phase and in aqueous solution by using hybrid B3LYP/6-31G*calculations. The studied properties have evidenced that the most stable C1c form presentthe higher populations in both media while the predicted infrared, Raman, 1H-NMR and 13C-NMR and ultra-visible spectra suggest that probably other forms in lower proportioncould be also present in water, chloroform and benzene solutions, as evidenced by the lowRMSD values observed in the 1H- and 13C-NMR chemical shifts. The C1c form presentsthe lower corrected solvation energy in water while the NBO and AIM studies suggest forthis form a high stability in both media. In addition, the predicted ECD spectra of all (+)and (-)-lupinine forms in methanol solution evidence clearly that the C1b forms is presentin the solution because its spectrum presents a negative Cotton effect as observed in the experimental one.Fil: Ruiz Hidalgo, José. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin

Predicting properties of species derived from N-(1H-indol-3-ylmethyl)-N,N-dimethylamine, Gramine, a indol alkaloid.

Hybrid B3LYP/6-31G* calculations were employed to study the structural, electronic,topological and vibrational properties of free base, cationic and hydrochloride species ofindol alkaloid, N-(1H-indol-3-ylmethyl)-N,N-dimethylamine known as gramine. Theexperimental available IR, Raman, 1H- and 13C-NMR spectra were compared with thecorresponding predicted showing reasonable concordanceproperties were studies with the polarized continuum (PCM) and the universal solvationmodel. The cationic species of gramine presents a corrected solvation energy ofkJ/mol slightly higher than the corresponding to cocaine (studies have evidenced higher stabilities for free base and hydrochloride species while thecomparisons of N-CH3 distances obtained for three species of gramine with similarcompounds have evidenced that the hydrochloride species of gramine in solution presentspractically the same value than the corresponding species of heroin. The frontier orbitalsstudies suggest higher reactivities for the hydrochloride species in both media due to itslow gap values while on the contrary are observed for the cationic species in both media.Furthermore, the cationic species of gramine shows global nucleophilicity andelectrophilicity indexes closer to cocaine. Probably, these results could justify why thecorrected solvation energy value observed for the cationic species is approximately closerto the value corresponding to cocaine. The harmonic force fields, force constants and thecomplete vibrational assignments for the 75, 78 and 81 normal vibration modes of freebase, cationic and hydrochloride species are reported for first time.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Ruiz Hidalgo, José. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin

Structural, Electronic, Topological and Vibrational Properties of Isomers of Thymidine ? A Study Combining Spectroscopic Data with DFT Calculations

In this work, the structural, electronic, topological and vibrationalproperties of six Cis and Trans isomers of Thymidine (THY) in gasand aqueous solution phases were studied combining the hybridB3LYP/6-31G* method with the Polarized Continuum Model(PCM) model and the available experimental infrared, Raman, 1HNMR,13C-NMR and UV spectra. Hence, theoretical molecularstructures of two Cis isomers and one Trans isomers of THY weredetermined in the two media for first time. The population analysessuggest the presence in solution of a Trans isomer and of two Cisisomers in accordance with the experimental structures reported byX-ray diffraction by different authors. The study of the charges showclearly the differences between the Cis and Trans isomers where thecharges on the O atoms belonging to the ribose rings in all thestructures, on the N atoms belonging to the glycosidic bond and onthe two chiral C atoms show the higher modifications. TheMolecular Electrostatic Potential (MEP) surface mapped evidenceclearly that the group´s acceptors of H bonds in all the isomers arethe two C=O groups of the pyrimidine rings while the OH groups ofthe ribose rings and the NH group of the pyrimidine rings are donorsof H bonds showing their surfaces colorations red and blue in thosesites, respectively. Natural Bond Orbital (NBO) and QuantumAtoms in Molecules (QAIM) calculations clearly reveal the highstabilities of those three isomers of THY in both media. The frontierorbitals show that in gas phase the decreasing of the gap values aredifferent than those in solution. The vibrational analyses show thepresence of different isomers in both media and confirm that thedifferent positions of the bands are characteristic of their differentstructures. Here, the 1H-NMR, 13C-NMR and UV spectra present areasonable concordance with the corresponding experimental ones.Finally, the spectroscopic studies support the presence of more of anisomer of THY in solution.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ledesma, Ana Estela. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Romani, Davide. No especifíca;Fil: Brandan, Silvia Antonia. Universidad Nacional de Santiago del Estero; Argentin

Structures, Reactivities and Vibrational Study of Species Derived from the Adrenergic Α 2 Receptor Agonist Guanfacine Agent

In the present work, eight different species of adrenergic α 2 receptor agonist guanfacine have been theoretically studied in gas phase and in aqueous solution combining hybrid B3LYP/6- 31G* calculations with the Scaled Mechanical Quantum Force Field (SQMFF) methodology and the experimental available infrared and Raman spectra in order to perform their complete vibrational assignments. Hence, the different structures of three tautomeric forms of free base (A, B and C), two cationic (E and G), one anionic (D) and two hydrochloride (F and H) species of that antihypertensive agent were optimized in solution with the Integral Equation F variant Polarised Continuum Method (IEFPCM) and the universal solvation model. The anionic species of guanfacine presents the higher corrected solvation energy with valor of -301,60 kJ/mol, slightly lower than the corresponding to scopolamine alkaloid (-310.34 J/mol) and higher than the corresponding to cocaine alkaloid (-255.24 J/mol). The studies of the frontier orbitals have evidenced that in gas phase, the anionic D species is the most reactive while in solution the hydrochloride H species is the most reactive together with the anionic species. High global nucleophilicity (E) and electrophilicity indexes (ω) values have evidenced both cationic species E and G while the lower values of both indexes are predicted for the anionic D species in both media. In addition, the harmonic force fields, force constants and the complete vibrational assignments for the 63, 66, 69 and 72 vibration normal modes expected for the anionic, free bases, cationic and hydrochloride species of guanfacine are respectively reported for first time.Fil: Romani, Davide. Servicio Sanitario Della Toscana; ItaliaFil: Ruiz Hidalgo, José. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Inorganica. Cátedra de Química General.; Argentin

Solvation of potassium 5-hydroxy pentanoyl trifluoroborate salt in aqueous environment by using ft-raman and uv-visible spectra

The hydration process of potassium 5-hydroxypentanoyltrifluoroborate salt, K[C5H9BF3O2] and its 5-hydroxypentanoyltrifluoroborate [C5H9BF3O2]- anion have been studied by combining the experimental FT-Raman and ultraviolet-visible spectra in aqueous solution with hybrid B3LYP/6-311++G** calculations. Solvent effects have been considered with the self-consistent reaction field (SCRF) and solvation (SM) models. Here, the structures of [C5H9BF3O2].[H2O]n clusters of anion, with n from 1 to 5 implicit water molecules, were proposed in order to study the number of water molecules that could hydrate the anion. Calculations were performed in the gas phase and an aqueous solution to observe the effect of the medium on the dipole moment and volume values. Calculated solvation energies for all clusters were corrected by zero-point vibrational energy (ZPVE), non-electrostatic terms and by basis set superposition energy (BSSE). The dipole moment of salt in solution (10.19 D) suggests that the number of water molecules that could hydrate the anion vary between 3 and 4, in total agreement with the observed and predicted bands in the UV-Vis spectra for the salt and these two clusters in water between 180 and 400 nm. Comparisons among experimental and predicted Raman spectra show clearly the hydration effect because the bands attributed to OH, BF3 and C=O groups are shifted in solution, while, the predicted Raman spectra for all clusters in solution show strong changes in the intensities of many bands, in accordance with the corresponding experimental one. Evidently, the hydration occurs on the OH, BF3 and C=O groups.Fil: Iramain, Maximiliano Alberto. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Imbarack, Elizabeth. Pontificia Universidad Católica de Valparaíso; ChileFil: Bongiorno, Patricio Leyton. Pontificia Universidad Católica de Valparaíso; ChileFil: Lizarraga, Emilio Fernando. Universidad Nacional de Tucumán; Argentina. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; ArgentinaFil: Brandan, Silvia Antonia. Universidad Nacional de Tucumán; Argentin

Spectroscopic studies on the potassium 1-fluorobenzoyltrifluoroborate salt by using the FT-IR, Raman and UV–Visible spectra and DFT calculations

Potassium 1-fluorobenzoyltrifluoroborate (FBTFB) salt was characterized using Fourier Transformed Infrared (FT-IR) and Raman solid-state spectroscopies as well as ultraviolet–visible spectroscopy in aqueous solution. The functional hybrid B3LYP with the 6-311++G** basis set have optimized the structures of salt in gas phase and in aqueous solution with CS symmetries. In solution, the influence of solvent was studied at the same level of theory with the integral equation formalism variant polarised continuum method (IEFPCM) and the universal solvation model. FBTFB has evidenced the lower solvation energy (−81.54 kJ/mol), as compared with other trifluoroborate salts probably due to the presence of F in the 1st position of phenyl ring that decreases the solubility of this salt. NBO studies clearly support the ionic characteristics of K+F− and K+O− bonds and the high energy values of LPF17→ LP*B14 transitions (ΔΕn→n*) while AIM analyses suggest a high stability of salt in both media due to three ionic and one C–H⋅⋅⋅F interactions. Analyses of frontier orbitals have suggested that the FBTFB salt is more reactive in solution than in gas phase and, than 2-phenylacetyl-trifluoroborate (PTFB) in the two media possibly because FBTFB presents higher global electrophilicity (ω) and nucleophilicity indexes (E) in both media than PTFB. Here, the calculated harmonic force fields, scaled force constants and complete assignments of all vibration normal modes expected for FBTFB in both media are reported. Predicted IR, Raman and UV–Visible spectra have shown good concordance when they are compared with the corresponding experimental ones.Fil: Iramain, Maximiliano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica. Cátedra de Química General; ArgentinaFil: Ledesma, Ana Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Noa Sur. Centro de Investigación en Biofísica Aplicada y Alimentos. - Universidad Nacional de Santiago del Estero. Centro de Investigación en Biofísica Aplicada y Alimentos; ArgentinaFil: Imbarack, Elizabeth. Pontificia Universidad Católica de Valparaíso; ChileFil: Bongiorno, Patricio Leyton. Pontificia Universidad Católica de Valparaíso; ChileFil: Brandan, Silvia Antonia. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Inorgánica. Cátedra de Química General; Argentin