Influence of Structural Features of Tri-functionalized Aryl phosphates on the Outcome of the SRN1 Process with Stannyl Anions: a DFT Study

Under irradiation, 1,3-bis(diethoxyphosphoryloxy)-4-chlorobenzene (2), 1,4-bis(diethoxyphosphoryloxy)-3-chlorobenzene (3) and 1,3-bis(diethoxyphosphoryloxy)-5-chlorobenzene (4) react with trimethyltinsodium(1) in liquid ammonia giving entirely different distribution of stannylated products. These differences are explained through theoretical DFT studies. Experimental evidence for the involvement of an SRN1 mechanism was obtainedFil: Dorn, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Silbestri, Gustavo Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Lockhart, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Chopa, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Instituto de Química del Sur; Argentina. Universidad Nacional del Sur; ArgentinaFil: Pierini, Adriana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto de Investigaciones En Físicoquímica de Córdoba; Argentina. Universidad Nacional de Córdoba; Argentin

Zn thiosacharinates: From ionic to polymeric structures. Synthesis, characterization and cell proliferation inhibition studies

A series of Zn thiosacharinates complexes with nitrogen donor co-ligands were synthesized: [Zn(tsac)2(o-phen)], [Zn(tsac)2(TMDP)]n, [(4,4′-bipy)H2][Zn(tsac)4] [Zn(tsac)2(2,2′-bipy)], [Zn(tsac)2(2,2′-bquin)], (tsac, thiosaccharinate anion: 1,1-dioxo-1,2-benzisothiazole-3-thiolato, C7H4NO2S2−, o-phen: 1,10′-phenantroline, TMDP: trimethylenedipyridine, 2,2′-bipy: 2,2′-bipyridine, 4,4′-bipy: 4,4′-bipyridine, 2,2′-bquin: 2,2′-biquinoline). They were fully characterized by means of FTIR, 13C and 1H NMR, elemental analysis and conductivity measurements. Three of them, [Zn(tsac)2(o-phen)], [(4,4′-bipy)H2][Zn(tsac)4], [Zn(tsac)2(TMDP)]n were also characterized by X-ray single crystal diffractometry and their crystal structures are described herein. DFT geometry optimization for the [Zn(tsac)2(o-phen)] complex was performed and its vibrational spectra was predicted. Moreover, we studied the effects of the five complexes on cell proliferation, thus providing preliminary evidence for their therapeutic potential as anti-cancer drugs.Fil: Delgado, Fermin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Freire Espeleta, Eleonora. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Baggio, Ricardo. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: González Pardo, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Dorn, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Dennehy, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

Ni-thiosaccharinate complexes: Synthesis, characterization and DFT studies. Biological properties as superoxide dismutase mimetics and as anti-carcinogenic agents

This report describes the synthesis and characterization of two nickel thiosaccharinate complexes, [Ni(tsac)2(PPh3)2] (1) and [Ni(tsac)2(dppe)]·CH3CN (2), where tsac = thiosaccharinate anion, PPh3 = triphenylphosphane and dppe = bis(diphenylphosphanyl)ethane. Elemental analysis, FTIR, 1H, 13C and 31P NMR spectra and single crystal X ray diffraction studies of the complexes are presented. DFT optimizations of the two new compounds were performed in order to verify the FTIR vibrational assignations. The two nickel(II) thiosaccharinate complexes consist of mononuclear units in which the Ni atoms are the centre of square-planar coordination spheres, surrounded by two sulfur thiosaccharinate atoms and two phosphorous atoms from the phosphane ligands. In both complexes, the anions are mono-coordinated to the metal. In the [Ni(tsac)2(PPh3)2] structure, the phosphane moieties are located in trans position. In the [Ni(tsac)2(dppe)] structure, the dppe ligand chelates to the metal centre, as expected. Additionally, the superoxide dismutase (SOD) mimetic activity of the complexes was measured and it is reported herein. The effects of the complexes on cell proliferation were also studied and are described.Fil: Delgado, Fermin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Nicova, Eva. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Agotegaray, Mariela Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: González Pardo, María Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Dorn, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Burrow, Robert A.. Universidade Federal de Santa Maria; BrasilFil: Dennehy, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

Applications of Computational and NMR Methodologies to the Study of Homoallylic Alcohols Diastereomers

Through reducing the system InCl3-Li-DTBB(cat.) in THF at room temperature and in the absence of any additives or anti-caking ligand, we have synthesized indium nanoparticles (InNPs) of about 4 nm. The catalyst was employed in the allylation of carbonyl compounds, giving excellent yields of the corresponding homoallylic alcohols. We have established that the reaction products come from a γ-coupling via a six members cyclic transition state, type Zimmerman–Traxler. Relative to the selectivity, the allylation with crotyl bromide of ortho substituted benzaldehydes (e.g., o-NO2, o-OMe, o-Cl, o-CF3) showed syn selectivity. With the aim to improve the mentioned selectivity, we synthetized o-iPrO-benzaldehyde, and evaluated the reaction with crotyl bromide and InNPs. The homoallylic alcohol 1-(2-isopropoxyphenyl)-2-methylbut-3-en-1-ol was obtained almost quantitatively after 1h as a mixture of the syn- and anti- isomers. The relationship observed by 1H-RMN was 75:25, but we did not know if the syn-isomer was the dominant because the product has not been reported in the scientific literature. Based on this, and in order to determinate which 1H-NMR signals correspond to each isomer, we started computational theoretical and NMR studies. The initial conformational analysis was performed using the semiempirical PM3 method, then we work with the B3LYP functional, applying the 6-31+G* basis set and the solvent effect (chloroform) was evaluated with the PCM model as implemented in Gaussian09. So, we found thirteen low-energy conformations for the syn-diastereomer and six low-energy conformations for the anti-diastereomer. On the other hand, we have carried out NMR experiments such as 1H, 13C, HSQC, to assign the signals of each diastereomer; and experiments such as NOESY, selective NOE, JRes, homo- and hetero-nuclear J-coupled and J-decoupling, to be able to measure coupling constants and establish the structure of each diastereomer

The Sn2 Reaction: A Theoretical-Computational Analysis of a Simple and Very Interesting Mechanism

Bimolecular nucleophilic substitution (SN2) reaction is one of the most frequently processes chosen as model mechanism to introduce undergraduate chemistry students to computational chemistry methodology. In this work, we performed a computational analysis for the ionic SN2 reaction, where the nucleophile charged (X−; X=F, Cl, Br, I) attacks the carbon atom of the substrate (CH3Cl) through a backside pathway, and simultaneously, the leaving group is displaced (Cl−). The calculations were performed applying DFT methods with the Gaussian09 program, the B3LYP functional, the 6-31+G* basis set for all atoms except iodine (6-311G*), and the solvents effects (acetonitrile and cyclohexane) were evaluated with the PCM model. We evaluated the potential energy surface (PES) for the mentioned reaction considering the reactants, the formation of an initial complex between the nucleophile and the substrate, the transition state, a final complex where the leaving group is still bound to the substrate and the products. We analyzed the atomic charge (ESP) and the bond distance throughout the process. Gas phase and solvent studies were performed in order to analyze the solvation effects on the reactivity of the different nucleophiles. We observed that increasing solvent polarity, decreases reaction rates. On the other hand, we thought it would be enriching, to carry out a reactivity analysis from the point of view of molecular orbitals. Therefore, we analyzed the MOs HOMO and the MOs LUMO of the different stationary states on PES, both in a vacuum (gas phase) and in acetonitrile as the solvent

Mild bottom-up synthesis of indium(0) nanoparticles: Characterization and application in the allylation of carbonyl compounds

Very reactive, monodisperse (4.0 ± 0.5 nm) spherical indium(0) nanoparticles have been generated in situ, in a simple, mild and efficient way, by fast reduction of commercially available indium(iii) chloride with lithium sand and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB) in THF, at room temperature, and in the absence of any anti-agglomeration additives or ligands. The as-synthesized bare InNPs were applied for the allylation of a variety of aldehydes and ketones. For most of the compounds tested, the corresponding homoallylic alcohols were obtained as the major product in good to excellent yield.Fil: Dorn, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Chopa, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Radivoy, Gabriel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin

“TYC” Reaction between Alkynes and Catechol-Thiol Derivatives Prompted by Metal Nanocatalysis: Mechanism Study by DFT Calculation

A recently published article by our research group demonstrated that the hydrothiolation of activated alkynes is a successful way to functionalize thiols bearing catechols. The reaction was promoted by the CuNPs/TiO2 nanocatalyst and was regio- and stereoselective towards the anti-Markovnikov Z-vinyl sulfide with good to excellent yields (47–97%). The scope of the reaction was evaluated and, based on experimental observations, the reaction mechanism was investigated through DFT studies. Theoretical results and experimental data were consistent with a reaction mechanism based on a copper-catalyzed anti-Markovnikov hydrothiolation process that favors the formation of the Z-vinyl sulfide

“TYC” Reaction between Alkynes and Catechol-Thiol Derivatives Prompted by Metal Nanocatalysis: Mechanism Study by DFT Calculation

A recently published article by our research group demonstrated that the hydrothiolation of activated alkynes is a successful way to functionalize thiols bearing catechols. The reaction was promoted by the CuNPs/TiO2 nanocatalyst and was regio- and stereoselective towards the anti-Markovnikov Z-vinyl sulfide with good to excellent yields (47–97%). The scope of the reaction was evaluated and, based on experimental observations, the reaction mechanism was investigated through DFT studies. Theoretical results and experimental data were consistent with a reaction mechanism based on a copper-catalyzed anti-Markovnikov hydrothiolation process that favors the formation of the Z-vinyl sulfide

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

A new heterogeneous catalytic system consisting of cobalt nanoparticles (CoNPs) supported on MgO and tert-butylhydroperoxide (TBHP) as oxidant is presented. This CoNPs@MgO/tBuOOH catalytic combination allowed the epoxidation of a variety of olefins with good to excellent yield and high selectivity. The catalyst preparation is simple and straightforward from commercially available starting materials and it could be recovered and reused maintaining unaltered its high activity.Fil: Rossi Fernández, Lucía Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Dorn, Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; ArgentinaFil: Radivoy, Gabriel Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Química del Sur. Universidad Nacional del Sur. Departamento de Química. Instituto de Química del Sur; Argentin