2-Aminobenzothiazole-Containing Copper(II) Complex as Catalyst in Click Chemistry: An Experimental and Theoretical Study

The reaction of copper(II) acetate with the 2-aminobenzothiazole (abt) heterocycle affords the new copper(II) complex of formula [Cu(abt)2(OOCCH3)2] (1) in a straightforward manner. Compound 1 served as a precatalyst for azide/alkyne cycloaddition reactions (CuAAC) in water, leading to 1,4-disubstituted-1,2,3-triazole derivatives in a regioselective manner and with excellent yields at room temperature. The main advantages of the coordination of such a heterocyclic ligand in 1 are its strong σ-donating ability (N-Cu), nontoxicity and biological properties. In addition, the click chemistry reaction conditions using 1 allow the formation of a great variety of 1,2,3-triazole-based heterocyclic compounds that make this protocol potentially relevant from biological and sustainable viewpoints. A molecular electron density theory (MEDT) study was performed by using density functional theory (DFT) calculations at the B3LYP/6-31G(d,p) (LANL2DZ for Cu) level to understand the observed regioselectivity in the CuAAC reaction. The intramolecular nature of this reaction accounts for the regioselective formation of the 1,4-regioisomeric triazole derivatives. The ionic nature of the starting copper-acetylide precludes any type of covalent interaction throughout the reaction, as supported by the electron localization function (ELF) topological analysis, reaffirming the zwitterionic-type (zw-type) mechanism of the copper(I)/aminobenzothiazole-catalysed azide-alkyne cycloaddition reactions.

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Deciphering the Mechanism of Silver Catalysis of “Click” Chemistry in Water by Combining Experimental and MEDT Studies

Catalysts ◽

10.3390/catal10090956 ◽

2020 ◽

Vol 10 (9) ◽

pp. 956

Author(s):

Hicham Ben El Ayouchia ◽

Lahoucine Bahsis ◽

Ismail Fichtali ◽

Luis R. Domingo ◽

Mar Ríos-Gutiérrez ◽

...

Keyword(s):

Click Chemistry ◽

Density Functional ◽

Reaction Pathway ◽

Topological Analysis ◽

Intramolecular Interactions ◽

Stationary Points ◽

Ionic Character ◽

Energy Barriers ◽

Covalent Interaction ◽

Mechanistic Pathway

A combined experimental study and molecular electron density theory (MEDT) analysis was carried out to investigate the click of 1,2,3-triazole derivatives by Ag(I)-catalyzed azide-alkyne cycloaddition (AgAAC) reaction as well as its corresponding mechanistic pathway. Such a synthetic protocol leads to the regioselective formation of 1,4-disubstituted-1,2,3-triazoles in the presence of AgCl as catalyst and water as reaction solvent at room temperature and pressure. The MEDT was performed by applying Density Functional Theory (DFT) calculations at both B3LYP/6-31G(d,p) (LANL2DZ for Ag) and ωB97XD/6-311G(d,p) (LANL2DZ for Ag) levels with a view to decipher the observed regioselectivity in AgAAC reactions, and so to set out the number of silver(I) species and their roles in the formation of 1,4-disubstituted-1,2,3-triazoles. The comparison of the values of the energy barriers for the mono- and dinuclear Ag(I)-acetylide in the AgAAC reaction paths shows that the calculated energy barriers of dinuclear processes are smaller than those of the mononuclear one. The type of intramolecular interactions in the investigated AgAAC click chemistry reaction accounts for the regioselective formation of the 1,4-regiosisomeric triazole isomer. The ionic character of the starting compounds, namely Ag-acetylide, is revealed for the first time. This finding rules out any type of covalent interaction, involving the silver(I) complexes, along the reaction pathway. Electron localization function (ELF) topological analysis of the electronic structure of the stationary points reaffirmed the zw-type (zwitterionic-type) mechanism of the AgAAC reactions.

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Synthesis of 1,2,3–triazole compounds by click chemistry in aqueous medium and evaluation of bactericidal and antitumoral properties.

Current Bioactive Compounds ◽

10.2174/1573407217666211119092038 ◽

2021 ◽

Vol 17 ◽

Author(s):

Lucas Lima Zanin ◽

David Esteban Quintero Jimenez ◽

Willian Garcia Birolli ◽

Tiago Venâncio ◽

Talita Alvarenga Valdes ◽

...

Keyword(s):

Click Chemistry ◽

Biological Properties ◽

Antitumoral Activity ◽

Biological Assays ◽

Triazole Derivatives ◽

Optimization Study ◽

Water As Solvent ◽

Wide Range ◽

Screening Study ◽

High Yields

Background: Triazoles are heterocyclic synthetic compounds that have gained relevance after studies by Sharpless on regioselective methodologies for the synthesis of 1,2,3-triazole derivatives. In addition, they have a wide range of biological properties. Objective: The objective of this study is to develop a synthetic methodology aligned with the principles of click chemistry for the synthesis of 1,2,3-triazole derivatives and verify the profile of these compounds in biological assays. Methods: Initially, a model reaction was selected and an optimization study involving synthetic conditions was carried out. Using the most efficient condition, a series of compounds was developed by the reactions between 2-azido-1-phenylethan-1-one derivatives and terminal alkynes. In sequence, bactericidal and antitumoral assays were performed. Results: It was possible to synthesise ten examples using water as a sustainable solvent, in 1 hour, with good yields of 73–99%, including three compounds described for the first time. Two products presented bactericidal activity, one against the gram-negative Escherichia coli ATCC 25922 and other against the gram-positive Paenibacillus alvei CBMAI 2221. Moreover, other two triazole derivatives presented antitumoral activity for prostate and pancreas cancer cells in this screening study with the bioactivity quantified for compound 1-([1,1'-biphenyl]-4-yl)-2-(4-(p-tolyl)-1H-1,2,3-triazol-1-yl)ethan-1-one (IC50 = 132 µM). Conclusion: Herein, an efficient methodology for the synthesis of 1,2,3-triazole derivatives with high yields and using water as solvent was developed. Furthermore, some compounds presented positive results to bactericidal and antitumoral assays, justifying further exploration of these novel compounds and their biological properties.

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Epitaxial Graphene Sensors Combined with 3D-Printed Microfluidic Chip for Heavy Metals Detection

Sensors ◽

10.3390/s19102393 ◽

2019 ◽

Vol 19 (10) ◽

pp. 2393 ◽

Cited By ~ 5

Author(s):

Maria Francesca Santangelo ◽

Ivan Shtepliuk ◽

Daniel Filippini ◽

Donatella Puglisi ◽

Mikhail Vagin ◽

...

Keyword(s):

Heavy Metals ◽

Density Functional ◽

Topological Analysis ◽

Decomposition Analysis ◽

Epitaxial Graphene ◽

Phase Detection ◽

Lab On Chip ◽

Covalent Interaction ◽

3D Printed ◽

On Chip

In this work, we investigated the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb and Cd), showing fast and stable response and low detection limit. The sensing platform proposed includes 3D-printed microfluidic devices, which incorporate all features required to connect and execute lab-on-chip (LOC) functions. The obtained results indicate that EG exhibits excellent sensing activity towards Pb and Cd ions. Several concentrations of Pb2+ solutions, ranging from 125 nM to 500 µM, were analyzed showing Langmuir correlation between signal and Pb2+ concentrations, good stability, and reproducibility over time. Upon the simultaneous presence of both metals, sensor response is dominated by Pb2+ rather than Cd2+ ions. To explain the sensing mechanisms and difference in adsorption behavior of Pb2+ and Cd2+ ions on EG in water-based solutions, we performed van-der-Waals (vdW)-corrected density functional theory (DFT) calculations and non-covalent interaction (NCI) analysis, extended charge decomposition analysis (ECDA), and topological analysis. We demonstrated that Pb2+ and Cd2+ ions act as electron-acceptors, enhancing hole conductivity of EG, due to charge transfer from graphene to metal ions, and Pb2+ ions have preferential ability to binding with graphene over cadmium. Electrochemical measurements confirmed the conductometric results, which additionally indicate that EG is more sensitive to lead than to cadmium.

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Molecular Docking, Topological Analysis and Vibrational Studies on N-(2-Bromoethyl) Succinimide: Antidepressant Agent

Letters in Organic Chemistry ◽

10.2174/1570178617999201109203410 ◽

2020 ◽

Vol 17 ◽

Author(s):

Aslı Eşme

Keyword(s):

Molecular Docking ◽

Density Functional ◽

Topological Analysis ◽

Biological Properties ◽

Vibrational Frequencies ◽

Oscillator Strengths ◽

Potential Energy Distribution ◽

Geometrical Parameters ◽

Molecular Docking Study ◽

Excitation Energies

Abstract:: N-(2-Bromoethyl) succinimide (N2BES) is a compound with antidepressant pharmacological properties. N-(2-Bromoethyl) succinimide was analyzed for its structural, electronic, vibrational, topological, and biological properties. The molecular geometrical parameters such as bond lengths (Å), bond angles (º), and dihedral angles (º) of N2BES and harmonic vibrational frequencies were investigated using the density functional theory calculations with the B3LYP/6-311++G(d,p) level of theory. Experimental vibrational frequencies of N2BES were recorded in the region 4000–400 cm-1 (FT-IR) and 4000–100 cm-1 (FT-Raman) and compared with the theoretical frequencies were made on the basis of potential energy distribution (PED) analysis. Frontier molecular orbitals (FMOs), global reactivity descriptors, density of states (DOS) prop-erties, molecular electrostatic potential (MEP), natural bond orbital (NBO) analysis, topological analysis of the reduced density gradient (RDG), localized orbital locator (LOL), bond critical points (BCP) for N2BES are investigated by theoret-ical calculations. The experimental UV-Vis measured within the 200-500 nm and calculated electronic transitions of ab-sorption wavelength (λ), excitation energies (E), oscillator strengths (f), and assignments in ethanol solvent. In addition, the molecular docking study of the title molecule predicts its binding orientation in the active site of the target serotonin 1A (5-HT1A) protein.

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Understanding the regio-and diastereoselective synthesis of a potent antinociceptive isoxazolidine from C-(pyridin-3-yl)-N-phenylnitrone in the light of molecular electron density theory

Journal of the Serbian Chemical Society ◽

10.2298/jsc190914136a ◽

2020 ◽

Vol 85 (6) ◽

pp. 765-779

Author(s):

Nivedita Acharjee

Keyword(s):

Electron Density ◽

Density Functional ◽

Topological Analysis ◽

Transition States ◽

Cycloaddition Reaction ◽

Aim Analysis ◽

Conceptual Density Functional Theory ◽

Covalent Interaction ◽

Molecular Electron ◽

Molecular Electron Density Theory

[3+2] cycloaddition reaction of C-(pyridin-3-yl)-N-phenylnitrone and 2-propen-1-ol yields stereochemically defined potent antinociceptive isoxazolidine derivative. Computational quantum calculations (CQC) are performed for this synthesis to predict the polar character, mechanism and selectivity within the framework of molecular electron density theory (MEDT). Topological analysis of the electron localization function (ELF) classifies the nitrone as a zwitter-ionic(zw-) type three atom component (TAC) showing absence of any pseudoradical or carbenoid centre. Four reaction channels corresponding to the possible regio- and stereoselective pathways are studied at DFT/ /B3LYP/6-311G(d,p) level of theory. The reaction follows one-step mechanism with asynchronous transition states and the computed activation energies agree well with experimental data. The reaction can be differentiated into nine ELF topological phases, with faster C?C bond formation. Global electron density theory (GEDT) at the favoured transition state and conceptual density functional theory (CDFT) indices at the ground state of the reagents indicate non-polar character. Non-covalent interactions are predicted by atoms-in-molecules (AIM) analysis and non-covalent interaction (NCI) plots at the transition states.

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Shedding Light on the Chemistry and the Properties of Münchnone Functionalized Graphene

Nanomaterials ◽

10.3390/nano11071629 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1629

Author(s):

Giulia Neri ◽

Enza Fazio ◽

Antonia Nostro ◽

Placido Giuseppe Mineo ◽

Angela Scala ◽

...

Keyword(s):

Density Functional ◽

Antimicrobial Properties ◽

Biological Properties ◽

Azomethine Ylide ◽

Functionalized Graphene ◽

Functional Theory ◽

Pyrrole Derivatives ◽

Transmission Electron ◽

Scanning Transmission ◽

Direct Functionalization

Münchnones are mesoionic oxazolium 5-oxides with azomethine ylide characteristics that provide pyrrole derivatives by a 1,3-dipolar cycloaddition (1,3-DC) reaction with acetylenic dipolarophiles. Their reactivity was widely exploited for the synthesis of small molecules, but it was not yet investigated for the functionalization of graphene-based materials. Herein, we report our results on the preparation of münchnone functionalized graphene via cycloaddition reactions, followed by the spontaneous loss of carbon dioxide and its further chemical modification to silver/nisin nanocomposites to confer biological properties. A direct functionalization of graphite flakes into few-layers graphene decorated with pyrrole rings on the layer edge was achieved. The success of functionalization was confirmed by micro-Raman and X-ray photoelectron spectroscopies, scanning transmission electron microscopy, and thermogravimetric analysis. The 1,3-DC reactions of münchnone dipole with graphene have been investigated using density functional theory to model graphene. Finally, we explored the reactivity and the processability of münchnone functionalized graphene to produce enriched nano biomaterials endowed with antimicrobial properties.

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Combining Oxidative N-Heterocyclic Carbene Catalysis with Click Chemistry: A Facile One-Pot Approach to 1,2,3-Triazole Derivatives

Chemistry - An Asian Journal ◽

10.1002/asia.201300138 ◽

2013 ◽

Vol 8 (7) ◽

pp. 1489-1496 ◽

Cited By ~ 11

Author(s):

B. T. Ramanjaneyulu ◽

Virsinha Reddy ◽

Panjab Arde ◽

Sriram Mahesh ◽

R. Vijaya Anand

Keyword(s):

Click Chemistry ◽

One Pot ◽

Triazole Derivatives

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Electronic Structure Of (AgSb)xPbn-2xTen

MRS Proceedings ◽

10.1557/proc-793-s8.27 ◽

2003 ◽

Vol 793 ◽

Author(s):

Daniel I Bilc ◽

S.D. Mahanti ◽

M.G. Kanatzidis

Keyword(s):

Electronic Structure ◽

Ab Initio ◽

Density Functional ◽

Full Potential ◽

Generalized Gradient ◽

Two Component System ◽

Functional Theory ◽

Covalent Interaction ◽

Salt Structure ◽

Linearized Augmented Plane Wave

ABSTRACTComplex quaternary chalcogenides (AgSb)xPbn-2xTen (0<x<n/2) are thought to be narrow band-gap semiconductors which are very good candidates for room and high temperature thermoelectric applications. These systems form in the rock-salt structure similar to the well known two component system PbTe (x=0). In these systems Ag and Sb occupy Pb sites randomly although there is some evidence of short-range order. To gain insights into the electronic structure of these compounds, we have performed electronic structure calculations in AgSbTe2 (x=n/2). These calculations were carried out within ab initio density functional theory (DFT) using full potential linearized augmented plane wave (LAPW) method. The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. Spinorbit interaction (SOI) was incorporated using a second variational procedure. Since it is difficult to treat disorder in ab initio calculations, we have used several ordered structures for AgSbTe2. All these structures show semimetallic behavior with a pseudogap near the Fermi energy. Te and Sb p orbitals, which are close in energy, hybridize rather strongly indicating a covalent interaction between Te and Sb atoms.

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Regioselective Synthesis of Novel 4,4′-and 5,5′-bi-(1,2,4-triazole) Derivatives

Journal of Chemical Research ◽

10.3184/030823407x237876 ◽

2007 ◽

Vol 2007 (8) ◽

pp. 472-474 ◽

Cited By ~ 10

Author(s):

Ahmad M. Farag ◽

Kamal M. Dawood ◽

Nabila A. Khedr

Keyword(s):

Regioselective Synthesis ◽

Dipolar Cycloaddition ◽

Cycloaddition Reactions ◽

Triazole Derivatives

A regioselective synthesis is reported of a series of polysubstituted 1,2,4-triazoles and 4,4′- and 5,5′-bi-(1,2,4-triazoles) via 1,3-dipolar cycloaddition reactions of nitrilimines with some aza- and diaza-butadiene derivatives.

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