Saturated N,X-Heterocyclic Carbenes (X=N, O, S, P, Si, C, and B): Stability, Nucleophilicity, and Basicity

Azizi, Zahra; Ghambarian, Mehdi; Rezaei, Mohammad A.; Ghashghaee, Mohammad

doi:10.1071/ch14715

Cited by 31 publications

(8 citation statements)

References 79 publications

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“…The more electron deficient nature of carbene carbon in IOH relative to IH was already reported. 49 This reduced Bronsted basicity of IOH supports the increased ΔE for the proton abstraction step (ΔE 1 ). WBI values suggested TS1 in IOH to be a late TS in comparison to IH in agreement with our earlier conclusion (Tables 2 and 4).…”

Section: Analysis Of the Effect Of Changing The Heterocycle Increasing The Conjugation Ring Expansion And Substitutionmentioning

confidence: 78%

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Jayasree

Reshma

Aswathy

2021

Int J of Quantum Chemistry

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The present work is intended to bring to the forefront a relatively less explored area of N-Heterocyclic Carbene (NHC) catalyzed alkyne hydro-thiolation and selenation reactions by exploring the reaction mechanism. Reaction mechanism involves chalcogenol activation followed by alkyne insertion and the second step is the rate determining step. A comparison with the reported uncatalyzed gas phase reaction showed that a simple imidazol-2-ylidene catalyst can lower the free energy barrier by 28.74 and 21.73 kcal/mol respectively for acetylene hydro-thiolation and selenation reaction. All the employed NHCs are proved to be better catalyst for both hydrothiolation and hydroselenation. Factors such as changing the heterocycle, increasing the conjugation, ring expansion and electronic/steric substitution at the heteroatom were found to affect the energy barriers due to the geometric variations at NHCcarbon and S/Se in the intermediate and the transition structure corresponding to alkyne insertion. Effect of solvent polarity on the reaction energetics and selectivity has also been analyzed employing THF, DMSO and MeOH as the solvents.

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Section: Analysis Of the Effect Of Changing The Heterocycle Increasing The Conjugation Ring Expansion And Substitutionmentioning

confidence: 78%

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Jayasree

Reshma

Aswathy

2021

Int J of Quantum Chemistry

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“…Molecular orbital calculations can be used to estimate 13 C NMR chemical shifts. Ab initio and DFT calculations of NMR shielding at very accurate levels of approximation are available in the literature . The GIAO (Gauge Including Atomic Orbital) method, implemented in the Gaussian package, is now widely used for these purposes.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines

Llabres-Campaner

Guijarro

Giarratano

et al. 2017

Chemistry A European J

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New diquat derivatives based on [1,2,3]triazolo[1,5-a]pyridine and [1,2,3]triazolo[1,5-a]quinoline have been synthesized in excellent yields. To evaluate the effect of the alkyl bridge length, ethane and propane dibromo alkane substrates were used for their synthesis. Theoretical calculations predicted a very small energetic barrier between the two possible enantiomers P (R ) and M (S ), which makes them very difficult to resolve. Thermal denaturation studies, UV/Visible spectroscopy, and fluorescence titrations with ct-DNA evidenced the intercalation of the quinoline derivatives in DNA.

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“…In many research studies [16][17][18], TiCl 4 is reported to be utilized as precursor, but the solvent used was water. However, use of water increases the size of particle due to higher degree of hydrolysis.…”

Section: Resultsmentioning

confidence: 99%

TiO₂ nanoparticles synthesis for application in proton exchange membranes

Mishra

Solanki

Murthy

2013

Crystal Research and Technology

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In the present paper, suitable TiO2 nanoparticles are successfully synthesized by sol‐gel method, in order to utilize the freshly prepared TiO2 nanoparticles for proton exchange membrane (PEM) preparation. Titanium tetrachloride (TiCl4) is used as precursor and ethanol as a solvent. The optimum and suitable TiO2 nanoparticles were obtained by varying gelatinisation time (4–120 h), concentration of precursor (TiCl4) in ethanol (2–15 vol%), and reaction temperature (15–35 °C). The morphology, size and purity of the nanoparticles are investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and X‐ray diffraction (XRD). Optimum results were found at 4 h of gelatinisation time, 10% precursor concentration and 25 °C temperature for preparation of TiO2 nanoparticles. Thus prepared nanoparticles are found to be suitable for preparation of nanocomposite PEM, and consequently the prepared PEM indicates enhanced properties, such as, higher thermal stability (high glass transition temperature of 184.1 °C), excellent proton conductivity (0.0822 S cm−1 at room temperature) and low methanol permeability (1.11 × 10−9 cm2 s−1).

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Saturated N,X-Heterocyclic Carbenes (X=N, O, S, P, Si, C, and B): Stability, Nucleophilicity, and Basicity

Cited by 31 publications

References 79 publications

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Synthesis, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines

TiO₂ nanoparticles synthesis for application in proton exchange membranes

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Saturated N,X-Heterocyclic Carbenes (X=N, O, S, P, Si, C, and B): Stability, Nucleophilicity, and Basicity

Cited by 31 publications

References 79 publications

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Computationally unraveling the mechanism and selectivity of five and six membered N‐heterocyclic carbene‐catalyzed alkyne hydrochalcogenation

Synthesis, Optical Properties, and DNA Interaction of New Diquats Based on Triazolopyridines and Triazoloquinolines

TiO2 nanoparticles synthesis for application in proton exchange membranes

Contact Info

Product

Resources

About

TiO₂ nanoparticles synthesis for application in proton exchange membranes