scholarly journals Superalkalis as Building Block for Efficient Lewis Base

2021 ◽  
Author(s):  
Swapan Sinha ◽  
Subhra Das ◽  
Gourisankar Roymahapatra ◽  
Santanab Giri
Keyword(s):  
Charge Transfer ◽  
Lewis Acid ◽  
Building Block ◽  
In Silico ◽  
Ionization Energy ◽  
Conceptual Dft ◽  
Lewis Base ◽  
The Stability ◽  
Additional Support

Abstract In quest for efficient Lewis base an in-silico investigation on NH3 and its structurally similar different molecules have been carried out. It has been observed that the ionization energy of the groups attached to N-centre play an important role in determining their stability and reactivity. Among different groups, superalkali ligands make better Lewis base. Several conceptual DFT descriptors like electrophilicity, nucleophilicity, dual descriptors have been used to analyse the stability and reactivity of proposed Lewis base. Calculated charge transfer descriptor describes the efficiency of the designed Lewis base to form an adduct with Lewis acid. nc-2e (n=1,2) AdNDP calculation lend additional support to the bonding of the studied molecules.

Empirical Lewis acid strengths for 135 cations bonded to oxygen

2017 ◽  
Vol 73 (5) ◽  
pp. 956-961 ◽  
Author(s):  
Olivier Charles Gagné ◽  
Frank Christopher Hawthorne
Keyword(s):  
Lewis Acid ◽  
Strong Correlation ◽  
Ionization Energy ◽  
Acid Strength ◽  
Lewis Base

New and updated Lewis acid strengths are listed for 135 cations bonded to oxygen for use with published Lewis base strengths. A strong correlation between Lewis acid strength and ionization energy is shown, and correlation with electronegativity is confirmed.

In Silico and in Vitro Evaluation of Deamidation Effects on the Stability of the Fusion Toxin DAB389IL-2

2019 ◽  
Vol 16 (4) ◽  
pp. 307-313 ◽  
Author(s):  
Nasrin Zarkar ◽  
Mohammad Ali Nasiri Khalili ◽  
Fathollah Ahmadpour ◽  
Sirus Khodadadi ◽  
Mehdi Zeinoddini
Keyword(s):  
In Silico ◽  
Catalytic Domain ◽  
Md Simulations ◽  
Special Importance ◽  
Native Form ◽  
Vitro Experiment ◽  
In Vitro Experiment ◽  
Pharmaceutical Protein ◽  
The Stability

Background: DAB389IL-2 (Denileukin diftitox) as an immunotoxin is a targeted pharmaceutical protein and is the first immunotoxin approved by FDA. It is used for the treatment of various kinds of cancer such as CTCL lymphoma, melanoma, and Leukemia but among all of these, treatment of CTCL has special importance. DAB389IL-2 consists of two distinct parts; the catalytic domain of Diphtheria Toxin (DT) that genetically fused to the whole IL-2. Deamidation is the most important reaction for chemical instability of proteins occurs during manufacture and storage. Deamidation of asparagine residues occurs at a higher rate than glutamine residues. The structure of proteins, temperature and pH are the most important factors that influence the rate of deamidation. Methods: Since there is not any information about deamidation of DAB389IL-2, we studied in silico deamidation by Molecular Dynamic (MD) simulations using GROMACS software. The 3D model of fusion protein DAB389IL-2 was used as a template for deamidation. Then, the stability of deamidated and native form of the drug was calculated. Results: The results of MD simulations were showed that the deamidated form of DAB389IL-2 is more unstable than the normal form. Also, deamidation was carried by incubating DAB389IL-2, 0.3 mg/ml in ammonium hydrogen carbonate for 24 h at 37o C in order to in vitro experiment. Conclusion: The results of in vitro experiment were confirmed outcomes of in silico study. In silico and in vitro experiments were demonstrated that DAB389IL-2 is unstable in deamidated form.

scholarly journals Colloidal CdSe nanocrystals are inherently defective

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tamar Goldzak ◽  
Alexandra R. McIsaac ◽  
Troy Van Voorhis
Keyword(s):  
Charge Transfer ◽  
Energy Spectrum ◽  
Surface Structure ◽  
Short Range ◽  
Surface Defects ◽  
Low Energy ◽  
Lewis Base ◽  
Cdse Nanocrystals ◽  
Photoinduced Charge Transfer ◽  
Photoinduced Charge

AbstractColloidal CdSe nanocrystals (NCs) have shown promise in applications ranging from LED displays to medical imaging. Their unique photophysics depend sensitively on the presence or absence of surface defects. Using simulations, we show that CdSe NCs are inherently defective; even for stoichiometric NCs with perfect ligand passivation and no vacancies or defects, we still observe that the low energy spectrum is dominated by dark, surface-associated excitations, which are more numerous in larger NCs. Surface structure analysis shows that the majority of these states involve holes that are localized on two-coordinate Se atoms. As chalcogenide atoms are not passivated by any Lewis base ligand, varying the ligand should not dramatically change the number of dark states, which we confirm by simulating three passivation schemes. Our results have significant implications for understanding CdSe NC photophysics, and suggest that photochemistry and short-range photoinduced charge transfer should be much more facile than previously anticipated.

scholarly journals Charge Transfer Complexes of Ketotifen with 2,3-Dichloro-5,6-dicyano-p-benzoquinone and 7,7,8,8-Tetracyanoquodimethane: Spectroscopic Characterization Studies

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2039
Author(s):  
Gamal A. E. Mostafa ◽  
Ahmed Bakheit ◽  
Najla AlMasoud ◽  
Haitham AlRabiah
Keyword(s):  
Charge Transfer ◽  
Spectroscopic Characterization ◽  
Molar Ratio ◽  
Charge Transfer Complexes ◽  
Physical Parameters ◽  
Spectrophotometric Methods ◽  
Theoretical Approaches ◽  
The Stability ◽  
Ct Complexes

The reactions of ketotifen fumarate (KT) with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) as π acceptors to form charge transfer (CT) complexes were evaluated in this study. Experimental and theoretical approaches, including density function theory (DFT), were used to obtain the comprehensive, reliable, and accurate structure elucidation of the developed CT complexes. The CT complexes (KT-DDQ and KT-TCNQ) were monitored at 485 and 843 nm, respectively, and the calibration curve ranged from 10 to 100 ppm for KT-DDQ and 2.5 to 40 ppm for KT-TCNQ. The spectrophotometric methods were validated for the determination of KT, and the stability of the CT complexes was assessed by studying the corresponding spectroscopic physical parameters. The molar ratio of KT:DDQ and KT:TCNQ was estimated at 1:1 using Job’s method, which was compatible with the results obtained using the Benesi–Hildebrand equation. Using these complexes, the quantitative determination of KT in its dosage form was successful.

Interfacing RuO2 with Pt to induce efficient charge transfer from Pt to RuO2 for highly efficient and stable oxygen evolution under acidic media

2021 ◽  
Author(s):  
Taehyun Kwon ◽  
Heesu Yang ◽  
Minki Jun ◽  
Taekyung Kim ◽  
Jinwhan Joo ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Acidic Media ◽  
Highly Efficient ◽  
Efficient Charge ◽  
Stable Oxygen ◽  
The Stability

The oxygen evolution reaction (OER) requires a large overpotential which undermines the stability of electrocatalysts, typically IrOx or RuOx. RuOx is particularly vulnerable to high overpotential in acidic media, due...

An in Silico Investigation of Binding Modes and Pathway of APTO-253 on c-KIT G-Quadruplex DNA

2020 ◽  
Author(s):  
Saikat Pal ◽  
Sandip Paul
Keyword(s):  
Cancer Therapy ◽  
In Silico ◽  
Binding Modes ◽  
Quadruplex Dna ◽  
G Quadruplex ◽  
The Stability

The stability of c-KIT G-quadruplex DNA by ligands has been a significant concern in the growing field of cancer therapy. Thus, it is very important to understand the mechanism behind...

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