Results 1 to 10 of about 134,654 (299)

Mutual Relations between Substituent Effect, Hydrogen Bonding, and Aromaticity in Adenine-Uracil and Adenine-Adenine Base Pairs [PDF]

Molecules, 2020
The electronic structure of substituted molecules is governed, to a significant extent, by the substituent effect (SE). In this paper, SEs in selected nucleic acid base pairs (Watson-Crick, Hoogsteen, adenine-adenine) are analyzed, with special emphasis ...
Paweł A. Wieczorkiewicz, Halina Szatylowicz, Tadeusz M. Krygowski   +2 more
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Vibronic Effects Analysis of the Substituent Effect on the Spectral Properties of the EMI and CPL of Three [7]Helicene Derivatives [PDF]

Molecules
The substituent effect has a significant influence on the optical properties of spectral shape, width, and wavelength, and the intensities of the maximum peaks of emission (EMI) and circularly polarized luminescence (CPL).
Qiushuang Xu, Meishan Wang, Yanli Liu
doaj   +2 more sources

Quantifying Through‐Space Substituent Effects [PDF]

Angewandte Chemie, 2020
AbstractThe description of substituents as electron donating or withdrawing leads to a perceived dominance of through‐bond influences. The situation is compounded by the challenge of separating through‐bond and through‐space contributions. Here, we probe the experimental significance of through‐space substituent effects in molecular interactions and ...
Rebecca J. Burns, Ioulia K. Mati, Kamila B. Muchowska, Catherine Adam, Scott L. Cockroft   +4 more
openaire   +4 more sources

Energetic and Geometric Characteristics of the Substituents: Part 2: The Case of NO₂, Cl, and NH₂ Groups in Their Mono-Substituted Derivatives of Simple Nitrogen Heterocycles

Molecules, 2021
Variously substituted N-heterocyclic compounds are widespread across bio- and medicinal chemistry. The work aims to computationally evaluate the influence of the type of N-heterocyclic compound and the substitution position on the properties of three ...
Paweł A. Wieczorkiewicz, Halina Szatylowicz, Tadeusz M. Krygowski   +2 more
doaj   +1 more source

Transmission of dipolar substituent effects: ionization of a series 3-(7-substituted-1-naphthyl) propynoic acid (E)-3-(7-substituted-1-naphthyl) propenoic acids and their Esterification with Diazodiphenylmethane

Al-Kitab Journal for Pure Sciences, 2023
Alkaline hydrolysis rates coefficients for the series of methyl 3-(7-substituted-1-naphthyl) propynoate was calculated in 70%v/v dimethylsulphoxide-water at various temperatures (25,30,40, and 50̊ C).
Khalaf D. F. Ghadir, Sameerah Saadoon Mustafa, Ghaidaa Neamah Kadhim, Hadeel Ahmed Hasan   +3 more
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Naphthalene vs. Benzene as a Transmitting Moiety: Towards the More Sensitive Trifluoromethylated Molecular Probes for the Substituent Effects

Molecules, 2022
The application of DFT computational method (B3LYP/6-311++G(d,p)) to mono- and poly(CF3)substituted naphthalene derivatives helps to study changes in the electronic properties of these compounds under the influence of 11 substituents (-Br, -CF3, -CH3 ...
Adam Sokół, Henryk Koroniak, Marcin Hoffmann, Tomasz Siodła   +3 more
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Bathochromic Shift of Fluorescence Peak in Dipyrrolo[1,2-a:2′,1′-c]quinoxaline by Introducing Each of Electron-Donating and Electron-Withdrawing Substituent

Molecules, 2023
Development of organic fluorophore is an important theme. Especially, the fluorophores with longer fluorescence peaks are useful to biological probes. One of the methods to change the fluorescence peak is the introduction of substituents.
Shoji Matsumoto, Makoto Takamori, Motohiro Akazome   +2 more
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Influence of the Solvent on the Stability of Aminopurine Tautomers and Properties of the Amino Group

Molecules, 2023
Amino derivatives of purine (2-, 6-, 8-, and N-NH2) have found many applications in biochemistry. This paper presents the results of a systematic computational study of the substituent and solvent effects in these systems.
Anna Jezuita, Paweł A. Wieczorkiewicz, Tadeusz M. Krygowski, Halina Szatylowicz   +3 more
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Kinetic Study of the Reaction of Benzofuroxans with 2-Acetylthiophene: Effect of the Substituents on the Reaction Rate Using Hammett Equation

Orbital: The Electronic Journal of Chemistry, 2020
The present work reports kinetic study of the reaction of benzofuroxan and its derivatives with 2-acetylthiophene. Hammett equation was used to determine the rate of the reaction and substituent effect. Specifically, chloro, nitro and methyl substituted
Intisar Salih Ahmed, Damra Elhaj Mustafa
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Substituent effect of Cp2TiCl2 catalyst for ethylene polymerization: A DFT study [PDF]

Polyolefins Journal, 2023
The substituents on cyclopentadienyl (Cp) can regulate the electronic effect and hindrance of the active center in the metallocene catalyst. This modification can greatly change the catalytic activity of the catalyst and affect some features of the ...
Kefeng Xie, Wei Hao, Shengyuan Xu, Jie Wang, Xiong Wang, Zhengang Han   +5 more
doaj   +1 more source