Modification of a H-terminated silicon surface by organic sulfide molecules: the mechanism and origin of reactivity

2020 ◽  
Vol 44 (26) ◽  
pp. 11056-11063
Author(s):  
Na Yang ◽  
Weiyi Li ◽  
Liang Dong
Keyword(s):  
Silicon Surface ◽  
Steric Effect ◽  
Electronic Effect ◽  
Organic Sulfide ◽  
Dissociation Energies

For the reactions of disulfide molecules (RSSR), the steric effect rather than the electronic effect of the R group is the main origin of the different reactivity. In the reactions of sulfide molecules (RSXR′, X = S, P, Si, O, N, C), charges on the S atom and dissociation energies of the S–X bonds have a great impact on the reactivity of these reactions.

scholarly journals Steric vs Electronic Effects: A New Look into Stability of Diastereomers, Conformers and Constitutional Isomers

2021 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Steric Effect ◽  
Electronic Effect ◽  
Electronic Effects ◽  
Gauche Conformation ◽  
Prevalence Data ◽  
The Stability ◽  
Stable Forms ◽  
The Right ◽  
Backbone Atoms ◽  
Meta Isomer

<div>A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of halogenated compounds made of H, F, Cl, Br, I, C, N, P, O and S atoms. The prevalence of formula in which its Z configuration, gauche conformation and meta isomer are the most stable forms is calculated and discussed. The prevalence data shows that in compounds made of carbon backbones, the electronic effect is weaker than the steric effect. The electronic factor is more important as the backbone atoms are replaced with atoms on the right and upper part of the periodic table.</div>

scholarly journals Steric vs Electronic Effects: A New Look into Stability of Diastereomers, Conformers and Constitutional Isomers

2021 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Steric Effect ◽  
Electronic Effect ◽  
Electronic Effects ◽  
Gauche Conformation ◽  
Prevalence Data ◽  
The Stability ◽  
Stable Forms ◽  
The Right ◽  
Backbone Atoms ◽  
Meta Isomer

<div>A quantum chemical investigation of the stability of compounds with identical formulas was carried out on 23 classes of halogenated compounds made of H, F, Cl, Br, I, C, N, P, O and S atoms. The prevalence of formula in which its Z configuration, gauche conformation and meta isomer are the most stable forms is calculated and discussed. The prevalence data shows that in compounds made of carbon backbones, the electronic effect is weaker than the steric effect. The electronic factor is more important as the backbone atoms are replaced with atoms on the right and upper part of the periodic table.</div>

Hydrogen Bonds and FTIR Peaks of Polyether Polyurethane-Urea

2019 ◽  
Vol 815 ◽  
pp. 151-156
Author(s):  
Xu Zhao ◽  
Yu Hong Qi ◽  
Ke Jiao Li ◽  
Zhan Ping Zhang
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Steric Effect ◽  
Electronic Effect ◽  
Theoretical Foundation ◽  
Microphase Separation ◽  
Ether Linkage ◽  
Proton Donors ◽  
Hard Segments ◽  
Degree Of Order

Various types of hydrogen bonds exist in polyether polyurethane, polyurethane-urea and polyurea (PUA) and can cause microphase separation. The morphology, properties and applications of polyether PUA are determined by the microphase separation. All kinds of hydrogen bonds make it difficult to assignments of Fourier transform infrared spectroscopy (FTIR) peaks of ether linkage, amine and carbonyl group. This affects the calculation of the hydrogen bonding degree of the hard segments for estimating the degree of microphase separation. This paper summarized hydrogen bonding structures between proton donors and proton acceptors. By analyzing the influence of electronic effect, steric effect, various types of hydrogen bonds and the degree of order of hydrogen bonding on infrared peaks, the relationships between hydrogen bonding structures and infrared peaks are established. Lay the theoretical foundation for evaluating the degree of microphase separation by FTIR method.

C(sp3)–H bond functionalization by sequential hydride transfer/cyclization: electronic effect and steric effect controlled regioselectivity

2016 ◽  
Vol 3 (5) ◽  
pp. 635-638 ◽  
Author(s):  
Liang Wang ◽  
Jian Xiao
Keyword(s):  
Steric Effect ◽  
Electronic Effect ◽  
Hydride Transfer ◽  
Bond Functionalization ◽  
Hydrogen Donors

The electronic effect and steric effect have a dramatic impact on the fascinating cascade [1,n]-hydride transfer/cyclization. The regioselectivity of two potential hydrogen donors could be perfectly tuned to construct different skeletons.

Polypyridyl Co Complex-based Water Reduction Catalysts: Why Replace a Pyridine Group with Isoquinoline rather than Quinoline?

2021 ◽  
Author(s):  
Xusheng Guo ◽  
Chao Li ◽  
Weibo Wang ◽  
Yuanjun Hou ◽  
Baowen Zhang ◽  
...  
Keyword(s):  
Steric Effect ◽  
Electronic Effect ◽  
Molecular Water ◽  
Water Reduction ◽  
Pyridine Group ◽  
Reduction Catalysts

The substituent‘s electronic effect has been fully leveraged in improving the activity of molecular water reduction catalysts (WRCs). However, the steric effect of the substituents received less attention. In this...

Facial Selectivity in the Addition of Lithium Dimethylcuprate to 6-Substituted Tricyclo[5.2.1.02,6]deca-4,8-dienones. Synthesis of β-Substituted Cyclopentenones Using Flash Vacuum Thermolysis

2014 ◽  
Vol 67 (9) ◽  
pp. 1243 ◽  
Author(s):  
Antonius J. H. Klunder ◽  
Andries A. Volkers ◽  
Binne Zwanenburg
Keyword(s):  
Nucleophilic Addition ◽  
Steric Effect ◽  
Electronic Effect ◽  
Facial Selectivity ◽  
Stereoelectronic Control

The stereoselectivity of the nucleophilic addition of lithium dimethylcuprate and lithium di-n-pentylcuprate to 6-substituted tricyclo[5.2.1.02,6]deca-4,8-dienones was investigated. It was shown that substituents at the 6-position can either exert a steric effect or an electronic effect. Steric approach control predominantly giving the endo product was observed for 6-alkyl substituents. Stereoelectronic control could be adequately rationalised using the Cieplak model. Flash vacuum thermolysis was used to prepare a series of β-substituted cyclopentenoids. The sequence leading to cyclopentenoids has an attractive scope.

scholarly journals Copper(II)-Dioxygen Facilitated Activation of Nitromethane: Nitrogen Donors for the Synthesis of Substituted 2-Hydroxyimino-2-phenylacetonitriles and Phthalimides

2021 ◽  
Vol 8 ◽  
Author(s):  
Shiqun Xiang ◽  
Yinghua Li ◽  
Weibin Fan ◽  
Jiang Jin ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Reaction Mechanism ◽  
Efficient Method ◽  
Steric Effect ◽  
Electronic Effect ◽  
Intramolecular Charge Transfer ◽  
Experimental Studies ◽  
Methyl Nitrite ◽  
Nitrogen Donors

A simple and efficient method is explored for the synthesis of 2-hydroxyimino-2-phenylacetonitriles (2) and phthalimides (4), by using nitromethane as nitrogen donors. Both reactions are promoted by Cu(II) system with the participation of dioxygen as an oxidant. The scope of the method has been successfully demonstrated with a total of 51 examples. The flexible and diversified characteristics of reactions are introduced in terms of electronic effect, steric effect, position of substituted groups, and intramolecular charge transfer. Experimental studies suggest that the methyl nitrite could be a precursor in the path to the final products. A possible reaction mechanism is proposed, including the Cu(II)/O2-facilitated transformation of nitromethane to methyl nitrite, the base-induced formation of 2-hydroxyimino-2-phenylacetonitriles, and the base-dioxygen-promoted formation of phthalimides.

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