Substituent effects in the polarography of aromatic diazonium salts

1969 ◽  
Vol 34 (4) ◽  
pp. 854-857 ◽  
Author(s):  
Richard M. Elofson ◽  
F. F. Gadallah
Keyword(s):  
Substituent Effects ◽  
Diazonium Salts

Reactions of aryl diazonium salts and arylazo alkyl ethers. III. Substituent effects in the ionization of anti-arylazo ethyl ethers in ethanol

1978 ◽  
Vol 31 (7) ◽  
pp. 1519 ◽  
Author(s):  
TJ Broxton
Keyword(s):  
Substituent Effects ◽  
Parameter Analysis ◽  
Diazonium Salts ◽  
Resonance Effects ◽  
Inductive Effects ◽  
Alkyl Ethers

A dual substituent parameter analysis of substituent effects on the ionization of anti-arylazo ethyl ethers in ethanol shows that the reaction is affected primarily by inductive effects. The reaction is insensitive to resonance effects and an explanation for this behaviour is offered.

Reactions of Aryl Diazonium Salts and Arylazo Alkyl Ethers. IV. Substituent Effects on the Rates of Some Reactions of syn-Arylazo Ethyl Ethers in Ethanol

1979 ◽  
Vol 32 (5) ◽  
pp. 1031 ◽  
Author(s):  
TJ Broxton
Keyword(s):  
Substituent Effects ◽  
Diazonium Salts ◽  
Recombination Mechanism ◽  
Alkyl Ethers

Substituent effects on the rates of ionization (kIS), decomposition (kD) and syn-anti interconversion (kp) for a number of syn-arylazo ethyl ethers have been measured. The rates of ionization and syn-anti interconversion correlate well with sigma while the rates of decomposition correlate with σ+. Substituent effects on the ionization of the syn-ethers are compared to those for ionization of the anti-ethers. Substituent effects on the rate of syn-anti interconversion support the proposed ionization-recombination mechanism.

Reactions of aryl diazonium salts and arylazo alkyl ethers. VI. A comparison of the available methods for the measurement of the rate of ionization of (Z)-arylazo alkyl ethers in alcoholic solvents

1982 ◽  
Vol 35 (2) ◽  
pp. 319 ◽  
Author(s):  
TJ Broxton ◽  
MJ Mcleish
Keyword(s):  
Substituent Effects ◽  
Ionization Rate ◽  
New Method ◽  
Diazonium Salts ◽  
Advantages And Disadvantages ◽  
Diazonium Ions ◽  
Alkyl Ethers ◽  
Trapping Agent ◽  
Ionization Rates

Two previously reported methods for the determination of the ionization rate of (Z)-arylazo alkyl ethers by using x-naphtholate ions as a trapping agent are compared. A new method, which uses thiophenolate ions to trap the free diazonium ions formed in this ionization, is reported. This method is recommended in preference to the earlier methods because it includes a correction for the effect of the ionic strength of the solution on the rate of ionization. Rates measured by the thiophenolate method are consequently lower than those measured by either of the two previous methods. The advantages and disadvantages of the new method are discussed. The magnitude of salt effects and substituent effects on the ionization of (Z)- and (E)-arylazo alkyl ethers are compared.

Substituent effects and solvents

1992 ◽  
Vol 89 ◽  
pp. 1567-1571
Author(s):  
O Pytela ◽  
M Ludwig
Keyword(s):  
Substituent Effects

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

Tropolone-Based Treatments for Visualising Latent Fingermarks on Porous Surfaces

2019 ◽  
Author(s):  
Clara M. Agapie ◽  
Melissa Sampson ◽  
William Gee
Keyword(s):  
Amino Acids ◽  
Uv Radiation ◽  
Membered Ring ◽  
Diazonium Salts ◽  
Chemical Detection ◽  
Latent Fingerprints ◽  
Porous Surfaces

The work describes a new chemical means of visualising latent fingerprints (fingermarks) using tropolone. Tropolone reacts with amino acids within the fingermark residue to form adducts that absorb UV radiation. These adducts provide useful contrast on highly-fluorescent prous surfaces will illuminated with UV radiation. The conjugated seven-membered ring of the tropolone adduct can be reacted further diazonium salts, which is demonstrated here with formation of two dyes. The methodology is extremely rapid, occurring in minutes with mild heating, and can be applied before ninhydrin in a chemical detection sequence. <br>

Chemistry of Unsymmetrical C1-Substituted Oxabenzonorbornadienes

2021 ◽  
Vol 17 ◽  
Author(s):  
Austin Pounder ◽  
Angel Ho ◽  
Matthew Macleod ◽  
William Tam
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Substituent Effects ◽  
Face Selectivity ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Synthetic Intermediate

: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate which can be readily activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain on the alkene. To date, the understanding of transition-metal catalyzed reactions of OBD itself has burgeoned; however, this has not been the case for unsymmetrical OBDs. Throughout the development of these reactions, the nature of C1-substituent has proven to have a profound effect on both the reactivity and selectivity of the outcome of the reaction. Upon substitution, different modes of reactivity arise, contributing to the possibility of multiple stereo-, regio-, and in extreme cases, constitutional isomers which can provide unique means of constructing a variety of synthetically useful cyclic frameworks. To maximize selectivity, an understanding of bridgehead substituent effects is crucial. To that end, this review outlines hitherto reported examples of bridgehead substituent effects on the chemistry of unsymmetrical C1-substituted OBDs.

Influence of solvents on transmission of substituent effects by the oxygen and sulfur bridges

1974 ◽  
Vol 39 (7) ◽  
pp. 1862-1868 ◽  
Author(s):  
A. Perjéssy ◽  
G. Melikian ◽  
P. Hrnčiar ◽  
M. Lácová
Keyword(s):  
Substituent Effects ◽  
Influence Of Solvents
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