Substituent Correlations Characterized by Hammett Constants in the Spiropyran–Merocyanine Transition

2017 ◽  
Vol 121 (13) ◽  
pp. 2683-2687 ◽  
Author(s):  
Oliver Brügner ◽  
Thomas Reichenbach ◽  
Michael Sommer ◽  
Michael Walter
Keyword(s):  
Hammett Constants

Quantification and classification of substituent effects in organic chemistry: a theoretical molecular electrostatic potential study

2016 ◽  
Vol 18 (30) ◽  
pp. 20615-20626 ◽  
Author(s):  
Geetha S. Remya ◽  
Cherumuttathu H. Suresh
Keyword(s):  
Organic Chemistry ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Organic Molecules ◽  
Substituent Effects ◽  
Conjugated Organic Molecules ◽  
Hammett Constants ◽  
Strong Linear Correlation ◽  
Potential Parameters

The molecular electrostatic potential parameters show a strong linear correlation with Hammett constants and serve as tools for designing π-conjugated organic molecules with highly tuned electronic properties.

scholarly journals Polysubstituted ferrocenes as tunable redox mediators

2018 ◽  
Vol 14 ◽  
pp. 1004-1015 ◽  
Author(s):  
Sven D Waniek ◽  
Jan Klett ◽  
Christoph Förster ◽  
Katja Heinze
Keyword(s):  
Fast Electron ◽  
Chemical Shifts ◽  
Redox Mediators ◽  
Redox Titration ◽  
H Nmr ◽  
Redox Couples ◽  
Hammett Constants ◽  
Stretching Vibrations ◽  
The Impact ◽  
Potential Use

A series of four ferrocenyl ester compounds, 1-methoxycarbonyl- (1), 1,1’-bis(methoxycarbonyl)- (2), 1,1’,3-tris(methoxycarbonyl)- (3) and 1,1’,3,3’-tetrakis(methoxycarbonyl)ferrocene (4), has been studied with respect to their potential use as redox mediators. The impact of the number and position of ester groups present in 1–4 on the electrochemical potential E 1/2 is correlated with the sum of Hammett constants. The 1/1 + –4/4 + redox couples are chemically stable under the conditions of electrolysis as demonstrated by IR and UV–vis spectroelectrochemical methods. The energies of the C=O stretching vibrations of the ester moieties and the energies of the UV–vis absorptions of 1–4 and 1 + –4 + correlate with the number of ester groups. Paramagnetic 1H NMR redox titration experiments give access to the chemical shifts of 1 + –4 + and underline the fast electron self-exchange of the ferrocene/ferrocenium redox couples, required for rapid redox mediation in organic electrosynthesis.

scholarly journals THE USE OF HAMMETT CONSTANTS TO UNDERSTAND THE NON-COVALENT BINDING OF AROMATICS

2012 ◽  
Vol 1 (1) ◽  
pp. e201204004 ◽  
Author(s):  
Michael Lewis ◽  
Christina Bagwill ◽  
Laura K.E. Hardebeck ◽  
Selina Wireduaah
Keyword(s):  
Covalent Binding ◽  
Hammett Constants

Antimycobacterial thiobenzanilides

1990 ◽  
Vol 55 (1) ◽  
pp. 307-316 ◽  
Author(s):  
Karel Waisser ◽  
Nestor Houngbedji ◽  
Miloš Macháček ◽  
Miroslav Sekera ◽  
Josef Urban ◽  
...  
Keyword(s):  
Silica Gel ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Antimycobacterial Activity ◽  
Uv Spectra ◽  
Mycobacterium Kansasii ◽  
Aromatic Rings ◽  
H Nmr ◽  
Hammett Constants ◽  
Thioamide Group

A group of 30 thiobenzanilides active against Mycobacterium kansasii have been synthesized and their 1H NMR and UV spectra and RM values (TLC on silica gel impregnated with methylsilicone oil) have been measured. From the correlation between the chemical shifts of the thioamide proton in the 1H NMR spectra and the Hammett constants it can be concluded that the substituents in both aromatic rings uniformly affect the electron density of the thioamide group. The antimycobacterial activity is probably connected with local molecular parameters and can be considered to be approximately additive with respect to both parts of the molecule.

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