Complexation of monosubstituted benzenes and methanes by cyclotetrachromotropylene in aqueous solution: Substituent effects on ?-? and Ch-? interactions

1994 ◽  
Vol 18 (1) ◽  
pp. 93-99 ◽  
Author(s):  
Bo-Long Poh ◽  
Chi Ming Tan
Keyword(s):  
Aqueous Solution ◽  
Substituent Effects ◽  
Monosubstituted Benzenes

Nuclear Magnetic Resonance Chemical Shifts of some Monosubstituted Isothiazoles

1975 ◽  
Vol 53 (4) ◽  
pp. 596-603 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Thomas R. Clem ◽  
Edwin D. Becker
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Charge Densities ◽  
Monosubstituted Benzenes ◽  
Proton Chemical Shifts ◽  
Nuclear Magnetic

Carbon-13 and proton chemical shifts have been measured for several monosubstituted isothiazoles. Substituent effects upon these chemical shifts are compared with those observed for monosubstituted benzenes, pyridines, and thiophenes. In general the observed substituent effects in the isothiazoles and thiophenes closely parallel one another. Correlations between the observed carbon-13 Chemical shifts and CNDO/2 calculated charge densities are examined.

Substituent effects on the binding of phenols to cyclodextrins in aqueous solution

1989 ◽  
Vol 93 (18) ◽  
pp. 6863-6867 ◽  
Author(s):  
Gary L. Bertrand ◽  
James R. Faulkner ◽  
Soon M. Han ◽  
Daniel W. Armstrong
Keyword(s):  
Aqueous Solution ◽  
Substituent Effects

scholarly journals Substituenteneinflüsse auf die 13C–NMR-chemischen Verschiebungen cis- und trans-konfigurierter Trimethincyanine / Substituent Effects on the 13C NMR Chemical Shifts of Trimethincyanines with cis and trans Configuration

1976 ◽  
Vol 31 (12) ◽  
pp. 1641-1645 ◽  
Author(s):  
Walter Grahn
Keyword(s):  
13C Nmr ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Electron Systems ◽  
Coupling Constant ◽  
Electronic Effects ◽  
Nmr Chemical Shifts ◽  
Monosubstituted Benzenes ◽  
Cis And Trans ◽  
C Nmr

The 13C NMR chemical shifts of fifteen 6 substituted 2,3-dihydro-1,4-diazepinium salts (cis trimethincyanines) (1) and twelve 2 substituted bis(dimethylamino)trimethinium salts (trans trimethincyanines) (2) have been determined. A comparison of the substituentinduced shifts (13C SCS) of 1 and 2 allows no distinction between steric and electronic effects. In the three 6 п-electron systems 1, 2 and monosubstituted benzenes the 13C SCS are similar for the substituent bearing carbon atoms. A surprisingly large 4JFCCNC coupling constant has been observed.

Electrophilic Aromatic Nitration: Substituent Effects of Monosubstituted Benzenes

2010 ◽  
Vol 57 (5A) ◽  
pp. 967-971 ◽  
Author(s):  
Peng-Cheng Wang ◽  
Jing Chen ◽  
Ming Lu
Keyword(s):  
Substituent Effects ◽  
Monosubstituted Benzenes ◽  
Aromatic Nitration

scholarly journals Carbonyl Addition Reactions: Factors Affecting the Hydrate–Hemiacetal and Hemiacetal–Acetal Equilibrium Constants

1975 ◽  
Vol 53 (6) ◽  
pp. 898-906 ◽  
Author(s):  
J. Peter Guthrie
Keyword(s):  
Aqueous Solution ◽  
Carbonyl Compounds ◽  
Equilibrium Constants ◽  
Substituent Effects ◽  
Steric Effects ◽  
Addition Reactions ◽  
Free Energies ◽  
Electronic Effects ◽  
Factors Affecting ◽  
Analogous Formula

Equilibrium constants for hydrate–hemiacetal interconversion in aqueous solution at 25° have been measured for four fluorinated carbonyl compounds: compound, alcohol, K4 (M−1): CF3CHO, C2H5OH, 2.3; CF3COCH3, CH3OH, 1.0; CF3COPh, CH3OH, 3.5; CF3COCF3, CH3OH, 0.14. These values, combined with values from the literature, permit an examination of substituent effects upon the equilibrium constant for[Formula: see text]The free energy change for this process, corrected for symmetry and steric effects, follows the equation[Formula: see text]Thus electronic effects upon this equilibrium are generally small and in fact are often smaller than steric effects.This analysis permits and justifies the calculation of free energies of formation of [Formula: see text] compounds from the (more generally measurable) free energies of formation of the analogous [Formula: see text] compounds.

Substituent effects on the N.M.R. spectra of carboxylic acid derivatives. III. Correlation of 13C N.M.R. spectra of para substituted acetanilides and 4'-nitrophenyl 4-substituted benzoates with infrared carbonyl stretching frequencies, 1H N.M.R., rate and equilibrium data

1984 ◽  
Vol 37 (3) ◽  
pp. 497 ◽  
Author(s):  
CJ O'Conner ◽  
DJ McLennan ◽  
DJ Calvert ◽  
TD Lomax ◽  
AJ Porter ◽  
...  
Keyword(s):  
Free Energy ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Linear Free Energy Relationships ◽  
Reactive Site ◽  
Linear Free Energy ◽  
Equilibrium Data ◽  
Energy Relationships ◽  
Monosubstituted Benzenes ◽  
Best Fit

The 13C n.m.r. spectra of 17 monosubstituted benzenes, 14 para substituted acetanilides and ten 4'-nitrophenyl 4-substituted benzoates have been measured in (CD3)2SO and the chemical shifts have been compared with the infrared carbonyl stretching frequencies of the substrates (in CCl4), the 1H n.m.r. chemical shifts of protons close to the reactive site of protonation, rates of hydrolysis or aminolysis and literature values of the corresponding basicity constants and rate constants. The observed substituent chemical shifts are non-additive and this result has been discussed in terms of the electronic properties of -NHCOCH3 and -COOC6H4NO2. The 13C n.m.r. and the i.r. data have been treated by single parameter and dual substituent parameter linear free energy relationships and σR values of best fit have been identified. Relative resonance and inductive contributions have been discussed.

A Comparison of Substituent Effects on the Stability of .alpha.,.alpha.-Dimethylbenzyl Carbocations in Aqueous Solution and in the Gas Phase: How Significant is Nucleophilic Solvation?

1994 ◽  
Vol 116 (15) ◽  
pp. 6706-6712 ◽  
Author(s):  
John P. Richard ◽  
Vandannapu Jagannadham ◽  
Tina L. Amyes ◽  
Masaaki Mishima ◽  
Yuho Tsuno
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Substituent Effects ◽  
The Stability ◽  
Nucleophilic Solvation

Thermodynamic functions of ionization of t-butyl-substituted and methoxysubstituted phenols

1972 ◽  
Vol 25 (1) ◽  
pp. 75 ◽  
Author(s):  
PD Bolton ◽  
FM Hall ◽  
J Kudrynski
Keyword(s):  
Aqueous Solution ◽  
Thermodynamic Functions ◽  
Spectrophotometric Method ◽  
Substituent Effects ◽  
Steric Effects ◽  
Ionization Process ◽  
Ionization Constants ◽  
Temperature Range

Thermodynamic ionization constants of 2-t-butylphenol, 3-t-butylphenol, 4-t-butylphenol, 3,5-di-t-butylphenol, and 3,5-dimethoxyphenol have been measured in aqueous solution by an e.m.f./spectrophotometric method within the temperature range 5-60�C and the thermodynamic functions of ionization ΔG25, ΔH25, ΔS25, and ΔCp25 calculated. These results confirm the additivity of substituent effects noted previously for the ionization of 3,5-disubstituted phenols and indicate that this ionization process is relatively insensitive to steric effects.

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