Infrared intensities as a quantitative measure of intramolecular interactions. III. Further monosubstituted benzenes and monosubstituted durenes

13C-NMR Based Evaluation of the Electronic and Steric Interactions in Aromatic Amines

“…It has been proven by its unsuccessful diazo coupling with p-nitrobenzenediazonium salts [35]. The σ R o for the twisted -N< group in benzoquinuclidine is equal to -0.134 [63] (as compared to -0.53 for NMe 2 group [64]). On the other hand, another hindered amine, i.e.…”

Electronic Effects of Nitro, Nitroso, Amino and Related Groups

“…Measurements of infrared intensities do, however, give information about 0 R constants for CR substituents. Katritzky and colleagues 154 give a 0 R value of 0.174 for NO 2 based on measurements with a solution of nitrobenzene in carbon tetrachloride. (Note: the sign of 0 R is not actually given by the correlation of infrared intensities, because the square of 0 R is involved.…”

Electronic Effects of Groups Containing Carbon–Carbon or Carbon–Oxygen Double Bonds

“…For certain substituents there was a proliferation of values based on reactivity under various conditions or on 19 F NMR in different solvents. Slightly later, correlation analysis of infrared data led in particular to new 0 R values and, to a lesser extent, new I values, which were described as 'IR-based' 39,40,46 . Somewhat later the same development occurred in connection with 13 C NMR, leading to ' 13 C NMR-based values' 37,38 .…”

“…Correlation analysis of the infrared intensities of the 16 ring bands of monosubstituted benzenes involves the squares of 0 R constants. Thus it is capable of leading to new numerical values of such substituent constants, but the signs must be inferred from other evidence 46 . In the case of vinyl the numerical value is 0.05, to which is added a negative sign in accord with the well-recognized behaviour of vinyl as a R substituent.…”