Excited‐state substituent constants σ from substituted benzenes

Abstract

In this work, 13 compounds of 4,4′‐disubstituted stilbenes and 5 compounds of 3‐methyl‐4′‐substituted stilbenes were prepared and their UV spectra were measured. A new substituent effect constant, namely excited‐state substituent constant, was proposed, which was calculated directly from the UV absorption energy data of substituted benzenes. The investigation result shows that the proposed constant is different from the existing polar substituent constants and radical substituent constants in nature. The availability of the new constant was confirmed by the good correlations with the UV absorption energy of four kinds of compounds, 1,4‐disubstituted benzenes, 4,4′‐disubstituted stilbenes, substituted ethenes, and m‐Y‐substituted aromatic compounds. It is expected that the excited‐state substituent constant can be applied in QSPR study on organic compounds at the excited state. Copyright © 2008 John Wiley & Sons, Ltd.

Cobalt Antiferromagnetic Ring and Grid Single‐Molecule Magnet

“…studied the correlation between free radical constant and the molecular UV absorption energy, and single‐parameter (radical substituent parameter) equation or dual‐parameter (polar and radical substituent parameters) equation. (3) Excited‐state substituent parameter17–19; Cao et al 19. recently proposed a new excited‐state substituent parameter ${\rm \sigma }_{\rm CC}^{\rm ex} $ , and recommended the single‐parameter equation (1) in terms of excited‐state substituent parameter ${\rm \sigma }_{\rm CC}^{\rm ex} $ , or the dual‐parameter equation (2) in terms of a combination of σ p and ${\rm \sigma }_{\rm CC}^{\rm ex} $ to correlate the UV absorption wavenumbers ( υ max ) of monosubstituted benzene derivatives, monosubstituted stilbene derivatives and monosubstituted ethene derivatives.…”

“…For the monosubstituted conjugated organic compounds XA (X denotes different substituents and A denotes the molecular structures of parents), Cao et al 19. reported that their UV absorption energy could be well correlated with single‐parameter equation (1) or dual‐parameter equation (2).…”

Comparison of the 13C (C = N) chemical shifts of substituted N‐(phenyl‐ethylene)‐anilines and substituted N‐(benzylidene)‐anilines

“…Based on Fig. and Eqn , we try to add the excited‐state substituent parameters of X and Y into Eqn ; then Eqn was obtained by adding ( X ) and ( Y ). …”

Effects of substituent and solvent on the UV absorption energy of 4,4′-disubstituted stilbenes

“…If the 4,4'-disubstituted stilbene derivatives is to be used as optical materials, the effects of substituent and solvent on their UV absorption energy must be known. In author's recent works [16][17][18], the excited-state substituent parameter ex CC  was proposed to scale the effect of intramolecular substituent effect. It is found that the energy of UV absorption max wavelengths of trans-4,4'-disubstituted stilbene derivatives (XPhCH=CHPhY) can be correlated well with two parameters in a given solvent, the sum of ex CC  of substituents X and Y and the interaction between substituents X and Y, ex CC  (X) ex CC  (Y), in which the correlation result using parameter ex CC  is better than that of using polar substituent constant  x or spin-delocalization substituent constant  • [16][17][18].…”