Ab initio electronic absorption spectra of para-nitroaniline in different solvents: Intramolecular charge transfer effects.
J Comput Chem
; 2024 Aug 30.
Article
in En
| MEDLINE
| ID: mdl-39212073
ABSTRACT
Intramolecular charge transfer (ICT) effects of para-nitroaniline (pNA) in eight solvents (cyclohexane, toluene, acetic acid, dichloroethane, acetone, acetonitrile, dimethylsulfoxide, and water) are investigated extensively. The second-order algebraic diagrammatic construction, ADC(2), ab initio wave function is employed with the COSMO implicit and discrete multiscale solvation methods. We found a decreasing amine group torsion angle with increased solvent polarity and a linear correlation between the polarity and ADC(2) transition energies. The first absorption band involves π â π* transitions with ICT from the amine and the benzene ring to the nitro group, increased by 4%-11% for different solvation models of water compared to the vacuum. A second band of pNA is characterized for the first time. This band is primarily a local excitation on the nitro group, including some ICT from the amine group to the benzene ring that decreases with the solvent polarity. For cyclohexane, the COSMO implicit solvent model shows the best agreement with the experiment, while the explicit model has the best agreement for water.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Comput Chem
/
J. comput. chem
/
Journal of computational chemistry
Journal subject:
QUIMICA
Year:
2024
Document type:
Article
Affiliation country:
Brazil
Country of publication:
United States