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Combined Spectroscopic and TD‐DFT Analysis to Elucidate Substituent and Acidochromic Effects in Organic Dyes: A Case Study on Amino‐ versus Nitro‐Substituted 2,4‐Diphenylquinolines
Author(s) -
Santos Giovanny Carvalho,
Roldao Juan Carlos,
Shi Junqing,
MiliánMedina Begoña,
SilvaFilho Luiz Carlos,
Gierschner Johannes
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000452
Subject(s) - protonation , chemistry , substituent , nitro , solvent , absorption spectroscopy , absorption (acoustics) , spectral line , computational chemistry , organic chemistry , materials science , optics , physics , ion , alkyl , astronomy , composite material
A combined spectroscopic and TD‐DFT case study was performed, to identify a robust method to calculate the complex near UV/Vis absorption spectra of various amino‐ vs. nitro‐substituted 2,4‐diphenylquinolines, which vary strongly under neutral and successively acidic conditions. For this, different DFT functionals were tested for geometry optimization and the TD part to calculate the neutral and different protonated species in a fast screening approach, i. e. using single point calculations in an implicit solvent. Offset‐corrected M06HF, hitherto only applied to polymers, was identified as a suitable method to reproduce the absorption spectra in a reasonable fashion for all different substitution pattern and all different protonated species at different pH values; moreover, the method properly predicts the energetic ordering of low‐lying n‐π* and ππ* transitions, which is decisive for the non‐/emissive nature of the different compounds. In all, this might provide a valuable tool for computer‐aided design of related classes of compounds.