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Regioselective
Counterion Association Governs Organohalogenochromism
in Ferrocenyl Ionic Push-Pull Chromophores
Ignacio Aburto (23926056)
Raúl Mera-Adasme (1717771)
Fabián Martínez-Gómez (20205087)
Carolina Aliaga (2144944)
Moisés Domínguez (17790191)
Biophysics
Biochemistry
Physiology
Chemical Sciences not elsewhere classified
Inorganic Chemistry
Plant Biology
regioselective interaction centered
key factor governing
ict transition energies
ferrocenyl ionic push
82 × 10
38 × 10
1 </ sub
1 </ sup
>< sub
π </
results indicate
quinolinium derivatives
quinolinium acceptors
pull chromophores
pairing model
pair equilibria
organohalogenochromism arises
optical response
explained solely
directly controlled
dft calculations
counterion association
controlled modulation
azaheterocyclic acceptor
Two organometallic cationic D-<i>π</i>-A dyes incorporating
ferrocene donors and pyridinium or quinolinium acceptors were synthesized
and evaluated for their organohalogenochromic (OHC) behavior in halogenated
and non-halogenated solvents. Both dyes exhibited pronounced bathochromic
shifts in halogenated media that cannot be explained solely by conventional
solvent polarity effects. Triflate titration experiments demonstrated
that ICT transition energies are directly controlled by counterion
association, while <sup>1</sup>H NMR measurements revealed a regioselective
interaction centered at the azaheterocyclic acceptor. Benesi–Hildebrand
analysis yielded association constants of 4.82 × 10<sup>–2</sup> M<sup>–1</sup> and 1.38 × 10<sup>–2</sup> M<sup>–1</sup> for the pyridinium and quinolinium derivatives, respectively.
Complementary <i>T</i><sub>1</sub> measurements and TD-DFT
calculations further supported a solvent-dependent ion-pairing model.
Collectively, the results indicate that organohalogenochromism arises
from solvent-controlled modulation of ion-pair equilibria, highlighting
regioselective counterion association as a key factor governing the
optical response of ferrocenyl ionic push-pull chromophores.
2026-09-29T00:00:00Z
Text
Journal contribution
10.1021/acs.jpcb.6c05161.s001
https://figshare.com/articles/journal_contribution/Regioselective_Counterion_Association_Governs_Organohalogenochromism_in_Ferrocenyl_Ionic_Push-Pull_Chromophores/34024792
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