New insight into catechol photochemistry: the role of different monomer and dimer configurations in radiation-less decay of the S<sub>1</sub>electronic excited state

Bende, Attila; Farcaș, Alex-Adrian; Fălămaș, Alexandra; Petran, Anca

doi:10.1039/d2cp03702e

Cited by 3 publications

(1 citation statement)

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“…[106][107][108][109] Since excited states can be localize on one or the other constituent of the molecule-surface complex, or charges can easily migrate from the molecule to the surface or vice versa, relaxation processes can also occur either on the components separately or even inside the binary system. Accordingly, it was already shown, that non-radiative relaxation can occur either on the graphene surface 110 itself or in the binary complex, [111][112][113][114][115][116][117][118] but at the same time, excited states in the case of slightly modified GrNP can also decay via fluorescence phenomena. 119,120 Given that the relatively moderate size of the chosen graphene model (62 carbon and 22 hydrogen atoms) does not require the use of, e.g., a solid-state based physical model, in the present case the binary molecule-graphene complex will be considered as a macromolecular system with two interacting constituents and treated with the ordinary DFT and TDDFT methods suitable for molecular systems.…”

Section: Excited State Relaxation Dynamicsmentioning

confidence: 99%

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Farcaş,

Bende

2024

Phys. Chem. Chem. Phys.

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Section: Excited State Relaxation Dynamicsmentioning

confidence: 99%

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Farcaş,

Bende

2024

Phys. Chem. Chem. Phys.

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Intermolecular-Type Conical Intersections in Benzene Dimer

Bende

Farcaș

2023

IJMS

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The equilibrium and conical intersection geometries of the benzene dimer were computed in the framework of the conventional, linear-response time-dependent and spin-flipped time-dependent density functional theories (known as DFT, TDDFT and SF-TDDFT) as well as using the multiconfigurational complete active space self-consistent field (CASSCF) method considering the minimally augmented def2-TZVPP and the 6–31G(d,p) basis sets. It was found that the stacking distance between the benzene monomers decreases by about 0.5 Å in the first electronic excited state, due to the stronger intermolecular interaction energy, bringing the two monomers closer together. Intermolecular-type conical intersection (CI) geometries can be formed between the two benzene molecules, when (i) both monomer rings show planar deformation and (ii) weaker (approximately 1.6–1.8 Å long) C–C bonds are formed between the two monomers, with parallel and antiparallel orientation with respect to the monomer. These intermolecular-type CIs look energetically more favorable than dimeric CIs containing only one deformed monomer. The validity of the dimer-type CI geometries obtained by SF-TDDFT was confirmed by the CASSCF method. The nudged elastic band method used for finding the optimal relaxation path has confirmed both the accessibility of these intermolecular-type CIs and the possibility of the radiationless deactivation of the electronic excited states through these CI geometries. Although not as energetically favorable as the previous two CI geometries, there are other CI geometries characterized by the relative rotation of monomers at different angles around a vertical C–C axis.

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Nature of Charge Transfer Effects in Complexes of Dopamine Derivatives Adsorbed on Graphene-Type Nanostructures

Farcaş,

Bende

2024

IJMS

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Continuing the investigation started for dopamine (DA) and dopamine-o-quinone (DoQ) (see, the light absorption and charge transfer properties of the dopamine zwitterion (called dopamine-semiquinone or DsQ) adsorbed on the graphene nanoparticle surface is investigated using the ground state and linear-response time-dependent density functional theories, considering the ωB97X-D3BJ/def2-TZVPP level of theory. In terms of the strength of molecular adsorption on the surface, the DsQ form has 50% higher binding energy than that found in our previous work for the DA or DoQ cases (−20.24 kcal/mol vs. −30.41 kcal/mol). The results obtained for electronically excited states and UV-Vis absorption spectra show that the photochemical behavior of DsQ is more similar to DA than that observed for DoQ. Of the three systems analyzed, the DsQ-based complex shows the most active charge transfer (CT) phenomenon, both in terms of the number of CT-like states and the amount of charge transferred. Of the first thirty electronically excited states computed for the DsQ case, eleven are purely of the CT type, and nine are mixed CT and localized (or Frenkel) excitations. By varying the adsorption distance between the molecule and the surface vertically, the amount of charge transfer obtained for DA decreases significantly as the distance increases: for DoQ it remains stable, for DsQ there are states for which little change is observed, and for others, there is a significant change. Furthermore, the mechanistic compilation of the electron orbital diagrams of the individual components cannot describe in detail the nature of the excitations inside the complex.

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New insight into catechol photochemistry: the role of different monomer and dimer configurations in radiation-less decay of the S₁electronic excited state

Abstract: The equilibrium geometries of the ground and first electronic excited states as well as the radiotinless deactivation channels of catechol in its monomer and dimer configuration have been investigated using...

Cited by 3 publications

References 63 publications

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Intermolecular-Type Conical Intersections in Benzene Dimer

Nature of Charge Transfer Effects in Complexes of Dopamine Derivatives Adsorbed on Graphene-Type Nanostructures

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New insight into catechol photochemistry: the role of different monomer and dimer configurations in radiation-less decay of the S1electronic excited state

Abstract: The equilibrium geometries of the ground and first electronic excited states as well as the radiotinless deactivation channels of catechol in its monomer and dimer configuration have been investigated using...

Cited by 3 publications

References 63 publications

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Theoretical insights into dopamine photochemistry adsorbed on graphene-type nanostructures

Intermolecular-Type Conical Intersections in Benzene Dimer

Nature of Charge Transfer Effects in Complexes of Dopamine Derivatives Adsorbed on Graphene-Type Nanostructures

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Product

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New insight into catechol photochemistry: the role of different monomer and dimer configurations in radiation-less decay of the S₁electronic excited state