Investigating the excited state optical properties and origin of large stokes shift in Benz[c,d]indole N-Heteroarene BF2 dyes with ab initio tools

Gawale, Yogesh; Sekar, Nagaiyan

doi:10.1016/j.jphotobiol.2017.12.006

Cited by 23 publications

(11 citation statements)

References 56 publications

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“…In front of this curious phenomenon, multiple theoretical investigations were undertaken [ 30 , 31 , 32 , 33 , 34 , 35 , 36 ], and emphasis on the computational method, types of the basis sets, the importance of the solvent field, the use of excited state molecular dynamics, and even empirical corrections, were made [ 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Ab initio calculations were also reported with good results, but the computational time is also an unneglectable parameter to consider [ 47 , 48 ].…”

Section: Introductionmentioning

confidence: 99%

The TDDFT Excitation Energies of the BODIPYs; The DFT and TDDFT Challenge Continues

et al. 2021

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The derivatives of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) are pivotal ingredients for a large number of functional, stimuli-responsive materials and therapeutic molecules based on their photophysical properties, and there is a urgent need to understand and predict their optical traits prior to investing a large amount of resources in preparing them. Density functional theory (DFT) and time-dependent DFT (TDDFT) computations were performed to calculate the excitation energies of the lowest-energy singlet excited state of a large series of common BODIPY derivatives employing various functional aiming at the best possible combination providing the least deviations from the experimental values. Using the common “fudge” correction, a series of combinations was investigated, and a methodology is proposed offering equal or better performances than what is reported in the literature.

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Section: Introductionmentioning

confidence: 99%

The TDDFT Excitation Energies of the BODIPYs; The DFT and TDDFT Challenge Continues

et al. 2021

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“…Conversely, in case of RSH, these results were found to be underestimates the data for dyes 2 a‐e . By looking at the charge transfer nature of studied dyes, the range‐separated hybrid functionals supposed to give meaningful estimates but surprisingly global hybrids such as B3LYP gave better estimates when we correlated with the experimentally observed results.…”

Section: Resultsmentioning

confidence: 79%

Tuning ‘Stokes Shift’ and ICT Character by Varying the Donor Group in Imidazo[1,5 a]pyridines: A Combined Optical, DFT, TD‐DFT and NLO Approach

Mohbiya

Sekar

2018

ChemistrySelect

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Imidazo [1, 5a]pyridine based novel donor-acceptor dyes (2a-e) with the large Stokes shift (ca. 140-200 nm) were synthesized and characterized. We report on the steady-state and nanosecond time-resolved emission studies of 2a-e in different microenvironments which reveal that the dyes 2a-c (average lifetime of 0.65, 1.36 and 1.63 ns respectively) perform reversible proton motion in chloroform due to variable donor group present at the para position of substituted phenyl group attached to imidazopyridine core as an acceptor group whereas 2d and 2e (average lifetime of 3.50 and 4.06 ns respectively) compete with 2a-c in agreement with considerable intramolecular charge transfer (ICT) characteristics. Solvent polarity plots viz. Lippert-Mataga, McRae, and Bakhshiev equation furnish the confirmation of ICT character. Density functional theory (DFT) calculations [(B3LYP/6-311 + +G(d, p)] provide the information of structural as well as the electronic properties of dyes 2a-e. Natural bond orbital (NBO) analyses enlighten the nature of the charge or proton transfer within the selected donor-acceptor orbital interaction with the large energy of stabilization (the donor-acceptor orbital interactions increases in the order 2a > 2b > 2c > 2d > 2e). The large difference in dipole moment (ca. 1.57-21.55 D) results in a strong non-linear optical (NLO) properties. The NLO properties were evaluated theoretically as well as spectroscopically in solvents of different polarities and the resulting hyperpolarizabilities fall within the expected limiting values. These results bring new findings in coupled ICT and proton transfer reactions which will be useful for further research and promising applications in sensing polarity or H-bonding of microenvironments similar to that of the biological ones.

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“…A plot of trends in Stokes shifts and singlet excited state dipole moment of D1-D8 is showed in Figure 7. The increase in excited state dipole moment and consequently geometric distortion are found to be responsible for the increased Stokes shifts [56]. The change in geometry in excited state suggests that electronic delocalization along the p-spacer is improved.…”

Section: Uv-vis Fluorescence Spectra and Stokes Shiftsmentioning

confidence: 91%

DFT and TD-DFT study on quadratic NLO response and optoelectronic activity in novel Y-shaped imidazole-based push-pull chromophores

Zaitri

Mekelleche

2021

J Mol Model

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A theoretical analysis of a series of imidazole-based Y-shaped chromophores, D1-D8, is performed in order to investigate their non(linear) optical, fluorescence, and charge-transport properties. The calculations have been carried out employing DFT and TD-DFT methods at CAM-B3LYP and M06-2X levels of theory. FMO analysis reveals that in ground state, highest occupied molecular orbital is localized on the 4,5-dimethylanilino donor moiety and imidazole core while lowest unoccupied molecular orbital spreads on p-linker and nitro acceptor moieties. Vertical absorption and fluorescence transitions are characterized as intramolecular charge transfer and maximum absorption and fluorescence wavelengths show that by changing the p-bridge to the imidazole C2, we can tune fluorescence color from cyan to orange. Calculated (hyper)polarizabilities show that elongation of πlinker by polarizable subunits, such as double bonds or heteroaromatic rings, increases significantly the nonlinear response and shifts the charge-transfer band bathochromically. Calculated reorganization energies indicate that the studied compounds are hole-transporting materials rather than electron-transporters. Interestingly, D7 and D8, with higher hyperpolarizabilities, are predicted to be potent candidates for NLOdevices while D5 and D8 molecules are expected to be promising candidates for luminescent materials and good hole-transport materials for organic light emitting diodes.

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Investigating the excited state optical properties and origin of large stokes shift in Benz[c,d]indole N-Heteroarene BF2 dyes with ab initio tools

Cited by 23 publications

References 56 publications

The TDDFT Excitation Energies of the BODIPYs; The DFT and TDDFT Challenge Continues

The TDDFT Excitation Energies of the BODIPYs; The DFT and TDDFT Challenge Continues

Tuning ‘Stokes Shift’ and ICT Character by Varying the Donor Group in Imidazo[1,5 a]pyridines: A Combined Optical, DFT, TD‐DFT and NLO Approach

DFT and TD-DFT study on quadratic NLO response and optoelectronic activity in novel Y-shaped imidazole-based push-pull chromophores

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