Impact of low-cost methods in the description of excimer and exciplex formation: pyrene–pyrene and pyrene–naphthalene case studies

Casal, Mariana T. do; Cardozo, Thiago Messias

doi:10.1007/s00214-020-02658-0

Cited by 11 publications

(6 citation statements)

References 77 publications

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“…25,27,37,38,89 Some other studies recognised the dispersion problem, but for a lack of a better choice, followed Huenerbein and Grimme's recommendation to use a global-hybrid combined with DFT-D2, 6,90–95 while fewer applied the newer, ground-state based DFT-D3 method in its zero-damping 96 [DFT-D3(0)] or in its Becke–Johnson-damping 97–99 [DFT-D3(BJ) 40 ] form. 100–106 To our knowledge, only three studies have considered adjusting dispersion corrections for excited states. In the first, Ikabata and Nakai 107 calculated excited-state dispersion coefficients within the local-response dispersion 108,109 (LRD) model to explore the interaction energies of exciton-localised molecular complexes from the S66 (ref.…”

Section: Introductionmentioning

confidence: 99%

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Noncovalently bound excited-state dimers: a perspective on current time-dependent density functional theory approaches applied to aromatic excimer models

Hancock

Goerigk

2022

RSC Adv.

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Section: Introductionmentioning

confidence: 99%

“…Most of the aforementioned exciplex studies used older global-hybrid DFAs, while some 85,86,90,91,102,105,106,116 used range-separated hybrids. Of the two studies that investigated DHDFAs 94,102 both utilised TDA-DFT, instead of the full TD-DFT scheme, but only Krueger and Blanquart 102 considered a dispersion correction.…”

Section: Introductionmentioning

confidence: 99%

Noncovalently bound excited-state dimers: a perspective on current time-dependent density functional theory approaches applied to aromatic excimer models

Hancock

Goerigk

2022

RSC Adv.

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“…The pyrene centroid–centroid distance in CCP is 4.0 Å, whereas it is 4.8 Å in BNP . The plane-to-plane distances are equal (3.5 Å for both BNP and CCP ), a value which was reported for unsubstituted pyrene and BN-pyrene as well. , Consequently, in BNP and CCP , a charge carrier transport between the pyrene planes should be possible. ,,, While the overlap area of two stacked molecules of BNP is 35%, it is largely elevated in CCP (58%), which is comparable with unsubstituted pyrene (60%) and a number of substituted pyrenes that throughout exhibit excimer formation in the solid state . We will discuss the consequences of this overlap angle on the optical properties later in the article.…”

Section: Resultsmentioning

confidence: 55%

“… 70 , 84 Consequently, in BNP and CCP , a charge carrier transport between the pyrene planes should be possible. 68 , 70 , 85 , 86 While the overlap area of two stacked molecules of BNP is 35%, it is largely elevated in CCP (58%), which is comparable with unsubstituted pyrene (60%) and a number of substituted pyrenes that throughout exhibit excimer formation in the solid state. 68 We will discuss the consequences of this overlap angle on the optical properties later in the article.…”

Section: Resultsmentioning

confidence: 97%

BN-Substitution in Dithienylpyrenes Prevents Excimer Formation in Solution and in the Solid State

et al. 2022

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Boron–nitrogen substitutions in polycyclic aromatic hydrocarbons (PAHs) have a strong impact on the optical properties of the molecules due to a significantly more heterogeneous electron distribution. However, besides these single-molecule properties, the observed optical properties of PAHs critically depend on the degree of intermolecular interactions such as π–π-stacking, dipolar interactions, or the formation of dimers in the excited state. Pyrene is the most prominent example showing the latter as it exhibits a broadened and strongly bathochromically shifted emission band at high concentrations in solution compared to the respective monomers. In the solid state, the impact of intermolecular interactions is even higher as it determines the crystal packing crucially. In this work, a thiophene-flanked BN-pyrene ( BNP ) was synthesized and compared with its all-carbon analogue ( CCP ) in solution and in the solid state by means of crystallography, NMR spectroscopy, UV–vis spectroscopy, and photoluminescence (PL) spectroscopy. In solution, PL spectroscopy revealed the solvent-dependent presence of excimers of CCP at high concentrations. In contrast, no excimers were found in BNP . Clear differences were also observed in the single-crystal packing motifs. While CCP revealed overlapped pyrene planes with centroid distances in the range of classical π-stacking interactions, the BNP scaffolds were displaced and significantly more spatially separated.

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“…Computational investigations are fundamental to unveiling the mechanisms that govern the photoinduced processes of π-conjugated chromophores and exploiting their properties in functional photonic materials. Several computational investigations have focused on the determination of the equilibrium structure and stabilization of pyrene’s excimer [ 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. Concerning nitrogen-substituted derivatives, a systematic computational analysis on the effect of the position and nature (graphitic vs. pyridinic) in di-azapyrene has been reported [ 35 ].…”

Section: Introductionmentioning

confidence: 99%

Eclipsed and Twisted Excimers of Pyrene and 2-Azapyrene: How Nitrogen Substitution Impacts Excimer Emission

Dai,

Rambaldi,

Negri

2024

Molecules

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Due to their unique photophysical and electronic properties, pyrene and its analogues have been the subject of extensive research in recent decades. The propensity of pyrene and its derivatives to form excimers has found wide application in various fields. Nitrogen-substituted pyrene derivatives display similar photophysical properties, but for them, excimer emission has not been reported to date. Here, we use time-dependent density functional theory (TD-DFT) calculations to investigate the low-lying exciton states of dimers of pyrene and 2-azapyrene. The excimer equilibrium structures are determined and the contribution of charge transfer (CT) excitations and intermolecular interactions to the exciton states is disclosed using a diabatization procedure. The study reveals that the dimers formed by the two molecules have quite similar exciton-state patterns, in which the relevant CT contributions govern the formation of excimer states, along with the La/Lb state inversion. In contrast with pyrene, the dipole–dipole interactions in 2-azapyrene stabilize the dark eclipsed excimer structure and increase the barrier for conversion into a bright twisted excimer. It is suggested that these differences in the nitrogen-substituted derivative might influence the excimer emission properties.

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Impact of low-cost methods in the description of excimer and exciplex formation: pyrene–pyrene and pyrene–naphthalene case studies

Cited by 11 publications

References 77 publications

Noncovalently bound excited-state dimers: a perspective on current time-dependent density functional theory approaches applied to aromatic excimer models

Noncovalently bound excited-state dimers: a perspective on current time-dependent density functional theory approaches applied to aromatic excimer models

BN-Substitution in Dithienylpyrenes Prevents Excimer Formation in Solution and in the Solid State

Eclipsed and Twisted Excimers of Pyrene and 2-Azapyrene: How Nitrogen Substitution Impacts Excimer Emission

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