Interfacing High‐Energy Charge‐Transfer States to a Near‐IR Sensitizer for Efficient Electron Transfer upon Near‐IR Irradiation

Pinjari, Dilip; Alsaleh, Ajyal Z.; Patil, Yuvraj; Misra, Ranjita; D’Souza, Francis

doi:10.1002/ange.202013036

Cited by 11 publications

(3 citation statements)

References 60 publications

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“…The respective CT states may originate from the n−π* transition of the urea to the dicyanovinyl moieties via bond and space (field effect) . It has been previously observed strong quenching of emission for TCBD-type push–pull molecules, suggesting the occurrence of excited-state events such as energy or electron transfer. , …”

Section: Resultsmentioning

confidence: 97%

“…40 It has been previously observed strong quenching of emission for TCBD-type push−pull molecules, suggesting the occurrence of excited-state events such as energy or electron transfer. 57,58 Lifetime measurements were carried out for the emission of Hexyl-TCBD using the time-correlated single-photon counting (TCSPC) method to further understand the steady-state fluorescence results (Table 1). Among medium-polarity aprotic solvents, we have chosen THF and CH 3 CN as they feature distinct polarity with dielectric constants of 7.58 and 37.5, respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Nanotechnology-Assisted, Single-Chromophore-Based White-Light-Emitting Organic Materials with Bioimaging Properties

Dar¹,

Gowri²,

Mishra³

et al. 2021

Langmuir

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White-light-emitting (WLE) organic materials, especially small molecules comprising a single chromophoric unit, have received much attention due to their tremendous use in modern-day electronic devices and biomaterials. They can increase the efficiency and lifetime of devices compared to the currently used combination approach. Herein, we explored a small symmetric push–pull organic molecule Hexyl-TCBD with a single 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) chromophoric unit containing urea as a key functional group on an acceptor–donor∼donor–acceptor (A–D∼D–A) backbone for its ability to show white-light emission in solution as well as in the solid state. The luminescence was absent in the solid state due to the H-bonding- and π-stacking-driven quenching processes, while emission behavior in solution was tunable with variable CIE chromaticity index values via hydrogen (H)-bonding-governed disaggregation phenomena. Translation of WLE from the Hexyl-TCBD solution to a solid state was demonstrated by utilizing nonemissive polystyrene (80 wt % with respect to the chromophore) as the matrix to obtain WLE nanofibers (made by the electrospun technique) via segregating the molecules. The optical microscopy study validated the WLE nanofibers. The presence of multicolor photoluminescence, including white light, could be fine-tuned through various excitation wavelengths, solvent polarities, and polystyrene matrices. Furthermore, the detailed photophysical studies, including lifetime measurements, indicated that the inherent intramolecular charge transfer (ICT) bands of Hexyl-TCBD exhibit better ICT state stabilization by space charge distribution through the modulation of H-bonding between urea groups. Finally, a cytotoxicity study was performed for Hexyl-TCBD on normal and cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay to explore bioimaging applications in biosystems. MTT results revealed significant toxicity toward cancer cells, whereas normal cells exhibited good biocompatibility.

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Section: Resultsmentioning

confidence: 97%

Section: ■ Results and Discussionmentioning

confidence: 99%

Nanotechnology-Assisted, Single-Chromophore-Based White-Light-Emitting Organic Materials with Bioimaging Properties

Dar¹,

Gowri²,

Mishra³

et al. 2021

Langmuir

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“…[20][21][22][23][24][25][26] Pertaining to artificial photosynthetic systems, even though the presence of TPA as sacrificial electron donor leads to the stabilization of the charge-separated state due to hole migration, 27 the optical absorption localized majorly at around 300 nm hinders its use as a panchromatic dye. To address this, and transform TPA into a broad wavelength range absorber, the core of the molecule has been integrated with chromophores such as porphyrin, [27][28][29][30][31][32][33][34][35][36][37] corrole, 38,39 phenothiazine, 40 carbazole, 41 subphthalocyanine, 42 borondipyrromethene (BODIPY), [43][44][45][46][47] azaBODIPY, 48,49 metal complexes, 50,51 heterocyclics such as quinoxaline, 52 thiophene, 53 pyrrolopyrrole, 54 aryldiimides, [55][56][57][58] and various light-harvesting molecules imposing potential applications in DSSCs, [20][21][22][23]…”

Section: Introductionmentioning

confidence: 99%

Investigating the role of corrole as an excitation energy relay in light‐induced processes in closely connected N,N'‐bis(biphenyl‐4‐yl)aniline functionalized corrole donor–acceptor dyad

Chuncha,

Achary Balahoju,

Dutta

et al. 2024

Photochem & Photobiology

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A photosynthetic antenna‐reaction center model, BBA‐PFCor comprised of N,N'‐bis(biphenyl‐4‐yl)aniline (BBA) covalently functionalized to bis(pentafluoro)corrole moiety has been prepared and the contribution of the BBA as the photoinduced energy transfer antenna was investigated. UV–visible studies have shown that integrating the electron‐rich BBA chromophore into the corrole core has broadened the soret band of the corrole moiety with the absorption spanning from 300 to 700 nm. Electrochemical studies, in corroboration with the computational calculations, revealed that, BBA moiety can act as an electron reservoir and, in the excited state, it would transfer the excited energy to the corrole moiety in the dyad. Steady‐state fluorescence studies have demonstrated that, upon photoexcitation of the BBA moiety of BBA‐PFCor at 310 nm in solvents of varied polarity, the BBA emission centered at 400 nm was observed to be quenched, with the concomitant appearance of the corrole emission from 500 to 700 nm, indicating the happening of photoinduced energy transfer (PEnT) from 1BBA* to corrole moiety. Parallel control experiments involving the excitation of the corrole moiety at 410 nm did not result in the diminishing of the corrole emission, suggesting that the quenching of the BBA emission in BBA‐PFCor is majorly due to intramolecular PEnT from 1BBA* to corrole moiety leading to the formation of singlet excited corrole, that is, 1BBA*‐PFCor ➔ BBA‐1PFCor*. The free energy changes of PEnT, ΔGEnT, were found to be thermodynamically feasible in all the solvents used for the study. Parallel time‐resolved fluorescence studies were congruent with the steady‐state fluorescence results and provided further evidence for the occurrence of ultrafast PEnT from 1BBA*➔corrole in the dyad with the rates of energy transfer (kEnT) of ~108 s−1.

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Photoinduced Charge Separation Prompted Intervalence Charge Transfer in a Bis(thienyl)diketopyrrolopyrrole Bridged Donor‐TCBD Push‐Pull System

et al. 2021

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Intervalence charge transfer (IVCT), aphenomenon observed in molecular systems comprised of two redox centers differing in oxidation states by one unit, is reported in anovel, newly synthesized, multi-modular donor-acceptor system comprised of central bis(thienyl)diketopyrrolopyrrole (TDPP) hosting two phenothiazine-tetracyanobutadiene (PTZ-TCBD) entities on the opposite sides.One-electron reduction of TCBD promoted electron exchange between the two TCBD resulting in IVCT transition in the near-infrared region. The stabilization energy, ÀDG com and comproportionation equilibrium constant, K com calculated from peak potentials of the split reduction waves were found to be 1.06 10 4 Jmol À1 ,a nd 72.3 M À1 ,r espectively.F urther,t he IVCT transition was also witnessed during the process of thermodynamically feasible electron transfer upon excitation of the TDPP entity in the system, and served as ad iagnostic marker to characterizet he electron transfer product. Subsequent transient absorption spectral studies and data analysis by Global and Target analyses revealed occurrence of ultrafast charge separation (k cs % 10 10 s À1 )owing to the close proximity and good communication between the entities of the multi-modular donoracceptor system. The role of central TDPP in promoting IVCT is borne out from the present investigation.

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Interfacing High‐Energy Charge‐Transfer States to a Near‐IR Sensitizer for Efficient Electron Transfer upon Near‐IR Irradiation

Cited by 11 publications

References 60 publications

Nanotechnology-Assisted, Single-Chromophore-Based White-Light-Emitting Organic Materials with Bioimaging Properties

Nanotechnology-Assisted, Single-Chromophore-Based White-Light-Emitting Organic Materials with Bioimaging Properties

Investigating the role of corrole as an excitation energy relay in light‐induced processes in closely connected N,N'‐bis(biphenyl‐4‐yl)aniline functionalized corrole donor–acceptor dyad

Photoinduced Charge Separation Prompted Intervalence Charge Transfer in a Bis(thienyl)diketopyrrolopyrrole Bridged Donor‐TCBD Push‐Pull System

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