Synthesis of asymmetric indolonaphthyridines with enhanced excited state charge-transfer character

Purdy, Michael; Fallon, Kealan J.; Congrave, Daniel G.; Toolan, Daniel T. W.; Zeng, Weixuan; Bronstein, Hugo

doi:10.1039/d1tc06054f

Cited by 10 publications

(8 citation statements)

References 34 publications

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“…Therefore, the increased ability for OHAC to undergo singlet fission is a result of heightened electronic coupling, as opposed to improved energy-level alignment. Electronic coupling to TT states can often be charge-transfer mediated in singlet fission, and a previous study by our group showed that INDT derivatives have charge-transfer contribution to the photoexcited S 1 state . Therefore, while we did not observe direct evidence of charge transfer states in the TA data, it is possible the singlet fission mechanism may be charge-transfer mediated in OHAC.…”

Section: Resultscontrasting

confidence: 74%

Aza-Cibalackrot: Turning on Singlet Fission Through Crystal Engineering

et al. 2023

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Singlet fission is a photophysical process that provides a pathway for more efficient harvesting of solar energy in photovoltaic devices. The design of singlet fission candidates is non-trivial and requires careful optimization of two key criteria: (1) correct energetic alignment and (2) appropriate intermolecular coupling. Meanwhile, this optimization must not come at the cost of molecular stability or feasibility for device applications. Cibalackrot is a historic and stable organic dye which, although it has been suggested to have ideal energetics, does not undergo singlet fission due to large interchromophore distances, as suggested by single crystal analysis. Thus, while the energetic alignment is satisfactory, the molecule does not have the desired intermolecular coupling. Herein, we improve this characteristic through molecular engineering with the first synthesis of an aza-cibalackrot and show, using ultrafast transient spectroscopy, that singlet fission is successfully “turned on.”

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Section: Resultscontrasting

confidence: 74%

Aza-Cibalackrot: Turning on Singlet Fission Through Crystal Engineering

et al. 2023

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“…However, a recent study by our group showed IND desymmetrization can blue shift IND excited state energies. Therefore, synthesis of asymmetric IND dimers may improve the triplet energy for solar cell application [44] …”

Section: Synthesis and Dimer Designmentioning

confidence: 99%

“…Therefore, synthesis of asymmetric IND dimers may improve the triplet energy for solar cell application. [44]…”

Section: Synthesis and Dimer Designmentioning

confidence: 99%

Re‐Thinking Dimer Design Principles with Indolonaphthyridine Intramolecular Singlet Fission

Purdy

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Fallon

et al. 2023

Chemistry A European J

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Singlet fission is a phenomenon that could significantly improve the efficiency of photovoltaic devices. Indolonaphthyridine thiophene (INDT) is a photostable singlet fission material that could potentially be utilised in singlet fission‐based photovoltaic devices. Here, we investigate the intramolecular singlet fission (i‐SF) mechanism of INDT dimers linked via para‐phenyl, meta‐phenyl and fluorene bridging groups. Using ultra‐fast spectroscopy we find the highest rate of singlet fission in the para‐phenyl linked dimer. Quantum calculations show the para‐phenyl linker encourages enhanced monomer electronic coupling. Increased rates of singlet fission were also observed in the higher polarity o‐dichlorobenzene, relative to toluene, indicating that charge‐transfer states have a role in mediating the process. We find the mechanistic picture of polarisable singlet fission materials, such as INDT, extends beyond the traditional mechanistic landscape.

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“…Our efforts were crowned with the first total syntheses of melovinone (5) and waltherione-F (6). 9 During these studies, we also noticed that compounds like 7 are synthetic intermediates to new materials of importance in optoelectronics 10 and that 8 is a potent and selective inhibitor of the enzyme monoamino-oxidase B (MAO B, IC 50 = 0.66 nM). 11 We also realized that certain 4-substituted isatins like 9 induce dopaminergic or D2-agonist activity useful for treating hypertension 12a and others such as 10 proved to be relevant inhibitors of enzyme CDK2.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Our efforts were crowned with the first total syntheses of melovinone ( 5 ) and waltherione-F ( 6 ) . During these studies, we also noticed that compounds like 7 are synthetic intermediates to new materials of importance in optoelectronics and that 8 is a potent and selective inhibitor of the enzyme monoamino-oxidase B (MAO B, IC 50 = 0.66 nM) …”

Section: Introductionmentioning

confidence: 99%

Step-Economic Total Synthesis of Melosatin A from Eugenol

et al. 2023

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An efficient and straightforward route toward the isatin-type natural product melosatin A is reported, employing a trisubstituted aniline as a key intermediate. The latter was synthesized in 4 steps and 60% overall yield from eugenol, through its regioselective nitration, sequentially followed by a Williamson methylation, an olefin cross-metathesis with 4-phenyl-1-butene and the simultaneous reduction of olefin and nitro groups. The final step, a Martinet cyclocondensation of the key aniline with diethyl 2ketomalonate, provided the natural product with 68% yield.

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Synthesis of asymmetric indolonaphthyridines with enhanced excited state charge-transfer character

Abstract: Indolonaphthyridines (IND) are valuable chromophores with wide-ranging optoelectronic applications. Here, we present a new class of asymmetric IND derivatives, synthesised using novel high yielding methodology. We compare the absorption properties...

Cited by 10 publications

References 34 publications

Aza-Cibalackrot: Turning on Singlet Fission Through Crystal Engineering

Aza-Cibalackrot: Turning on Singlet Fission Through Crystal Engineering

Re‐Thinking Dimer Design Principles with Indolonaphthyridine Intramolecular Singlet Fission

Step-Economic Total Synthesis of Melosatin A from Eugenol

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