Push–pull systems comprising of triphenylamine–tetracyanobutadiene (TPA‐TCBD), a high‐energy charge‐transfer species, are linked to a near‐IR sensitizer, azaBODIPY, for promoting excited‐state CS. These systems revealed panchromatic absorption owing to intramolecular CT and near‐IR absorbing azaBODIPY. Using electrochemical and computational studies, energy levels were established to visualize excited state events. Fs‐TA studies were performed to monitor excited state CT events. From target analysis, the effect of solvent polarity, number of linked CT entities, and excitation wavelength dependence in governing the lifetime of CS states was established. Electron exchange between two TPA‐TCBD entities in 3 seem to prolong lifetime of the CS state. We have been successful in demonstrating efficient CS upon both high‐energy CT and low‐energy near‐IR excitations, signifying importance of these push–pull systems for optoelectronic applications operating in the wide optical window.

A far‐red absorbing sensitizer, BF2‐chelated azadipyrromethane (azaBODIPY) has been employed as an electron acceptor to synthesize a series of push‐pull systems linked with a series of nitrogenous electron donors, viz., N,N‐dimethylaniline, triphenylamine, and phenothiazine via an acetylene linker. The structural integrity of the newly synthesized triads was established by spectroscopic, electrochemical, spectroelectrochemical, and DFT methods. Differential pulse voltammetry studies revealed different redox states and helped in the estimation of the energies of the charge‐separated states. Further, spectroelectrochemical studies performed revealed diagnostic peaks of azaBODIPY•– in the visible and near‐IR regions. Free‐energy calculations revealed the charge separation from one of the covalently linked donors to the 1azaBODIPY* to yield Donor•+‐azaBODIPY•– to be energetically favorable in a polar solvent, benzonitrile. The femtosecond pump‐probe studies revealed the occurrence of excited charge transfer (CT) in nonpolar toluene while a complete charge separation (CS) for all three triads in polar benzonitrile. The CT/CS products populated the low‐lying 3azaBODIPY* prior to returning to the ground state. Global target (GloTarAn) analysis of the transient data revealed the lifetime of the final charge‐separated states (CSS) to be 195 ps for NND‐derived, 50 ps for TPA‐derived, and 85 ps for PTZ‐derived triads in benzonitrile.

Push–pull systems comprising of triphenylamine–tetracyanobutadiene (TPA‐TCBD), a high‐energy charge‐transfer species, are linked to a near‐IR sensitizer, azaBODIPY, for promoting excited‐state CS. These systems revealed panchromatic absorption owing to intramolecular CT and near‐IR absorbing azaBODIPY. Using electrochemical and computational studies, energy levels were established to visualize excited state events. Fs‐TA studies were performed to monitor excited state CT events. From target analysis, the effect of solvent polarity, number of linked CT entities, and excitation wavelength dependence in governing the lifetime of CS states was established. Electron exchange between two TPA‐TCBD entities in 3 seem to prolong lifetime of the CS state. We have been successful in demonstrating efficient CS upon both high‐energy CT and low‐energy near‐IR excitations, signifying importance of these push–pull systems for optoelectronic applications operating in the wide optical window.

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Starker intramolekularer Ladungstransfer in Push‐Pull‐Systemen mit panchromatischer Spektralabdeckung wird im Forschungsartikel von Rajneesh Misra, Francis D′Souza und Mitarbeitern auf S. 23905 demonstriert. Dazu wurde die Ladungstransferspezies Triphenylamin‐Tetracyanobutadien kovalent mit dem Nah‐IR‐Sensibilisator azaBODIPY verbunden. Eine effiziente Ladungstrennung wird entweder durch den hochenergetischen Ladungstransfer oder durch die niederenergetischen Nah‐IR‐Anregungen beobachtet. Die Blumen illustrieren die durch den Ladungstransfer erzeugten Farben.