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The current bottleneck in the development of efficient photocatalysts for hydrogen evolution is the limited availability of high‐performance acceptor units. Over the past nine years, dibenzo[b,d]thiophene sulfone (DBS) has been the preferred choice for the acceptor unit. Despite extensive exploration of alternative structures as potential replacements for DBS, a superior substitute remains elusive. In this study, a symmetry‐breaking strategy was employed on DBS to develop a novel acceptor unit, BBTT‐1SO. The asymmetric structure of BBTT‐1SO proved beneficial for increasing multiple moment and polarizability. BBTT‐1SO‐containing polymers showed higher efficiencies for hydrogen evolution than their DBS‐containing counterparts by up to 166 %. PBBTT‐1SO exhibited an excellent hydrogen evolution rate (HER) of 222.03 mmol g−1 h−1 and an apparent quantum yield of 27.5 % at 500 nm. Transient spectroscopic studies indicated that the BBTT‐1SO‐based polymers facilitated electron polaron formation, which explains their superior HERs. PBBTT‐1SO also showed 14 % higher HER in natural seawater splitting than that in deionized water splitting. Molecular dynamics simulations highlighted the enhanced water‐PBBTT‐1SO polymer interactions in salt‐containing solutions. This study presents a pioneering example of a substitute acceptor unit for DBS in the construction of high‐performance photocatalysts for hydrogen evolution. [ABSTRACT FROM AUTHOR]

Photocatalytic hydrogen production (PHP) from water is a promising solution for environmental pollution due to its high energy density and the abundant availability of water and solar energy on Earth. 1,1-dicyanomethylene-3-indanone (IC) has been widely used as an end group in organic photovoltaics owing to its strong electron-withdrawing ability and planarity. However, research on the application of IC structures in PHP is limited due to synthesis challenges. In this study, we designed a series of novel IC-based monomers incorporating a dibenzothiophene-S,S-dioxide unit through Suzuki coupling. These monomers were used to synthesize polymers with varying degrees of malononitrile substitution, referred to as ICFTDB, ICTDB, and IDMTDB. We investigated the correlation between the optical, electrochemical, and hydrogen evolution performances of these polymers. Through transient absorption spectroscopy, we demonstrated that ICTDB exhibited enhanced capabilities for ultrafast electron transfer and reduced recombination effects. As a result, ICTDB, photocatalysts with IC-containing structures achieved a hydrogen evolution rate of 30.0 mmol g−1 h−1, which was 11.5 times higher than that of ICFTDB, the polymer with no malononitrile substitution. This study provides valuable insights into the potential of IC-based conjugated polymers for photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Ten ionic manganese(II) complexes of [EMIm]2[MnX2Y2] (EMIm=1‐ethyl‐3‐methylimidazolium ion; X, Y=Cl, Br or I) and [BnMIm]2[MnX2Y2] (BnMIm=1‐benzyl‐3‐methylimidazolium ion; X, Y=Cl, Br or I) types were synthesized and studied in terms of their thermal and photophysical properties. Complexes with [BnMIm]+ cation were found to exhibit higher crystallinity, owing to the aromatic π‐stacking, and superior photoluminescent quantum yields, promoted by the increased Mn⋅⋅⋅Mn distance. For complexes with chlorine and bromine ligands efficient tunability of photophysical parameters was demonstrated. Out of all complexes, [BnMIm]2[MnBr4] was found to have the highest photoluminescence quantum yield at room temperature (Φ=0.59). To highlight the importance of a large Mn⋅⋅⋅Mn distance for achieving high Φ values, a mixed‐anion analog of complex [BnMIm]2[MnBr4] was prepared, with the suggested formula of [BnMIm]4[MnBr4]Br2. The latter have shown a significant improvement in d–d absorption efficiency and a reduction in nonradiative deactivation, which led to an outstanding Φ value of 0.97. Finally, the optical band gap of [BnMIm]4[MnBr4]Br2 was estimated to describe its applicability as light‐emitting material. [ABSTRACT FROM AUTHOR]

The current bottleneck in the development of efficient photocatalysts for hydrogen evolution is the limited availability of high-performance acceptor units. Over the past nine years, dibenzo[b,d]thiophene sulfone (DBS) has been the preferred choice for the acceptor unit. Despite extensive exploration of alternative structures as potential replacements for DBS, a superior substitute remains elusive. In this study, a symmetry-breaking strategy was employed on DBS to develop a novel acceptor unit, BBTT-1SO. The asymmetric structure of BBTT-1SO proved beneficial for increasing multiple moment and polarizability. BBTT-1SO-containing polymers showed higher efficiencies for hydrogen evolution than their DBS-containing counterparts by up to 166 %. PBBTT-1SO exhibited an excellent hydrogen evolution rate (HER) of 222.03 mmol g -1  h -1 and an apparent quantum yield of 27.5 % at 500 nm. Transient spectroscopic studies indicated that the BBTT-1SO-based polymers facilitated electron polaron formation, which explains their superior HERs. PBBTT-1SO also showed 14 % higher HER in natural seawater splitting than that in deionized water splitting. Molecular dynamics simulations highlighted the enhanced water-PBBTT-1SO polymer interactions in salt-containing solutions. This study presents a pioneering example of a substitute acceptor unit for DBS in the construction of high-performance photocatalysts for hydrogen evolution., (© 2024 Wiley-VCH GmbH.)