Diiodo-BODIPY Sensitizing of the [Mo₃S₁₃]^2– Cluster for Noble-Metal-Free Visible-Light-Driven Hydrogen Evolution within a Polyampholytic Matrix

Abstract

We report on a photocatalytic setup that utilizes the organic photosensitizer (PS) diiodo-BODIPY and the non-precious-metal-based hydrogen evolution reaction (HER) catalyst (NH4)2[Mo3S13] together with a polyampholytic unimolecular matrix poly(dehydroalanine)-graft-poly(ethylene glycol) (PDha-g-PEG) in aqueous media. The system shows exceptionally high performance with turnover numbers (TON > 7300) and turnover frequencies (TOF > 450 h–1) that are typical for noble-metal-containing systems. Excited-state absorption spectra reveal the formation of a long-lived triplet state of the PS in both aqueous and organic media. The system is a blueprint for developing noble-metal-free HER in water. Component optimization, e.g., by modification of the meso substituent of the PS and the composition of the HER catalyst, is further possible.

Light‐Induced Charge Separation in Covalently Linked BODIPY‐Quinone‐Alkyne Dyads

“…To evaluate the electronic structure of the quinone-substituted bodipy dyads, quantum chemical simulations were performed at the DLNPO-NEVPT2 as well as at the density and time-dependent density functional (DFT and TDDFT) levels of theory. In contrast to DLPNO-NEVPT2 and in agreement with the literature, [41][42][43][44][45][46][47][48] the TDDFT calculated energies of the lowest dipole-allowed π!π* transition of the bodipy chromophore are overestimated by approximately 0.3 eV (for further information, see SI). For Me 4 Bodipy-BQ this excitation is (HOMO!LUMO + 1) predicted at 2.93 eV (423 nm).…”

“…This can be also observed in the emission spectra, where a strong asymmetric fluorescence band can be detected at ~514 nm (CHCl 3 )/~510 nm (MeCN). After iodination in the bodipys’ 2,2’ position, a diminished and bathochromic shifted emission signal can be observed at ~558 nm (CHCl 3 )/552 nm (MeCN), due to the possible population of triplet excited states [48] . A drop of more than 90 % in signal intensity is observed when comparing the non‐iodinated species Me 4 BodipyN 3 with the iodinated I 2 Me 4 BodipyN 3 (see SI Figure S81).…”

“…After iodination in the bodipys' 2,2' position, a diminished and bathochromic shifted emission signal can be observed at ~558 nm (CHCl 3 )/552 nm (MeCN), due to the possible population of triplet excited states. [48] A drop of more than 90 % in signal intensity is observed when comparing the non-iodinated species Me 4 BodipyN 3 with the iodinated I 2 Me 4 BodipyN 3 (see SI Figure S81). Also, oxidation of Me 4 Bodipy-BQH 2 to Me 4 Bodipy-BQ resulted in a further drop of emission intensity (by ~90 % in MeCN/~99 % in CHCl 3 ).…”

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

“…Microporous membranes are much less expensive, and the particulate size of redox-active polymers could be tuned to prevent unwanted crossover. Photosensitizers and catalysts have been successfully immobilized in polymeric matrices, which is also another approach to phase separation [ 61 – 62 ].…”

Visible-Light-Driven Hydrogen Evolution of PtNP/[Ru(bpy)3]2+/Polyampholyte Hybrid Hydrogels

“…Recent years have seen a drastic increase in interest in light-driven hydrogen evolution when considered in the context of environmental issues relating to carbon emissions . On the one hand, new-generation catalysts (CAT) and light harvesters or photosensitizers (PS) are being developed; on the other hand, polymer materials such as micelles, membranes, and hydrogels are utilized as matrices for more effective and controllable systems. − Soft matter materials, with their feature of mimicking the compartmentalization of photosynthetic organelles in plants, provide spatial control over the light harvester and the catalyst that is crucial for the charge transfer in a given photocatalytic process . Whereas PS and CAT remain positioned in a certain proximity within the hydrogel network, other units required for the photocatalytic reaction such as the electron donor and solvent can freely move in and out of the hydrogel .…”