TY - JOUR A1 - Das, Prasenjit A1 - Chakraborty, Gouri A1 - Yang, Jin A1 - Roeser, Jérôme A1 - Küçükkeçeci, Hüseyin A1 - Nguyen, Anh Dung A1 - Schwarze, Michael A1 - Gabriel, Jose A1 - Penschke, Christopher A1 - Du, Shengjun A1 - Weigelt, Vincent A1 - Khalil, Islam E. A1 - Schmidt, Johannes A1 - Saalfrank, Peter A1 - Oschatz, Martin A1 - Rabeah, Jabor A1 - Schomäcker, Reinhard A1 - Emmerling, Franziska A1 - Thomas, Arne T1 - The Effect of Pore Functionality in Multicomponent Covalent Organic Frameworks on Stable Long‐Term Photocatalytic H2 Production N2 - AbstractIn nature, organic molecules play a vital role in light harvesting and photosynthesis. However, regarding artificial water splitting, the research focus is primarily on inorganic semiconductors. Although organic photocatalysts have high structural variability, they tend to exhibit lower quantum efficiencies for water splitting than their inorganic counterparts. Multicomponent reactions (MCRs) offer an attractive route to introduce different functional units into covalent organic frameworks (COFs) and enable semiconducting properties and high chemical stability, creating promising materials for long‐term photocatalytic applications, such as H2 production. Herein, five highly crystalline donor‐acceptor based, 4‐substituted quinoline‐linked MCR‐COFs are presented that are prepared via the three‐component Povarov reaction. The pore functionality is varied by applying different vinyl derivatives (e.g., styrene, 2‐vinyl pyridine, 4‐vinylpyridine, 4‐vinyl imidazole, 2,3,4,5,6‐pentafluorostyrene), which has a strong influence on the obtained photocatalytic activity. Especially an imidazole‐functionalized COF displays promising photocatalytic performance due to its high surface area, crystallinity, and wettability. These properties enable it to maintain its photocatalytic activity even in a membrane support. Furthermore, such MCR‐COFs display dramatically enhanced (photo)chemical stability even after long‐term solar light irradiation and exhibit a high and steady H2 evolution for at least 15 days. KW - Sstability KW - Covalent organic frameworks KW - Pore functionality KW - Long-term H2 production KW - Multicomponent reactions PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639787 DO - https://doi.org/10.1002/aenm.202501193 SN - 1614-6832 SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-63978 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ehlert, Christopher A1 - Holzweber, Markus A1 - Lippitz, Andreas A1 - Unger, Wolfgang A1 - Saalfrank, Peter T1 - A detailed assignment of NEXAFS resonances of imidazolium based ionic liquids N2 - In Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy X-Ray photons are used to excite tightly bound core electrons to low-lying unoccupied orbitals of the system. This technique offers insight into the electronic structure of the system as well as useful structural information. In this work, we apply NEXAFS to two kinds of imidazolium based ionic liquids ([CnC₁im]⁺[NTf₂]⁻ and [C₄C₁im]⁺[I]⁻). A combination of measurements and quantum chemical calculations of C K and N K NEXAFS resonances is presented. The simulations, based on the transition potential density functional theory method (TP-DFT), reproduce all characteristic features observed by the experiment. Furthermore, a detailed assignment of resonance features to excitation centers (carbon or nitrogen atoms) leads to a consistent interpretation of the spectra. KW - Ionic liquids KW - NEXAFS KW - DFT spectrum simulations PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367223 DO - https://doi.org/10.1039/c5cp07434g SN - 1463-9076 SN - 1463-9084 VL - 18 IS - 12 SP - 8654 EP - 8661 PB - Royal Society of Chemistry CY - Cambridge, UK AN - OPUS4-36722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -