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3. Tunable Isometric Donor‐Acceptor Wurster‐Type Covalent Organic Framework Photocathodes.

Author

Guntermann, Roman, Helminger, David, Frey, Laura, Zehetmaier, Peter M., Wangnick, Christian, Singh, Apeksha, Xue, Tianhao, Medina, Dana D., and Bein, Thomas

Subjects
AROMATIC amines, THIN films, OPTICAL properties, CRYSTAL structure, PHOTOCATHODES, TRIPHENYLAMINE
Abstract

Covalent organic frameworks (COFs) offer remarkable versatility, combining ordered structures, high porosity, and tailorable functionalities in nanoscale reaction spaces. Herein, we report the synthesis of a series of isostructural, photoactive Wurster‐type COFs achieved by manipulating the chemical and electronic nature of the Wurster aromatic amine building blocks. A series of donor‐acceptor‐donor (D‐A‐D) Wurster building block molecules was synthesized by incorporating heteroaromatic acceptors with varying strengths between triphenylamine donor groups. These tailored building blocks were integrated into a 2D COF scaffold, resulting in highly crystalline structures and similar morphologies across all COFs. Remarkably, this structural uniformity was also achieved in the synthesis of homogeneous and oriented thin films. Steady‐state photoluminescence revealed a tunable red‐shift in film emission exceeding 100 nm, demonstrating effective manipulation of their optical properties. Furthermore, photoelectrochemical (PEC) water splitting studies exhibited a doubled current density (8.1 μA cm−2 at 0.2 VRHE) for the COF with the strongest acceptor unit. These findings highlight the potential of Wurster D‐A‐D COFs in photoelectrochemical water splitting devices and pave the way for further exploration of chemical functionality‐reactivity‐property relationships in this promising class of photoactive materials. [ABSTRACT FROM AUTHOR]

Published
2024
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8. An electrically conducting 3D coronene-based metal-organic framework.

Author

Schönherr, Marina I., Scheurle, Patricia I., Frey, Laura, Martínez-Abadí, Marta, Döblinger, Markus, Mähringer, Andre, Fehn, Dominik, Gerhards, Lena, Santourian, Irina, Schirmacher, Alfred, Quast, Tatjana, Wittstock, Gunther, Bein, Thomas, Meyer, Karsten, Mateo-Alonso, Aurelio, and Medina, Dana D.

Abstract

A novel cubic mesoporous metal-organic framework (MOF), consisting of hexahydroxy-cata-hexabenzocoronene (c-HBC) and FeIII ions is presented. The highly crystalline and porous MOF features broad optical absorption over the whole visible and near infrared spectral regions. An electrical conductivity of 10-4 S cm-1 was measured on a pressed pellet. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Building Blocks and COFs Formed in Concert—Three‐Component Synthesis of Pyrene‐Fused Azaacene Covalent Organic Framework in the Bulk and as Films

Author

Frey, Laura, primary, Oliveira, Orlando, additional, Sharma, Ashish, additional, Guntermann, Roman, additional, Fernandes, Soraia P. S., additional, Cid‐Seara, Krystal M., additional, Abbay, Hosanna, additional, Thornes, Henry, additional, Rocha, João, additional, Döblinger, Markus, additional, Kowalczyk, Tim, additional, Rao, Akshay, additional, Salonen, Laura M., additional, and Medina, Dana D., additional

Published
2023
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10. Building Blocks and COFs Formed in Concert—Three‐Component Synthesis of Pyrene‐Fused Azaacene Covalent Organic Framework in the Bulk and as Films

Author

Frey, Laura, Oliveira, Orlando, Sharma, Ashish, Guntermann, Roman, Fernandes, Soraia PS, Cid‐Seara, Krystal M, Abbay, Hosanna, Thornes, Henry, Rocha, João, Döblinger, Markus, Kowalczyk, Tim, Rao, Akshay, Salonen, Laura M, Medina, Dana D, Salonen, Laura M [0000-0001-8194-6014], and Apollo - University of Cambridge Repository

Subjects
3403 Macromolecular and Materials Chemistry, 34 Chemical Sciences, 3405 Organic Chemistry, 40 Engineering
Abstract

A three‐component synthesis methodology is described for the formation of covalent organic frameworks (COFs) containing extended aromatics. Notably, this approach enables synthesis of the building blocks and COF along parallel reaction landscapes, on a similar timeframe. The use of fragmental building block components, namely pyrene dione diboronic acid as aggregation‐inducing COF precursor and the diamines o‐phenylenediamine (Ph), 2,3‐diaminonaphthalene (Naph), or (1R,2R)‐(+)‐1,2‐diphenylethylenediamine (2Ph) as extending functionalization units in conjunction with 2,3,6,7,10,11‐hexahydroxytriphenylene, resulted in the formation of the corresponding pyrene‐fused azaacene, i.e., Aza‐COF series with full conversion of the dione moiety, long‐range order, and high surface area. In addition, the novel three‐component synthesis was successfully applied to produce highly crystalline, oriented thin films of the Aza‐COFs with nanostructured surfaces on various substrates. The Aza‐COFs exhibit light absorption maxima in the blue spectral region, and each Aza‐COF presents a distinct photoluminescence profile. Transient absorption measurements of Aza‐Ph‐ and Aza‐Naph‐COFs suggest ultrafast relaxation dynamics of excited‐states within these COFs.

Published
2023

12. Benzene-1,4-Di(dithiocarboxylate) Linker-Based Coordination Polymers of Mn2+, Zn2+, and Mixed-Valence Fe2+/3+

Author

Aust, Margit, Schönherr, Marina I., Halter, Dominik P., Schröck, Lena, Pickl, Thomas, Deger, Simon N., Hussain, Mian Z., Jentys, Andreas, Bühler, Raphael, Zhang, Zihan, Meyer, Karsten, Kuhl, Matthias, Eichhorn, Johanna, Medina, Dana D., Pöthig, Alexander, and Fischer, Roland A.

Abstract

Three new coordination polymers (CPs) constructed from the linker 1,4-di(dithiocarboxylate) (BDDTC2–)─the sulfur-analog of 1,4-benzenedicarboxylate (BDC2–)─together with Mn-, Zn-, and Fe-based inorganic SBUs are reported with description of their structural and electronic properties. Single-crystal X-ray diffraction revealed structural diversity ranging from one-dimensional chains in [Mn(BDDTC)(DMF)2] (1) to two-dimensional (2D) honeycomb sheets observed for [Zn2(BDDTC)3][Zn(DMF)5(H2O)] (2). Gas adsorption experiments confirmed a 3D porous structure for the mixed-valent material [Fe2(BDDTC)2(OH)] (3). 3contains a 1:1 ratio of Fe2+/3+ions, as evidenced by 57Fe Mössbauer, X-band EPR, and X-ray absorption spectroscopy. Its empirical formula was established by elemental analysis, thermal gravimetric analysis, infrared vibrational spectroscopy, and X-ray absorption spectroscopy in lieu of elusive single-crystal X-ray diffraction data. In contrast to the Mn- and Zn-based compounds 1and 2, the Fe2+/3+CP 3showed remarkably high electrical conductivity of 5 × 10–3S cm–1(according to van der Pauw measurements), which is within the range of semiconducting materials. Overall, our study confirms that sulfur derivatives of typical carboxylate linkers (e.g., BDC) are suitable for the construction of electrically conducting CPs, due to acceptedly higher covalency in metal–ligand bonding compared to the electrically insulating carboxylate CPs or metal-organic frameworks. At the same time, the direct comparison between insulating CPs 1and 2with CP 3emphasizes that the electronic structure of the metal is likewise a crucial aspect to construct electrically conductive materials.

Published
2024
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13. Helical Anthracene–Ethyne-Based MOF-74 Analogue

Author

Scheurle, Patricia I., primary, Mähringer, Andre, additional, Haug, Tabea, additional, Biewald, Alexander, additional, Axthammer, Daniel, additional, Hartschuh, Achim, additional, Harms, Lena, additional, Wittstock, Gunther, additional, Medina, Dana D., additional, and Bein, Thomas, additional

Published
2022
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16. Excited-State Dynamics in Fully Conjugated 2D Covalent Organic Frameworks

Author

Jakowetz, Andreas C, Hinrichsen, Ture F, Ascherl, Laura, Sick, Torben, Calik, Mona, Auras, Florian, Medina, Dana D, Friend, Richard H, Rao, Akshay, Bein, Thomas, Jakowetz, Andreas C [0000-0001-7804-7210], Auras, Florian [0000-0003-1709-4384], Medina, Dana D [0000-0003-4759-8612], Friend, Richard H [0000-0001-6565-6308], Rao, Akshay [0000-0003-4261-0766], Bein, Thomas [0000-0001-7248-5906], and Apollo - University of Cambridge Repository

Subjects
0306 Physical Chemistry (incl. Structural), 0303 Macromolecular and Materials Chemistry
Abstract

Covalent organic frameworks (COFs) are a highly versatile group of porous materials constructed from molecular building blocks, enabling deliberate tuning of their final bulk properties for a broad range of applications. Understanding their excited-state dynamics is essential for identifying suitable COF materials for applications in electronic devices such as transistors, photovoltaic cells, and water-splitting electrodes. Here, we report on the ultrafast excited-state dynamics of a series of fully conjugated two-dimensional (2D) COFs in which different molecular subunits are connected through imine bonds, using transient absorption spectroscopy. Although these COFs feature different topologies and chromophores, we find that excited states behave similarly across the series. We therefore present a unified model in which charges are generated through rapid singlet-singlet annihilation and show lifetimes of several tens of microseconds. These long-lived charges are of particular interest for optoelectronic devices, and our results point toward the importance of controlling the singlet-singlet annihilation step in order to increase the yield of separated charges.

Published
2019

18. An Electrically Conducting Three‐Dimensional Iron–Catecholate Porous Framework

Author

Mähringer, Andre, primary, Döblinger, Markus, additional, Hennemann, Matthias, additional, Gruber, Christoph, additional, Fehn, Dominik, additional, Scheurle, Patricia I., additional, Hosseini, Pouya, additional, Santourian, Irina, additional, Schirmacher, Alfred, additional, Rotter, Julian M., additional, Wittstock, Gunther, additional, Meyer, Karsten, additional, Clark, Timothy, additional, Bein, Thomas, additional, and Medina, Dana D., additional

Published
2021
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19. Cover Picture: An Electrically Conducting Three‐Dimensional Iron–Catecholate Porous Framework (Angew. Chem. Int. Ed. 33/2021)

Author

Mähringer, Andre, primary, Döblinger, Markus, additional, Hennemann, Matthias, additional, Gruber, Christoph, additional, Fehn, Dominik, additional, Scheurle, Patricia I., additional, Hosseini, Pouya, additional, Santourian, Irina, additional, Schirmacher, Alfred, additional, Rotter, Julian M., additional, Wittstock, Gunther, additional, Meyer, Karsten, additional, Clark, Timothy, additional, Bein, Thomas, additional, and Medina, Dana D., additional

Published
2021
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20. Templating mesoporous silica with chiral block copolymers and its application for enantioselective separation

Author

Gabashvili, A., Medina, Dana D., Gedanken, A., and Mastai, Y.

Subjects
Chirality -- Observations, Silica -- Research, Silica -- Chemical properties, Chemicals, plastics and rubber industries
Abstract

The preparation and structural characterization of chiral mesoporous silica based on chiral block copolymers of poly(ethylene oxide) and of D-phenylalanine (PEO-b-D-Phe) as a surfactant template is described.

Published
2007

21. Titelbild: An Electrically Conducting Three‐Dimensional Iron–Catecholate Porous Framework (Angew. Chem. 33/2021)

Author

Mähringer, Andre, primary, Döblinger, Markus, additional, Hennemann, Matthias, additional, Gruber, Christoph, additional, Fehn, Dominik, additional, Scheurle, Patricia I., additional, Hosseini, Pouya, additional, Santourian, Irina, additional, Schirmacher, Alfred, additional, Rotter, Julian M., additional, Wittstock, Gunther, additional, Meyer, Karsten, additional, Clark, Timothy, additional, Bein, Thomas, additional, and Medina, Dana D., additional

Published
2021
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43. Oriented Films of Conjugated 2D Covalent Organic Frameworks as Photocathodes for Water Splitting

Author

Sick, Torben, primary, Hufnagel, Alexander G., additional, Kampmann, Jonathan, additional, Kondofersky, Ilina, additional, Calik, Mona, additional, Rotter, Julian M., additional, Evans, Austin, additional, Döblinger, Markus, additional, Herbert, Simon, additional, Peters, Kristina, additional, Böhm, Daniel, additional, Knochel, Paul, additional, Medina, Dana D., additional, Fattakhova-Rohlfing, Dina, additional, and Bein, Thomas, additional

Published
2017
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