Article
Chemistry, Analytical
P. R. Ipte, Abhishek Sharma, H. Pal, A. K. Satpati
Summary: The study revealed a good interaction between Cf and dsDNA, forming a stable complex in solution through electrostatic interaction and intercalative binding. The presence of Cf led to the condensation of dsDNA, facilitated by electrostatic interaction and specific functional group interactions.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Sreya Malayam Parambath, Ashley E. Williams, Leigh Anna Hunt, Dhanashree Selvan, Nathan Hammer, Saumen Chakraborty
Summary: This study reports the construction of a de novo-designed artificial hydrogenase (ArH) inspired by [NiFe] hydrogenases, which produces H-2 gas photocatalytically and shows bell-shaped pH-dependence on activity. Spectroscopic studies elucidate the reaction mechanism and a fine balance is found between solution acidity and electron transfer steps for maximizing H-2 production.
Review
Microbiology
Simone Morra
Summary: FeFe-hydrogenases are complex metalloenzymes that play a key role in microbial energy metabolism. They use protons from water as terminal electron acceptors to dissipate excess reducing equivalents and produce hydrogen. FeFe-hydrogenases also have additional physiological functions, such as H-2 uptake, H-2 sensing, and CO2 fixation. Recent advancements in identifying and characterising novel FeFe-hydrogenases have expanded our understanding of their multiple roles and mechanisms.
FRONTIERS IN MICROBIOLOGY
(2022)
Article
Chemistry, Physical
Sven T. Stripp
Summary: Earth-abundant transition metals play essential roles in cellular gas metabolism, forming gas-processing metalloenzymes that catalyze redox reactions. Biophysicists use techniques like Fourier-transform infrared spectroscopy to study the reaction principles of GPMs. Infrared spectroscopy provides information on catalytic cofactors, amino acid residues, and protein structural changes.
Article
Chemistry, Multidisciplinary
Samuel J. Cobb, Azim M. Dharani, Ana Rita Oliveira, Ines A. C. Pereira, Erwin Reisner
Summary: The electrolysis of dilute CO2 streams is hampered by low concentrations of dissolved substrate and rapid depletion at the electrolyte-electrocatalyst interface. To address this issue, a bio-inspired strategy mimicking the carboxysome in cyanobacteria is introduced. It utilizes microcompartments with nanoconfined enzymes in a porous electrode to accelerate CO2 hydration kinetics and minimize substrate depletion, enabling efficient reduction of low-concentration CO2 to formate even at atmospheric concentrations. This concept demonstrates the potential of the carboxysome as a blueprint for the reduction of low-concentration CO2 streams to chemicals.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Jaloliddin Khushvakov, Robin Nussbaum, Cecile Cadoux, Jifu Duan, Sven T. Stripp, Ross D. Milton
Summary: Gas-processing metalloenzymes, such as hydrogenases and nitrogenases, are of interest for future bio- and bioinspired technologies. This study uses RRDE and MS techniques to track the production of hydrogen and isotopes by the [FeFe]-hydrogenase, providing insights into catalytic mechanisms and the design of bioinspired catalysts for H-2 production and N-2 fixation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Review
Chemistry, Physical
Qianqi Lin
Summary: Electrochemistry has promising potential in studying interfacial electron transfers and redox reactions, but the lack of molecular structural information hinders understanding of complex systems. Complementary optical and spectroscopic techniques that provide electronic and structural identification of reactants and products are necessary for visualizing the electrochemical processes. Recent advancements in instrumentation and nanostructures allow for spatiotemporal resolution of molecules during complex reactions, enabling the optical revelation of intermediates, mechanisms, and rates, which are essential for fundamental and theoretical electrochemistry. This short review introduces the latest feasible optical and spectroscopic techniques, including dark-field, Raman, infrared, and ultraviolet-visible-near-infrared opto-and spectro-electrochemistry, for electrochemists to begin with.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Biochemical Research Methods
Kassandra J. Naughton, Regina E. Trevino, Peter J. Moore, Ashlee E. Wertz, J. Alex Dickson, Hannah S. Shafaat
Summary: Genetic encoding of artificial enzymes offers advantages over traditional catalyst optimization, but has limitations in the field of artificial metalloenzymes. The development of a methodology for in vivo production of nickel-substituted rubredoxin provides a new approach for generating artificial metalloenzymes.
ACS SYNTHETIC BIOLOGY
(2021)
Article
Chemistry, Physical
Riza Bayrak, Secil Kirlangic Atasen, Ismail Yilmaz, Izzet Yalcin, Murat Erman, Yasemin Unver, Ismail Degirmencioglu
Summary: This study focuses on synthesizing and characterizing new metallophthalocyanines to examine their redox properties. A new synthesis method was used to increase yield and shorten reaction time. The electron transfer capabilities of ZnPcs, CoPcs, and MnPcs were investigated through electrochemical methods.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Inorganic & Nuclear
Alexander Hildebrandt, Eduard Kovalski, Marcus Korb
Summary: The synthesis of a platinum alkynyl compound was achieved, and the study found that the feedback from platinum to the pi-system influenced the redox processes, leading to multiple oxidation reactions. Spectroelectrochemical studies revealed a high degree of delocalization in the ligand, while direct electron transfer through platinum was not observed.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jialong Peng, Qianqi Lin, Tamas Foldes, Hyeon-Ho Jeong, Yuling Xiong, Charalampos Pitsalidis, George G. Malliaras, Edina Rosta, Jeremy J. Baumberg
Summary: This article introduces an in-situ spectro-electrochemical technique for observing the redox dynamics of conductive polymers at the nanoscale to understand their doping mechanism. By encapsulating plasmonic nanoparticles with thin shells of different conductive polymers and tuning their refractive index, actively tunable scattering colors are achieved. Surface-enhanced Raman scattering combined with cyclic voltammetry enables detailed studies of the redox/doping processes of conductive polymers.
Article
Chemistry, Multidisciplinary
Eduard Kovalski, Dieter Schaarschmidt, Alexander Hildebrandt
Summary: A sigma-alkynyl gold(I) complex with an anthryl pi-system and a triarylamine functionality was synthesized through a ligand exchange reaction. Electrochemical oxidation of the triarylamine functionality led to the formation of a new organic molecule with multiple redox processes and an irreversible oxidation event. Spectro-electrochemical studies confirmed the generation of the new molecule with intense charge transfer excitations.
Article
Biochemistry & Molecular Biology
Samuel Quinn, E. Stephen Davies, Nicholas Pearce, Callum Rosenberg, Constance R. R. Pfeiffer, Georgia R. F. Orton, Neil R. R. Champness
Summary: This study describes donor-acceptor dyads and triads composed of core-substituted naphthalene diimide (NDI) chromophores and either phenothiazine or phenoxazine donors. Synthesis, electrochemical, and spectroelectrochemical investigations are used to characterize the different redox states of these molecules, confirming their ability to combine electron donating and accepting moieties while retaining the individual redox properties.
Article
Chemistry, Multidisciplinary
Marta Meneghello, Alexandre Uzel, Marianne Broc, Rita R. Manuel, Axel Magalon, Christophe Leger, Ines A. C. Pereira, Anne Walburger, Vincent Fourmond
Summary: Metal-based formate dehydrogenases are enzymes that require molybdenum or tungsten ions to catalyze the conversion between formate and CO2. The coordination of the metal ion in the active form prevents direct binding of formate to the metal. The study's findings provide strong evidence for the hypothesis that the oxidation of formate occurs in the second coordination sphere of the metal.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Review
Chemistry, Multidisciplinary
Marta Meneghello, Christophe Leger, Vincent Fourmond
Summary: Only two enzymes, CO dehydrogenase and formate dehydrogenase, are capable of directly reducing CO2, producing CO and formate respectively. These metalloenzymes are rapid, energy-efficient, and specific in product. Researchers have studied their mechanisms using protein film electrochemistry, and also exploited their catalytic performance to build biotechnological devices.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Multidisciplinary
Jifu Duan, Anja Hemschemeier, David J. Burr, Sven T. Stripp, Eckhard Hofmann, Thomas Happe
Summary: In this study, the crystal structures of CN--treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum were obtained, revealing that extrinsic CN- binds to the open coordination site of the cofactor. The binding of CN- leads to conformational changes in conserved residues within the proton transfer pathway, potentially facilitating efficient proton transfer. This observation provides important insights into the mechanism of CN- inhibition and proton transfer in hydrogenases.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Beatrice Battistella, Linda Iffland-Muehlhaus, Maximillian Schuetze, Beatrice Cula, Uwe Kuhlmann, Holger Dau, Peter Hildebrandt, Thomas Lohmiller, Stefan Mebs, Ulf-Peter Apfel, Kallol Ray
Summary: In many metalloenzymes, sulfur-containing ligands play a role in catalytic processes, particularly in electron transfer reactions. By mimicking biological systems, we demonstrate the significance of S-ligation in cobalt-mediated oxygen reduction reactions (ORR). A comparison between the catalytic ORR capabilities of two cobalt complexes, one with nitrogen ligands and the other with sulfur ligands, shows that the introduction of chalcogen improves the catalytic performance. The involvement of sulfur in the O-2 reduction process is found to be the key for the enhanced catalytic ORR capabilities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Inorganic & Nuclear
Vladimir Pelmenschikov, Chien-Hong Chen, I-Jui Hsu, Ulf-Peter Apfel, Giorgio Caserta, Lars Lauterbach, Tsai-Te Lu, Yu-Ting Tseng, Linda Iffland-Mu''hlhaus, Donato Calabrese, Yu-Che Chang, Konstantin Laun, Chih-Wen Pao, Ilya Sergueev, Yoshitaka Yoda, Wen-Feng Liaw
Summary: Efforts are being made to develop earth-abundant metal catalysts for dehydrogenation/hydrolysis of amine boranes. In this study, complex 3-K-crown was explored as a pre-catalyst for the dehydrogenation of DMAB, and the transformation of 3-K-crown into intermediate A during H-2 generation was supported by experimental and computational results. The substrate-gated transformation of pre-catalyst 3 into intermediate A was also observed in the reaction of complex 4-Na-crown with CO as an alternative synthetic route.
INORGANIC CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Rieke Haas, Vera Engelbrecht, Oliver Lampret, Shanika Yadav, Ulf-Peter Apfel, Silke Leimkuehler, Thomas Happe
Summary: The active site of [FeFe]-hydrogenases contains a cubane [4Fe4S]-cluster and a unique diiron cluster with biologically unusual CO and CN ligands. The biogenesis of the diiron site, termed [2FeH], requires the involvement of maturation proteins HydE, HydF, and HydG. However, our study suggests that the proposed binding mechanism and the presence of a [4Fe-4S]-cluster in HydF are not involved in the binding or transfer of [2Fe(P)].
Article
Chemistry, Inorganic & Nuclear
Henrika M. Hueppe, Linda Iffland-Muehlhaus, Joshua Heck, Maverick Eilers, Hans Gildenast, Sophie Schoenfeld, Andreas Duerrmann, Alexander Hoffmann, Birgit Weber, Ulf-Peter Apfel, Sonja Herres-Pawlis
Summary: This study presents a synthesis route for tri(quinolin-8yl)amine (L), a member of the tetradentate tris(2-pyridylmethyl)amine (TPA) ligand family. The coordination environment of the [Fe(L)]2+ complex and the spin state can be controlled by changing the coligands. The study sheds light on the coligand competition of triflate and acetonitrile and provides insights into the influence of different coligands on the geometry and spin state of the complexes.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Alexander. Katsyv, Anuj Kumar, Patricia Saura, Maximilian C. Poverlein, Sven A. Freibert, Sven T. Stripp, Surbhi Jain, Ana P. Gamiz-Hernandez, Ville R. I. Kaila, Volker Mueller, Jan M. Schuller
Summary: Electron bifurcation is a fundamental energy coupling mechanism used by microorganisms in anoxic conditions to reduce CO2 using hydrogen. The enzyme responsible for these reactions, HydABC, uses a single flavin mononucleotide (FMN) cofactor to transfer electrons to NAD(P)+ and low-potential ferredoxins (Fd), and switches between NAD(P)+ reduction and Fd reduction modes. Understanding the mechanistic principles of electron-bifurcating hydrogenases can provide insight into energy conversion processes in microorganisms.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Inorganic & Nuclear
Tatiana Guseva, Philipp Gerschel, Daniel Siegmund, Ulf-Peter Apfel
Summary: This work investigates ligand exchange reactions between a [FeFe] hydrogenase model and phosphines. By varying the properties of the phosphines, the reaction conditions, and the amount of phosphines, the formation of complexes with multiple phosphines or altered binding modes was studied. The ligand exchanges resulted in specific main products at room temperature, but reflux conditions induced decomposition and altered binding modes in some cases. Additionally, the electrochemical investigation of the novel phosphine substituted models revealed a shift in cathodic behavior compared to the starting material.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Linda Iffland-Muehlhaus, Beatrice Battistella, Daniel Siegmund, Kallol Ray, Ulf-Peter Apfel
Summary: Cobalt complexes are used as bioinspired models for oxygenase enzymes, and a new Co-II complex with isocyclam ligand was synthesized and characterized. The new complex shows higher reduction activity for O-2 compared to the known Co(cyclam) complex, and forms stable mu-peroxo Co-III dimer as the main product upon O-2 activation. The geometrical modifications of the ligand in the new complex also impart enhanced reactivity in oxygen atom transfer reactions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Cheng-Jhe Liao, Yu-Ting Tseng, Yu-An Cheng, Loise Ann Dayao, Linda Iffland-Muehlhaus, Leland B. Gee, Ryan D. Ribson, Ting-Shan Chan, Ulf-Peter Apfel, Tsai-Te Lu
Summary: This study discovered low-molecular-weight/protein-bound dinitrosyl iron complexes (DNICs) as a metallocofactor assembled under inflammatory conditions with elevated levels of nitric oxide (NO) and superoxide (O-2(-)). The study found that the supporting/bridging ligands in DNICs control the selective monooxygenation of NO and redox interconversion between O-2(-) and O-2.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Biochemistry & Molecular Biology
Jason W. Sidabras, Sven T. Stripp
Summary: This article reviews 25 years of scientific literature on [FeFe]-hydrogenase and provides a personal account on essential research papers and review articles regarding catalytic mechanism, O-2 sensitivity, and the in vivo synthesis of the active site cofactor. It also highlights future directions in structural biology and molecular biophysics and aims to inspire young investigators in the competitive field of [FeFe]-hydrogenase research.
JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Till Kahlstorf, J. Niklas Hausmann, Indranil Mondal, Konstantin Laun, Ingo Zebger, Tobias Sontheimer, Prashanth W. Menezes
Summary: Electrochemical production of large-scale chemicals and fuels is crucial for carbon neutrality. In this study, a rapid, green, and cost-effective method was developed to fabricate a new type of electrode using water-soluble materials for the oxygen evolution reaction and the oxidation of organics.
Article
Chemistry, Multidisciplinary
Julia Joekel, Esma Birsen Boydas, Joeel Wellauer, Oliver S. Wenger, Marc Robert, Michael Roemelt, Ulf-Peter Apfel
Summary: The recent study reported the highly efficient photocatalytic CO2 reduction activity of (CuCoII)-Co-I complex, which was synthesized using an asymmetric cryptand {(NNN)-N-S}(m) comprising distinct sulphur- and nitrogen-rich binding sites. Under visible light irradiation, (CuCoII)-Co-I-{(NNN)-N-S}(m) exhibited high efficiency and selectivity for the CO2-to-CO conversion, primarily attributed to the synergistic catalysis between copper and cobalt.
Article
Chemistry, Multidisciplinary
David Tetzlaff, Tilo Rensch, Leonard Messing, Petra Banke, Sven Graetz, Daniel Siegmund, Lars Borchardt, Ulf-Peter Apfel
Summary: Utilizing carbon sources as milling additives, Fe3Co3Ni3S8/carbon (Pn/C) materials were synthesized via a direct mechanochemical one-pot synthesis, allowing the adjustment of carbon content and overall physicochemical properties. When employed as electrocatalysts, Pn/C materials achieved high current density at low cell potential and exhibited stable performance, offering a sustainable synthesis procedure for future energy storage applications.
Review
Chemistry, Multidisciplinary
Julian T. Kleinhaus, Jonas Wolf, Kevinjeorjios Pellumbi, Leon Wickert, Sangita C. Viswanathan, Kai Junge Puring, Daniel Siegmund, Ulf-Peter Apfel
Summary: This tutorial review provides a comprehensive overview of the basic principles, practical application, and recent advances of electrochemical hydrogenation reactions, with a focus on the challenges of scaling up and potential solutions. The future prospects and research directions of electrochemical hydrogenation reactions are also discussed.
CHEMICAL SOCIETY REVIEWS
(2023)