Article
Chemistry, Analytical
Koichiro Takao, Taro Tsubomura
Summary: An optically transparent thin-layer electrode (OTTLE) cell compatible with both absorption and luminescence spectroelectrochemistry was developed and its effectiveness was demonstrated through experiments in both absorption and luminescence spectroelectrochemistry.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Nahide Gulsah Deniz, Cigdem Sayil, Duygu Akyuz, Atif Koca
Summary: A novel series of 1,4-naphthoquinones substituted containing sulfur, nitrogen, oxygen atoms were synthesized and characterized using various spectroscopic techniques. The study found that the substituents significantly altered the redox mechanism of the NQ derivatives.
JOURNAL OF MOLECULAR STRUCTURE
(2021)
Article
Chemistry, Multidisciplinary
Julia Beerhues, Maren Neubrand, Sebastian Sobottka, Nicolas I. Neuman, Hannes Aberhan, Shubhadeep Chandra, Biprajit Sarkar
Summary: Extensive electrochemical investigations on 1,2,3-triazolylidene selenium adducts revealed a correlation between their reduction potentials and molecular structures. Unexpected quasi-reversibility was discovered in the reduction of two triazoline selones. Through spectroelectrochemical studies and calculations, the radical anion was successfully assigned to be triazoline centered, providing design principles for stabilizing radicals based on MICs.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Electrochemistry
Eduardo Laborda, Juan Garcia-Martinez, Angela Molina
Summary: The theoretical investigation on the value of spectroelectrochemistry for elucidating electrode reactions with complex stoichiometries is presented. The analytical equations allow for modeling absorbance response in various modes and potential-controlled techniques, with a demonstration on how SPEC can assist in determining stoichiometric coefficients of redox species concurrently and unequivocally.
ELECTROCHEMISTRY COMMUNICATIONS
(2021)
Article
Chemistry, Analytical
Sara Caruncho-Perez, M. Prado-Comesanana, Maria Arellano, Marta Pazos, M. Angeles Sanroman, Elisa Gonzalez-Romero
Summary: Water quality is crucial for human and ecosystem health. This study aimed to develop a sensitive and selective methodology to create a customized portable device that can detect emerging pollutants in water. The results showed that this methodology allows for simpler and cheaper decentralized analysis without losing sensitivity. It also enables real-time electrochemical measurements without the need for sample treatment. The portable device offers comfort and high specificity in monitoring and improving water quality.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2022)
Article
Chemistry, Analytical
Zeynep Ozyildiz, Celal Erkan, Nahide Gulsah Deniz, Zeliha Gokmen, Ozlem Uguz Neli, Atif Koca
Summary: Quinones are a widely found class of compounds in nature that have significant applications in pharmaceutical, medical, and environmental fields. They show strong biological activity against various pathogens and cancer cells. This study synthesized novel derivatives of naphthoquinones and investigated their electrochemical characteristics, providing insights into the formation of semiquinone radical in different environments.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Wen-Bin Wang, Hai-Jie Cao, Guo-Ling Li
Summary: A dielectric barrier discharge plasma can etch the Fe(CN)(6) group of the NiFe Prussian blue analogue framework in situ, altering the local electronic structure and coordination environment of Fe sites and improving the catalytic properties for oxygen evolution reaction.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Amol Kumar, Jingguo Li, A. Ken Inge, Sascha Ott
Summary: The power of isoreticular chemistry was leveraged to design metal-organic frameworks (MOFs) with tunable optoelectronic properties. XDI linkers with different lengths and properties were used to construct a series of Zn-XDI MOFs, which exhibited distinct electrochromic properties. The thin films of these MOFs were grown on FTO substrates and characterized by XRD and SEM. The MOFs showed reversible redox events and changes in optical properties, depending on the linker length and redox state. Among them, Zn-PDI@FTO exhibited a record high coloration efficiency and excellent stability, suggesting its potential for practical applications.
Article
Electrochemistry
Sergio Fernandez, Santiago Canellas, Federico Franco, Josep M. Luis, Miquel A. Pericas, Julio Lloret-Fillol
Summary: The study introduces two new cobalt(II) complexes for electrochemical CO2 reduction, one with a coordinating N-H group and the other with a coordinating N-Me group, showing different catalytic activities. The presence of the N-H group enhances the nucleophilic character of the Co-I intermediate, stabilizing reaction intermediates and transition states. Additionally, the study identifies the dissociation of CO from the Co(I)-CO intermediate as a bottleneck in the catalytic cycle, which can be overcome with light irradiation to increase total CO production.
Article
Chemistry, Analytical
Renata Selesovska, Romana Sokolova, Kateroina Krejcova, Karolina Schwarzova-Peckova, Tomas Mikysek, Oleksandr Matvieiev
Summary: The first study on the electrochemical oxidation of triazole fungicide tebuconazole was conducted using an oxygen-terminated boron-doped diamond electrode. The research explored the irreversible anodic process occurring at +1.75 V (vs Ag/AgCl/KCl(sat.)) in 0.1 mol/L HNO3 through various techniques such as cyclic voltammetry, IR spectroelectrochemistry, and density functional theory calculations. The study provided insights into the oxidation mechanisms, revealing the formation of hydroxylated and dihydroxylated derivatives as well as an o-quinone derivative.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Stefan Benndorf, Sihem Groni, Leanne M. Stafast, Helmar Gorls, Claire Fave, Bernd Schollhorn, Wolfgang Weigand
Summary: In this study, mimicking complexes of [FeFe] hydrogenase (H(2)ase) with lipoic and selenolipoic acid moieties were synthesized and characterized. Different spectroscopic methods, including X-ray diffraction analysis, were used to determine their molecular structures. Cyclic voltammetry (CV) investigations revealed different redox behaviors among the mimics in the presence and absence of acetic acid (AcOH). The elaboration of surface confined systems and the formation of self-assembled monolayers (SAMs) on Pt electrodes were also studied.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Stefan Benndorf, Elisabeth Hofmeister, Maria Waechtler, Helmar Goerls, Phil Liebing, Kalina Peneva, Stefanie Graefe, Stephan Kupfer, Benjamin Dietzek-Ivansic, Wolfgang Weigand
Summary: Hydrogenase mimicking complexes with N-substituted naphthalene monoimide (NMI) of peri-substituted dichalcogenides as bridging ligands were prepared and characterized using various spectroscopic techniques. The redox behavior of these complexes was investigated through cyclic voltammetry, IR and UV-Vis spectroelectrochemistry, EPR spectroscopy and quantum chemical simulations. EPR experiments revealed the non-innocent character of the NMI bridging ligands, showing the formation of an organic radical and a dimeric structure after successive reductions.
EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Vlasta Brezova, Zuzana Barbierikova, Michal Zalibera, Karol Luspai, Andrea Tholtova, Dana Dvoranova
Summary: In this study, cyclic nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and its derivatives were used to investigate the mechanism of paramagnetic intermediate generation in a photocatalytic system. The EPR spectra of β-fluorine spin-adducts of DMPO analogs were reported for the first time.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Gurkan Kesan, Emrah Ozcan, Pavel Chabera, Tomas Polivka, Marcel Fuciman
Summary: This study investigates the influence of applied external voltage on the excited-state properties of 8'-apo-beta-carotenal in acetonitrile. The results show that the amplitude of the signal associated with the ICT state can be tuned by applying an external voltage.
Article
Chemistry, Analytical
Zeynep Ozyildiz, Dilan Gezer, Nahide Gulsah Deniz, Zeliha Gokmen, Ozlem Uguz Neli, Atif Koca
Summary: The class of quinone compounds is important in biologically redox-active compounds as they play significant roles in the bioactivation, metabolism/catabolism, and ligand-target interactions of redox-active drugs. This study focuses on the electrochemical and photoelectrochemical properties of amino(substituted)-1,4-naphthoquinone (NQ) derivatives. The synthesized NQ derivatives exhibit two reductions and one oxidation processes, with the reversibility of the redox processes being influenced by the substituent environments of the NQ structure.
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Matthew N. Podgorski, Tom Coleman, Peter D. Giang, C. Ruth Wang, John B. Bruning, Paul Bernhardt, James J. De Voss, Stephen G. Bell
Summary: The cytochrome P450 superfamily of heme monooxygenases is involved in important chemical transformations, with azole drugs inhibiting their function by binding to the enzyme. Different inhibitors bind to CYP199A4 in distinct ways, affecting the optical spectra; imidazolyl ligands coordinate with iron, while triazolyl inhibitors interact with the iron's aqua ligand.
INORGANIC CHEMISTRY
(2022)
Article
Plant Sciences
Taizong Wu, Angela A. Salim, Hui Cui, Zeinab G. Khalil, Paul Bernhardt, Robert J. Capon
Summary: Chemical investigations into a pasture plant-derived Streptomyces sp. from an Australian sheep station yielded rare compounds with potential anticancer properties that can reverse drug resistance in cells.
JOURNAL OF NATURAL PRODUCTS
(2022)
Article
Chemistry, Organic
Tyler Fahrenhorst-Jones, Paul Bernhardt, G. Paul Savage, Craig M. Williams
Summary: The synthesis of the 6-aza[1.0]triblattane skeleton and the unexpected construction of the 7-azatetracyclo[4.2.1.0(2,5).0(3,7)]-nonane framework are reported. Key steps include the 1,6-cycloaddition product from the reaction of chlorosulfonyl isocyanate with cyclohept-1,3,5-triene, followed by intramolecular electrocyclization and aminium radical cyclization.
Article
Chemistry, Physical
Matthew N. Podgorski, Joshua S. Harbort, Joel H. Z. Lee, Giang T. H. Nguyen, John B. Bruning, William A. Donald, Paul Bernhardt, Jeffrey R. Harmer, Stephen G. Bell
Summary: In this study, it was found that mutating a highly conserved threonine residue in CYP199A4 to glutamate can convert it to a peroxygenase and improve its peroxygenase activity. The crystal structure of the mutant demonstrated a change in spin state upon substrate binding, which was linked to the modification of the oxygen-binding groove and the retention of the iron-bound aqua ligand. The detailed characterization of this engineered heme peroxygenase will aid in the development of new methods for the selective C-H bond activation using heme enzymes.
Article
Chemistry, Multidisciplinary
Madeleine J. Fort, Sophia M. Click, Evan H. Robinson, Felix M. C. He, Paul Bernhardt, Sandra J. Rosenthal, Janet E. Macdonald
Summary: Light-induced charge separation plays a crucial role in solar harvesting technologies, and the internal reorganization energy has a profound impact on charge transfer rates. Experimental and theoretical studies demonstrate that reducing the reorganization energy can greatly increase charge transfer rates, even more significantly than the driving force. This suggests that careful design of redox mediators to minimize reorganization energy is a promising approach to enhance the efficiency of quantum dot applications.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Palraj Kalimuthu, Dominik Hege, Agnieszka Winiarska, Yvonne Gemmecker, Maciej Szaleniec, Johann Heider, Paul V. Bernhardt
Summary: In contrast to molybdenum enzymes, tungsten enzymes have lower redox potentials and can perform reversible redox transformations. However, the electrochemical properties of tungsten enzymes have received less attention. In this study, the tungsten enzyme aldehyde oxidoreductase (AOR) from Aromatoleum aromaticum was immobilized on a glassy carbon electrode. The system showed electrocatalytic oxidation of aromatic and aliphatic aldehydes in the presence of electron transfer mediators. The different mediators had different electron transfer rates and methylene blue acted as a two-electron acceptor. This work demonstrates a highly energy efficient catalytic process for aldehyde oxidation at low applied electrochemical potential.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Medicinal
Mahendiran Dharmasivam, Busra Kaya, Tharushi Wijesinghe, Mahan Gholam Azad, Miguel A. Gonzalvez, Mohammad Hussaini, Jason Chekmarev, Paul Bernhardt, Des R. Richardson
Summary: A novel and selective antitumor agent, 3-thiosemicarbazone (PPP44mT), and its analogues with distinctive properties were synthesized and characterized. The inclusion of a styrene moiety prevented the oxidation of oxy-myoglobin or oxy-hemoglobin, which is different from other potent thiosemicarbazones such as DpC or Dp44mT. PPP44mT and its Cu(II) complexes exhibited immediate cytotoxicity against SK-N-MC tumor cells, while [Zn(PPP44mT)2] showed delayed antiproliferative efficacy and superior inhibition of cyclin D1 expression compared to DpC or Dp44mT.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Miguel A. Gonzalvez, Craig M. Williams, Manuel Martinez, Paul V. Bernhardt
Summary: Organocopper(II) reagents are a relatively unexplored frontier in copper catalysis. This study investigates the stability and reactivity of Cu-II-C bonds, proposing two main pathways for their cleavage: homolysis and heterolysis. Experimental results provide insights into the reaction pathways of organocopper(II) complexes, which are relevant to their application as catalysts in C-C bond forming reactions.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Inorganic & Nuclear
Masnun Naher, Chuyi Su, Jeffrey R. Harmer, Craig M. Williams, Paul V. Bernhardt
Summary: The utility and scope of Cu-catalyzed halogen atom transfer chemistry have been exploited in a variety of fields. This study demonstrates the ability to modulate the reactivity of the Cu catalyst using electrochemistry, resulting in unprecedented rate acceleration in Cu-catalyzed bulk electrosynthesis.
INORGANIC CHEMISTRY
(2023)
Article
Chemistry, Organic
Tyler Fahrenhorst-Jones, Dehui Kong, Jed M. Burns, Gregory K. Pierens, Paul V. Bernhardt, G. Paul Savage, Craig M. Williams
Summary: It is found that seco-1-Azacubane-2-carboxylic acid can undergo amide bond formation at both the N- and C-termini using proline-based bioactive molecule templates as a concept platform.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Palraj Kalimuthu, Sheron Hakopian, Dimitri Niks, Russ Hille, Paul V. Bernhardt
Summary: In this study, an electrocatalytically active formate oxidation/CO2 reduction system was developed based on FdsDABG from Cupriavidus necator, providing new insights into the kinetics of the enzyme catalytic mechanism.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Multidisciplinary
Tyler Fahrenhorst-Jones, David L. Marshall, Jed. M. Burns, Gregory K. Pierens, Robert E. Hormann, Allison M. Fisher, Paul V. Bernhardt, Stephen J. Blanksby, G. Paul Savage, Philip E. Eaton, Craig M. Williams
Summary: Highly strained cage hydrocarbons have been widely used to explore chemical stability and reactivity, probe physical properties, and as bioactive molecules and in materials discovery. However, the nitrogenous congeners have received less attention. This study presents the synthesis of 1-azahomocubane and its comprehensive characterization, physical property analysis, and chemical reactivity investigation. The findings suggest that nitrogen is well tolerated in a highly strained environment.
Article
Chemistry, Multidisciplinary
Jeffrey R. Harmer, Sheron Hakopian, Dimitri Niks, Russ Hille, Paul V. Bernhardt
Summary: This article investigates the redox properties of an oxygen-tolerant and molybdenum-dependent formate dehydrogenase, providing insights into the highly efficient catalytic activity of formate oxidation and CO2 reduction associated with the enzyme.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Paul V. Bernhardt
Summary: The accurate measurement of protein redox potentials is an important task. Traditional methods have significant experimental errors. This paper proposes an automated approach that combines continuous scanning potential with time-resolved UV-vis spectroscopy, allowing for fast and accurate measurement of protein redox potentials.
Article
Chemistry, Multidisciplinary
Miguel A. Gonzalvez, Chuyi Su, Craig M. Williams, Paul Bernhardt
Summary: Organocopper(i) complexes are commonly used in chemical synthesis, while organocopper(ii) complexes are rare. A new method to generate organocopper(ii) species using electrochemistry was discovered, which showed high reactivity towards functionalized alkenes under catalytic control. The organocopper(ii) complexes act as a source of masked radicals, reacting with alkenes to form gamma-halonitriles via atom transfer radical addition (ATRA) with good yields. This electrochemical method allows for continuous regeneration of the organocopper(ii) complexes, with low copper loadings and the potential for catalyst recovery.