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Dithiolopyrrolones (DTPs), such as holomycin, are natural products that hold promise as scaffolds for antibiotics as they exhibit inhibitory activity against antibiotic-resistant pathogens. They consist of a unique bicyclic core containing a disulfide that is crucial for their biological activity. Herein, we establish the DTPs as prochelators. We show that the disulfides are reduced at cellular gluathione levels. This activates the drugs and initiates interactions with targets, particularly metal coordination. In addition, we report an expedient synthesis for the DTPs thiolutin and aureothricin, providing facile access to important natural DTPs and derivatives thereof.

The controlled electrochemical reduction of carbon dioxide to value added chemicals is an important strategy in terms of renewable energy technologies. Therefore, the development of efficient and stable catalysts in an aqueous environment is of great importance. In this context, we focused on synthesizing and studying a molecular MnIII‐corrole complex, which is modified on the three meso‐positions with polyethylene glycol moieties for direct and selective production of acetic acid from CO2. Electrochemical reduction of MnIII leads to an electroactive MnII species, which binds CO2 and stabilizes the reduced intermediates. This catalyst allows to electrochemically reduce CO2 to acetic acid in a moderate acidic aqueous medium (pH 6) with a selectivity of 63 % and a turn over frequency (TOF) of 8.25 h−1, when immobilized on a carbon paper (CP) electrode. In terms of high selectivity towards acetate, we propose the formation and reduction of an oxalate type intermediate, stabilized at the MnIII‐corrole center., Electrochemical reduction of CO2 to acetic acid is achieved with a molecular MnIII‐corrole complex. Electroreduction of MnIII leads to the electroactive MnII species, which binds CO2 and stabilizes the reduced intermediates to allow the reduction of CO2 to acetic acid in a moderately acidic aqueous medium (pH 6) with a selectivity of 63 % and a turnover frequency of 8.25 h−1, when immobilized on a carbon paper (CP) electrode.

Among the numerous homogeneous electrochemical CO2 reduction catalysts, [Ni(cyclam)]2+ is known as one of the most potent catalysts. Likewise, [Ni(isocyclam)]2+ was reported to enable electrochemic...

The tetradentate azamacrocycle cyclam (=1,4,8,11-tetraazacyclotetradecane) was studied profoundly for the coordination of transition metal ions, and the resulting complexes were investigated extensively for their catalytic performance in, e.g., O2 activation and electrocatalytic CO2 reduction. Although the successful synthesis of analogous P4 macrocycles was described earlier, no tetradentate N,P mixed 14-membered macrocycles have been prepared to date and their chemistry remains elusive. Thus, in this work, we showcase the synthesis of phospha-aza mixed cyclam-based macrocycles by selectively “exchanging” one or two secondary amines in the macrocycle isocyclam (=1,4,7,11-tetraazacyclotetradecane) with tertiary phosphines. In addition, we herein present the preparation of the corresponding nickel complexes along with their complex chemical and structural characterization to provide first coordination studies.

Zusammenfassung. Zielsetzung: Um ein möglichst umfassendes und differenziertes Bild der Verbreitung von Methamphetamin (MA) in Deutschland zu zeichnen, wird im vorliegenden Beitrag mittels verschiedener Datenquellen ein überblick zur Verbreitung des Konsums von MA sowie einschlägiger Straftaten in Deutschland und Europa gegeben. Ergänzend werden Angaben zur Beratungs-/Behandlungsnachfrage in Deutschland gemacht. Methodik: Es werden verfügbare aktuelle Daten zur Konsumverbreitung, Beschlagnahmungen und Straftaten sowie von repräsentativen nationalen und regionalen Bevölkerungsstudien, Abwasseranalysen, Strafverfolgung sowie Suchtberatung und -behandlung berichtet. Ergebnisse: Insgesamt zeigt sich mit Prävalenzraten von 0,6 % (Lebenszeit) und 0,2 % (letzte 12 Monate), dass der Konsum von MA in der erwachsenen Allgemeinbevölkerung eine eher untergeordnete Rolle spielt. Es finden sich in mehreren Datenquellen regionale Unterschiede, die darauf schließen lassen, dass die Verbreitung von MA in Sachsen, Thüringen und Bayern deutlich höher ist als in anderen Regionen Deutschlands. Schlussfolgerungen: Konsum und Problemlage von MA weisen regionale Schwerpunkte insbesondere in den Grenzregionen zur Tschechischen Republik auf. Aufgrund der hohen Belastung in den betroffenen Regionen wurden in den letzten Jahren zahlreiche Interventionen initiiert, die von spezifischen Programmen zur Frühintervention bis zu strukturierten Behandlungsprogrammen reichen. Die Verbesserung der Situation in betroffenen Regionen bedarf weiterer aktiver Unterstützung durch politische und soziale Maßnahmen.

The replacement of the opposing nitrogen atoms in 1,4,8,11-tetraazacyclotetradecane (cyclam) with two sulfur atoms in 1,8-dithia-4,11-diazacyclotetradecane (dithiacyclam) enables the electrochemical reduction of protons and CO2via the corresponding nickel(ii) complex at more positive potentials. In addition, a 10-fold enhancement in the proton reduction rate of [Ni(dithiacyclam)]2+ relative to [Ni(cylcam)]2+ was observed. The study provides vital insight into Nature's choice of employing predominantly sulfur based ligand platforms in achieving biological proton and CO2 reductions.

A mononuclear oxoiron(iv) complex 1-trans bearing two equatorial sulfur ligations is synthesized and characterized as an active-site model of the elusive sulfur-ligated FeIV[double bond, length as m-dash]O intermediates in non-heme iron oxygenases. The introduction of sulfur ligands weakens the Fe[double bond, length as m-dash]O bond and enhances the oxidative reactivity of the FeIV[double bond, length as m-dash]O unit with a diminished deuterium kinetic isotope effect, thereby providing a compelling rationale for nature's use of the cis-thiolate ligated oxoiron(iv) motif in key metabolic transformations.

Among the various homogenous electrocatalysts, especially Re(bpy)(CO)3Cl and [Ni(cyclam)]2+ were shown to be highly efficient for the selective conversion of CO2 to CO at moderate potentials. However, a purposeful combination of a ReI tricarbonyl unit with a cyclam ligand hitherto received no attention. Herein, we report on a series of cyclam based Re complexes comprising the original {N4} as well as heteroatom-altered ligand frameworks, describe their synthesis, reveal their coordination behavior and furthermore investigate their performance towards the electrochemical CO2 reduction.