Synthesis and Characterization of Phosphorus-Containing Isocyclam Macrocycles and Their Nickel Complexes

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

Efficient Reagent-Saving Method for the N‑Terminal Labeling of Bioactive Peptides with Organometallic Carboxylic Acids by Solid-Phase Synthesis

Labeling of biomolecules with organometallic moieties holds great promise as a tool for chemical biology and for the investigation of biochemical signaling pathways. Herein, we report a robust and reproducible synthetic strategy for the synthesis of ruthenocenecarboxylic acid, giving the acid in 53% overall yield. This organometallic label was conjugated via solid-phase peptide synthesis in near-quantitative yield to a number of different biologically active peptides, using only 1 equiv of the acid and coupling reagents, thereby avoiding wasting the precious organometallic acid. This optimized method of stoichiometric N-terminal acylation was then also successfully applied to conjugating ferrocenecarboxylic acid and a novel organometallic Re^I(CO)₃ complex, showing the generality of the synthetic procedure

Efficient Reagent-Saving Method for the N‑Terminal Labeling of Bioactive Peptides with Organometallic Carboxylic Acids by Solid-Phase Synthesis

Labeling of biomolecules with organometallic moieties holds great promise as a tool for chemical biology and for the investigation of biochemical signaling pathways. Herein, we report a robust and reproducible synthetic strategy for the synthesis of ruthenocenecarboxylic acid, giving the acid in 53% overall yield. This organometallic label was conjugated via solid-phase peptide synthesis in near-quantitative yield to a number of different biologically active peptides, using only 1 equiv of the acid and coupling reagents, thereby avoiding wasting the precious organometallic acid. This optimized method of stoichiometric N-terminal acylation was then also successfully applied to conjugating ferrocenecarboxylic acid and a novel organometallic Re^I(CO)₃ complex, showing the generality of the synthetic procedure

Trimetallic Pentlandites (Fe,Co,Ni)₉S₈ for the Electrocatalytical HER in Acidic Media

Recently, pentlandite materials have been shown to exhibit promising properties with respect to the hydrogen evolution reaction (HER). A whole series of trimetallic FeCoNi-pentlandite materials and composites have been synthesized from the elements using high-temperature synthesis and categorized in terms of purity. Furthermore, the electrocatalytic properties regarding the HER were determined and correlated to hydrogen adsorption energies, which were determined by means of density functional theory (DFT) calculations. The relationships between activity and its origin generated in this way help to better understand the pentlandite system and provide meaningful approaches for catalyst synthesis