Biomimetic Modelling of Copper Enzymes: Synthesis, Characterization, EPR Analysis and Enantioselective Catalytic Oxidations by a New Chiral Trinuclear Copper(II) Complex

Abstract

The new octadentate ligand (R)-(+)-N,NЈ-dimethyl-N,NЈ-bis{-2-[bis(1-methyl-2-benzimidazolylmethyl)]-2-methyl- at low temperatures. In the case of [Cu 2 L] 4+ , a weak dipolar interaction between the two spin centres was found. A similar weak spin interaction occurred in the trinuclear copper cluster, which could be treated likewise as a weakly coupled three-spin system. The analysis was substantiated by studying the complex EPR temperature behaviour, where population of the quartet state occurred only at high temperature (77 K), whereas at cryogenic temperatures (4 K) the system adopted a doublet state as a ground-state spin configuration. Titration with sodium azide of [Cu 2 L] 4+ was consistent with terminal binding of one N 3 -molecule to each copper ion.

Hydroxyl‐Functionalized Imidazoles: Highly Active Additives for the Potassium Iodide‐Catalyzed Synthesis of 1,3‐Dioxolan‐2‐one Derivatives from Epoxides and Carbon Dioxide

“…The first observation from the data in Table 1 is that chirality at the carbon atom directly bonded to the catechol ring is clearly not recognized by the complex and, hence, no significant discrimination occurs between the enantiomers of norepinephrine. This result is not new and was obtained previously for structurally different dinuclear complexes 8b,8c. On the other hand, some significant enantioselectivity is observed with the l‐ / D ‐Dopa substrates, particularly for the methyl ester derivatives (Figure 3).…”

Aerobic Copper-Catalyzed Organic Reactions

“…967,1008 The k rel of the transformation, taken as the ratios of the k cat /K M values for each enantiomer, is 3.96. The difference in reactivity between enantiomers is attributed to the much stronger binding of D-dopa to the catalyst and a slightly faster reaction for the D-dopa–catalyst adduct.…”

Approaches for multicopper oxidases in the design of electrochemical sensors for analytical applications

“…The functional mimicking of biological redox processes by molecular models is particularly challenging, especially when dioxygen or partially reduced oxygen species play a role in the process. In this case, the development of synthetic models for metalloproteins and metalloenzymes remains an active and productive area of bioinorganic chemistry [26,27].…”