Molecular fusion of surfactant and Lewis-acid properties for attacking dirt by catalytic bond cleavage

Abstract

The capability of ordinary surfactants in solubilizing hydrophobic compounds can come to a limit, if the extension of a contaminant is too large. An attractive goal is the development of surfactants which can actively reduce the size of dirt. Because strong Lewis acids are known to catalyze both bond formation and cleavage, an integration into the surfactant's molecular framework is tempting. End-group functionalized hepta-dentate ligands, which coordinate to metal ions preventing deactivation by hydrolysis over a broad range of pH values while maintaining strong Lewis-acidity, are herein presented. After proof of amphiphilicity and surfactant characteristics, catalytic properties are investigated for different reactions including the cleavage of proteins. The compounds perform better than benchmark catalysts concerning the attack of unreactive amide bonds. A study with two Sc3+ species as the active site, one non-amphiphilic, the other one being surface-active, underlines the positive effect of surfactant properties for boosting catalytic efficiency.

Relation Between Coordination and Lewis‐Acid Property of MOF‐Derived Mononuclear Zn(II) Catalyst Toward Epoxide Hydroxylation

“…[9] For this reason, it is important to stabilize the metal cations by choosing a suitable organic/inorganic support, with the requirement of exposing more free sites at the metal centers to retain the sufficiently high electrophilicity in the heterogeneous Lewis-acid catalysts. [10] The metal centers coordinate to unknown numbers of electron-rich atoms on the supports, leading to totally different catalytic activity and selectivity. [11] Modulation of the coordination environment, including coordination numbers and coordination atoms, therefore becomes vital in heterogeneous Lewis-acid catalysis, whereas it still remains a big challenge.…”

Small-Molecule-Based Strategy for Mitigating Deactivation of Chiral Lewis Acid Catalysis

“…7 Herein, we present a novel small-molecule strategy to create long-lived reaction sites within well-defined catalysts. 8,9 We propose anchoring WCAs to metal complexes with planar multicoordination sites to enhance the stability of chiral Lewis acids while preserving activity. A 2,2′-bipyridine framework with 6,6′-dicarbinol substituents 10 was selected as a N 2 O 2 cavity for the metal ion (Figure 1b).…”