Acid catalysis in basic solution: a supramolecular host promotes orthoformate hydrolysis.
Although many enzymes can promote chemical reactions by tuning substrate properties purely through the electrostatic environment of a docking cavity, this strategy has proven challenging to mimic in synthetic host-guest systems. Here, we report a highly charged, water-soluble, metal-ligand assembly with a hydrophobic interior cavity that thermodynamically stabilizes protonated substrates and consequently catalyzes the normally acidic hydrolysis of orthoformates in basic solution, with rate accelerations of up to 890-fold. The catalysis reaction obeys Michaelis-Menten kinetics and exhibits competitive inhibition, and the substrate scope displays size selectivity, consistent with the constrained binding environment of the molecular host.
Pluth
Michael D
MD
Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA.
Bergman
Robert G
RG
Raymond
Kenneth N
KN