Acid Catalysis in Basic Solution: A Supramolecular Host Promotes Orthoformate Hydrolysis
Michael D. Pluth,
Robert G. Bergman,*
Kenneth N. Raymond*
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.
Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA.
* To whom correspondence should be addressed. E-mail: rbergman{at}berkeley.edu (R.G.B.); raymond{at}socrates.berkeley.edu (K.N.R.)
