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A Self‐Assembled Cage with Endohedral Acid Groups both Catalyzes Substitution Reactions and Controls Their Molecularity
Author(s) -
Bogie Paul M.,
Holloway Lauren R.,
Ngai Courtney,
Miller Tabitha F.,
Grewal Divine K.,
Hooley Richard J.
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201902049
Subject(s) - chemistry , catalysis , substrate (aquarium) , nucleophilic substitution , nucleophile , stereochemistry , substitution reaction , cage effect , product inhibition , cage , supramolecular chemistry , affinities , computational chemistry , combinatorial chemistry , medicinal chemistry , organic chemistry , non competitive inhibition , enzyme , molecule , oceanography , mathematics , combinatorics , geology
A self‐assembled Fe 4 L 6 cage complex internally decorated with acid functions is capable of accelerating the thioetherification of activated alcohols, ethers and amines by up to 1000‐fold. No product inhibition is seen, and effective supramolecular catalysis can occur with as little as 5 % cage. The substrates are bound in the host with up to micromolar affinities, whereas the products show binding that is an order of magnitude weaker. Most importantly, the cage host alters the molecularity of the reaction: whereas the reaction catalyzed by simple acids is a unimolecular, S N 1‐type substitution process, the rate of the host‐mediated process is dependent on the concentration of nucleophile. The molecularity of the cage‐catalyzed reaction is substrate‐dependent, and can be up to bimolecular. In addition, the catalysis can be prevented by a large excess of nucleophile, where substrate inhibition dominates, and the use of tritylated anilines as substrates causes a negative feedback loop, whereby the liberated product destroys the catalyst and stops the reaction.