Supramolecular catalyst functions in catalytic amount: cucurbit[8]uril accelerates the photodimerization of Brooker’s merocyanine

Abstract

As low as 1% content of a supramolecular catalyst, cucurbit[8]uril, is sufficient to accomplish the photodimerization of Brooker’s merocyanine within 10 minutes.

Templating and Catalyzing [2+2] Photocycloaddition in Solution Using a Dynamic G‐Quadruplex

“…The host sequesters alkenes so that they dimerize upon irradiation. Sometimes, these reactions are catalytic as cyclobutane product exchanges with reactants, enabling turnover . Intermolecular H‐bonding of 2 alkenes to a template can also trigger [2+2] cycloaddition of cinnamate esters in solution, and some of these H‐bonding templates act as catalysts .…”

Expected and unexpected photoreactions of 9-(10-)substituted anthracene derivatives in cucurbit[n]uril hosts

“…Inspired by a previous sample, 33 we investigated whether CB [10] could act as a supramolecular catalyst to convert G2 into DG2 exclusively. In the presence of 0.1 equiv.…”

“…[26][27][28][29] Similar to other hosts, CB[n]s have also been employed to promote various organic reactions, especially photodimerization reactions, [30][31][32] but have acted as supramolecular catalysts in only a few examples because the product is usually "trapped" in the CB[n] cavity, inhibiting the catalytic process. 33,34 In this work, we investigated host-guest complexation between CB[n] (n ¼ 8, 10) and 9-(10-)substituted anthracene derivatives (G1-G3) ( Fig. 1) in aqueous solution, and the CB[n]mediated (n ¼ 8, 10) photoreaction of these guests.…”

Supramolecularly Catalyzed Polymerization: From Consecutive Dimerization to Polymerization

“…As the two-step-binding constants of CB [8] and Brooker merocyanine are K a1 of 2.95 10 5 m À1 and K a2 of 2.88 10 6 m À1 with ac ooperativity factor (a)o f3 9.0, the complexation of CB [8] and Brooker merocyanine is ap ositively cooperating process. [46] Therefore,when CB [8] is located at the chain end of polymers/oligomers with one BM end group in its cavity,it will be likely to bind another BM end groups,e ither from aM PM monomer or from another polymer/oligomer chain. In either case,t he chain elongation is promoted.…”