Switchable Catalysis with a Light‐Responsive Cavitand

Berryman, Orion B.; Sather, Aaron C.; Lledó, Agustí; Rebek, Julius

doi:10.1002/anie.201105374

Cited by 110 publications

(63 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Main azobenzenes are stable photochromic units that have been employed extensively as photoswitches in the development of light‐modulated host–guest systems . Examples of their incorporation in calix[4]arene, and resorcin[4]arene derivatives are abundant , . For example, we described the attachment of four terminal azobenzene groups to tetraurea calix[4]arenes.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Binding Studies of a Tetra‐α Aryl‐Extended Photoresponsive Calix[4]pyrrole Receptor Bearing meso‐Alkyl Substituents

2018

View full text Add to dashboard Cite

Abstract:We report the synthesis of the tetra-α isomer of a meso-azobenzene-extended calix[4]pyrrole receptor bearing alkyl substituents at its lower rim. In solution, the photo-irradiation of the all-trans receptor induces the isomerization of its azobenzene units producing at the photostationary state a mixture of cis-enriched counterparts in which the all-cis receptor is the major component (85 %). Simple molecular modelling studies show that the cone conformation of the all-trans isomer possesses a deep aromatic cavity open at one end. Otherwise, the isomers containing cis-azobenzene groups display a signifi-

show abstract

Section: Introductionmentioning

confidence: 99%

Synthesis and Binding Studies of a Tetra‐α Aryl‐Extended Photoresponsive Calix[4]pyrrole Receptor Bearing meso‐Alkyl Substituents

2018

View full text Add to dashboard Cite

show abstract

“…Upon photoswitching, the basic piperidine nitrogen atom is exposed in the ( Z )‐isomer, allowing enhancement of the rate of the aza‐Henry reaction of nitroethane to p ‐nitroanisaldehyde as compared to the ( E )‐isomer ( k Z / k E =35.5). Rebek and co‐workers introduced a light‐responsive cavitand/piperidinium complex that displayed switchable catalytic activity for the Knoevenagel condensation of aromatic aldehydes with malonitrile . The cavitand features an azobenzene arm capable of competing with the piperidinium ion for the cavity when irradiated with UV light, allowing reversible control of the guest binding and reactivity.…”

Section: Introductionmentioning

confidence: 99%

“…External control of catalytic systemsb yl ight is ah ighly challenging and still underdeveloped field of moderno rganic chemistry.I nt he quest for responsive catalytic systems, many advantages arise from the use of light as ac lean, non-invasive stimulus,i nw hich judicious choiceo fi rradiation wavelength may allow precise control over catalyst function, activity and selectivity.Anumber of photoresponsive catalysts have been developed over the last decade, exploiting the established switching properties of azobenzenes,d iarylethenesa nd overcrowded alkenes. [1][2][3][4][5] Promising resultsi np hotochemical control of catalyst activity or selectivity have been achieved through different approaches by harnessing cooperative, [6][7][8][9][10][11][12] steric [13][14][15][16][17][18][19][20] and electronic effects [21][22][23][24][25] of the photo-accessible isomers.…”

Section: Introductionmentioning

confidence: 99%

Bifunctional Molecular Photoswitches Based on Overcrowded Alkenes for Dynamic Control of Catalytic Activity in Michael Addition Reactions

Pizzolato

Collins

Leeuwen

et al. 2017

Chemistry A European J

View full text Add to dashboard Cite

The emerging field of artificial photoswitchable catalysis has recently shown striking examples of functional light-responsive systems allowing for dynamic control of activity and selectivity in organocatalysis and metal-catalysed transformations. While our group has already disclosed systems featuring first generation molecular motors as the switchable central core, a design based on second generation molecular motors is lacking. Here, the syntheses of two bifunctionalised molecular switches based on a photoresponsive tetrasubstituted alkene core are reported. They feature a thiourea substituent as hydrogen-donor moiety in the upper half and a basic dimethylamine group in the lower half. This combination of functional groups offers the possibility for application of these molecules in photoswitchable catalytic processes. The light-responsive central cores were synthesized by a Barton-Kellogg coupling of the prefunctionalized upper and lower halves. Derivatization using Buchwald-Hartwig amination and subsequent introduction of the thiourea substituent afforded the target compounds. Control of catalytic activity in the Michael addition reaction between (E)-3-bromo-β-nitrostyrene and 2,4-pentanedione is achieved upon irradiation of stable-(E) and stable-(Z) isomers of the bifunctional catalyst 1. Both isomers display a decrease in catalytic activity upon irradiation to the metastable state, providing systems with the potential to be applied as ON/OFF catalytic photoswitches.

show abstract

“…More than a decade later, Rebek and co‐workers reported another interesting method for controlling catalytic activity upon photoirradiation . They designed a photoswitchable receptor system in which a covalently attached azobenzene moiety controls the binding of an organocatalyst (piperidine acetate) in the cavity of receptor 8 (Scheme ).…”

Section: Introductionmentioning

confidence: 99%

Dynamic Responsive Systems for Catalytic Function

Vlatković

Collins

Feringa

2016

Chemistry A European J

113

View full text Add to dashboard Cite

Responsive systems have recently gained much interest in the scientific community in attempts to mimic dynamic functions in biological systems. One of the fascinating potential applications of responsive systems lies in catalysis. Inspired by nature, novel responsive catalytic systems have been built that show analogy with allosteric regulation of enzymes. The design of responsive catalytic systems allows control of catalytic activity and selectivity. In this Review, advances in the field over the last four decades are discussed and a comparison is made amongst the dynamic responsive systems based on the principles underlying their catalytic mechanisms. The catalyst systems are sorted according to the triggers used to achieve control of the catalytic activity and the distinct catalytic reactions illustrated.

show abstract

Switchable Catalysis with a Light‐Responsive Cavitand

Cited by 110 publications

References 38 publications

Synthesis and Binding Studies of a Tetra‐α Aryl‐Extended Photoresponsive Calix[4]pyrrole Receptor Bearing meso‐Alkyl Substituents

Synthesis and Binding Studies of a Tetra‐α Aryl‐Extended Photoresponsive Calix[4]pyrrole Receptor Bearing meso‐Alkyl Substituents

Bifunctional Molecular Photoswitches Based on Overcrowded Alkenes for Dynamic Control of Catalytic Activity in Michael Addition Reactions

Dynamic Responsive Systems for Catalytic Function

Contact Info

Product

Resources

About