Photoswitchable ring-opening polymerization of lactide catalyzed by azobenzene-based thiourea

Dai, Zhongran; Cui, Yaqin; Chen, Changjuan; Wu, Jincai

doi:10.1039/c6cc04090j

Cited by 41 publications

(33 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although the reversible light‐induced switchability was demonstrated, compound 21 revealed to be inactive in the catalysis of the polymerization of lactide. Therefore, a variant of 21 was proposed, namely compound 22 (Figure ) . In this case, the nitro substituent in the Z isomer engages in intramolecular H‐bonds with the thiourea moiety.…”

Section: Configurational Selection Following H‐bonding Complexes Formmentioning

confidence: 99%

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Tecilla

Bonifazi

2020

ChemistryOpen

View full text Add to dashboard Cite

Azobenzene is one of the most studied light-controlled molecular switches and it has been incorporated in a large variety of supramolecular systems to control their structural and functional properties. Given the peculiar isomeric distribution at the photoexcited state (PSS), azobenzene derivatives have been used as photoactive framework to build metastable supramolecular systems that are out of the thermodynamic equilibrium. This could be achieved exploiting the peculiar E/Z photoisomerization process that can lead to isomeric ratios that are unreachable in thermal equilibrium conditions. The challenge in the field is to find molecular architectures that, under given external circumstances, lead to a given isomeric ratio in a reversible and predictable manner, ensuring an ultimate control of the configurational distribution and system composition. By reviewing early and recent works in the field, this review aims at describing photoswitchable systems that, containing an azobenzene dye, display a controlled configurational equilibrium by means of a molecular recognition event. Specifically, examples include programmed photoactive molecular architectures binding cations, anions and H-bonded neutral guests. In these systems the non-covalent molecular recognition adds onto the thermal and light stimuli, equipping the supramolecular architecture with an additional external trigger to select the desired configuration composition.[a] Prof. P. Tecilla

show abstract

Section: Configurational Selection Following H‐bonding Complexes Formmentioning

confidence: 99%

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Tecilla

Bonifazi

2020

ChemistryOpen

View full text Add to dashboard Cite

show abstract

“…A photoisomerizable organocatalyst, an azobenzene-based thiourea, was developed for the polymerization of rac-LA. 132 Therein, Wu and coworkers found that when the E isomer (39 E ) (Scheme 6b) is used, the coordination site is open and polymerizations reach 90% monomer conversion in 24 h. Upon UV irradiation (330−400 nm), isomerization to the analogous Z isomer 39 Z occurs, leading to a drastic decrease in polymerization activity compared with 39 E (k = 2.08 × 10 −4 vs 2.08 × 10 −3 min −1 , respectively). This change in catalytic activity was hypothesized to result from the intramolecular hydrogen bonding between the nitro group and the urea of 39 Z , which blocks the active site from monomer coordination.…”

Section: Photochemical Controlmentioning

confidence: 99%

Advances in Polymerizations Modulated by External Stimuli

et al. 2020

View full text Add to dashboard Cite

Synthetic polymer chemistry endeavors to imitate the spatial and temporal control exhibited within biological systems to obtain well-defined polymeric materials with unique structures, properties, and applications. This is often approached through the development of dynamic catalyst (or initiator) systems that use external stimuli to elicit discrete, site-specific transformations that impact the polymerization. Herein we highlight developments in polymerizations that are modulated by external stimuli, with particular focus on those systems that enable notable changes in kinetics, monomer selectivity, polymer architecture, or tacticity. Examples of external stimuli include chemical oxidants or reductants, light, applied voltage, and mechanical force.

show abstract

“…In a similar vein, 12 was later used as a photoswitchable catalyst in the ring-opening polymerization of lactide. 23…”

Section: Photoswitchable Bifunctional Catalystsmentioning

confidence: 99%

Photoswitchable catalysis based on the isomerisation of double bonds

2019

View full text Add to dashboard Cite

show abstract

Photoswitchable ring-opening polymerization of lactide catalyzed by azobenzene-based thiourea

Cited by 41 publications

References 47 publications

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Configurational Selection in Azobenzene‐Based Supramolecular Systems Through Dual‐Stimuli Processes

Advances in Polymerizations Modulated by External Stimuli

Photoswitchable catalysis based on the isomerisation of double bonds

Contact Info

Product

Resources

About