Water-in-oil microemulsions as microreactors to control the regioselectivity in the photocycloaddition of 9-substituted anthracenes

Wu, Dayong; Zhang, Liping; Wu, Li‐Zhu; Wang, Bo‐Jie; Tung, Chen‐Ho

doi:10.1016/s0040-4039(01)02360-7

Cited by 22 publications

(12 citation statements)

References 7 publications

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“…Based on the regiochemical effects observed for other classes of mechanophores, we were also curious to investigate the impact of regiochemistry on the predicted mechanochemical reactivity of the anthracene dimer. The photodimerization of anthracene derivatives typically produces the head-to-tail isomer selectively; however, the head-to-head configuration is also accessible under certain conditions. , The typical CoGEF operation performed on alternative head-to-head dimers 48′ and 49′ predicts the desired cycloelimination reactions. Although mechanistic interpretations should again be treated with caution, the CoGEF simulations performed on the anthracene dimer indicate that the cycloelimination reaction does not proceed via a concerted retro-[4 + 4] cycloaddition reaction.…”

Section: Resultsmentioning

confidence: 99%

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

et al. 2020

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The development of force-responsive molecules called mechanophores is a central component of the field of polymer mechanochemistry. Mechanophores enable the design and fabrication of polymers for a variety of applications ranging from sensing to molecular release and self-healing materials. Nevertheless, an insufficient understanding of structure−activity relationships limits experimental development, and thus computation is necessary to guide the structural design of mechanophores. The constrained geometries simulate external force (CoGEF) method is a highly accessible and straightforward computational technique that simulates the effect of mechanical force on a molecule and enables the prediction of mechanochemical reactivity. Here, we use the CoGEF method to systematically evaluate every covalent mechanophore reported to date and compare the predicted mechanochemical reactivity to experimental results. Molecules that are mechanochemically inactive are also studied as negative controls. In general, mechanochemical reactions predicted with the CoGEF method at the common B3LYP/6-31G* level of density functional theory are in excellent agreement with reactivity determined experimentally. Moreover, bond rupture forces obtained from CoGEF calculations are compared to experimentally measured forces and demonstrated to be reliable indicators of mechanochemical activity. This investigation validates the CoGEF method as a powerful tool for predicting mechanochemical reactivity, enabling its widespread adoption to support the developing field of polymer mechanochemistry. Secondarily, this study provides a contemporary catalog of over 100 mechanophores developed to date.

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Section: Resultsmentioning

confidence: 99%

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

et al. 2020

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“…The excess was attributed to the micellar orientation of the two starting compounds in aqueous environment yielding predominantly one regioisomer. Similar observations were made by Wu et al for the photocycloaddition of 9-substituted anthracenes (with polar or ionic substituents) in w/o microemulsions . While in methylene chloride predominantly head-to-tail photocyclomers were obtained, in microemulsion exclusively head-to-head regioisomers were formed due to a preorientation of the substrate molecules at the interface (see Figure ).…”

Section: Reactions At the (Droplet) Interfacementioning

confidence: 99%

Reactions and Polymerizations at the Liquid–Liquid Interface

et al. 2015

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Reactions and polymerizations at the interface of two immiscible liquids are reviewed. The confinement of two reactants at the interface to form a new product can be advantageous in terms of improved reaction kinetics, higher yields, and selectivity. The presence of the liquid-liquid interface can accelerate the reaction, or a phase-transfer catalyst is employed to draw the reaction in one phase of choice. Furthermore, the use of immiscible systems, e.g., in emulsions, offers an easy means of efficient product separation and heat dissipation. A general overview on low molecular weight organic chemistry is given, and the applications of heterophase polymerization, occurring at or in proximity of the interface, (mostly) in emulsions are presented. This strategy can be used for the efficient production of nano- and microcarriers for various applications.

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“…Cycloaddition of the aromatic rings at the 9 and 10 positions yields head-to-tail (h–t) or head-to-head (h–h) photocyclomers. Tung and co-workers 115 revealed an interesting regioselectivity attributed to “oil”/water interactions. When the anthracene bears a polar or charged functional group, such as –CH 2 N + (CH 3 ) 3 Br − , –CH 2 COO–Na + , or –CH 2 OH, the substituent orients itself towards the water phase.…”

Section: Applicationsmentioning

confidence: 99%

Water as the reaction medium in organic chemistry: from our worst enemy to our best friend

et al. 2021

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Water-in-oil microemulsions as microreactors to control the regioselectivity in the photocycloaddition of 9-substituted anthracenes

Cited by 22 publications

References 7 publications

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

Reactions and Polymerizations at the Liquid–Liquid Interface

Water as the reaction medium in organic chemistry: from our worst enemy to our best friend

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