Photoswitchable Catalysis by a Self-Assembled Molecular Cage

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(31), С. 21196 - 21202

Опубликована: Июль 25, 2024

A heteroleptic [Pd

Язык: Английский

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Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

Beilstein Journal of Organic Chemistry, Год журнала: 2025, Номер 21, С. 421 - 443

Опубликована: Фев. 24, 2025

The bespoke environments in enzyme active sites can selectively accelerate chemical reactions by as much 1019. Macromolecular and supramolecular chemists have been inspired to understand mimic these accelerations selectivities for applications catalysis sustainable synthesis. Over the past 60+ years, mimicry strategies evolved with changing interests, understanding, synthetic advances but, ubiquitously, research has focused on use of a molecular "cavity". activities different cavities vary subset features available particular cavity type. Unsurprisingly, without access mimics able encompass more/all functional sites, examples cavity-catalyzed processes demonstrating enzyme-like rate remain rare. This perspective will briefly highlight some key traditional catalysis, type, order contextualize recent development robust organic cage catalysts, which exploit stability, functionality, reduced symmetry enable promising catalytic modes.

Язык: Английский

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Dissecting the Effects of Cage Structure in the Catalytic Activation of Imide Chlorenium-Ion Donors

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Март 21, 2025

Imide-based chlorinating reagents are mild and easy to use yet can lack the reactivity of charged chlorenium-ion donors. Here, we present a simple strategy for increasing these neutral species by encapsulation inside cationic coordination cage. Using this approach, demonstrate that two different-sized Pd2L4 cages catalyze chlorolactonization chlorocycloetherification reactions acid alcohol functionalized α β-substituted styrene substrates with either 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) or N-chlorosuccinimide (NCS) as chlorenium sources. A kinetic study shows proficient catalysts significant acceleration up 105. However, an unexpected dichotomy is revealed wherein smaller cage, which best preorganized bind nominally provide maximum activation imide reagent, order magnitude less than larger cage has apparently mismatched host–guest chemistry. When scope further extended chlorination simple, unfunctionalized α-methylstyrene, same pattern observed, suggesting differences not explained coencapsulation. Computational studies indicate trend in caused transition state being fixed allowing it find optimal binding thereby generate stronger interactions. This investigation highlights importance understanding underlying mechanisms design new noncovalent greater range transformations.

Язык: Английский

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Formation of a Pd₁₆ Molecular Basket Architecture of Reduced Symmetry and Angular Deviation in a Fluorenone Scaffold to Govern the Host–Guest Chemistry of Pd₆ Trifacial Tubes

JACS Au, Год журнала: 2025, Номер 5(5), С. 2368 - 2378

Опубликована: Май 9, 2025

The employment of flexible ligands with significant conformational freedom in coordination-driven self-assembly enables the formation unique and intricate structures. In this study, such a fluorenone-appended ligand (L1) sterically demanding acceptor, [Pd-(tmed)-(ONO2)2] (M1), generated new molecular basket architecture, (M1) 16 8 (B), featuring large hollow cavity. B possesses an unusual twisted architecture low symmetry, consisting Pd-(II) centers arranged as four tetrahedra connected by eight ligands, representing structurally complex system reminiscent biological architectures. Designing entropically disfavored, architectures reduced symmetry is challenging but desirable, since they can act ideal models to study complicated natural systems. host-guest property supramolecular hosts governed confined cavities noncovalent interactions, which are dictated angular disposition coordination sites. To explore this, fluorenone scaffold was used synthesize two other tetradentate (L2 L3) that differed spatial distributions their vectors. these [Pd-(en)-(ONO2)2] (M2) resulted water-soluble 6 (L1/L2/L3) 3 trifacial tubes different geometries varying internal cavity dimensions. These variations further altered orientation carbonyl groups within cavities, thereby modulating guest binding abilities highlighting importance tailoring for specific binding.

Язык: Английский

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Photoswitchable catalysis by a self-assembled molecular cage

Опубликована: Июнь 25, 2024

A heteroleptic [Pd2L2L'2]4+ coordination cage containing a photoswitchable azobenzene-derived ligand catalyzes the Michael addition reaction between methyl vinyl ketone and benzoyl nitromethane within its cavity. The correspond-ing homoleptic cages are catalytically inactive. can be reversibly disassembled reassembled using 530 nm light 405 light, respectively, allowing catalysis to switched ON OFF at will.

Язык: Английский

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