Molecular rotor based on an oxidized resorcinarene

Payne, Daniel T.; Labuta, Jan; Futera, Zdeněk; Březina, Václav; Hanyková, Lenka; Chahal, Mandeep K.; Hill, Jonathan P.

doi:10.1039/d1qo01479j

Cited by 3 publications

(4 citation statements)

References 104 publications

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“…VT-UV–vis data in Figure show only minor differences between racemic and (Δ)-enantiopure spectral sets, as shown in Figure b for two wavelengths. Moreover, the presence of stable isosbestic points at 358, 422, and 484 nm in the entire temperature range indicates apparent dominance of only two absorbing species, , i.e., monomer and only one type of dimer (either homochiral or heterochiral dimer) in the racemic solution of Bu- Ir (Figure b). Close inspection of VT 1 H NMR data (Figures and S26 and S27) for enantiopure and racemic Bu- Ir solutions shows only one set of resonances corresponding to the formation of only one type of dimer, the homochiral dimer.…”

Section: Resultsmentioning

confidence: 99%

Thermo-/Mechano-Chromic Chiral Coordination Dimer: Formation of Switchable and Metastable Discrete Structure through Chiral Self-Sorting

Takimoto,

Shimada,

Nagura

et al. 2023

J. Am. Chem. Soc.

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Although strong chiral self-sorting often emerges in extended covalent or supramolecular polymers, the phenomenon is generally weak in discrete assemblies (e.g., dimers and oligomers) of small molecules due to the lack of a cooperative growth mechanism. Consequently, chiral self-sorting has been overlooked in the design of switchable and metastable discrete supramolecular structures. Here, we report a butyl-benzo[h]quinoline-based iridium(III) complex (Bu-Ir) with helical chirality at its metal center, which forms preferentially a homochiral dimer and exhibits thermo-/mechano-chromism based on a monomer−dimer transformation. While a five-coordinate monomer is formed in a racemic or an enantiopure Bu-Ir solution at 25 °C, a six-coordinate homochiral dimer complex is formed almost exclusively at low temperatures, with a higher degree of dimerization in enantiopure Bu-Ir solution. Estimation of apparent dimerization binding constants (K) and thermodynamic parameters (ΔH and ΔS) based on variable temperature ultraviolet−visible (UV−vis) and 1 H NMR spectra reveals a strong preference for homochiral dimerization (largest known value for the coordination complex, K homo /K hetero > 50). Notably, crystals of the homochiral dimer are metastable, undergoing a distinct color change upon grinding (from yellow to red) due to mechanical cleavage of coordination bonds (i.e., a dimer to monomer transformation). A comparison with control compounds having different substituents (proton, methyl, isopropyl, and phenyl groups) reveals that Bu-Ir dimerization involves both strong homochiral self-sorting preference and connected thermo-/mechano-chromic behavior, which is based on matched propeller-shaped chirality and subtle steric repulsion between alkyl substituents that render the homochiral dimer switchable and metastable. These findings provide substantial insights into the emergence of dynamic functionality based on the rational design of discrete chiral assemblies.

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Section: Resultsmentioning

confidence: 99%

Thermo-/Mechano-Chromic Chiral Coordination Dimer: Formation of Switchable and Metastable Discrete Structure through Chiral Self-Sorting

Takimoto,

Shimada,

Nagura

et al. 2023

J. Am. Chem. Soc.

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“…They can undergo reversible oxidation/reduction processes based on interconversion of phenol hemiquinonoid macrocyclic “ meso ” substituents . Oxidative transformations of the compounds have led to their application as multimodal molecular switches, molecular rotors and efficient singlet oxygen photosensitizers in organic solvents . However, only singly (Ox 1 ) and doubly (Ox 2 ) oxidized fuchsonarenes had been accessible due to synthetic conditions employed in previous studies, despite the possibility of the existence of the quadruply oxidized Ox 4 compounds by analogy with a closely related porphyrin system. ,, The installation of hemiquinonoid substituents at the meso position is critical for the activity of this class of compounds as 1 O 2 photosensitizers due to the incorporation of multiple fuchsone-type chromophores into the macrocycle according to the overall oxidation state .…”

Section: Molecular Synthesis and Structurementioning

confidence: 99%

“…75 They can undergo reversible oxidation/reduction processes based on interconversion of phenol hemiquinonoid macrocyclic "meso" substituents. 76 Oxidative transformations of the compounds have led to their application as multimodal molecular switches, 76 molecular rotors 77 and efficient singlet oxygen photosensitizers in organic solvents. 75 However, only singly (Ox 1 ) and doubly (Ox 2 ) oxidized fuchsonarenes had been accessible due to synthetic conditions employed in previous studies, despite the possibility of the existence of the quadruply oxidized Ox 4 compounds by analogy with a closely related porphyrin system.…”

Section: ■ Molecular Synthesis and Structurementioning

confidence: 99%

Photosensitizer Encryption with Aggregation Enhanced Singlet Oxygen Production

et al. 2022

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Chromophores that generate singlet oxygen ( 1 O 2 ) in water are essential to developing noninvasive disease treatments using photodynamic therapy (PDT). A facile approach for formation of stable colloidal nanoparticles of 1 O 2 photosensitizers, which exhibit aggregation enhanced 1 O 2 generation in water toward applications as PDT agents, is reported. Chromophore encryption within a fuchsonarene macrocyclic scaffold insulates the photosensitizer from aggregation induced deactivation pathways, enabling a higher chromophore density than typical 1 O 2 generating nanoparticles. Aggregation enhanced 1 O 2 generation in water is observed, and variation in molecular structure allows for regulation of the physical properties of the nanoparticles which ultimately affects the 1 O 2 generation. In vitro activity and the ability of the particles to pass through the cell membrane into the cytoplasm is demonstrated using confocal fluorescence microscopy with HeLa cells. Photosensitizer encryption in rigid macrocycles, such as fuchsonarenes, offers new prospects for the production of biocompatible nanoarchitectures for applications involving 1 O 2 generation.

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“…Macrocyclic compounds (e.g., crown ethers, cyclodextrins (CDs) derivatives, resorcinarene, calixarenes, and cryptands) are bioinspired catalysts that mimic the cavity of natural enzymes. This provides an environment where substrates are isolated from the surrounding, while the substrate-binding sites of cavities provide a suitable preorganization to accelerate reactions, even without any catalytic moieties. − For instance, CDs are cyclic oligosaccharides, having hydrophobic cavities that can accommodate small hydrophobic molecules and catalyze reactions. − In recent years, there has been a great deal of enthusiasm about the enzymatic potential of CDs, especially when combined with metal ions, metal clusters, organometallic metal complexes, and metal nanoparticles. Studies have shown that CDs can act as the enzyme mimetics in oxidation, reduction, hydrogenation, hydroforming, ring-opening/formation, and coupling reactions .…”

Section: Catalysis Applications Of Biomimetic Metal Nanoparticlesmentioning

confidence: 99%

Biomimetic Metallic Nanostructures for Biomedical Applications, Catalysis, and Beyond

Yaraki

Nasab

Zare³

et al. 2022

Ind. Eng. Chem. Res.

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Nature has inspired scientists to develop green and sustainable nanomaterials with biomimetic functions. Particularly, biomimetic metallic nanostructures (biometal NPs) with unique optical, catalytic, and electrical properties have received tremendous attention in many fields, ranging from healthcare and agriculture to energy and environmental sciences. Biometal NPs synthesized by various natural resources such as plant extracts, biomolecules, bacteria, and even viruses possess unique biomimetic functions including but not limited to precise biorecognition, selfassembly, antibacterial/antiviral, and enzymatic properties. In this report, we first review the bioinspired synthesis of industrially important metal nanoparticles, followed by the discussion on how the different biological sources affect the biomimetic functions of the as-synthesized biometal NPs. Next, we review the recent advancement and applications of these biometal NPs in the fields of biomedical engineering and catalysis, which include the development of metallic nanobiosensors, biomedical imaging probes, nanotherapeutics (e.g., antimicrobial and photodynamic/photothermal therapeutic agents), as well as the design of multifunctional nanozymes and artificial metalloenzymes for chemical and biopharmaceutical industries. Finally, we highlight some of the latest advancements in nanobiomimicry and their emerging applications in clean energy, electronic devices, and data storage, which shows the game-changing role of biomimetic metallic nanostructures for various technological applications in the near future.

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Molecular rotor based on an oxidized resorcinarene

Abstract: Rate of rotation of substituents in a molecular single stator-double rotor based on an oxidized resorcinarene with unsaturated hemiquinonoid groups at its meso positions (i.e., a fuchsonarene) has been controlled according to solvent polarity and acidity.

Cited by 3 publications

References 104 publications

Thermo-/Mechano-Chromic Chiral Coordination Dimer: Formation of Switchable and Metastable Discrete Structure through Chiral Self-Sorting

Thermo-/Mechano-Chromic Chiral Coordination Dimer: Formation of Switchable and Metastable Discrete Structure through Chiral Self-Sorting

Photosensitizer Encryption with Aggregation Enhanced Singlet Oxygen Production

Biomimetic Metallic Nanostructures for Biomedical Applications, Catalysis, and Beyond

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