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Ion Pairing of Cationic and Anionic Ir(III) Photosensitizers for Photocatalytic CO 2 Reduction at Lipid-Membrane Surfaces. J Am Chem Soc 2023. [PMID: 37410114 DOI: 10.1021/jacs.3c03625] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
We synthesized an ion pair comprising cationic and anionic Ir(III) photosensitizers ([Ir1+][Ir2-]) for photocatalytic CO2 reduction and showed that the cationic component imparts stability, while the cyclometalating ligands in the anionic component ensure effective visible-light absorption. The triplet excited state of [Ir1+] is the key photoredox species in this system and is mainly generated through the transfer of triplet excitation energy from the anionic moiety due to Coulombic interactions and appropriate triplet energy alignment between the two ionic components. The positive photosensitization effect of ion pairing was demonstrated by photocatalytic CO2 reduction in cooperation with a Re(I) molecular catalyst incorporated into a vesicle membrane.
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2
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Luminescent Thermoresponse via Excimer/Exciplex Transition of Pyrene Derivative in Polymer Networks Containing [3]Rotaxane. ACS Macro Lett 2023:751-758. [PMID: 37212259 DOI: 10.1021/acsmacrolett.3c00196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The modulation of molecular interaction with a [3]rotaxane structure enabled a luminescent thermoresponse with high sensitivity over a wide temperature range. Herein, a pyrene moiety was encapsulated by permethylated α-cyclodextrins and was introduced into a polymer network material of poly(vinyl alcohol) as a cross-linker. The luminescence nature associated with the pyrene moiety was continuously switched from a static pyrene-pyrene excimer emission mode at 193 K to a dynamic pyrene-dimethylaniline (DMA) exciplex emission mode at 293 K. A series of [3]rotaxane structures revealed the impact of supramolecular control of the interaction among pyrenes and DMA. Consequently, the continuously coupled two luminescent modes of pyrene (excimer and exciplex) provided a monotonical luminescence change over a wide temperature range (100 K) with high sensitivity of the wavelength variation (0.64 nm/K) as a distinguished thermoresponsive material to visualize the thermal information.
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3
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Effects of Alkyl Ester Chain Length on the Toughness of PolyAcrylate-Based Network Materials. Polymers (Basel) 2023; 15:polym15102389. [PMID: 37242964 DOI: 10.3390/polym15102389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Polyacrylate-based network materials are widely used in various products owing to their facile synthesis via radical polymerization reactions. In this study, the effects of alkyl ester chains on the toughness of polyacrylate-based network materials were investigated. Polymer networks were fabricated via the radical polymerization of methyl acrylate (MA), ethyl acrylate (EA), and butyl acrylate (BA) in the presence of 1,4-butanediol diacrylate as a crosslinker. Differential scanning calorimetry and rheological measurements revealed that the toughness of MA-based networks drastically increased compared with that of EA- and BA-based networks; the fracture energy of the MA-based network was approximately 10 and 100 times greater than that of EA and BA, respectively. The high fracture energy was attributed to the glass transition temperature of the MA-based network (close to room temperature), resulting in large energy dissipation via viscosity. Our results set a new basis for expanding the applications of polyacrylate-based networks as functional materials.
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4
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Fabrication of Photoprocessable Materials via Photopolymerization Using an Acid-Induced Photocleavable Platinum-Acetylide Crosslinker. Angew Chem Int Ed Engl 2023:e202305374. [PMID: 37106273 DOI: 10.1002/anie.202305374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 04/29/2023]
Abstract
Photopolymerization and photoprocessing are core technologies for molding and tuning polymer materials. However, they are incompatible with single materials owing to their contradictory photoreactivity. Herein, an acid-induced photocleavable crosslinker, a platinum-acetylide complex covered by permethylated cyclodextrins, enables the fabrication of photoprocessable materials via photopolymerization with N-(2-hydroxyethyl)acrylamide. The polymer networks are molded by 365 nm irradiation as well as softened and degraded by a cooperative reaction with HCl as an acidic additive under 365 nm UV light, or 470 nm visible light in the presence of a photosensitizer. Moreover, the crosslinker is applied to a photoadhesive triggered by 365 nm irradiation. The adhesion is detachable on-demand through acid-induced photodegradation with the same wavelength and intensity of irradiation. Thus, acid-induced photocleavage allows the integration of light-induced molding and processing under various lights of various wavelengths, opening up new strategies for polymer technologies.
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5
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Multistate Structural Switching of [3]Catenanes with Cyclic Porphyrin Dimers by Complexation with Amine Ligands. Angew Chem Int Ed Engl 2023; 62:e202217002. [PMID: 36625214 DOI: 10.1002/anie.202217002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/22/2022] [Accepted: 01/09/2023] [Indexed: 01/11/2023]
Abstract
Catenanes with multistate switchable properties are promising components for next-generation molecular machines and supramolecular materials. Herein, we report a ligand-controlled switching method, a novel method for the multistate switching of catenanes controlled by complexation with added amine ligands. To verify this method, a [3]catenane comprising cyclic porphyrin dimers with a rigid π-system has been synthesized. Owing to the rigidity, the relative positions among the cyclic components of the [3]catenane can be precisely controlled by complexation with various amine ligands. Moreover, ligand-controlled multistate switching affects the optical properties of the [3]catenanes: the emission intensity can be tuned by modulating the sizes and coordination numbers of integrated amine ligands. This work shows the utility of using organic ligands for the structural switching of catenanes, and will contribute to the further development of multistate switchable mechanically interlocked molecules.
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6
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Multistate Structural Switching of [3]Catenanes with Cyclic Porphyrin Dimers by Complexation with Amine Ligands. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/anie.202302639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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7
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Multistate Structural Switching of [3]Catenanes with Cyclic Porphyrin Dimers by Complexation with Amine Ligands. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202302639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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8
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Multistate Structural Switching of [3]Catenanes with Cyclic Porphyrin Dimers by Complexation with Amine Ligands. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202217002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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9
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Systematic Synthesis of Macrocycles Bearing up to Six 2,2'-Bipyridine Moieties through Self-Assembled Double Helix Structure. J Org Chem 2022; 87:13331-13338. [PMID: 36173111 DOI: 10.1021/acs.joc.2c01194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A new synthetic strategy for macrocycles bearing multiple coordination moieties was developed. A self-assembled double helix structure, composed of two linear strands bearing 2,2'-bipyridine units and Cu(I) ions, provided access to macrocycles bearing a defined number of 2,2'-bipyridine moieties and a defined ring size, via an olefin-metathesis reaction between two linear strands in the helix. The double helix structure improved the selectivity of the macrocycle synthesis by bringing the reaction points in close proximity even in the case of large macrocycles.
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10
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Insulation of a coumarin derivative with [1]rotaxane to control solvation-induced effects in excited-state dynamics for enhanced luminescence. Phys Chem Chem Phys 2022; 24:15195-15200. [PMID: 35703560 DOI: 10.1039/d2cp02221d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A coumarin derivative bearing a [1]rotaxane structure with permethylated α-cyclodextrins suppressed unwanted solvation-induced effects and increased luminescent quantum yields in medium- and high-polarity solvents. The non-radiative decay was suppressed by the twist in the π-conjugated system and the radiative decay was enhanced by the suppression of the polarity-induced structural changes.
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11
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Stochastic Binding Dynamics of a Photoswitchable Single Supramolecular Complex. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200022. [PMID: 35233985 PMCID: PMC9069358 DOI: 10.1002/advs.202200022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/30/2022] [Indexed: 06/11/2023]
Abstract
In this work, a real-time precise electrical method to directly monitor the stochastic binding dynamics of a single supramolecule based on the host-guest interaction between a cyclodextrin and an azo compound is reported. Different intermolecular binding states during the binding process are distinguished by conductance signals detected from graphene-molecule-graphene single-molecule junctions. In combination with theoretical calculations, the reciprocating and unidirectional motions in the trans form as well as the restrained reciprocating motion in the cis form due to the steric hindrance is observed, which could be reversibly switched by visible and UV irradiation. The integration of individual supramolecules into nanocircuits not only offers a facile and effective strategy to probe the dynamic process of supramolecular systems, but also paves the way to construct functional molecular devices toward real applications such as switches, sensors, and logic devices.
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12
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Principal Component Analysis of Surface-Enhanced Raman Scattering Spectra Revealing Isomer-Dependent Electron Transport in Spiropyran Molecular Junctions: Implications for Nanoscale Molecular Electronics. ACS OMEGA 2022; 7:5578-5583. [PMID: 35187372 PMCID: PMC8851897 DOI: 10.1021/acsomega.1c07105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The characterization of single-molecule structures could provide significant insights into the operation mechanisms of functional devices. Structural transformation via isomerization has been extensively employed to implement device functionalities. Although single-molecule identification has recently been achieved using near-field spectroscopy, discrimination between isomeric forms remains challenging. Further, the structure-function relationship at the single-molecule scale remains unclear. Herein, we report the observation of the isomerization of spiropyran in a single-molecule junction (SMJ) using simultaneous surface-enhanced Raman scattering (SERS) and conductance measurements. SERS spectra were used to discriminate between isomers based on characteristic peaks. Moreover, conductance measurements, in conjunction with the principal component analysis of the SERS spectra, clearly showed the isomeric effect on the conductance of the SMJ.
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13
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Linked Rotaxane Structure Restricts Local Molecular Motions in Solution to Enhance Fluorescence Properties of Tetraphenylethylene. Chemistry 2022; 28:e202103175. [PMID: 34981571 DOI: 10.1002/chem.202103175] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Indexed: 01/02/2023]
Abstract
The restriction of local molecular motions is critical for improving the fluorescence quantum yields (FQYs) and the photostability of fluorescent dyes. Herein, we report a supramolecular approach to enhance the performance of fluorescent dyes by incorporating a linked rotaxane structure with permethylated α-cyclodextrins. Tetraphenylethylene (TPE) derivatives generally exhibit low FQYs in solution due to the molecular motions in the excited state. We show that TPE with linked rotaxane structures on two sides displays up to 15-fold higher FQYs. Detailed investigations with variable temperature 1 H NMR, UV-Vis, and photoluminescence spectroscopy revealed that the linked rotaxane structure rigidifies the TPE moiety and thus suppresses the local molecular motions and non-radiative decay. Moreover, the linked rotaxane structure enhances the FQY of the dye in various solvents, including aqueous solutions, and improves the photostability through the inhibition of local molecular motions in the excited TPE.
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14
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Irradiation with UV Light Accelerates the Migita–Kosugi–Stille Coupling Reaction in Air. CHEM LETT 2021. [DOI: 10.1246/cl.210665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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15
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Solvatofluorochromic Contrast with Supramolecular Stereoisomers Using Linked Rotaxane Structures to Investigate Local Solvation in Excited Donor-bridge-acceptor Systems. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Precision synthesis of linear oligorotaxanes and polyrotaxanes achieving well-defined positions and numbers of cyclic components on the axle. Chem Commun (Camb) 2021; 58:1644-1660. [PMID: 34927653 DOI: 10.1039/d1cc03507j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Interest in macromolecules has increased because of their functional properties, which can be tuned using precise organic synthetic methods. For example, desired functions have been imparted by controlling the nanoscale structures of such macromolecules. In particular, compounds with interlocked structures, including rotaxanes, have attracted attention because of their unique supramolecular structures. In such supramolecular structures, the mobility and freedom of the macrocycles are restricted by an axle and dependent on those of other macrocycles, which imparts unique functions to these threaded structures. Recently, methods for the ultrafine engineering and synthesis, as well as functions, of "defined" rotaxane structures that are not statistically dispersed on the axle (i.e., control over the number and position of cyclic molecules) have been reported. Various synthetic strategies allow access to such well-defined linear oligo- and polyrotaxanes, including [1]rotaxanes and [n]rotaxanes (mostly n > 3). These state-of-the-art synthetic methods have resulted in unique functions of these oligo-and polyrotaxane materials. Herein, we review the effective synthetic protocols and functions of precisely constructed one-dimensional oligomers and polymers bearing defined threaded structures, and discuss the latest reports and trends.
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Electrical detection of ppb region NO 2 using Mg-porphyrin-modified graphene field-effect transistors. NANOSCALE ADVANCES 2021; 3:5793-5800. [PMID: 36132664 PMCID: PMC9417097 DOI: 10.1039/d1na00519g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 07/28/2021] [Indexed: 06/16/2023]
Abstract
The trace detection of NO2 through small sensors is essential for air quality measurement and the health field; however, small sensors based on electrical devices cannot detect NO2 with the desired selectivity and quantitativity in the parts per billion (ppb) concentration region. In this study, we fabricated metalloporphyrin-modified graphene field-effect transistors (FETs). Mg-, Ni-, Cu-, and Co-porphyrins were deposited on the graphene FETs, and the transfer characteristics were measured. With the introduction of NO2 in the ppb concentration region, the FETs of pristine graphene and Ni-, Cu-, and Co-porphyrin-modified graphene showed an insufficient response, whereas the Mg-porphyrin-modified graphene exhibited large voltage shifts in the transport characteristics. This indicates that Mg-porphyrin acts as an adsorption site for NO2 molecules. An analysis of the Dirac-point voltage shifts with the introduction of NO2 indicates that the shifts were well-fitted with the Langmuir adsorption isotherm model, and the limit of detection for NO2 was found to be 0.3 ppb in N2. The relationship between the mobility and the Dirac-point voltage shift with the NO2 concentration shows that the complex of NO2 and Mg-porphyrin behaves as a point-like charge impurity. Moreover, the Mg-porphyrin-modified graphene FETs show less response to other gases (O2, H2, acetic acid, trimethylamine, methanol, and hexane), thus indicating high sensitivity for NO2 detection. Furthermore, we successfully demonstrated the quantitative detection of NO2 in air, which is near the environmental standards. In conclusion, the results of the Mg-porphyrin-modified graphene FETs enable a rapid, easy, and selective detectability.
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18
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Maximizing Conversion of Surface Click Reactions for Versatile Molecular Modification on Metal Oxide Nanowires. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5172-5179. [PMID: 33890792 DOI: 10.1021/acs.langmuir.1c00106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Click reactions (e.g., Huisgen cycloaddition) on metal oxide nanostructures offer a versatile and robust surface molecular modification for various applications because they form strong covalent bonds in a wide range of molecular substrates. This study reports a rational strategy to maximize the conversion rate of surface click reactions on single-crystalline ZnO nanowires by monitoring the reaction progress. p-Polarized multiple-angle incidence resolution spectrometry (pMAIRS) and Fourier-transformed infrared (FT-IR) spectroscopy were employed to monitor the reaction progress of an azide-terminated self-assembled monolayer (SAM) on single-crystalline ZnO nanowires. Although various reaction parameters including the concentration of Cu(I) catalysts, triazolyl ligands, solvents, and target alkynes were systematically examined for the surface click reactions, 10-30% of terminal azide on the nanowire surface remained unreacted. Temperature-dependent FT-IR measurements revealed that such unreacted residual azides deteriorate the thermal stability of the nanowire molecular layer. To overcome this observed conversion limitation of click reactions on nanostructure surfaces, we considered the steric hindrance around the closely packed SAM reaction points, then experimented with dispersing the azide moiety into a methyl-terminated SAM. The mixed-SAM method significantly improved the azide conversion rate to almost 100%. This reaction method enables the construction of spatially patterned molecular surface modifications on metal oxide nanowire arrays without detrimental unreacted azide groups.
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19
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Rational Strategy for Space-Confined Seeded Growth of ZnO Nanowires in Meter-Long Microtubes. ACS APPLIED MATERIALS & INTERFACES 2021; 13:16812-16819. [PMID: 33784465 DOI: 10.1021/acsami.0c22709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Seeded crystal growths of nanostructures within confined spaces offer an interesting approach to design chemical reaction spaces with tailored inner surface properties. However, such crystal growth within confined spaces tends to be inherently difficult as the length increases as a result of confinement effects. Here, we demonstrate a space-confined seeded growth of ZnO nanowires within meter-long microtubes of 100 μm inner diameter with the aspect ratio of up to 10 000, which had been unattainable to previous methods of seeded crystal growths. ZnO nanowires could be grown via seeded hydrothermal crystal growth for relatively short microtubes below the length of 40 mm, while any ZnO nanostructures were not observable at all for longer microtubes above 60 mm with the aspect ratio of 600. Microstructural and mass spectrometric analysis revealed that a conventional seed layer formation using zinc acetate is unfeasible within the confined space of long microtubes as a result of the formation of detrimental residual Zn complex compounds. To overcome this space-confined issue, a flow-assisted seed layer formation is proposed. This flow-assisted method enables growth of spatially uniform ZnO nanowires via removing residual compounds even for 1 m long microtubes with the aspect ratio of up to 10 000. Finally, the applicably of ZnO-nanowire-decorated long microtubes for liquid-phase separations was demonstrated.
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A single-molecule electrical approach for amino acid detection and chirality recognition. SCIENCE ADVANCES 2021; 7:eabe4365. [PMID: 33658198 PMCID: PMC7929498 DOI: 10.1126/sciadv.abe4365] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 01/15/2021] [Indexed: 05/27/2023]
Abstract
One of the ultimate goals of analytic chemistry is to efficiently discriminate between amino acids. Here we demonstrate this ability using a single-molecule electrical methodology based on molecular nanocircuits formed from stable graphene-molecule-graphene single-molecule junctions. These molecular junctions are fabricated by covalently bonding a molecular machine featuring a permethylated-β-cyclodextrin between a pair of graphene point contacts. Using pH to vary the type and charge of the amino acids, we find distinct multimodal current fluctuations originating from the different host-guest interactions, consistent with theoretical calculations. These conductance data produce characteristic dwell times and shuttling rates for each amino acid, and allow accurate, statistical real-time, in situ measurements. Testing four amino acids and their enantiomers shows the ability to distinguish between them within a few microseconds, thus paving a facile and precise way to amino acid identification and even single-molecule protein sequencing.
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21
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Change in the rate of pseudo[1]rotaxane formation by elongating the alkyl-chain-substituted diphenylethynylene linked to permethyl α-cyclodextrin. Tetrahedron Lett 2020. [DOI: 10.1016/j.tetlet.2020.152061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Suppression of Undesirable Isomerization and Intermolecular Reactions of Double Bonds by a Linked Rotaxane Structure. Chem Asian J 2020; 15:1890-1895. [PMID: 32291947 DOI: 10.1002/asia.202000350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/07/2020] [Indexed: 11/11/2022]
Abstract
For luminescent materials, the isomerization and intermolecular reactions of their double bonds are often undesirable because they cause a reduction in the luminescence properties of the π-system. Herein, we report a new methodology to simultaneously prevent isomerization and intermolecular reactions by utilizing the steric effect of a linked rotaxane structure. The ring units are covalently linked in order to prevent any undesired shuttling effect from occurring during isomerization. In addition, the insulated structure provides robust optical properties by prevention of intermolecular reactions. Bulky linked rotaxane structures on both sides of the N=N and C=C double bonds suppress E/Z isomerization; photoluminescence quantum yield (PLQY) measurements reveal that this results in suppression of PLQY reduction caused by isomerization. Moreover, an improvement in the stability under light irradiation and air atmosphere is demonstrated.
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Mechanical switching of current-voltage characteristics in spiropyran single-molecule junctions. NANOSCALE 2020; 12:7527-7531. [PMID: 32219263 DOI: 10.1039/d0nr00277a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The electrical properties of a single-molecule junction of spiropyran are investigated through the break junction (BJ) method, and the current-voltage (I-V) characteristics are switched from rectified to symmetric through mechanical stimulus. This phenomenon indicates isomerization from spiropyran to merocyanine. In addition, an increase in the conductance associated with isomerization is observed.
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Synthesis of Insulated Heteroaromatic Platinum-Acetylide Complexes with Color-Tunable Phosphorescence in Solution and Solid States. J Org Chem 2020; 85:3082-3091. [PMID: 31965802 DOI: 10.1021/acs.joc.9b02967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phosphorescence colors of cyclodextrin-based insulated Pt-acetylide complexes were tuned by the molecular engineering of the chromophores. A series of Pt complexes bearing various acetylide ligands, including heteroaromatics, were prepared via self-inclusion of the linked macrocycles with the complexes. The decline in the inclusion efficiency derived from the heteroaromatics was overcome by the late-stage insulation via intramolecular slippage after the construction of the Pt-acetylide complexes. The cyclic protection of the thus-formed complexes prevented phosphorescence quenching via molecular interactions, even in the solid state. Accordingly, the tuned emission colors in a dilute system were replicated in the solid state.
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Macroscopic Change in Luminescent Color by Thermally Driven Sliding Motion in [3]Rotaxanes. Chemistry 2020; 26:3385-3389. [PMID: 31867786 DOI: 10.1002/chem.201905342] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Indexed: 12/18/2022]
Abstract
Systematic investigation of rotaxane structures has revealed a rational design for thermally driven switching of their macroscopic properties. At low temperature, the luminophore is insulated by the macrocycles and displays monomer emission, whereas at high temperature, the luminophore is exposed owing to a change in the macrocyclic location distribution and interacts with external molecules, affording a thermally driven luminescent color change with high reversibility and responsiveness. This macroscopic switching through efficient thermal sliding was made possible by appropriate tuning of both the macrocycle-luminophore interactions within the rotaxane and the coupling between the excited luminophore and external molecules in an exciplex. The ability to switch properties by a simple and clean thermal stimuli should expand the utilization of rotaxanes as components of thermally driven molecular systems.
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Insulated conjugated bimetallopolymer with sigmoidal response by dual self-controlling system as a biomimetic material. Nat Commun 2020; 11:408. [PMID: 31964865 PMCID: PMC6972936 DOI: 10.1038/s41467-019-14271-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/27/2019] [Indexed: 12/13/2022] Open
Abstract
Biological systems are known to spontaneously adjust the functioning of neurotransmitters, ion channels, and the immune system, being promoted or regulated through allosteric effects or inhibitors, affording non-linear responses to external stimuli. Here we report that an insulated conjugated bimetallopolymer, in which Ru(II) and Pt(II) complexes are mutually connected with insulated conjugations, exhibits phosphorescence in response to CO gas. The net profile corresponds to a sigmoidal response with a dual self-controlling system, where drastic changes were exhibited at two threshold concentrations. The first threshold for activation of the system is triggered by the depolymerization of the non-radiative conjugated polymer to luminescent monomers, while the second one for regulation is triggered by the switch in the rate-determining step of the Ru complex. Such a molecular design with cooperative multiple transition metals would provide routes for the development of higher-ordered artificial molecular systems bearing bioinspired responses with autonomous modulation.
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Synthetic Methodology for Structurally Defined and Insulated Molecular Wires Bearing Non-centrosymmetric Conjugated Axle Components via Iterative Intramolecular Slippage. Chem Asian J 2019; 14:1667-1671. [PMID: 30537351 DOI: 10.1002/asia.201801706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/06/2018] [Indexed: 11/07/2022]
Abstract
Insulated molecular wires (IMWs) bearing non-centrosymmetric conjugated axle components were precisely synthesized via iterative cross-coupling reactions in organic solvents and subsequent intramolecular slippage transformation in aqueous solvents. This programmable synthetic procedure selectively afforded both insulated and uninsulated molecular wires bearing oligo(phenylene ethynylene) and permethylated α-cyclodextrins with well-defined conjugation lengths and supramolecular structures. High selectivity of this method was confirmed by NMR and mass spectroscopic analyses. The resultant IMWs exhibited distinct optical properties because of different conjugation lengths and insulated structures. This synthetic strategy for structurally defined IMWs bearing non-centrosymmetric conjugated axle components could provide a platform for obtaining diverse functionalized materials useful in the fields of non-centrosymmetric molecular machines and molecular electronics.
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Rational Method of Monitoring Molecular Transformations on Metal-Oxide Nanowire Surfaces. NANO LETTERS 2019; 19:2443-2449. [PMID: 30888179 DOI: 10.1021/acs.nanolett.8b05180] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Metal-oxide nanowires have demonstrated excellent capability in the electrical detection of various molecules based on their material robustness in liquid and air environments. Although the surface structure of the nanowires essentially determines their interaction with adsorbed molecules, understanding the correlation between an oxide nanowire surface and an adsorbed molecule is still a major challenge. Herein, we propose a rational methodology to obtain this information for low-density molecules adsorbed on metal oxide nanowire surfaces by employing infrared p-polarized multiple-angle incidence resolution spectroscopy and temperature-programmed desorption/gas chromatography-mass spectrometry. As a model system, we studied the surface chemical transformation of an aldehyde (nonanal, a cancer biomarker in breath) on single-crystalline ZnO nanowires. We found that a slight surface reconstruction, induced by the thermal pretreatment, determines the surface chemical reactivity of nonanal. The present results show that the observed surface reaction trend can be interpreted in terms of the density of Zn ions exposed on the nanowire surface and of their corresponding spatial arrangement on the surface, which promotes the reaction between neighboring adsorbed molecules. The proposed methodology will support a better understanding of complex molecular transformations on various nanostructured metal-oxide surfaces.
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Synthesis and Acid-Responsiveness of an Insulated π-Conjugated Polymer Containing Spiropyrans in Its Backbone. Molecules 2019; 24:molecules24071301. [PMID: 30987095 PMCID: PMC6480293 DOI: 10.3390/molecules24071301] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 03/29/2019] [Accepted: 04/01/2019] [Indexed: 11/18/2022] Open
Abstract
A π-conjugated polymer containing spiropyrans (SPs), which could be almost completely converted to protonated merocyanines (MCH+) and back to the SP form by adding an acid and a base, respectively, was developed. The insulation of the π-conjugated polymer, referred to as insulated spiropyran-containing poly(p-phenylene ethynylene) (ins-SP-PPE), using permethylated α-cyclodextrins (PM α-CD) suppressed the π-π interaction between the polymer chains containing MCH+, and the installation of PM α-CD improved the switching ability of SPs. The polymer exhibited repeatable acidochromism with almost complete conversion between the SP and MCH+ forms. Photoluminescence measurements were conducted and the acid-induced luminescence quenching of the polymer in the solution was observed, which stemmed from energy transfer from the PPE to MCH+ moieties. In the solid state, the quantum yield of ins-SP-PPE was more than twice that of the uninsulated polymer, which derived from the insulation effects. The acid-induced luminescence quenching was also observed in the solid state.
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Synthetic Methodologies for Structurally Defined Linked-[n]Rotaxanes with Permethylated Cyclodextrins: Platform for Functionalized Molecular Electronics. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2019. [DOI: 10.1246/bcsj.20180349] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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31
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Luminescent and mechanical enhancement of phosphorescent hydrogel through cyclic insulation of platinum-acetylide crosslinker. Polym Chem 2019. [DOI: 10.1039/c9py00700h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An insulated Pt-acetylide complex was incorporated into a polymer network as a crosslinker to afford a phosphorescent gel.
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Two-step template method for synthesis of axis-length-controlled porphyrin-containing hollow structures. Chem Commun (Camb) 2019; 55:6755-6758. [DOI: 10.1039/c9cc02866h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
π-Conjugated porphyrin-containing hollow structures with defined axis-length were successfully synthesized by a two-step template method, i.e., template-assisted cyclization and oligomerization.
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Copper-Catalyzed [4+2] Cycloaddition Using N
-(2-Pyridyl)ketimines and Terminal Alkynes. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201800704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Kinetic stabilization of a Ni(ii) bis(dithiobenzoate)-type complex achieved using three-dimensional insulation by a [1]rotaxane structure. Chem Commun (Camb) 2018; 54:2487-2490. [PMID: 29441397 DOI: 10.1039/c8cc00351c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We describe herein the synthesis of a Ni(ii) bis(dithiobenzoate)-type complex three-dimensionally insulated by a [1]rotaxane structure to reveal the importance of the insulation. Under cyclic voltammetry conditions, the complex showed a stable and reversible redox behavior in contrast to a non-insulated reference complex, clearly demonstrating the effectiveness of the rotaxane-type insulation as a new method of kinetic metal complex stabilization.
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Synthesis and Characterization of Carboxylic Acids Bearing
Poly(ethylene glycol) Chains. Synlett 2017. [DOI: 10.1055/s-0036-1591840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Carboxylic acids 1a and 1b bearing three poly(ethylene glycol) (PEG) chains and carboxylic acid 1c bearing one PEG chain were designed and synthesized. The carboxylic acids 1a–c were fully characterized by NMR and ESI-HRMS analyses. In a Pd-catalyzed aerobic oxidation of 1-phenylethanol, 1a and 1b worked well as carboxylate ligands.
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Cover Feature: Programmed Synthesis of Molecular Wires with Fixed Insulation and Defined Length Based on Oligo(phenylene ethynylene) and Permethylated α-Cyclodextrins (Chem. Eur. J. 60/2017). Chemistry 2017. [DOI: 10.1002/chem.201703958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Thieme Chemistry Journals Awardees – Where Are They Now? Synthesis of a Dinuclear Copper NHC Complex Bearing a Rigid π-Conjugated Cyclic Framework. Synlett 2017. [DOI: 10.1055/s-0036-1588824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Macrocyclic dinuclear complexes have been gaining popularity in the design of homogeneous catalysts. Herein, we report the design of such a complex featuring catalytically active sites fixed inside the ring and its synthesis using a cross-coupling reaction.
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Programmed Synthesis of Molecular Wires with Fixed Insulation and Defined Length Based on Oligo(phenylene ethynylene) and Permethylated α-Cyclodextrins. Chemistry 2017; 23:15073-15079. [DOI: 10.1002/chem.201701428] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Indexed: 12/24/2022]
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Hetero Face-to-Face Porphyrin Array with Cooperative Effects of Coordination and Host-Guest Complexation. Chem Asian J 2017; 12:1900-1904. [DOI: 10.1002/asia.201700738] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Indexed: 11/08/2022]
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Regio- and Stereoselective Synthesis of Triarylalkene-Capped Rotaxanes via Palladium-Catalyzed Tandem Sonogashira/Hydroaryl Reaction of Terminal Alkynes. J Org Chem 2017; 82:5449-5455. [DOI: 10.1021/acs.joc.7b00442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Back Cover: Boraformylation and Silaformylation of Allenes (Angew. Chem. Int. Ed. 6/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/anie.201700328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rücktitelbild: Boraformylation and Silaformylation of Allenes (Angew. Chem. 6/2017). Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
The boraformylation of allenes with B2 (pin)2 and a formate ester as boron and formyl source, respectively, proceeds in the presence of a copper catalyst. The reaction selectively affords the corresponding β-boryl β,γ-unsaturated aldehydes in good to high yields. Furthermore, the silaformylation of allenes was achieved with a formate ester and PhMe2 Si-B(pin) as the silicon source.
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Copper-catalyzed hydroallylation of allenes employing hydrosilanes and allyl chlorides. Chem Commun (Camb) 2017; 53:7898-7900. [PMID: 28513657 DOI: 10.1039/c7cc02816d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The hydroallylation of allenes was developed by employing a hydrosilane and allyl chlorides in the presence of a copper catalyst.
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Titelbild: A Typical Metal-Ion-Responsive Color-Tunable Emitting Insulated π-Conjugated Polymer Film (Angew. Chem. 43/2016). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Cover Picture: A Typical Metal-Ion-Responsive Color-Tunable Emitting Insulated π-Conjugated Polymer Film (Angew. Chem. Int. Ed. 43/2016). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/anie.201608031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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