Conformer-dependent self-assembled metallacycles with photo-reversible response

Li, Mengqi; Chen, Li Jun; Zhang, Zhipeng; Luo, Qianfu; Yang, Hai‐Bo; Tian, He; Zhu, Weihong

doi:10.1039/c9sc00757a

Cited by 24 publications

(20 citation statements)

References 61 publications

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“…[19] Meanwhile, the signals of H l of the thiophene rings show upfield shifts, which is due to the loss of aromaticity of the thiophene rings after the photocyclization reaction. [20] Similar changes in the 31 PNMR spectra resulted from structural transformationw ere also observed. After irradiation with UV light for 200 min, the originalp eak at 15.88 ppm for o-M-F disappeared almost completely anda new peak at 15.75 ppm, which was identicalt ot hat of the c-M-F,w as identified (Figure 2B).…”

Section: Photochromism and Fluorescence Of The Supramolecular Metallacyclessupporting

confidence: 54%

“…As shown in Figure 2 A, upon UV irradiation ( λ =313±20 nm) of o ‐M‐F , signals at 8.55 and 8.47 ppm, which are attributed to protons on the pyridine unit in the open‐form of the metallacycle, gradually disappeared while new peaks in the downfield area (8.71 ppm), which are related to protons of c ‐M‐F , appeared in the 1 H NMR spectrum [19] . Meanwhile, the signals of H l of the thiophene rings show upfield shifts, which is due to the loss of aromaticity of the thiophene rings after the photocyclization reaction [20] . Similar changes in the 31 P NMR spectra resulted from structural transformation were also observed.…”

Section: Resultsmentioning

confidence: 99%

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Photoswitchable Fluorescent Self‐Assembled Metallacycles with High Photostability

Chen

Cai

et al. 2021

Chemistry A European J

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In this study, photoswitchable fluorescent supramolecular metallacycles with high fatigue‐resistance have been constructed by coordination‐driven self‐assembly by using bithienylethene with dipyridyl units (BTE) as a coordination donor and a fluorescent di‐platinum(II) (Pt‐F) as a coordination acceptor. The photo‐triggered reversible transformation between the ring‐open and ring‐closed form of the metallacycles was confirmed by 1H NMR, 31P NMR, and UV/Vis spectroscopy. This unique property enabled a reversible noninvasive “off–on” switching of fluorescence through efficient Förster resonance energy transfer (FRET). Importantly, the metallacycles remained structurally intact after up to 10 photoswitching cycles. The photoresponsive property and exceptional photostability of the metallacycles posit their potential promising application in optical switching, image storage, and super‐resolution microscopy.

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Section: Photochromism and Fluorescence Of The Supramolecular Metallacyclessupporting

confidence: 54%

Section: Resultsmentioning

confidence: 99%

Photoswitchable Fluorescent Self‐Assembled Metallacycles with High Photostability

Chen

Cai

et al. 2021

Chemistry A European J

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“… 8 , 10 , 36 , 37 Similar systems have been applied to control the topology of supramolecular gels 38 and to tune the emission properties of Eu 2 L 4 helicates 39 or have been implemented in Pt-based metallacycles to trigger structural rearrangements or photochromic properties. 25 , 40 …”

Section: Introductionmentioning

confidence: 99%

Light-Powered Dissipative Assembly of Diazocine Coordination Cages

et al. 2022

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Stimuli-responsive coordination cages allow reversible control over guest binding and release, relevant for adaptive receptors, carriers, catalysts, and complex systems. Light serves as an advantageous stimulus, as it can be applied with precise spatial and temporal resolution without producing chemical waste products. We report the first Pd-mediated coordination cage based on ligands embedding a diazocine photoswitch. While the thermodynamically more stable cis -photoisomer sloppily assembles to a mixture of species with general formula [Pd n cis -L 2 n ], the less stable trans -isomer yields a defined [Pd 2 trans -L 4 ] cage that reversibly converts back to the cis -system by irradiation at 530 nm or thermal relaxation. The [Pd n cis -L 2 n ] species do not bind a given guest; however, [Pd 2 trans -L 4 ] is able to encapsulate a bis-sulfonate as long as it is kept assembled, requiring continuous irradiation at 385 nm. In the absence of UV light, thermal relaxation results in back-switching and guest release. Assembly and properties of the system were characterized by a combination of NMR, ion mobility ESI-MS, single-crystal X-ray diffraction, and UV–vis absorption studies.

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“…[[12c] Complexes formed by platinum and DAE have thus attracted much attention. Zhu et al [129] reported a series of DAE-containing, photoactive, conformer-dependent metallacycles and explored their self-assembly behavior between ligands with different conformations and di-platinum(II) acceptors. Through coordination-driven self-assembly, reversible switching of the DAE donor building blocks between the antiparallel (ap-) and parallel (p-) configurations precisely adjusted the sizes and shapes of the photoswitchable scaffold.…”

Section: Metal Complexes Containing Daementioning

confidence: 99%

Future‐Oriented Advanced Diarylethene Photoswitches: From Molecular Design to Spontaneous Assembly Systems

et al. 2022

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cycloreversion of DAE under light irradiation produces many exciting functional effects, such as changes in photophysical and photochemical properties, [12] changes in the shape or mechanical properties of the solid, [13] electrical conductivity, [7b,14] and the generation of reactive oxygen species (ROS). [15] This type of photochromic compound can be considered a stilbene derivative. At this time, the most widely known and systematically studied DAE derivative structure contains two aryl groups and a benzene ring (usually two identical or different thiophene units with low aromatic stabilization energy [16] ) and a five-membered ring of perfluorocyclopentene and cyclopentene units [17] where the ethene bridge is located, which significantly improve photochromism. [18] In essence, the DAE photoisomerization process is a reversible electrocyclic reaction of the central 6π-electron systems. [2] Under light irradiation, DAE can rapidly and reversibly transform between its open and closed forms, and that transformation is accompanied by a color change caused by a change in the π-conjugation distribution. [2] The important thing is that the colorless opened-and colored closed-ring isomers are both thermally stable; that is, cyclization and cycloreversion do not proceed spontaneously in the dark; they need to be driven by external light irradiation at specific wavelengths. [2,19] Compared with classic lightresponsive molecules such as azobenzene, [20] the light intensity required to drive the isomerization of DAE is relatively low. Moreover, even after multiple cycles, the photochromic performance does not show significant fatigue in either the solution or solid state. [2,18b,21] DAE research to this point can be roughly divided into three stages in chronological order: early exploration of DAE's molecular structure and theory, nearly two decades of purpose-oriented molecular structure modification research, and about ten years of research into practical applications of DAE in assembly systems. Research before about 2000 focused mainly on developing more abundant DAE-derivative structures and advancing the systematic understanding of DAE's physical and chemical properties and switching performance. To regulate its switching performance and give it new functionality, many strategies for modifying the ethene bridge and aryl groups of DAE have been proposed. [22] In the first two research stages, the mechanisms and structural modification of DAE isomerization were thoroughly and systematically explored, and countless important Diarylethene (DAE) photoswitch is a new and promising family of photochromic molecules and has shown superior performance as a smart trigger in stimulus-responsive materials. During the past few decades, the DAE family has achieved a leap from simple molecules to functional molecules and developed toward validity as a universal switching building block. In recent years, the introduction of DAE into an assembly system has been an attractive strategy that enables the photochromic behavior of the b...

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Conformer-dependent self-assembled metallacycles with photo-reversible response

Abstract: The scaffold sizes and shapes of a series of photoswitchable metallacycles are precisely controlled by the conformer of photoresponsive units.

Cited by 24 publications

References 61 publications

Photoswitchable Fluorescent Self‐Assembled Metallacycles with High Photostability

Photoswitchable Fluorescent Self‐Assembled Metallacycles with High Photostability

Light-Powered Dissipative Assembly of Diazocine Coordination Cages

Future‐Oriented Advanced Diarylethene Photoswitches: From Molecular Design to Spontaneous Assembly Systems

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