A Lockable Light‐Driven Molecular Shuttle with a Fluorescent Signal

Wang, Qiao‐Chun; Qu, Da‐Hui; Ren, Jun; Chen, Kongchang; Tian, He

doi:10.1002/ange.200453708

Cited by 57 publications

(40 citation statements)

References 30 publications

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“…When the a-CD macrocycle is located near a fluorescent stopper, the vibrations and rotations of the methylene bonds between the stopper and the recognition site are hindered which leads to an increase in the fluorescence intensity of the stopper. [10] This was also confirmed by the weaker fluorescence observed for the lone dumbbell 2, for which vibrations and rotations are relatively facile in the absence of the macrocycle. [14] Because of the total reversibility of the photoisomerization processes, the photoinduced shuttling motions of the a-CD ring on the dumbbell could be repeated and monitored by means of the reversible fluorescent output signals.…”

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A Half Adder Based on a Photochemically Driven [2]Rotaxane

2005

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A Half Adder Based on a Photochemically Driven [2]Rotaxane

2005

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“…The uses of such supramolecular systems add attractive features to the construction of advanced nanoscale molecular machinery because of their potential to undergo controllable intramolecular complexation in response to a particular stimulus.Of these self-assembling systems, secondary dialkylammonium ions (R 2 NH 2 + ) are well-known for their ability to thread through, for example, a dibenzo [24] [6] have combined both the dibenzo[24]crown-8 and dialkylammonium ion structural motifs into a single system, most of these feature versatile intermolecular complexation rather than unique intramolecular self-complexation.Herein we report the design, characterization, and operation of a lockable [7] light-driven molecular rotary motor featuring a self-complexing [1]pseudorotaxane system. By taking advantage of the complexation between the R 2 NH 2 + and the DB24C8 units in the system, acid-basecontrolled threading-dethreading movements can be utilized to unlock or lock the molecular rotary motor.…”

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Controlling Molecular Rotary Motion with a Self‐Complexing Lock

Feringa

2010

Angew Chem Int Ed

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Biological motors, such as the kinesin or myosin linear and ATPase rotary motor systems, [1] have been a source of inspiration for the development of a variety of artificial molecular mechanical devices [2] (including switches, shuttles, muscles, and rotors) and of elegant molecular motor systems.[3] Selfcomplexing and self-assembling systems [4] represent important dynamic compounds that play a prominent role in the field of molecular recognition and molecular devices. The uses of such supramolecular systems add attractive features to the construction of advanced nanoscale molecular machinery because of their potential to undergo controllable intramolecular complexation in response to a particular stimulus.Of these self-assembling systems, secondary dialkylammonium ions (R 2 NH 2 + ) are well-known for their ability to thread through, for example, a dibenzo [24] [6] have combined both the dibenzo[24]crown-8 and dialkylammonium ion structural motifs into a single system, most of these feature versatile intermolecular complexation rather than unique intramolecular self-complexation.Herein we report the design, characterization, and operation of a lockable [7] light-driven molecular rotary motor featuring a self-complexing [1]pseudorotaxane system. By taking advantage of the complexation between the R 2 NH 2 + and the DB24C8 units in the system, acid-basecontrolled threading-dethreading movements can be utilized to unlock or lock the molecular rotary motor. The design of the molecular system with a self-complexing lock is illustrated in Scheme 1. The molecular system cis-1-H·PF 6 is composed of 1) a second-generation light-driven molecular motor [8][9][10] based on an overcrowded alkene, in which the molecular rotor (2,6-dioxonaphthalene, upper half) rotates 3608 relative to the stator (xanthene, lower half) upon repetitive photochemical trans-cis isomerizations and subsequent thermal irreversible helix inversion steps, 2) a DB24C8 macrocyclic ring incorporated into the xanthene lower stator half, which can act as a socket for the dialkylammonium moiety, and 3) a R 2 NH 2 + moiety attached to the upper rotor half by a short spacer, which can insert itself as a plug into the DB24C8 macrocycle socket. The free OH group at the end of the arm can be easily functionalized to construct interlocked rotaxanes. cis-1-H·PF 6 was prepared in 20 steps (Schemes S1-S4 in the Supporting Information) and characterized by 1 H and 13 C NMR spectroscopy and high-resolution mass spectrometry. [11] The 1 H NMR spectrum (500 MHz, 298 K) of the hexafluorophosphate salt cis-1-H·PF 6 (Figure 1 a), recorded in [D 6 ]DMSO, has similar splitting patterns as the spectrum of the unprotonated cis-1 in CD 2 Cl 2 (Figure 1 b), [6a] which can be rationalized by attributing it to the uncomplexed species, that is, the dialkylammonium ion does not reside inside the DB24C8 cavity.[6c] A more complicated 1 H NMR spectrum of cis-1-H·PF 6 was obtained in CD 2 Cl 2 (Figure 1 c), as is evident in the region d = 3.5-4.4 ppm corresponding to the resonanc...

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“…It is rather inconvenient to transform these spectral signals into easily detected output codes. Use of a change in fluorescence [18,19] as an output is an attractive approach because the fluorescent signal readily allows remote reading and is typically lowcost. However, reports on rotaxanes that switch between different fluorescent states (output) in response to light inputs are still rare.…”

Section: Introductionmentioning

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“…However, reports on rotaxanes that switch between different fluorescent states (output) in response to light inputs are still rare. [18,19] It is well known that cyclodextrins (CDs) form host-guest complexes. Many cyclodextrin-based catenanes, rotaxanes, and polyrotaxanes have been synthesized.…”

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confidence: 99%

“…Many cyclodextrin-based catenanes, rotaxanes, and polyrotaxanes have been synthesized. [2,5,8,12,15,18,[20][21][22] H NMR spectroscopy and by two-dimensional NMR spectroscopy. The light stimuli can induce shuttling motions of the two a-CD macrocycles on the molecular thread; concomitantly, the absorption and fluorescence spectra of the [3]rotaxane change in a regular way.…”

Section: Introductionmentioning

confidence: 99%

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A [3]Rotaxane with Three Stable States That Responds to Multiple‐Inputs and Displays Dual Fluorescence Addresses

Wang

et al. 2005

Chemistry A European J

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A [3]rotaxane molecular shuttle containing two alpha-cyclodextrin (alpha-CD) macrocycles, an azobenzene unit, a stilbene unit, and two different fluorescent naphthalimide units has been investigated. The azobenzene unit and the stilbene unit can be E/Z-photoisomerized separately by light excited at different wavelengths. Irradiation at 380 nm resulted in the photoisomerization of the azobenzene unit, leading to the formation of one stable state of the [3]rotaxane (Z1-NNAS-2CD); irradiation at 313 nm resulted in the photoisomerization of the stilbene unit, leading to the formation of another stable state of the [3]rotaxane (Z2-NNAS-2CD). The reversible conversion of the Z1 and Z2 isomers back to the E isomer by irradiation at 450 nm and 280 nm, respectively, is accompanied by recovery of the absorption and fluorescence spectra of the [3]rotaxane. The E isomer and the two Z isomers have been characterized by 1H NMR spectroscopy and by two-dimensional NMR spectroscopy. The light stimuli can induce shuttling motions of the two alpha-CD macrocycles on the molecular thread; concomitantly, the absorption and fluorescence spectra of the [3]rotaxane change in a regular way. When the alpha-CD macrocycle stays close to the fluorescent moiety, the fluorescence of the moiety become stronger due to the rigidity of the alpha-CD ring. As the photoisomerization processes are fully reversible, the photo-induced shuttling motions of the alpha-CD rings can be repeated, accompanied by dual reversible fluorescence signal outputs. The potential application of such light-induced mechanical motions at the molecular level could provide some insight into the workings of a molecular machine with entirely optical signals, and could provide a cheap, convenient interface for communication between micro- and macroworlds.

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A Lockable Light‐Driven Molecular Shuttle with a Fluorescent Signal

Cited by 57 publications

References 30 publications

A Half Adder Based on a Photochemically Driven [2]Rotaxane

A Half Adder Based on a Photochemically Driven [2]Rotaxane

Controlling Molecular Rotary Motion with a Self‐Complexing Lock

A [3]Rotaxane with Three Stable States That Responds to Multiple‐Inputs and Displays Dual Fluorescence Addresses

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