Coupled molecular motions driven by light or chemical inputs: spiropyran to merocyanine isomerisation followed by pseudorotaxane formation

Hernández-Melo, Denhy; Tiburcio, Jorge

doi:10.1039/c5cc07056b

Cited by 11 publications

(9 citation statements)

References 47 publications

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“…The Klajn group and the Mukeherjee group reported that positively‐charged coordinated cages can stabilize the merocyanine isomer in water under room light. Crown ether, sulfonatocalixarene, and cucurbit[n]urils show binding preference to the positively charged region of the merocyanine isomer and thus stabilize this isomer. Cyclodextrins and octa acid capsules prefer the neutral spiro isomer.…”

Section: Figurementioning

confidence: 99%

Stabilization of the Closed‐Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked‐Eye Detection of Toxic Paraoxon

et al. 2020

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The thermodynamically unstable, colourless closed-ring isomer of spiropyran can be stabilized in water by the anti-configurational isomer of amide naphthotube. The influence of the binding on the thermodynamics and kinetics of spiropyran have been studied. The complex was further used to prepare a test paper that allows naked-eye detection of toxic paraoxon. Photoswitchable molecules, such as azobenzene, spiropyran, and diarylethene, have recently received increasing attention due to their applications in photoresponsive materials, molecular machines and devices, molecules sensing and other fields .[1] Among these molecules, spiropyran [2] is unique because of their rich responsive properties. For example, the closed-ring spiro isomer (2-SP in Figure 1a) of spiropyran is colourless, while the open-ring merocyanine isomer (2-MC) possesses a large π conjugated system and absorbs visible light. These two isomers can be interconverted by UV/visible light or heating. Thermodynamic stability of the two isomers largely depends on the environment. [2] In organic solvents, the spiro isomer is more stable; on the hand, the merocyanine isomer is more stable in water presumably due to the extensive hydrogen bonds with surrounding water molecules. [3] However, majority of the merocyanine isomer can be photochemically converted into the spiro isomer under environment light, producing a far-fromequilibrium state with a mixture of both spiro and merocyanine isomers in water. In dark, the spiro isomer will gradually relax back to the merocyanine isomer which is thermodynamically more stable. Host-guest chemistry can be used to modulate the relative stability between the spiro and merocyanine isomers of spiropyran compounds in water. The Klajn group and the Mukeherjee group [4] reported that positively-charged coordi-[a] W.

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Section: Figurementioning

confidence: 99%

Stabilization of the Closed‐Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked‐Eye Detection of Toxic Paraoxon

et al. 2020

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“…The incorporation of SP switches in guest's scaffolds is widely documented in literature [22,23,24,25] . The main aim of this strategy resides in coupling the isomerization of the switch to the thermodynamic stability of the resulting supramolecular complexes.…”

Section: Introductionmentioning

confidence: 99%

“…The incorporation of SP switches in guest's scaffolds is widely documented in literature. [ 22 , 23 , 24 , 25 ] The main aim of this strategy resides in coupling the isomerization of the switch to the thermodynamic stability of the resulting supramolecular complexes. In contrast, the number of examples describing the incorporation of SP units into the structures of host molecules is less frequent.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen‐Bonded Dimeric Capsules with Appended Spiropyran Units: Towards Controlled Cargo Release

Ferreira

Moncelsi

Aragay

et al. 2021

Chemistry A European J

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We report the synthesis of unprecedented tetraurea derivatives of calix [4]arene and calix [4]pyrrole containing four spiropyran (SP) units at their upper rim. We investigate the photo-and acid-induced isomerization of the monomeric and homo-dimeric tetra-ureas derivatives using UV-Vis and 1 H NMR spectroscopies. At micromolar concentration, irradiation of the samples with 365 nm light induces changes in their absorption spectra that are consistent with SP!merocyanine (MC) isomerization. However, analogous experiments at millimolar concentration do not produce noticeable changes in the 1 H NMR spectra. The addition of triflic acid to micromolar and millimolar solutions of the tetra-ureas produces the quantitative isomerization of the SP units to the protonated merocyanine form (E-MCH + ) and the simultaneous disassembly of the capsular dimers to form ill-defined aggregates. The neutralization of the acid solutions resets the SP form. Under these acid/base treatment conditions, the controlled release of the included guest and the reassembly of the all-SP tetra-urea dimers occurs at different extents depending on its calix[4]arene or calix[4]pyrrole scaffold.

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“…Photochromism – the reversible interconversion of a molecule, with at least one of the reactions being induced by absorption of light, between two forms having different absorption spectra4 – has been thoroughly investigated since the 1980s and become a key component of the supramolecular chemist toolbox. The prominent changes in structure and properties associated with photoisomerization have been exploited to control threading,5 self-assembly processes,6 and non-equilibrium behavior7 in [2]pseudorotaxanes, and molecular movements (shuttling, rotation),8 surface properties,9 catalysis10 and reactivity 11…”

Section: Introductionmentioning

confidence: 99%

Threading-gated photochromism in [2]pseudorotaxanes

et al. 2019

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Coupled molecular motions driven by light or chemical inputs: spiropyran to merocyanine isomerisation followed by pseudorotaxane formation

Cited by 11 publications

References 47 publications

Stabilization of the Closed‐Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked‐Eye Detection of Toxic Paraoxon

Stabilization of the Closed‐Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked‐Eye Detection of Toxic Paraoxon

Hydrogen‐Bonded Dimeric Capsules with Appended Spiropyran Units: Towards Controlled Cargo Release

Threading-gated photochromism in [2]pseudorotaxanes

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