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Pengyu Li, Qianfang Yao, Baozhong Lü, Guiping Ma, Meizhen Yin
A photoresponsive host-guest supramolecular complex (WP5⊃G) constructed by water-soluble pillar[5]arene (WP5) and spiropyran derivative (G) is presented. The spontaneous isomerization of G from spiropyran (SP) form to ring-opened merocyanine (MC) form happens either alone or in WP5⊃G in aqueous media. Irradiated by visible light, G can be converted into SP form completely and the hydrophilicity will be changed. G and WP5⊃G are both verified to self-assemble into nanospheres. Upon exposure to visible light, WP5⊃G reassemble into nanovesicles due to the change of supra-amphiphilicity, while G alone does not have this transition...
May 22, 2018: Macromolecular Rapid Communications
Lixia Cui, Honghong Zhang, Guomei Zhang, Ying Zhou, Li Fan, Lihong Shi, Caihong Zhang, Shaomin Shuang, Chuan Dong
Spiropyran compounds are well known as an isomeric system, the closed spiropyran (SP) could be converted into the open merocyanine (MC) via acid-induced because stable protonated merocyanine (MCH) were formed by combination of MC and H+ . In order to understand how the substituent affect the isomerization of spiropyran. A series of the chromene 7-subsituted spiropyran compounds were designed and synthesized. The photophysical properties of them were studied comparatively by UV-absorption and fluorescence spectra in different pH...
May 16, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
H A Schwartz, U Ruschewitz, L Heinke
Smart, molecularly structured materials with remote-controllable properties and functionalities attract particular attention and may enable advanced applications. In this respect, the embedment of stimuli-responsive molecules, such as azobenzenes, spiropyrans or diarylethenes, in metal-organic frameworks (MOFs) is a very fascinating approach, resulting in easily accessible photoswitchable, nanoporous hybrid materials. It is an attractive alternative to the incorporation of the smart moieties in the MOF scaffold, which usually demands complex synthetic efforts...
May 8, 2018: Photochemical & Photobiological Sciences
Kei Sadakane, Mao Takaichi, Shinsaku Maruta
In this study, we synthesized a novel photochromic inhibitor of the mitotic kinesin Eg5, which is composed of the photochromic compound spiropyran in order to photo-control the function of Eg5. The compound (S)-2,3-dispiropyran propionic acid (DSPPA) exhibits reversible spiropyran-merocyanine photoisomerization upon irradiation with visible or ultra-violet light. DSPPA induced reversible changes in the inhibitory effect on Eg5 ATPase and motor activities, which correlates with the spiropyran-merocyanine photoisomerization...
April 26, 2018: Journal of Biochemistry
Francesca Cardano, Marco Frasconi, Silvia Giordani
Photo-responsive multifunctional nanomaterials are receiving considerable attention for biological applications because of their unique properties. The functionalization of the surface of carbon nanotubes (CNTs) and graphene, among other carbon based nanomaterials, with molecular switches that exhibit reversible transformations between two or more isomers in response to different kind of external stimuli, such as electromagnetic radiation, temperature and pH, has allowed the control of the optical and electrical properties of the nanomaterial...
2018: Frontiers in Chemistry
Supaporn Kwangmettatam, Tibor Kudernac
We present the design and synthesis of spiropyran-based dynamic vesicles, for which the building block is the amphiphilic merocyanine isomer. Under irradiation with visible light, the photo-conversion of the protonated and charged merocyanine to the neutral spiropyran form leads to the transient and reversible expansion of these vesicles.
April 17, 2018: Chemical Communications: Chem Comm
Dipak Samanta, Daria Galaktionova, Julius Gemen, Linda J W Shimon, Yael Diskin-Posner, Liat Avram, Petr Král, Rafal Klajn
The original version of this Article contained an error in Fig. 4c, in which the right-most chemical structure included an 'N+ ' rather than an 'N'. This has been corrected in both the PDF and HTML versions of the Article.
April 12, 2018: Nature Communications
Aishling Dunne, Colm Delaney, Aoife McKeon, Pavel Nesterenko, Brett Paull, Fernando Benito-Lopez, Dermot Diamond, Larisa Florea
Micro-capillaries, capable of light-regulated binding and qualitative detection of divalent metal ions in continuous flow, have been realised through functionalisation with spiropyran photochromic brush-type coatings. Upon irradiation with UV light, the coating switches from the passive non-binding spiropyran form to the active merocyanine form, which binds different divalent metal ions (Zn2+ , Co2+ , Cu2+ , Ni2+ , Cd2+ ), as they pass through the micro-capillary. Furthermore, the merocyanine visible absorbance spectrum changes upon metal ion binding, enabling the ion uptake to be detected optically...
April 4, 2018: Sensors
Leixiao Yu, Christoph Schlaich, Yong Hou, Jianguang Zhang, Paul-Ludwig Michael Noeske, Rainer Haag
Dynamic regulation of the interactions between specific molecules on functional surfaces and biomolecules, e.g., proteins or cells, is critical for biosensor and biomedical devices. Herein, we present a spiropyran (SP) based light responsive surface coating, hPG (hyperbranched polygerol) -SP, to control the adsorption of proteins and adhesion of cells. In the normal state, the SP groups on the coating surface were in hydrophobic ring-closed form, which promote the nonspecific protein adsorption and cell adhesion...
March 26, 2018: Chemistry: a European Journal
Amandine Boulmier, Antoine Vacher, Dejin Zang, Shu Yang, Ali Saad, Jérôme Marrot, Olivier Oms, Pierre Mialane, Isabelle Ledoux, Laurent Ruhlmann, Dominique Lorcy, Anne Dolbecq
Three polyoxometalates (POMs) functionalized by tetrathiafulvalene (TTF) molecules have been synthesized by a coupling reaction between the Anderson-type POMs [MnMo6 O18 {(OCH2 )3 CNH2 }2 ]3- or [AlMo6 O18 (OH)3 {(OCH2 )3 CNH2 }]3- and the TTF carboxylic acid derivative (MeS)3 TTF(S-CH2 -CO2 H). The monofunctionalized TTF-AlMo6 POM contains one TTF group covalently grafted on an Al Anderson platform. The symmetrical TTF-MnMo6 -TTF POM possesses two TTF groups grafted on each side of a Mn Anderson derivative while the asymmetrical TTF-MnMo6 -SP POM contains a TTF and a spiropyran groups...
March 22, 2018: Inorganic Chemistry
Paula P Campos, Aishling Dunne, Colm Delaney, Cara Moloney, Simon E Moulton, Fernando Benito-Lopez, Marystela Ferreira, Dermot Diamond, Larisa Florea
Herein, we present the synthesis of linear photochromic norbornene polymers bearing spiropyran side groups (poly(SP-R)), and their assembly into LbL films on glass substrates when converted to the poly(MC-R) under UV irradiation. The LbL films were composed of bilayers of poly(allylamine hydrochloride) (PAH) and poly(MC-R), forming (PAH/poly(MC-R))n coatings. The MC form presents a significant absorption band in the visible spectral region which allowed the LbL deposition process to be tracked by UV-Vis spectroscopy, showing a linear increase of the characteristic MC absorbance band with increased number of bilayers...
March 19, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Kenji Kinashi, Takato Iwata, Hayato Tsuchida, Wataru Sakai, Naoto Tsutsumi
Polystyrene (PS)-based composite microfibers combined with a photochromic spiropyran dye, 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (6-nitro BIPS), and a photostimulable phosphor, europium-doped barium fluorochloride (BaFCl:Eu2+ ), were developed for the detection of X-ray exposure doses on the order of approximately 1 Gy. To produce the PS-based composite microfibers, we employed a forcespinning method that embeds a high concentration of the phosphor in the PS in a safe, inexpensive, and simple procedure...
March 19, 2018: ACS Applied Materials & Interfaces
Yuwei Hao, Hongliang Liu, Guannan Li, Haijun Cui, Lei Jiang, Shutao Wang
To overcome the low efficiency of single-responsive smart surfaces, we have constructed a dual-responsive smart surface - poly(spiropyran-co-N-isopropylacrylamide) (poly(SP-co-NiPAAm))-grafted silicon nanowire arrays - by combining photo-responsive SP and thermo-responsive NiPAAm units for enhancing the efficiencies of cancer-cell capture and release. These enhanced efficiencies probably originate from the binary cooperative effect of two responsive building units: NiPAAm units can decrease the steric hindrance between SP units during the isomerization while SP units can facilitate phase transition of NiPAAm units...
March 15, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Tetsuo Yamaguchi, Ayan Maity, Vivek Polshettiwar, Makoto Ogawa
A colored hybrid based on a merocyanine adsorbed in a nanoporous-silica-composed dendritic fibrous silica was prepared by adsorption onto the nanoporous silica from a spiropyran solution during UV irradiation (photoinduced adsorption). The obtained red hybrid thus exhibited negative photochromism by visible-light irradiation. The hybrid was further combined with an organophilic clay by a solid-state mixing without using solvent to achieve excellent reversibility of the color change, which was thought to be achieved by molecular diffusion through the two materials, where nanoporous silica and organophilic clay accommodated the colored (merocyanine) and colorless (photogenerated spiropyran) isomers, respectively...
April 2, 2018: Inorganic Chemistry
M Crawford Andrews, Ping Peng, Amit Rajput, Anthony F Cozzolino
Carboxamidines functionalized with either a spiropyran or fulgimide photoswitch were prepared on multigram scales. The thermal, electrochemical, and photochemical ring isomerizations of these compounds were studied and the results compared with related systems. The photochemical isomerisations were found to be reversible and could be followed by 1H NMR and UV-vis spectroscopy. The spiropyran/merocyanine couple was thermally active and an activation enthalpy of 116 kJ mol-1 was measured for ring-opening. These measurements yielded an enthalpy difference of 25 kJ mol-1 between the open and closed states which is consistent with DFT calculations...
April 18, 2018: Photochemical & Photobiological Sciences
Pramila Selvanathan, Vincent Dorcet, Thierry Roisnel, Kévin Bernot, Gang Huang, Boris Le Guennic, Lucie Norel, Stéphane Rigaut
We report the synthesis of two lanthanide complexes including a chelating merocyanine (MC) ligand obtained from the reaction of a bis(pyridinemethyl)amine substituted spiropyran with yttrium(iii) or dysprosium(iii) triflate salts, whose structures were confirmed both in the solid state and in solution by single crystal X-ray diffraction studies and NMR investigations. The obtained merocyanine metal complexes can reversibly undergo a photo-triggered transformation consisting of a partial isomerization of the trans-merocyanine ligand to its cis isomer (cis-MC) providing complexes in which the metal-phenolate bond is retained...
March 28, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Rui Yan, Seonah Moon, Samuel J Kenny, Ke Xu
As an elegant integration of the spatial and temporal dimensions of single-molecule fluorescence, single-molecule localization microscopy (SMLM) overcomes the diffraction-limited resolution barrier of optical microscopy by localizing single molecules that stochastically switch between fluorescent and dark states over time. While this type of super-resolution microscopy (SRM) technique readily achieves remarkable spatial resolutions of ∼10 nm, it typically provides no spectral information. Meanwhile, current scanning-based single-location approaches for mapping the positions and spectra of single molecules are limited by low throughput and are difficult to apply to densely labeled (bio)samples...
March 20, 2018: Accounts of Chemical Research
Dipak Samanta, Daria Galaktionova, Julius Gemen, Linda J W Shimon, Yael Diskin-Posner, Liat Avram, Petr Král, Rafal Klajn
Confining molecules to volumes only slightly larger than the molecules themselves can profoundly alter their properties. Molecular switches-entities that can be toggled between two or more forms upon exposure to an external stimulus-often require conformational freedom to isomerize. Therefore, placing these switches in confined spaces can render them non-operational. To preserve the switchability of these species under confinement, we work with a water-soluble coordination cage that is flexible enough to adapt its shape to the conformation of the encapsulated guest...
February 13, 2018: Nature Communications
Kevin P Liles, Angelique F Greene, Mary K Danielson, Nathan D Colley, Andrew Wellen, Jeremy M Fisher, Jonathan C Barnes
The use of light to actuate materials is advantageous because it represents a cost-effective and operationally straightforward way to introduce energy into a stimuli-responsive system. Common strategies for photoinduced actuation of materials typically rely on light irradiation to isomerize azobenzene or spiropyran derivatives, or to induce unidirectional rotation of molecular motors incorporated into a 3D polymer network. Although interest in photoredox catalysis has risen exponentially in the past decade, there are far fewer examples where photoinduced electron transfer (PET) processes are employed to actuate materials...
January 24, 2018: Macromolecular Rapid Communications
Fahimeh Khakzad, Ali Reza Mahdavian, Hamid Salehi-Mobarakeh, Mohammad Hossain Sharifian
HYPOTHESIS: Surfactant-free emulsion polymerization has become favorable due to circumventing instability issues reasonably. Incorporation of an appropriate hydrophilic macroRAFT, could provide controlled in-situ self-assembly via copolymerization with hydrophobic monomers into polymer particles. So far, this approach has mostly been studied in dispersion systems and further studies are needed in emulsions. Beside the corresponding mechanistic studies, the prepared latex particles would potentially exhibit smart behaviors by choosing stimuli-responsive monomers...
April 1, 2018: Journal of Colloid and Interface Science
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