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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 efficiencies of cancer cell capture and release. These enhanced efficiencies of cancer cell capture and release 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...
March 13, 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 by1 H 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...
March 12, 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...
February 22, 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...
February 14, 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...
January 4, 2018: Journal of Colloid and Interface Science
M S A Abdel-Mottaleb, M Saif, M S Attia, M M Abo-Aly, Sarah N Mobarez
A number of novel lanthanide (Gd3+, Sm3+, and Tb3+) complexes of the 1',3'-dihydro-8-methoxy-1',3',3'-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-(2H)-indole] (spiropyran; SP), a widely studied molecular photoswitch, were investigated. Comparative spectroscopic (absorption and fluorescence) and kinetic investigations of the stimulated photochromic and solvatochromic behavior were carried out in different media. SP embedded in a rigid thin film of poly(methylmethacrylate) might be exploited profitably as an optical sensor for the identification of a solvent's nature...
January 8, 2018: Photochemical & Photobiological Sciences
Hongyan Xia, Kang Xie, Gang Zou
Studies on the following were reviewed: (1) the structure of spiropyrans and spirooxazines (two kinds of spiro compounds) under external stimuli and (2) the construction and applications of composite systems based on fluorescence resonance energy transfer (FRET) with fluorescent materials. When treated with different stimuli (light, acids and bases, solvents, metal ions, temperature, redox potential, and so on), spiropyrans/spirooxazines undergo transformations between the ring-closed form (SP), the ring-opened merocyanine (MC) form, and the protonated ring-opened form (MCH)...
December 18, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Pardis Nazari, Aliyeh Bazi, Seyed AbdulMajid Ayatollahi, Hadi Dolati, Seyedeh Mahbobeh Mahdavi, Laleh Rafighdoost, Marzieh Amirmostofian
Infections are one of the most important causes of death, disability and inappropriate conditions for millions of people around the world. Therefore, the development in prognosis, prevention and treatment of infectious diseases made a considerable progress in designing and synthesis of new antimicrobial drugs. Nowadays, due to the increase in microbial resistance, discovery of new compounds with broad spectrum effects is granted. 4H-pyran derivatives and spiro compounds are the most important fragments in some effective drugs with antimicrobial activity...
2017: Iranian Journal of Pharmaceutical Research: IJPR
Maria E Genovese, Gianvito Caputo, Gabriele Nanni, Chiara Setti, Matteo Bustreo, Giovanni Perotto, Athanassia Athanassiou, Despina Fragouli
Photochromic spiropyran-doped silk fibroin poly(ethylene oxide) nanofibers which combine the attractive properties and biocompatibility of silk with the photocontrollable and reversible optical, mechanical, and chemical response of the spiropyran dopants are herein presented. As proved, the reversible variation of the absorption and emission signals of the mats and of their Young's modulus upon alternate UV and visible light irradiation is ascribed to the reversible photoconversion of the spiropyran form to its polar merocyanine counterpart...
November 22, 2017: ACS Applied Materials & Interfaces
Fabian Kempe, Oliver Brügner, Hannah Buchheit, Sarah Noemi Momm, Felix Riehle, Sophie Hameury, Michael Walter, Michael Sommer
A simple, straightforward and high-yielding route to tough polyarylenes of type poly(meta,meta,para-phenylene) (PmmpP) is developed. PmmpP is already tough in its as-synthesized state at intermediate molar mass of Mw ~60 kg/mol and exhibits outstanding mechanical properties for further optimized molecular weight (Mw = 96 kg/mol, E = 0.9 GPa, ε = 300 %). Statistical copolymers with para,para spiropyran (SP) are mechanochromic, whereby the tough behavior allows to investigate mechanochromism. Strained samples instantaneously lose color upon force release...
November 8, 2017: Angewandte Chemie
M Glaeske, P Bluemmel, S Juergensen, A Setaro, S Reich
The interaction of carbon nanotubes with the molecular dipole switch spiropyran is expected to affect the optical response of the tubes. Until now, the need of anchor groups to immobilize the switches on the tubes has hindered the experimental observation of the effects of switching on the emission behavior of the tubes. Here we present spiropyran-carbon nanotube complexes obtained by micelle swelling. This method does not require any anchor nor sophisticated chemistry to warrant close tube-switch proximity...
October 19, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Qingkai Qi, Chong Li, Xiaogang Liu, Shan Jiang, Zhaochao Xu, Richmond Lee, Mingqiang Zhu, Bin Xu, Wenjing Tian
Solid-state organic photoswitches with reversible luminescence modulation property are highly attractive because of their wide prospects in advanced photonic applications, such as optical data storage, anticounterfeiting and bioimaging. Yet, developing such materials has long been a significant challenge. In this work, we construct an efficient solid-state photoswitch based on a spiropyran-functionalized distyrylanthracene derivative (DSA-2SP) that exhibits exceptional reversible absorption/luminescence modulation ability...
November 15, 2017: Journal of the American Chemical Society
Junji Zhang, Youxin Fu, Hai-Hao Han, Yi Zang, Jia Li, Xiao-Peng He, Ben L Feringa, He Tian
Development of powerful fluorescence imaging probes and techniques sets the basis for the spatiotemporal tracking of cells at different physiological and pathological stages. While current imaging approaches rely on passive probe-analyte interactions, here we develop photochromic fluorescent glycoprobes capable of remote light-controlled intracellular target recognition. Conjugation between a fluorophore and spiropyran produces the photochromic probe, which is subsequently equipped with a glycoligand "antenna" to actively localize a target cell expressing a selective receptor...
October 17, 2017: Nature Communications
Heidi A Schwartz, Selina Olthof, Dominik Schaniel, Klaus Meerholz, Uwe Ruschewitz
1,3,3-Trimethylindolino-6'-nitrobenzopyrylospiran (SP-1) as an example of a photoswitchable spiropyran was loaded into the pores of different prototypical metal-organic frameworks, namely MOF-5, MIL-68(In), and MIL-68(Ga), by a vapor-phase process. The successful incorporation in the pores of the MOF was proven by X-ray powder diffraction, and the amount of the embedded photoswitchable guest was determined by X-ray photoelectron spectroscopy and elemental analysis. In contrast to the sterically hindered crystalline state, SP-1 embedded in solid MOF hosts shows photoswitching under irradiation with UV light from the spiropyran to its merocyanine form with a nearly complete photoisomerization...
November 6, 2017: Inorganic Chemistry
Tetsuo Yamaguchi, Ayan Maity, Vivek Polshettiwar, Makoto Ogawa
The photoinduced adsorption of a photochromic spiropyran (1-(2-hydroxyethyl)-3,3-dimethylindolino-6'-nitrobenzopyrylospiran) onto a dendritic fibrous nanosilica (DFNS) was investigated. By UV irradiation, the colorless suspension containing the spiropyran and DFNS changed to blue without stirring, while it turned to red by the irradiation under stirring. These two colors were attributed to the photogenerated merocyanine in a non polar environment (in toluene, blue) and on a protic environment (on DFNS, red)...
October 13, 2017: Journal of Physical Chemistry. A
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