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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 9, 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
Sindu Shree, Mathias Schulz-Senft, Nils H Alsleben, Yogendra Kumar Mishra, Anne Staubitz, Rainer Adelung
A self-reporting polythiourethane/tetrapodal-ZnO (PTU/T-ZnO) composite is produced using spiropyran as an additive at a concentration as low as 0.5 wt %. Exposure to heat, UV light and mechanical force caused the spiropyran to undergo reversible isomerization indicated by a reversible color change. The studies have been conducted with a constant spiropyran concentration at 0.5 wt %, meanwhile varying the T-ZnO concentration from 0 to 7.5 wt %. The tetrapodal ZnO served as a prism: the light scattering effect of T-ZnO created a visual impression of uniform color distribution...
October 19, 2017: ACS Applied Materials & Interfaces
Chang-Min Yoon, Yoonsun Jang, Jungchul Noh, Jungwon Kim, Jyongsik Jang
Electrophotorheological (EPR) fluids, whose rheological activity is dually responsive to light and electric fields (E fields), is formulated by mixing photosensitive spiropyran-decorated silica (SP-sSiO2) nanoparticles with zwitterionic lecithin and mineral oil. A reversible photorheological (PR) activity of the EPR fluid is developed via the binding and releasing mechanism of lecithin and merocyanine (MC, a photoisomerized form of SP) under ultraviolet (UV) and visible (VIS) light applications. Moreover, the EPR fluid exhibits an 8-fold higher electrorheological (ER) performance compared to the SP-sSiO2 nanoparticle-based ER fluid (without lecithin) under an E field, which is attributed to the enhanced dielectric properties facilitated by the binding of the lecithin and SP molecules...
October 24, 2017: ACS Nano
Mareen Gläske, Pascal Bluemmel, Sabrina Juergensen, Antonio Setaro, Stephanie 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 experimental observation of effects of switching on the emission behavior of the tubes. Here we present spiropyran-carbon nanotubes complexes obtained by micelle swelling. This method does not require any anchor nor sophisticated chemistry to warrant close tube-switch proximity. For the first time we observe the shifts predicted theoretically and their effect on the tubes' excitation and emission energies...
September 20, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Yong-Min Kho, Eun Ju Shin
Spiropyran derivatives have been studied as light-regulated chemosensors for a variety of metal cations and anions, but there is little research on chemosensors that simultaneously detect multiple metal cations. In this study, a spiropyran derivative with isoquinoline, SP-IQ, was prepared and it functions investigated as a light-regulated sensor for both Co(2+) and In(3+) cations. A colorless nonfluorescent SP-IQ converts to a pink-colored fluorescent MC-IQ by UV irradiation or standing in the dark, and MC-IQ returns to SP-IQ with visible light...
September 19, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Sabrina Heng, Xiaozhou Zhang, Jinxin Pei, Andrew D Abell
γ-Glutamyl-cysteinyl-glycine (GSH) plays a critical role in maintaining redox homeostasis in biological systems and a decrease in its cellular levels is associated with diseases. Existing fluorescence-based chemosensors for GSH acts as irreversible reaction-based probes that exhibit a maximum fluorescence ('turn-on') once the reaction is complete, regardless of the actual concentration of GSH. A reversible, reaction-based 'turn-off' probe ( 1 ) is reported here to sense the decreasing levels of GSH, a situation known to occur at the onset of various diseases...
September 6, 2017: Biosensors
Alexis Perry, Christina J Kousseff
Spiropyrans bearing an N-alkylcarboxylate tether are a common structure in dynamic, photoactive materials and serve as colourimetric/fluorimetric cation receptors. In this study, we describe an efficient synthesis of spiropyrans with 2-12 carbon atom alkylcarboxylate substituents, and a systematic analysis of their interactions with metal cations using (1)H NMR and UV-visible spectroscopy. All N-alkylcarboxyspiropyrans in this study displayed a strong preference for binding divalent metal cations and a modest increase in M(2+) binding affinity correlated with increased alkycarboxylate tether length...
2017: Beilstein Journal of Organic Chemistry
Mingsong Wang, Gregory Hartmann, Zilong Wu, Leonardo Scarabelli, Bharath Bangalore Rajeeva, Jeremy W Jarrett, Evan P Perillo, Andrew K Dunn, Luis M Liz-Marzán, Gyeong S Hwang, Yuebing Zheng
By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon-enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP-derived merocyanine (MC) molecules formed by photochemical ring-opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring-opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon-modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high...
August 21, 2017: Small
Noorjahan Aibani, Paola Fontoura da Costa, Jodie Masterson, Nino Marino, Françisco M Raymo, John Callan, Bridgeen Callan
The ability to control drug release at a specific physiological target enables the possibility of an enhanced therapeutic effect with reduced off-target toxic side effects. The discipline of controlled drug release has grown to include most areas of medicine with examples in the literature of targeted drug delivery to the majority of organs within the human body. In addition, a variety of external stimuli used to meditate the drug release process have also been investigated. Nonetheless, the concurrent real time monitoring of drug release has not been widely studied...
October 28, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
Juhyen Lee, Eun Jung Choi, Inwon Kim, Minhe Lee, Chinnadurai Satheeshkumar, Changsik Song
Tuning the sensing properties of spiropyrans (SPs), which are one of the photochromic molecules useful for colorimetric sensing, is important for efficient analysis, but their synthetic modification is not always simple. Herein, we introduce an alkyne-functionalized SP, the modification of which would be easily achieved via Cu-catalyzed azide-alkyne cycloaddition ("click reaction"). The alkyne-SP was conjugated with a bis(triethylene glycol)-benzyl group (EG-BtSP) or a simple benzyl group (BtSP), forming a triazole linkage from the click reaction...
August 7, 2017: Sensors
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