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We previously found that a copolymer, poly(NIPAM- co-BP), consisting of N-isopropylacrylamide (NIPAM) and benzophenone (BP) units, behaves as a photosensitizer showing temperature-controlled oxygenation activity by singlet oxygen ( 1O 2) in water ( J. Am. Chem. Soc.2006, 128, 8751−8753 ). This polymer shows a heat-induced oxygenation enhancement at <20 °C, while showing suppression at >20 °C. This is driven by a heat-induced phase transition of the polymer from coilto micelleand then to globulestate, controlling the stability and diffusion of 1O 2and the location of substrate. In the present work, effects of polymer concentration and BP content of the polymer on the oxygenation activity were studied at 5−35 °C. Increase in the polymer concentration leads to activity decrease at >20 °C due to strong polymer aggregation, suppressing incident light absorption of the BP units. With a decrease in BP content of the polymer, heat-induced oxygenation enhancement at <20 °C is more pronounced because formation of small size micelles accelerates 1O 2oxygenation. The obtained findings reveal that the polymer with low BP content, when used at high concentration, shows clear-cut off- on- offactivity change against the temperature window: very low activity at <5 °C and >25 °C, and very high activity at middle temperature range. [ABSTRACT FROM AUTHOR]

The local viscosity of Pluronic F127 triblock copolymer micelles in water was determined with cyanine dyes as fluorescent probes. These dyes show very weak fluorescence at a low temperature, but show enhanced fluorescence at a temperature higher than the critical micellization temperature (Tcm). This is because a viscous environment within the micelle suppresses the formation of a nonradiative twisted intramolecular charge transfer (TICT) excited state of the dyes. The good correlation between the fluorescence quantum yields of the dyes and the viscosity and the temperature of the media allows a determination of local viscosity of micelle based on the fluorescence quantum yields. The local viscosity of both core and corona regions of micelles increases at >Tcmand shows a maximum at a temperature 7−9 °C higher than Tcm, and decreases at higher temperature due to the increased fluidity. The core viscosity is larger than that of the corona, and the corona viscosity increases toward the micelle center. The polymer concentration has different effects on the core and corona viscosity: the corona viscosity increases with a polymer concentration increase at the entire temperature range, whereas the core viscosity increases only at a low temperature. The corona viscosity increase is due to the condensation of a large number of polyethylene oxide (PEO) blocks. In contrast, the dehydration degree of polypropylene oxide (PPO) blocks in the core scarcely changes, and the core has a similar composition regardless of polymer concentration. The larger polymer concentration promotes a micelle formation at lower temperature where the fluidity increase is very weak, resulting in larger core viscosity. [ABSTRACT FROM AUTHOR]

A simple copolymer, poly(NIPAM-co-SP), consisting of N-isopropylacrylamide and spiropyran units, behaves as a colorimetric thermometer exhibiting temperature-responsive linear and reversible bathochromic/hypsochromic shift of the absorption spectra under UV irradiation. [ABSTRACT FROM AUTHOR]

Photocatalytic activity of microporous titanosilicate ETS-10 has been studied in water. The photoactivated ETS-10 shows catalytic activity driven by size and polarity of substrates. ETS-10 efficiently catalyzes a conversion of substrates with a size larger than the pore diameter of ETS-10. In contrast, the reactivity of small substrates depends strongly on substrate polarity; less polar substrates show higher reactivity on ETS-10. Electron spin resonance analysis reveals that large substrates or less polar substrates scarcely diffuse inside the highly polarized micropores of ETS-10 and, hence, react efficiently with hydroxyl radicals (•OH) formed on titanol (Ti−OH) groups exposed on the external surface of ETS-10. In contrast, small polar substrates diffuse easily inside the micropores of ETS-10 and scarcely react with •OH, resulting in low reactivity. The photocatalytic activity of ETS-10 is successfully applicable to selective transformations of large reactants or less polar reactants to small polar products, enabling highly selective dehalogenation and hydroxylation of aromatics. [ABSTRACT FROM AUTHOR]

Photoirradiation of an acetone/water mixture containing olefins affords the corresponding methyl ketones highly efficiently via a water-assisted CC coupling between acetonyl radical and olefins. [ABSTRACT FROM AUTHOR]

A simple-structured copolymer, poly(NIPAM-co-HC), consisting of N-isopropylacrylamide (NIPAM) and 4-(4-dimethylaminostyryl)pyridine (hemicyanine, HC) units as thermoresponsive and fluorescent signaling parts, respectively, has been synthesized. This copolymer dissolved in water shows very weak fluorescence at <25 °C, while showing fluorescence enhancement at >25 °C. The fluorescence intensity increases with a rise in temperature and saturates at >40 °C, enabling temperature detection at 25−40 °C. The fluorescence enhancement is driven by a heat-induced phase transition of the polymer from coil to globule state. The HC units within the coil state polymer exist as the nonfluorescent benzenoid form; however, the less polar domain formed inside the globule state polymer leads to transformation of the HC unit to the fluorescent quinoid form, resulting in heat-induced fluorescence enhancement. The fluorescence intensity measured at 40 °C is >20-fold higher than the intensity at <25 °C, which is the highest enhancement value among the fluorescent thermometers proposed so far. The polymer shows reversible fluorescence enhancement/quenching, regardless of the heating/cooling process. In addition, the polymer shows high reusability with a simple recovery process. [ABSTRACT FROM AUTHOR]

A new rhodamine derivative (1) containing an ethylenediamine-N,N-diacetic acid moiety exhibits Cu(II)-selective strong green fluorescence, while showing very weak orange fluorescence with other metal cations. [ABSTRACT FROM AUTHOR]

We previously found that Ti-containing mesoporous silica (T-S) with isolated and tetrahedrally coordinated Ti-oxide species, when photoactivated in acetonitrile with molecular oxygen (O2), catalyzes highly selective epoxidation of olefins (Chem. Commun.2005, 5977). The system showed the highest epoxide selectivity among the photocatalytic systems proposed so far, but showed insufficient olefin conversion. In the present work, we have employed Ti-containing mesoporous organosilicas (T-OS), synthesized by a surfactant-templating method with an organosilane precursor, as the photocatalyst and have studied the effects on the olefin conversion and the epoxide selectivity. The T-OS catalysts demonstrate the same high epoxide selectivity as does T-S, but scarcely improve the olefin conversion. Photoluminescence measurement reveals that the T-OS catalysts with high surface hydrophobicity enhance the access of hydrophobic olefins to the photoexcited Ti-oxide species as expected, but destabilize the excited species themselves. ESR analysis demonstrates that the T-OS catalysts also destabilize the active oxygen radical (O3•-), a crucial oxidant for olefin epoxidation, formed on the excited Ti-oxide species. These destabilizations counteract the enhanced olefin access to the excited species, resulting in almost no improvement in olefin conversion. Through detailed analyses, we have summarized the changes in photocatalytic properties of the Ti-oxide species, associated with the organic modification of the catalyst. [ABSTRACT FROM AUTHOR]

Photocatalytic oxidation of olefins on Cr-containing silica with molecular oxygen by visible light irradiation (λ > 400 nm) has been investigated. Cr−SiO2 catalyst prepared by a conventional sol−gel method, containing highly dispersed chromate species, catalyzes efficient olefin oxidation with very high selectivity for partially oxidized products (>90%), whereas semiconductor TiO2 promotes complete decomposition (CO2 production). The Cr−SiO2 catalyst shows much higher activity than Cr/SiO2 prepared by an impregnation method or Cr∝MCM-41 prepared by a templating method. ESR analysis reveals that photoirradiation of the chromate species with a tetrahedral coordination (Td6+) on Cr/SiO2 and Cr∝MCM-41 catalysts leads to the formation of excited state Td5+ species (Td5+*), while irradiation to Td6+ on Cr−SiO2 produces Td4+* species. This can be explained by a homogeneous Td6+ arrangement with Si species on the Cr−SiO2 catalyst. On the strongly reduced Td4+*, olefins are strongly attracted by an electron and/or proton donation, resulting in high oxidation activity. The Cr−SiO2 catalyst is applicable to partial oxidation of various aliphatic and aromatic olefins with very high selectivity, and does not promote undesirable dimerization. The obtained findings suggest a potential use of Cr−SiO2 as an efficient and recyclable heterogeneous photocatalyst for partial oxidation of olefins. [ABSTRACT FROM AUTHOR]

A boradiazaindacene (BODIPY) derivative containing a simple NO bidentate ligand shows a Cu2+-selective fluorescence in aqueous media. This is promoted viaa coordination of Cu2+followed by oxidative dehydrogenation of an amine moiety, leading to a formation of a fluorescent Cu+–Schiff base complex. [ABSTRACT FROM AUTHOR]

Photoreductive synthesis of colloidal gold nanoparticles (AuNPs) from Au3+ is one important process for nanoprocessing. Several methods have been proposed; however, there is no report of a method capable of producing AuNPs with inexpensive reagents acting as both reductant and surface stabilizer, promoted solely under photoirradiation. We found that UV irradiation of water with Au3+ and benzoic acid successfully produces monodispersed AuNPs, where thermal reduction does not occur in the dark condition even at elevated temperatures. Photoexcitation of a benzoate-Au3+ complex reduces Au3+ while oxidizing benzoic acid. The benzoic acid molecules are adsorbed on the AuNPs and act as surface stabilizers. Change in light intensity and benzoic acid amount successfully creates AuNPs with controllable sizes. The obtained AuNPs can easily be redispersed in an organic solvent or loaded onto a solid support by simple treatments. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) is an essential chemical in modern society. It is currently manufactured by the Haber-Bosch process using H2 and N2 under extremely high-pressure (>200 bar) and high-temperature (>673 K) conditions. Photocatalytic NH3 production from water and N2 at atmospheric pressure and room temperature is ideal. Several semiconductor photocatalysts have been proposed, but all suffer from low efficiency. Here we report that a commercially available TiO2 with a large number of surface oxygen vacancies, when photoirradiated by UV light in pure water with N2, successfully produces NH3. The active sites for N2 reduction are the Ti3+ species on the oxygen vacancies. These species act as adsorption sites for N2 and trapping sites for the photoformed conduction band electrons. These properties therefore promote efficient reduction of N2 to NH3. The solar-to-chemical energy conversion efficiency is 0.02%, which is the highest efficiency among the early reported photocatalytic systems. This noble-metal-free TiO2 system therefore shows a potential as a new artificial photosynthesis for green NH3 production. [ABSTRACT FROM AUTHOR]

Solar-to-chemical energy conversion is a challenging subject for renewable energy storage. In the past 40 years, overall water splitting into H2 and O2 by semiconductor photocatalysis has been studied extensively; however, they need noble metals and extreme care to avoid explosion of the mixed gases. Here we report that generating hydrogen peroxide (H2O2) from water and O2 by organic semiconductor photocatalysts could provide a new basis for clean energy storage without metal and explosion risk. We found that carbon nitride–aromatic diimide–graphene nanohybrids prepared by simple hydrothermal- calcination procedure produce H2O2 from pure water and O2 under visible light (d > 420nm). Photoexcitation of the semiconducting carbon nitride–aromatic diimide moiety transfers their conduction band electrons to graphene and enhances charge separation. The valence band holes on the semiconducting moiety oxidize water, while the electrons on the graphene moiety promote selective two-electron reduction of O2. This metal-free system produces H2O2 with solar-to-chemical energy conversion efficiency 0.20%, comparable to the highest levels achieved by powdered water-splitting photocatalysts. [ABSTRACT FROM AUTHOR]

We synthesized a coumarin-spiropyran dyad with a hydrogenated pyran moiety (2), behaving as an off-on type fluorescent receptor for rapid, selective, and sensitive detection of cyanide anion (CN-) in aqueous media. The receptor itself shows almost no fluorescence with a quantum yield < 0.01, due to the delocalization of p-electrons over the molecule. Selective nucleophilic addition of CN- to the spirocarbon of the molecule rapidly promotes spirocycle opening within only 3 min. This leads to localization of p-electrons on the coumarin moiety and exhibits strong light-blue fluorescence at 459 nm with very high quantum yield (0.52). As a result of this, the receptor facilitates rapid, selective, and sensitive fluorometric detection of CN- as low as 1.0 µM. [ABSTRACT FROM AUTHOR]

We synthesized a pyrylium–coumarin dyad (1) and used it for colorimetric detection of cyanide anions (CN−) in aqueous media. The receptor itself exhibits a long-wavelength absorption band at 643 nm due to the strong intramolecular charge transfer (ICT) from the diethylaminocoumarin to the pyrylium moiety. Selective nucleophilic addition of CN−to the pyrylium ring triggers the ring cleavage rapidly (within 8 min). This suppresses the ICT and decreases the intensity of the 643 nm band, along with an appearance of a new shorter-wavelength band at 472 nm assigned to the π,π* transition of the diethylaminocoumarin moiety. This drastic absorption change (643 nm → 472 nm) facilitates ratiometric detection of CN−based on the intensities of these two absorption bands in the visible region and successfully detects CN−as low as 8 μM. [ABSTRACT FROM AUTHOR]

Aerobic oxidation on a heterogeneous catalyst driven by visible light (π >400 nm) at ambient temperature is a very important reaction for green organic synthesis. A metal particles/semiconductor system, driven by charge separation via an injection of "hot electrons (ehot-)" from photoactivated metal particles to semiconductor, is one of the promising systems. These systems, however, suffer from low quantum yields for the reaction (<5% at 550 nm) because the Schottky barrier created at the metal/semiconductor interface suppresses the ehot- injection. Some metal particle systems promote aerobic oxidation via a non-ehot--injection mechanism, but require high reaction temperatures (>373 K). Here we report that Pt nanoparticles (~5 nm diameter), when supported on semiconductor Ta2O5, promote the reaction without ehot- injection at room temperature with significantly high quantum yields (~25%). Strong Pt-Ta2O5 interaction increases the electron density of the Pt particles and enhances interband transition of Pt electrons by absorbing visible light. A large number of photogenerated ehot- directly activate O2 on the Pt surface and produce active oxygen species, thus promoting highly efficient aerobic oxidation at room temperature. [ABSTRACT FROM AUTHOR]

Platinum (Pt) nanoparticles with o4 nm diameter loaded on graphitic carbon nitride (g-C3N4) by reduction at 673 K behave as efficient co-catalysts for photocatalytic hydrogen evolution under visible light (λ>420 nm). This is achieved by strong Pt-support interaction due to the high temperature treatment, which facilitates efficient transfer of photoformed conduction band electrons on g-C3N4 to Pt particles. [ABSTRACT FROM AUTHOR]

Cyanine dyes with indolium-coumarin linkages exhibit selective fluorescence enhancement for cyanide anions (CN-) via the nucleophilic interaction of CN- with their indolium carbon atoms. This facilitates rapid (detection time: 1 min) and sensitive (detection limit: 0.4 µM) sensing of CN- in aqueous media. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study. Purpose: The aims of this study were to investigate the diagnostic value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in PET/computed tomography (CT) in the evaluation of spinal metastatic lesions. Overview of Literature: Recent studies described limitations regarding how many lesions with abnormal 18F-FDG PET findings in the bone show corresponding morphologic abnormalities. Methods: The subjects for this retrospective study were 227 patients with primary malignant tumors, who were suspected of having spinal metastases. They underwent combined whole-body 18F-FDG PET/CT scanning for evaluation of known neoplasms in the whole spine. 99mTc-methylene diphosphonate bone scan was performed within 2 weeks following PET/CT examinations. The final diagnosis of spinal metastasis was established by histopathological examination regarding bone biopsy or magnetic resonance imaging (MRI) findings, and follow-up MRI, CT and 18F-FDG PET for extensively wide lesions with subsequent progression. Results: From a total of 504 spinal lesions in 227 patients, 224 lesions showed discordant image findings. For 122 metastatic lesions with confirmed diagnosis, the sensitivity/specificity of bone scan and FDG PET were 84%/21% and 89%/76%, respectively. In 102 true-positive metastatic lesions, the bone scan depicted predominantly osteosclerotic changes in 36% and osteolytic changes in 19%. In 109 true-positive lesions of FDG PET, osteolytic changes were depicted predominantly in 38% while osteosclerotic changes were portrayed in 15%. Conclusions: 18F-FDG PET in PET/CT could be used as a substitute for bone scan in the evaluation of spinal metastasis, especially for patients with spinal osteolytic lesions on CT. [ABSTRACT FROM AUTHOR]

A simple copolymer, poly(NIPAM-co-BODIPY), consisting of N-isopropylacrylamide (NIPAM) and boradiazaindacene (BODIPY) units, behaves as a fluorescent thermometer in water. The copolymer exhibits weak fluorescence at <23 °C, but the intensity increases with a rise in temperature up to 35 °C, enabling an accurate indication of the solution temperature at 23−35 °C. The heat-induced fluorescence enhancement is driven by an increase in the polymer microviscosity, associated with a phase transition of the polymer from the coil to globule state. The viscous domain formed inside the globule-state polymer suppresses the rotation of the meso-pyridinium group of the excited-state BODIPY units, resulting in heat-induced fluorescence enhancement. The polymer shows reversible fluorescence enhancement/quenching regardless of the heating/cooling process and displays high reusability with a simple recovery process. [ABSTRACT FROM AUTHOR]

A spiropyran derivative (1) behaves as a selective and sensitive cyanide anion receptor in aqueous media under UV irradiation. The receptor can be reproduced just by irradiation with visible light. [ABSTRACT FROM AUTHOR]

A cross-linked poly- N-isopropylacrylamide (polyNIPAM) nanocapsule, TH@PC, containing thionine (TH), an organic photosensitizer, has been synthesized. This capsulated polymeric photosensitizer promotes a singlet oxygen oxygenation ( 1O 2) accurately controlled by temperature: it shows high oxygenation activity at low temperature, but shows activity decrease with a rise in temperature, resulting in almost zero activity at >40 °C. The clear on−off activity control is driven by a heat-induced structure change of the capsule from the swollensingle capsule to contractedstate, and then to aggregate, behaving as an intelligent 1O 2filter. At low temperature, the capsule exists as the swollen single capsule, which allows 1O 2diffusion to bulk water, resulting in high oxygenation activity. A rise in temperature leads to contraction of the capsule, reducing the mesh size of the capsule wall. This suppresses 1O 2diffusion to bulk water and shows decreased activity. Intercapsule aggregation at >30 °C further suppresses 1O 2diffusion and shows almost no activity. The capsule promotes reversible activity control regardless of the heating/cooling process and can be reused with a simple recovery process. [ABSTRACT FROM AUTHOR]

A simple copolymer, poly(NIPAM-co-RD), consisting of N-isopropylacrylamide (NIPAM) and rhodamine (RD) units, behaves as a fluorescent thermometer exhibiting selective emission enhancement at a specific temperature range in water. [ABSTRACT FROM AUTHOR]

Fluorescence properties of a diethylenetriamine bearing two end pyrene fragments (L) have been studied in water, where effects of adding metal cations (Zn2, Cd2, Cu2, Hg2, Ag) on the emission properties of Lhave been studied. Without metal cations, Lshows dual-mode fluorescence consisting of monomer and excimer emissions. The monomer emission intensity (IM) is strong at acidic pH but decreases with a pH increase because of an electron transfer (ET) from the unprotonated nitrogen atoms to the excited pyrene fragment. The excimer emission is due to the static excimer formed via a direct photoexcitation of the intramolecular ground-state dimer (GSD) of the end pyrene fragments. The excimer emission intensity (IE) is weak at acidic pH but increases with a pH increase because of the GSD stability increase associated with the deprotonation of the polyamine chain. Addition of metal cations leads to IMdecrease, where chelation-driven IMenhancement does not occur even with diamagnetic Zn2and Cd2at any pH. This is because a pyrene−metal cation -complex, formed via a donation of -electron of the pyrene fragment to the adjacent metal center, suppresses the monomer photoexcitation. IEalso decreases upon addition of metal cations because the pyrene−metal cation -complex weakens -stacking interaction of the end pyrene fragments, leading to GSD stability decrease. The emission properties of L−Zn2complexes were studied by means of time-resolved fluorescence decay measurements, and the effects of adding a less-polar organic solvent were also studied to clarify the detailed emission properties. [ABSTRACT FROM AUTHOR]

A bisnaphthyl azadiene derivative (L) demonstrates Hg2-selective intermolecular excimer emission. This emission is responsive to the number of coordinated Hg2atoms, where 2:2 and 2:3 L−Hg2complexes are the strongly emissive components, whereas the 2:1 complex is nonemissive. [ABSTRACT FROM AUTHOR]

Fluorescence behaviors of a simple-structured molecule (L), a diethylenetriamine bearing two end pyrene fragments, have been investigated in water. Effects of adding a less-polar organic solvent (acetonitrile:  MeCN) on the emission behaviors have been studied by means of steady-state and time-resolved fluorescence measurements. Ldissolved in water shows dual-mode fluorescence consisting of monomer and excimer emissions. The monomer emission shows an “on−off” intensity profile against the pH window (pH 2−12), whereas the excimer emission shows an “off−on” profile. Upon MeCN addition, the monomer emission maintains the “on−off” profile. In contrast, the “off−on” profile of the excimer emission is drastically changed:  Lshows two more types of profiles, “off−on−off−on” and “off−on−off”, along with the MeCN concentration increase, thus behaving as a multiply configurable fluorescent indicator of the pH window. The MeCN-driven excimer emission switching of Lis triggered by (i) the decrease in stability of the intramolecular ground-state dimer (GSD) formed between the end pyrene fragments, which suppresses the direct photoexcitation of GSD (suppression of the “static” excimer formation), leading to a decrease in the excimer emission intensity at basic pH; and (ii) the decrease in polarity of solution, which allows formation of a “dynamic” excimer via a monomer-to-excimer transition, resulting in an enhancement of the excimer emission intensity at acidic−neutral pH. [ABSTRACT FROM AUTHOR]

Fluorescence behaviors of a triethylenetetramine bearing anthracene (AN) and benzophenone (BP) fragments at the respective ends, L1, have been studied in water, where effects of pH (H) and metal cations on the emission properties have been studied in detail. L1behaves as a fluorescent molecular logic gate driven by H(Input1) and metal cations (Input2) as input chemicals. The most notable feature of L1is that this molecule expresses the “either−or” switchable dual logic functions. Operation of L1with Cu2as Input2expresses the INHIBIT logic function, where a strong AN fluorescence appears only at pH 4 (with H) without Cu2Input1(1)-Input2(0). In contrast, operations of L1with all other metal cations as Input2express the TRANSFER logic function, where the presence of Hallows strong AN fluorescence regardless of whether the metal cation exists or not Input1(1)-Input2(0); Input1(1)-Input2(1). These emission switching behaviors of L1are driven by the difference in the coordination stability between L1and metal cations and the photoinduced intramolecular electron and energy transfer processes:  (i) a pH-induced electron transfer from unprotonated nitrogen atoms of the polyamine chain to the photoexcited AN ELT(N→AN); (ii) a pH- and metal coordination-induced electron transfer from the photoexcited AN to the ground-state BP ELT(AN→BP); and (iii) a Cu2coordination-induced energy transfer from the photoexcited AN to Cu2ENT(AN→Cu2). [ABSTRACT FROM AUTHOR]

Vanadium-containing mesoporous silica molecular sieve (V∝HMS) with tetrahedrally coordinated V-oxide species (VVO4) has been prepared by a modified surfactant-templating method, consisting of an addition of surfactant to a mixture of water, alcohol, and Si and V precursors followed by calcination. The V∝HMS demonstrates high photocatalytic activity even in the presence of water, while other V∝HMS's prepared by conventional templating methods and V/HMS prepared by an impregnation method show almost no activity owing to hydrolysis of the VVO4 species. ESR and photoluminescence measurements reveal that the modified templating method creates VVO4 species confined within a silica layer, while other methods create VVO4 species exposed on silica surface. The former VVO4 species are highly stabilized by the confinement within the silica, thus suppressing the hydrolysis. Another notable property of the confined VVO4 species is the higher photocatalytic activity even without water, despite their confined structure. This is explained by higher electrophilicity and longer lifetime of the excited-state VVO4 species (VIVO4*) derived from their distorted structure. The obtained findings suggest potential use of the modified surfactant-templating method for synthesis of stable and recyclable V-containing mesoporous silica with high photocatalytic activity. [ABSTRACT FROM AUTHOR]

TiO2loading Pt nanoparticles (Pt@TiO2) promote one-pot synthesis of imines from alcohols and amines under UV irradiation at room temperature. This is achieved viaa Pt-assisted photocatalytic oxidation of alcohols and a catalytic condensation of the formed aldehydes with amines on the TiO2surface. [ABSTRACT FROM AUTHOR]

A polymeric photosensitizer, poly(NIPAM-co-RB), consisting of N-isopropylacrylamide and rose bengal units, demonstrates a temperature-controlled changeable oxygenation selectivity by singlet oxygen in water. [ABSTRACT FROM AUTHOR]