Azobenzene molecules show excellent application potential in many fields due to their photoisomerization properties.Azobenzene molecules will gradually change from trans-structure to cis-structure under the irradiatio...Azobenzene molecules show excellent application potential in many fields due to their photoisomerization properties.Azobenzene molecules will gradually change from trans-structure to cis-structure under the irradiation of UV.In this paper,we have synthesized 4,4'-dibromoazobenzene molecules and characterized their photoisomerization properties.We found that with the extension of UV time,the trans absorption peak at 343 nm decreased significantly,while the cis absorption peak at 435 nm showed an upward trend.Furthermore,photoisomerization of azobenzene is not a first-order reaction.展开更多
Montmorillonite/cationic azobenzene dye(p-(δ-triethylammoniobutoxy)-p'-methyl- azobenzene bromide) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure cat...Montmorillonite/cationic azobenzene dye(p-(δ-triethylammoniobutoxy)-p'-methyl- azobenzene bromide) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure cationic azo-dye, the thermal stability of the intercalated dye was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated dye shifted towards longer wave length by 38 nm. This could be ascribed to the strong conjugation of cationic azo-dye supramolecular order structure(J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. UV/vis spectra data show that the intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and daylight cis-to-trans back reaction. FTIR indicates the successful intercalation of cationic azo-dye into the montmorillonite interlayer.展开更多
Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(...Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(AZO)to immobilize cations in the lattice.During the nucleation process,the photoisomerized cis-AZO reacts with FA^(+),MA^(+)and Pb2+cations in the perovskite precursor by synergistic cation-πinteraction and Lewis base coordination,leading to heterogeneous nucleation to produce uniform perovskite film.Meanwhile,it accelerates conversion of intermediate yellowδ-phase to desired black aphase of FAPb I3for improved crystallinity with well-passivated grain surface.Consequently,defect density is effectively reduced for the perovskite film to demonstrate suppressed carrier recombination and enhanced carrier extraction.Subsequently,the solar cell efficiency is elevated from 21.29%to 23.58%with negligible J-V hysteresis.Long-term stability is also improved,with the bare device without any encapsulation retaining 84%of its initial efficiency after aging 744 hours in ambient.展开更多
Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized, and their photoisomerization was examined. The new PNA monomers showed reversible trans-cis isomerization with UVand visible li...Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized, and their photoisomerization was examined. The new PNA monomers showed reversible trans-cis isomerization with UVand visible light irradiation, which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA. Simultaneously, the fluorescence of the new PNA monomers might make them especially useful as structural probes.展开更多
The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor t...The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor to spatial optical soliton formation, modulational instability can be adjusted and controlled by the wavelength combinations of the signal and background beams. We also discuss the dependences of strength of modulational instability on intensities of two signal beams and background beam. These findings make it possible to predict the formation of incoherently coupled soliton pairs in azobenzene-containing polymer.展开更多
Montmorillonite/cationic azobenzene dye (GTL) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was great...Montmorillonite/cationic azobenzene dye (GTL) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated GTL shifted towards a longer wavelength by 55 nm, which could be ascribed to the strong conjugation of GTL supramolecular order structure (J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. The microstructures of the resulting intercalation compounds could be successfully controlled by varying the amount of dye loaded as evidenced by the basal spacing of the intercalation compounds. The intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and thermal cis-to-trans reaction. FTIR proved the successful intercalation of GTL into the silicate layer.展开更多
A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^* excitation and the results show that the formation ofcis isomer follows the rotational mo...A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^* excitation and the results show that the formation ofcis isomer follows the rotational motion around the N=N bond. The simulation find that the CNN bond angle bending vibrations also play a significant role in the vibronic coupling between the HOMO and LUMO, which essentially leads a nonadiabatic transition of the molecule to the electronic ground state.展开更多
A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was car...A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was carried out with this polymer-bound photosensitizer in ethanol and toluene solutions. The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaction mixtures.展开更多
The original technologies of growing silica films, impregnated with 7-dehydrocholesterol (provitamin D3) on quartz substrates and free transparent films on the basis of polyvinyl alcohol and polyvinyl butyral have bee...The original technologies of growing silica films, impregnated with 7-dehydrocholesterol (provitamin D3) on quartz substrates and free transparent films on the basis of polyvinyl alcohol and polyvinyl butyral have been developed. Provitamin D photoisomerization in the films under UVB irradiation was investigated by UV absorption spectroscopy. Remarkable changes in the absorption spectrum of 7-DHC were observed in silica and polyvinyl alcohol films as com-pared with ethanol solution, only in polyvinyl butyral film the spectrum was very nearly, while the spectral kinetics of 7-DHC photoisomerization in all the films was different from ethanol. We suggest that several films have potential as UV dosimeters to measure accumulated ‘antirachitic’ UV dose in the same manner as erythemic UV dose is measured by commonly used polysulphone film.展开更多
The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute U...The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute UV-irradiation, the yield of cw-stilbene is higher in W/O microemulsion than in homogeneous solvent-n-C5H11OH.展开更多
In this study, the photoisomerization of trans-stilbene was carded out in water in oil (W/O) microemulsions by using sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB) and cetyl trimethyl am...In this study, the photoisomerization of trans-stilbene was carded out in water in oil (W/O) microemulsions by using sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB) and cetyl trimethyl ammonium bromide (CTAB) as surfactant, respectively. The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactant. When there is no photosensitizer 9,10-dicyanoanthracene (DCA), the surfactant with shorter hydrophobic chain is preferred, while in the presence of DCA, the surfactant with anionic polar group is preferred.展开更多
The trans-cis photoisomerization of pentamethine cyanine dye (Cy5) has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the differe...The trans-cis photoisomerization of pentamethine cyanine dye (Cy5) has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the different bridge C-C bonds of the model. The relative stability of the isomers for the ground and first excited states as well as the corresponding excitation mechanism has been envisaged by DFT and time-dependent DFT method. The results show different conjugation degree of the isomers resulting in different absorption energy upon the different C-C bridge bond rotation. From the analyses of electronic density distribution of the frontier orbitals, it is predicted that there is charge transfer besides the π-π^* excitation for the cyanine dye model, which makes the mechanism and photo-properties different form those of other conjugated molecules.展开更多
In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF (CASSCF) molecular orbital method. Geometries of minima and transition states on the e...In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF (CASSCF) molecular orbital method. Geometries of minima and transition states on the excited and ground states are fully optimized at the CAS level with a 6-3 IG* basis set. A multireference MP2 algorithm that has been implemented in Gaussian is used to correct the energetics for dynamic correlation. The topology and reaction funnels of the singlet, triplet (S0, T1, T2) and potential energy surfaces have been characterized along the reaction coordinates corresponding to the mechanism. The reaction proceeds via two diradical intermediates, one intermediate product and four transition states. The two diradical S 1/T2 and T1/S0 energy surface crossing points are located along the reaction path and a T1/T2 conical intersection is also located. From this point the reaction soon returns to T1 surface. It is the most reasonable that the intersystem crossing from T1 to S0 takes place.展开更多
Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the ove...Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the overheating problem for a recently proposed laser-operated molecular locomotive. We present a single-molecule cooling theory, in which molecular details of the locomotive system are explicitly treated. This theory is able to quantitatively predict cooling efficiency for various candidates of molecular systems for the locomotive, and also suggests concrete strategies for improving the locomotive's cooling. It is found that water environment is able to cool the hot locomotive down to room temperature within 100 picoseconds after photon absorption. This cooling time is a few orders of magnitude shorter than the typical time for laser operation, effectively preventing any overheating for the nano-locomotive. However, when the cooling is less effective in non-aqueous environment, residual heat may build up. A continuous running of the motor will then lead to a periodic thermodynamics, which is a common character of many laser-operated nano-devices.展开更多
A silica gel-anchored photosensitizer was synthesized with anthracene as sensitizer moiety. The photoisomerization of tachysterol to previtamin D3 was carried out with this heterogeneous photosensitizer in ethanol. T...A silica gel-anchored photosensitizer was synthesized with anthracene as sensitizer moiety. The photoisomerization of tachysterol to previtamin D3 was carried out with this heterogeneous photosensitizer in ethanol. The experiment results demonstrate that this solid phase photosensitizer is efficient for the photoisomerization and can be simply separated from the reaction mixture by filtration.展开更多
The photoisomerization of provitamin D-3 is carrried out in silica gel-hexane matrix, ethanol and hexane. The results show that in silica gel-hexane matrix and ethanol, the desired product of provitamin D-3 and vitami...The photoisomerization of provitamin D-3 is carrried out in silica gel-hexane matrix, ethanol and hexane. The results show that in silica gel-hexane matrix and ethanol, the desired product of provitamin D-3 and vitamin D-3 can be obtained in high yield, while the undesirable byproducts are greatly limited.展开更多
Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the developme...Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the development of surface pressure with time. This process wan found to be a first-order reaction and complete within several minutes.展开更多
Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however...Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)- and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D3(7-dehydrocholesterol) and D2(ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active ‘antirachitic’ UV radiation.展开更多
基金The National Natural Science Foundation of China(21504010)Open Project of Engineering Research Center of Active Material Biotechnology,Ministry of Education,Chongqing Normal University(AS201609)Chongqing Key Laboratory of inorganic Function Materials,College of Chemistry,Chongqing Normal University,Chongqing 401331,P.R.China.
文摘Azobenzene molecules show excellent application potential in many fields due to their photoisomerization properties.Azobenzene molecules will gradually change from trans-structure to cis-structure under the irradiation of UV.In this paper,we have synthesized 4,4'-dibromoazobenzene molecules and characterized their photoisomerization properties.We found that with the extension of UV time,the trans absorption peak at 343 nm decreased significantly,while the cis absorption peak at 435 nm showed an upward trend.Furthermore,photoisomerization of azobenzene is not a first-order reaction.
基金the Applied and Basal Research Foundation of Sichuan Province(No.03JY029-026-2)
文摘Montmorillonite/cationic azobenzene dye(p-(δ-triethylammoniobutoxy)-p'-methyl- azobenzene bromide) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure cationic azo-dye, the thermal stability of the intercalated dye was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated dye shifted towards longer wave length by 38 nm. This could be ascribed to the strong conjugation of cationic azo-dye supramolecular order structure(J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. UV/vis spectra data show that the intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and daylight cis-to-trans back reaction. FTIR indicates the successful intercalation of cationic azo-dye into the montmorillonite interlayer.
基金supported by the National Natural Science Foundation of China(21603140)the 111 Project(B21005)。
文摘Ion migration is a notorious problem in perovskite solar cells(PSCs)that severely mutilates device performance.Herein,a strategy to inhibit ion migration in situ is developed by using photoisomerization of azobenzene(AZO)to immobilize cations in the lattice.During the nucleation process,the photoisomerized cis-AZO reacts with FA^(+),MA^(+)and Pb2+cations in the perovskite precursor by synergistic cation-πinteraction and Lewis base coordination,leading to heterogeneous nucleation to produce uniform perovskite film.Meanwhile,it accelerates conversion of intermediate yellowδ-phase to desired black aphase of FAPb I3for improved crystallinity with well-passivated grain surface.Consequently,defect density is effectively reduced for the perovskite film to demonstrate suppressed carrier recombination and enhanced carrier extraction.Subsequently,the solar cell efficiency is elevated from 21.29%to 23.58%with negligible J-V hysteresis.Long-term stability is also improved,with the bare device without any encapsulation retaining 84%of its initial efficiency after aging 744 hours in ambient.
基金the National Nature Science Foundation of China (No.20473106)the Innovation Group Project (No.50421502)973 project (No.2007CB607605)of the Chinese Ministry of Science & Technology.
文摘Phenylazonaphthalene peptide nucleic acid (PNA) monomers were successfully synthesized, and their photoisomerization was examined. The new PNA monomers showed reversible trans-cis isomerization with UVand visible light irradiation, which might be the foundation of photo-regulating the hybridization between PNA containing phenylazonaphthalene unit and DNA. Simultaneously, the fluorescence of the new PNA monomers might make them especially useful as structural probes.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574167)
文摘The modulational instability of two incoherently coupled beams in azobenzene-containing polymer with photoisomerization nonlinearity is investigated analytically and numerically. Our results show that as a precursor to spatial optical soliton formation, modulational instability can be adjusted and controlled by the wavelength combinations of the signal and background beams. We also discuss the dependences of strength of modulational instability on intensities of two signal beams and background beam. These findings make it possible to predict the formation of incoherently coupled soliton pairs in azobenzene-containing polymer.
基金This work was financially supported by the Science Council of Sichuan Province, China (No.03JY029-026-2).
文摘Montmorillonite/cationic azobenzene dye (GTL) intercalation compounds were prepared by the conventional ion exchange method. As compared with that of pure GTL, the thermal stability of the intercalated GTL was greatly enhanced, and the absorption band corresponding to azobenzene group in intercalated GTL shifted towards a longer wavelength by 55 nm, which could be ascribed to the strong conjugation of GTL supramolecular order structure (J cluster) confined in a nanoscale space of montmorillonite interlayer gallery. The microstructures of the resulting intercalation compounds could be successfully controlled by varying the amount of dye loaded as evidenced by the basal spacing of the intercalation compounds. The intercalated azo dye in the montmorillonite interlayer space exhibited reversible trans-to-cis photoisomerization and thermal cis-to-trans reaction. FTIR proved the successful intercalation of GTL into the silicate layer.
基金supported by the National Natural Science Foundation of China (No.20773168)Natural Science Foundation Project of CQ CSTC (No.2006BB2367 and 2006BB5368)Project of Science Technology Foundation of Chongqing Education Committee (No.KJ070506).
文摘A realistic dynamics simulation study is reported for the trans-cis photoisomerization of azobenzene triggered by the n →π^* excitation and the results show that the formation ofcis isomer follows the rotational motion around the N=N bond. The simulation find that the CNN bond angle bending vibrations also play a significant role in the vibronic coupling between the HOMO and LUMO, which essentially leads a nonadiabatic transition of the molecule to the electronic ground state.
文摘A polymer-bound photosensitizer was synthesized by the reaction of Merrifield resin with 9-anthracenemethanol in the presence of potassium hydride. The photoisomerization of trans-vitamin D3 to cis-vitamin D3 was carried out with this polymer-bound photosensitizer in ethanol and toluene solutions. The experiment results demonstrate that this solid photosensitizer is efficient for the photoismerization and easy for separation from the reaction mixtures.
文摘The original technologies of growing silica films, impregnated with 7-dehydrocholesterol (provitamin D3) on quartz substrates and free transparent films on the basis of polyvinyl alcohol and polyvinyl butyral have been developed. Provitamin D photoisomerization in the films under UVB irradiation was investigated by UV absorption spectroscopy. Remarkable changes in the absorption spectrum of 7-DHC were observed in silica and polyvinyl alcohol films as com-pared with ethanol solution, only in polyvinyl butyral film the spectrum was very nearly, while the spectral kinetics of 7-DHC photoisomerization in all the films was different from ethanol. We suggest that several films have potential as UV dosimeters to measure accumulated ‘antirachitic’ UV dose in the same manner as erythemic UV dose is measured by commonly used polysulphone film.
文摘The photoisomerization of trans-stilbene was studied in the water in oil (W/O) micro-emulsion formed by SDS (sodium dodecyl sulfate), n-C5H11OH (1-pentanol) and H2O. The experimental results show that after 2-minute UV-irradiation, the yield of cw-stilbene is higher in W/O microemulsion than in homogeneous solvent-n-C5H11OH.
文摘In this study, the photoisomerization of trans-stilbene was carded out in water in oil (W/O) microemulsions by using sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB) and cetyl trimethyl ammonium bromide (CTAB) as surfactant, respectively. The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactant. When there is no photosensitizer 9,10-dicyanoanthracene (DCA), the surfactant with shorter hydrophobic chain is preferred, while in the presence of DCA, the surfactant with anionic polar group is preferred.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (2008-890)The Key Project of Educational Committee of Anhui Province (KJ2010A143)+1 种基金Special Project (xzx200812)Doctor’s Project Grant of Anhui Normal University
文摘The trans-cis photoisomerization of pentamethine cyanine dye (Cy5) has been theoretically investigated by the analysis on an analogical molecule model. All possible isomers have been searched by rotating the different bridge C-C bonds of the model. The relative stability of the isomers for the ground and first excited states as well as the corresponding excitation mechanism has been envisaged by DFT and time-dependent DFT method. The results show different conjugation degree of the isomers resulting in different absorption energy upon the different C-C bridge bond rotation. From the analyses of electronic density distribution of the frontier orbitals, it is predicted that there is charge transfer besides the π-π^* excitation for the cyanine dye model, which makes the mechanism and photo-properties different form those of other conjugated molecules.
基金This project was supported by the Yunnan Provincial Science and Technology Department (2003A0003M)
文摘In the present work, the photoisomerization of 2-methylfuran to 3-methylfuran is investigated with the complete active space SCF (CASSCF) molecular orbital method. Geometries of minima and transition states on the excited and ground states are fully optimized at the CAS level with a 6-3 IG* basis set. A multireference MP2 algorithm that has been implemented in Gaussian is used to correct the energetics for dynamic correlation. The topology and reaction funnels of the singlet, triplet (S0, T1, T2) and potential energy surfaces have been characterized along the reaction coordinates corresponding to the mechanism. The reaction proceeds via two diradical intermediates, one intermediate product and four transition states. The two diradical S 1/T2 and T1/S0 energy surface crossing points are located along the reaction path and a T1/T2 conical intersection is also located. From this point the reaction soon returns to T1 surface. It is the most reasonable that the intersystem crossing from T1 to S0 takes place.
基金supported by the National Natural Science Foundation of China (Grant No 90403006)Chinese Ministry of Education (the Programme for New Century Excellent Talents in University)+1 种基金Shanghai Education Development Foundation of China (the Shuguang Programme)Shanghai Pujiang Programme of China (Grant No 05PJ14019)
文摘Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the overheating problem for a recently proposed laser-operated molecular locomotive. We present a single-molecule cooling theory, in which molecular details of the locomotive system are explicitly treated. This theory is able to quantitatively predict cooling efficiency for various candidates of molecular systems for the locomotive, and also suggests concrete strategies for improving the locomotive's cooling. It is found that water environment is able to cool the hot locomotive down to room temperature within 100 picoseconds after photon absorption. This cooling time is a few orders of magnitude shorter than the typical time for laser operation, effectively preventing any overheating for the nano-locomotive. However, when the cooling is less effective in non-aqueous environment, residual heat may build up. A continuous running of the motor will then lead to a periodic thermodynamics, which is a common character of many laser-operated nano-devices.
文摘A silica gel-anchored photosensitizer was synthesized with anthracene as sensitizer moiety. The photoisomerization of tachysterol to previtamin D3 was carried out with this heterogeneous photosensitizer in ethanol. The experiment results demonstrate that this solid phase photosensitizer is efficient for the photoisomerization and can be simply separated from the reaction mixture by filtration.
基金This work was supported by the Major State Basic Research Development Program,Grant No.G2000078100the National Natural Science Foundation of China,No.20172059 and Chinese Academy of Sciences.
基金This work was supported by the National Natural Science Foundation of China, No. 29971031 and the Chinese Academy of Sciences.
文摘The photoisomerization of provitamin D-3 is carrried out in silica gel-hexane matrix, ethanol and hexane. The results show that in silica gel-hexane matrix and ethanol, the desired product of provitamin D-3 and vitamin D-3 can be obtained in high yield, while the undesirable byproducts are greatly limited.
文摘Photoisomerization of a new polymer: monoesters of polymaleic acid containing naphthalene-azo-anthraquinone groups in side chains at the air-water interface of a Langmuir trough wan detected by recording the development of surface pressure with time. This process wan found to be a first-order reaction and complete within several minutes.
文摘Study of interfacial processes between incorporated biomolecules and hydrogel matrix is of primary importance for the application of synthetic hydrogels as biomaterials, sensors, etc. Their hydrophilic nature, however, hampers fat-soluble biomolecule incorporation. We synthesized N-isopropylacrylamide (NIPAAm)- and Acrylamide (AA)-based hydrogels with hydrophilic-lipophilic balance that under specific conditions permit homogeneous incorporation of provitamins D3(7-dehydrocholesterol) and D2(ergosterol) dissolved in ethanol. Similarity of provitamins D photoisomerization in such hydrogel matrices with the photoreaction in ethanol shows great potential of the novel material for personal dosimetry of biologically active ‘antirachitic’ UV radiation.