Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methyle...Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methylenes than compound 5. UV\|Vis spectra of compounds 5 and 6 were the simple superposition of the absorbance of the azobenzene and pyrazoling and showed that pyrazoline had no effect on the isomerization of azobenzene. When there were two methylenes between azobenzene and pyrazoline, the fluorescent intensity of compound 5 decreased greatly compared with that of compound 6. It means that the intramolecular Electronic Energy Transfer has taken place in compound 5. In compound 6, this process could not occur because of the longer flexible chain between the two chromophores.展开更多
A novel chiral methylpropargyl ester containing azobenzene moiety（S）-（-）-3-methyl-3-{4-[4-（n-octyloxy）phenylazophenyl]carbonyl}oxy-1-propyne 3（C25H30N2O3,Mr = 406.51） was synthesized and characterized by IR,NM...A novel chiral methylpropargyl ester containing azobenzene moiety（S）-（-）-3-methyl-3-{4-[4-（n-octyloxy）phenylazophenyl]carbonyl}oxy-1-propyne 3（C25H30N2O3,Mr = 406.51） was synthesized and characterized by IR,NMR and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21 with a=6.7610（17）,b=7.675（2）,c=22.749（7）,β=97.613（6）°,V=1170.1（6）3,Z=2,Dc=1.154,F（000）=436,μ=0.076 mm-1,R=0.0544 and wR=0.1569 for 2444 observed reflections with Ⅰ〉2σ（Ⅰ）.Structure analysis proved that the azobenzene presents a trans form, and intermolecular hydrogen bonds yield a 3D framework. The ehiral acetylene carrying azobenzene moieties can be a potential alternative nonlinear optical, helical polymer, and liquid crystalline material.展开更多
The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly tim...The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly times and concentration were also investigated.A two-step adsorption kinetics has been confirmed:the fast adsorption process and the following long-term reorganization.The equilibrium constant(K)for the adsorptioon and the interaction factor between adsorbate-adsorbate molecules () were evaluated based on the Frumkin isotherm and determined to be (3. 17±0. 13)× 106 mol.L(-1) and -0.34±0.04, respectively The Gibbs free energy (G)of SAM was determined to be -(37. 07±0. 13)kJ.mol(-1)展开更多
Azobenzene multilayers were fabricated on silicon substrates by electrostatic self-assembly technology. Rough silicon substrates were prepared by photolithography and the inductive coupling plasma deep etching techniq...Azobenzene multilayers were fabricated on silicon substrates by electrostatic self-assembly technology. Rough silicon substrates were prepared by photolithography and the inductive coupling plasma deep etching technique. Surface morphology and properties of azobenzene multilayer on the silicon substrate were characterized by SEM, UV-Vis spectra and contact angle(CA) measurement. Superhydrophobicity(CA is larger than 150°) on the multilayer was obtained by introducing geometrical structure onto the substrate surface. For the flat silicon substrate, CA on 10 bilayers was 83.4°±2.1°. For the rough substrate, CA was 150.9°±1.7°. After UV irradiation the CA decreased. A large reversible CA change about 37° was realized through ultraviolet and visible irradiation on the rough azobenzene film, comparing with that about 5° on the flat film. These results indicate that the surface roughness plays an important role in tuning surface wettability. Moreover, the reversible switching by photo-irradiation could be realized many times, and a good reversibility of surface wettability was observed.展开更多
文摘Bifunctional pyrazoline derivatives 5 and 6 containing azobenzene group were prepared. The difference between them was the length of the flexible chain connecting the two chromophores. Compound 6 had four more methylenes than compound 5. UV\|Vis spectra of compounds 5 and 6 were the simple superposition of the absorbance of the azobenzene and pyrazoling and showed that pyrazoline had no effect on the isomerization of azobenzene. When there were two methylenes between azobenzene and pyrazoline, the fluorescent intensity of compound 5 decreased greatly compared with that of compound 6. It means that the intramolecular Electronic Energy Transfer has taken place in compound 5. In compound 6, this process could not occur because of the longer flexible chain between the two chromophores.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘A novel chiral methylpropargyl ester containing azobenzene moiety（S）-（-）-3-methyl-3-{4-[4-（n-octyloxy）phenylazophenyl]carbonyl}oxy-1-propyne 3（C25H30N2O3,Mr = 406.51） was synthesized and characterized by IR,NMR and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21 with a=6.7610（17）,b=7.675（2）,c=22.749（7）,β=97.613（6）°,V=1170.1（6）3,Z=2,Dc=1.154,F（000）=436,μ=0.076 mm-1,R=0.0544 and wR=0.1569 for 2444 observed reflections with Ⅰ〉2σ（Ⅰ）.Structure analysis proved that the azobenzene presents a trans form, and intermolecular hydrogen bonds yield a 3D framework. The ehiral acetylene carrying azobenzene moieties can be a potential alternative nonlinear optical, helical polymer, and liquid crystalline material.
文摘The formation kinetics of the self-assembled monolayer (SAM) of an azobenzenealkanethiol,denoted as AzoC2SH on surface was studied using electrochemical techniques,and the monolayers prepared at different assembly times and concentration were also investigated.A two-step adsorption kinetics has been confirmed:the fast adsorption process and the following long-term reorganization.The equilibrium constant(K)for the adsorptioon and the interaction factor between adsorbate-adsorbate molecules () were evaluated based on the Frumkin isotherm and determined to be (3. 17±0. 13)× 106 mol.L(-1) and -0.34±0.04, respectively The Gibbs free energy (G)of SAM was determined to be -(37. 07±0. 13)kJ.mol(-1)
文摘Azobenzene multilayers were fabricated on silicon substrates by electrostatic self-assembly technology. Rough silicon substrates were prepared by photolithography and the inductive coupling plasma deep etching technique. Surface morphology and properties of azobenzene multilayer on the silicon substrate were characterized by SEM, UV-Vis spectra and contact angle(CA) measurement. Superhydrophobicity(CA is larger than 150°) on the multilayer was obtained by introducing geometrical structure onto the substrate surface. For the flat silicon substrate, CA on 10 bilayers was 83.4°±2.1°. For the rough substrate, CA was 150.9°±1.7°. After UV irradiation the CA decreased. A large reversible CA change about 37° was realized through ultraviolet and visible irradiation on the rough azobenzene film, comparing with that about 5° on the flat film. These results indicate that the surface roughness plays an important role in tuning surface wettability. Moreover, the reversible switching by photo-irradiation could be realized many times, and a good reversibility of surface wettability was observed.
