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991.
以铁氰化钾、磷酸二氢铵等为反应物,采用水热法合成了α-Fe2O3空心球,并用XRD,TEM,FESEM(场发射扫描电镜)、UV-Vis和低温氮吸附脱附对其进行了表征。结果表明,α-Fe2O3空心球直径在200~560 nm之间,其BET比表面积为80 m2·g-1,平均孔径为8.5 nm。考察了反应时间、反应物用量和反应温度等对α-Fe2O3空心球形貌和大小的影响,提出了其可能的形成机理。研究了室温下α-Fe2O3空心球吸附苯酚的性能,吸附达平衡时,其吸附苯酚的量达97 mg·g-1。 相似文献
992.
In this paper, we described the synthesis and characterization of new diphenylethylene bearing imino group. We concentrated particularly on the investigation of the possibility of the excited state intramolecular charge transfer (ESIPT) of the new dyes experimentally and theoretically. The absorption and fluorescence spectroscopy of the dyes were determined in various solvents. The results showed that the maximal absorption wavelength of 2‐[(4′‐N,N‐dimethylamino‐diphenylethylene‐4‐ylimino)methyl]phenol ( C1 ) and 4‐[(4′‐N,N‐dimethylamino‐diphenylethylene‐4‐ylimino)methyl]phenol ( C2 ) exhibited almost independence on the solvent polarity. While as contrast, the maximal fluorescence wavelength of the dyes showed somewhat dependence on the solvent polarity. In particular, C1 displayed well‐separated dual fluorescence spectroscopy. The second fluorescence peak was characterized with an "abnormal" fluorescence emission wavelength in aprotic solvents with large Stokes shift (ca. 140 nm in THF), which was much more than normal Stokes shift (ca. 30 nm in THF). This emission spectroscopy could be assigned to ESIPT emission. On the other hand, the ESIPT fluorescence of C1 was much reduced or lost in the protic solvents. While, only normal fluorescence emission was detected in various solvents. Although the absorption maxima of C1 exhibited about 10 nm red‐shift with respect to those of C2 , the normal fluorescence maxima of C1 and C2 were almost identical in various solvents. These results suggested that C1 could undergo ESIPT, but C2 was not able to proceed ESIPT. The molecular geometry optimization of phototautomers in the ground electronic state (S0) was carried out with HF method (Hartree‐Fock) and at DFT level (Density Functional Theory) using B3LYP both, while the CIS was employed to optimize the geometries of the first singlet excited state (S1) of the phototautomers of C1 and C2 respectively. The properties of the ground state and the excited state of the phototautomers of C1 and C2 , including the geometrical parameter, the energy, the frontier orbits, the Mulliken charge and the dipole moment change were performed and compared completely. The data were analyzed further based on our experimental results. Furthermore, the absorption and fluorescence spectra were calculated in theory and compared with the measured ones. The rate constant of internal proton transfer (9.831×1011 s?1) of C1 was much lower than that of salicylidene methylamine ( C3 , 2.045×1015 s?1), which was a typical Schiff base compound and was well demonstrated to undergo ESIPT easily under photoexcitation. 相似文献
993.
<正>In this letter,N-acryloyl-3-aminophenylboronic acid(AAPBA) was synthesized and then examined as a new functional monomer for protein imprinting.It was allowed to be copolymerized with acrylamide to produce hemoglobin- or lysozyme-imprinted hydrogels.In template rebinding tests,the imprinted gels showed significant increase in the specific binding with the increase of the AAPBA amounts in the prepolymerization recipes.These results indicate that AAPBA may be a useful functional monomer for its moderate interactions with protein molecules. 相似文献
994.
<正>One chloride-terminated ionic liquid(CTIL) and two hydroxyl-terminated ionic liquids(HTILs) were synthesized and used as stationary phases for capillary gas chromatography(CGC).Molecular interactions of these stationary phases were evaluated by Abraham solvation parameter model,indicating that the CTIL exhibits remarkably strong H-bond basicity and the HTILs possess both H-bond basicity and acidity.The molecular interactions were further confirmed by separation of a complex mixture consisting of ketones,aldehydes,esters,alcohols and aromatic compounds.It was found that the obtained solvation parameters correlate well with the chromatographic performances of the analytes in terms of elution order and resolution.The well correlated relationship between the solvation parameters and the selectivity of the CTIL and HTILs stationary phases is quite helpful in predicting and understanding the retention behaviors of different types of analytes on these stationary phases. 相似文献
995.
The synthesis and characterization of dimeric lanthanide amides stabilized by a dianionic N‐aryloxo functionalized β‐ketoiminate ligand are described in this paper. Reactions of 4‐(2‐hydroxy‐5‐tert‐butyl‐phenyl)imino‐2‐pentanone (LH2) with Ln[N(SiMe3)2]3(µ‐Cl)Li(THF)3 in a 1:1 molar ratio in THF gave the dimeric lanthanide amido complexes [LLn{N(SiMe3)2}(THF)]2 [Ln=Nd ( 1 ), Sm ( 2 ), Yb ( 3 ), Y ( 4 )] in good isolated yields. These complexes were characterized by IR spectroscopy, elemental analysis, and 1H NMR spectroscopy in the case of complex 4 . The definitive molecular structures of complexes 1 , 3 , and 4 were determined. It was found that complexes 1 to 4 can initiate the ring‐opening polymerization of L‐lactide. 相似文献
996.
<正>Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature,as well as to increase the excitation rate of lumophores at room temperature. 相似文献
997.
A series of novel 7′-azaindirubin (1a-g) and 7-azaindirubin (2a, 2c, 2e and 2f) derivatives were designed and synthesized. Their structures were characterized by 1H NMR and MS spectroscopy as well as by elemental analysis. Their inhibitory properties against CDK2/cylinA were evaluated in vitro. In contrast to indirubin, some of the described azaindirubins emerged as potent inhibitors of CDK2/cylinA and compound 2b had more potent activity. Biological tests also showed that nitrogen atom at 7-position of azaindirubin was more beneficial to enhance the kinase inhibitory activity. 相似文献
998.
999.
Brφnsted酸性离子液体催化合成长链脂肪酸甲酯 总被引:2,自引:0,他引:2
本文合成了以1-丁基-3-甲基咪唑为阳离子,HSO4-、H2PO4-和BF4-为阴离子的Brφnsted酸性离子液体,并以长链脂肪酸与甲醇的酯化反应考察了这些Brφnsted酸性离子液体的催化性能。实验结果表明,1-丁基-3-甲基咪唑硫酸氢根鎓盐([bmim][HSO4])离子液体具有很高的催化活性,当n(醇)∶n(酸)∶n(离子液体)=6∶1∶0.25,反应温度为70℃,不分水酯化反应2h,长链脂肪酸甲酯的产率可达到93.4%以上,选择性达到100%;且产物酯与离子液体分离容易;离子液体经干燥处理后可以循环使用5次以上,催化活性没有明显降低。 相似文献
1000.