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941.
《印度化学会志》2021,98(9):100122
Salophen is a weakly fluorescent Schiff base which forms emissive co-ordination complexes with Zn2+ and Al3+. The complex with Al3+ is significantly more fluorescent than that with Zn2+, presumably because the dimeric complex with Zn2+ is associated with additional nonradiative channels. This contention has been put to test, through a careful investigation of excited state dynamics of the anionic form of salophen (Sal2−), which is the form in which the ligand exists in the complexes. The emissive excited state of the anion (Sal2−) has been found to be solvated and conformationally relaxed, over tens of picosecond. It is significantly more fluorescent than the neutral compound, with fluorescence lifetime that is longer by almost two orders of magnitude. Fluorescence lifetime of the anion is in fact longer than that of the complex with Zn2+ and slightly less than that of the complex with Al3+. So, the earlier hypothesis about additional nonradiative deactivation pathways in the Zn2+ complex gains credence from the present study. 相似文献
942.
Xing Chen Wenguang Zhao Feng Wang Jie Xu .Dalian National Laboratory for Clean Energy State 《天然气化学杂志》2012,(5):481-487
Preparation of dispersed transition metal oxides catalyst with low oxidation state still remains a challenging task in heterogeneous catalysis.In this study,vanadium oxides supported on zeolite SBA-15 have been prepared under hydrothermal condition using V 2 O 5 and oxalic acid as sources of vanadium and reductant,respectively.The structures of samples,especially the oxidation state of vanadium,and the surface distribution of vanadium oxide species,have been thoroughly characterized using various techniques,including N 2-physisorption,X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),UV-visible spectra(UV-Vis) and UV-visible-near infrared spectra(UV-Vis-NIR).It is found that the majority of supported vanadium was in the form of vanadium(IV) oxide species with the low valence of vanadium.By adjusting hydrothermal treatment time,the surface distribution of vanadium(IV) oxide species can be tuned from vanadium(IV) oxide cluster to crystallites.These materials have been tested in the hydroxylation of benzene to phenol in liquid-phase with molecular oxygen in the absence of reductant.The catalyst exhibits high selectivity for phenol(61%) at benzene conversion of 4.6%,which is a relatively good result in comparison with other studies employing molecular oxygen as the oxidant. 相似文献
943.
The intent of this study is to examine nonequilibrium heat transfer in a copper-argon nanofluid by molecular dynamics simulation. Two different methods, the physical definition method and the curve fitting method, are introduced to calculate the coupling factor between nanoparticles and base fluid. The results show that the coupling factors obtained by these two methods are consistent. The coupling factor is proportional to the volume fraction of the nanoparticle and inversely proportional to nanoparticle diameter. In the temperature range of 90-200 K, the coupling factor is not affected by temperature. The nanoparticle aggregation results in a decrease of the coupling factor. 相似文献
944.
945.
《Communications in Nonlinear Science & Numerical Simulation》2014,19(6):2005-2011
A new 4-D fractional-order chaotic system without equilibrium point is proposed in this paper. There is no chaotic behavior for its corresponding integer-order system. By computer simulations, we find complex dynamical behaviors in this system, and obtain that the lowest order for exhibiting a chaotic attractor is 3.2. We also design an electronic circuit to realize this 4-D fractional-order chaotic system and present some experiment results. 相似文献
946.
通过将掺杂剂单元用化学键接到聚芴的侧链上,实现了掺杂剂单元在高分子主体中的分子水平分散,开发了一种新型的基于掺杂剂/主体材料体系的分子分散型蓝光聚芴衍生物.与纯聚芴相比,这种新的分子分散型蓝光聚芴衍生物具有很高的荧光量子效率.以这种新的分子分散型蓝光聚芴衍生物为增益介质的激光器件,在Nd:YAG 355 nm脉冲激光泵浦下,获得了较好的放大自发发射光谱,阈值达到0.25 m J/(pulse cm2).从光物理的角度对薄膜的光学增益和光学损耗进行了定量运算和分析,经过拟合发现,当泵浦能量为0.06m J/pulse时,该聚芴衍生物增益系数可达23.08 cm-1,损耗系数为6.96 cm-1.优良的放大自发发射特性表明该聚芴衍生物是非常好的有机激光增益介质材料. 相似文献
947.
Jiawei Zhang Yiliu Liu Bin Yuan Prof. Zhiqiang Wang Prof. Monika Schönhoff Prof. Xi Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(47):14968-14973
Stable multilayer films with cucurbit[8]uril have been fabricated on the basis of the alternating layer‐by‐layer assembly of a novel side‐chain pseudopolyrotaxane and a photoreactive polyanion. The as‐prepared multilayer films exhibit good properties as surface‐imprinted multilayers, because cucurbit[8]uril molecules that are locked inside the multilayers can act as nanocontainers with specific binding to certain guest molecules, and the loading and release of the guest is redox‐controllable and reversible. 相似文献
948.
949.
950.
Komuraiah Buduma Niranjana Kumar A Satya Srinivas KVN Kotesh Kumar J Srinivas Chinde Anand Kumar Domatti Yogesh Kumar Paramjit Grover Ashok Tiwari Feroz Khan 《Journal of heterocyclic chemistry》2021,58(11):2078-2089
Design, synthesis, and bioactivity evaluation of novel mannich bases ( 2a-2j ) and triazole-chalcone derivatives ( 7a-7k ) of Eugenol 1 were reported. Among all the derivatives tested for antiproliferative activity, di-amine manich derivative 2b (32.92 μM), and 4-methoxy chalcone triazole derivative 7d (33.05 μM) significantly inhibited HepG2 cell lines when compared to the standard doxorubicin (37.29 μM). Whereas most of the compounds such as diethylamine 2a (17.75 μM), (aminomethyl) methane diamine 2b (17.02 μM), and bis (chloromethyl) amine 2c (20.12 μM) showed moderate to better inhibition towards MCF-7 cell lines. The synthesized analogues were also tested for antidiabetic and antiobesity potentials. Compounds 2f (55.50%), 2c (54.34%), 7g (55.5%), and 2a (55.5%) have shown moderate inhibitory potentials toward intestinal α-glucosidase enzyme when compared to the standard Acarbose (72.86%). Likewise, compounds 7d (82.95%), 7f (76.19%), 7g (74.81%), 7e (74.81%), and 2g (72.50%) have shown significant to moderate inhibitory potentials toward Pancreatic lipase enzyme when compared to the standard orlistat (91.10%). ROS induces life-threatening diseases like diabetes, cancer, etc., and antioxidants play a major role in controlling their production. Compounds 2c (99.81%), 2i (99.80%), 2d (99.26%), 2g (98.79%), and 2f (98.42%) have shown significant antioxidant profiles in ABTS assay when compared to the standard Trolox (99.07%). Further, In silico Molecular docking and pharmacokinetic screening of the eugenol derivatives complemented the in vitro results indicating the drug likeness of the obtained active compounds. 相似文献