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991.
烟酸二聚体的结构与性质 总被引:1,自引:1,他引:0
用密度泛函理论B3LYP方法选取6-311+G(d,p)基组对烟酸-烟酸复合物进行了量子化学计算研究, 通过在相同水平下的频率振动分析发现了势能面上存在7个极小值点, 其最稳定构型1对应一N…H—O型强氢键, 其结合能在消除基组重叠误差后为-48.3 kJ·mol-1. 通过自然键轨道(NBO)分析, 研究了电荷转移及轨道相互作用. 通过自洽反应场(SCRF)理论中的极化连续模型(PCM)在介电常数分别为1.0(真空)、2.247(苯)、10.36(二氯乙烷)、20.7(丙酮)、32.63(甲醇)、78.39(水)的不同溶剂环境下重新优化烟酸复合物势能面上最稳定构型1, 研究了溶剂对烟酸复合物几何构型及结合能的影响. 发现溶剂化作用增大了烟酸复合物分子间的结合能, 导致N…H距离减小. 当溶液介电常数在1.0-32.63范围时, 溶剂效应十分显著, 当介电常数大于32.63后, 溶剂化作用趋于稳定. 相似文献
992.
Tsang‐Chi Lee Chiung‐Fang Chang Yuan‐Chieh Chiu Yun Chi Tzu‐Ying Chan Yi‐Ming Cheng Chin‐Hung Lai Pi‐Tai Chou Gene‐Hsiang Lee Chen‐Han Chien Ching‐Fong Shu Jens Leonhardt 《化学:亚洲杂志》2009,4(5):742-753
Long live the OLED! Rational design and synthesis of IrIII complexes bearing two cyclometalated ligands (C N) and one 2‐(diphenylphosphino)phenolate chelate (P O) as well as the corresponding IrIII derivatives with only one (C N) ligand and two P O chelates are reported. According to the observed photophysical data, a P O ligand is found to be able to fine‐tune the light‐emitting electronic transition of these complexes.
993.
This paper reports a facile and effortless method to realize three-dimensional (3D) molecular third-harmonic-generation (THG) microscopy through the technique of resonance enhancement with absorbing dye. Hematoxylin, a popular absorbing stain, is applied as an example to verify the multiphoton resonant enhancement based on the 1230 nm excitation light and can selectively enhance THG yield at cell nuclear sites in the studied specimens, serving as a cell nucleus contrast agent. It is concluded that combining THG microscopy with the mature staining technique can readily achieve 3D molecular imaging without using fluorescence. 相似文献
994.
Tai Xiang Sun 《数学学报(英文版)》2018,34(2):194-208
Let G be a graph and f : G → G be a continuous map. Denote by h(f), P(f), AP(f), R(f)and ω(x, f) the topological entropy of f, the set of periodic points of f, the set of almost periodic points of f, the set of recurrent points of f and the ω-limit set of x under f, respectively. In this paper,we show that the following statements are equivalent:(1) h(f) 0.(2) There exists an x ∈ G such that ω(x, f) ∩ P(f) = ? and ω(x, f) is an infinite set.(3) There exists an x ∈ G such that ω(x, f)contains two minimal sets.(4) There exist x, y ∈ G such that ω(x, f)-ω(y, f) is an uncountable set and ω(y, f) ∩ω(x, f) = ?.(5) There exist an x ∈ G and a closed subset A ? ω(x, f) with f(A) ? A such that ω(x, f)-A is an uncountable set.(6) R(f)-AP(f) = ?.(7) f |P(f)is not pointwise equicontinuous. 相似文献
995.
Stability of Periodic Orbits and Return Trajectories of Continuous Multi-valued Maps on Intervals 下载免费PDF全文
Let I be a compact interval of real axis R, and(I, H) be the metric space of all nonempty closed subintervals of I with the Hausdorff metric H and f : I → I be a continuous multi-valued map. Assume that Pn =(x_0, x_1,..., xn) is a return tra jectory of f and that p ∈ [min Pn, max Pn] with p ∈ f(p). In this paper, we show that if there exist k(≥ 1) centripetal point pairs of f(relative to p)in {(x_i; x_i+1) : 0 ≤ i ≤ n-1} and n = sk + r(0 ≤ r ≤ k-1), then f has an R-periodic orbit, where R = s + 1 if s is even, and R = s if s is odd and r = 0, and R = s + 2 if s is odd and r 0. Besides,we also study stability of periodic orbits of continuous multi-valued maps from I to I. 相似文献
996.
Jian Li Zu-Pei Liang Cheng-Yun Wang Xi-Shi Tai 《Journal of chemical crystallography》2009,39(9):638-641
Abstract The title compound N-(2,3,4-trimethoxy-6-methylbenzylidene)-2-methyl-benzenamine (C18H21NO3, M
r = 299.36) was synthesized and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The crystal
belongs to monoclinic, space group P21/n, with a = 7.2804(5), b = 8.5909(9), c = 26.117(3) ?, β = 92.056(2)°, V = 1,632.4(3) ?3, Z = 4, D
c = 1.218 g cm−3, λ = 0.71073 ?, μ(Mo Kα) = 0.083 mm−1, F(000) = 640. The final refinement gave R = 0.0497, wR(F
2) = 0.1157 for 2,879 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the dihedral angle between the two phenyl rings is 25.9 (2)°. The molecule adopts
a trans configuration about the central C=N functional bond. The crystal structure is stabilized by C–H…O hydrogen bonds and π–π stacking interactions. The title compound possesses moderate antibacterial activity.
Graphical Abstract The title compound N-(2,3,4-trimethoxy-6-methylbenzylidene)-2-methyl-benzenamine (C18H21NO3, M
r = 299.36) was synthesized and characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. The crystal
belongs to monoclinic, space group P21/n, with a = 7.2804(5), b = 8.5909(9), c = 26.117(3) ?, β = 92.056(2)°, V = 1,632.4(3) ?3, Z = 4, D
c = 1.218 g cm−3, λ = 0.71073 ?, μ(Mo Kα) = 0.083 mm−1, F(000) = 640. The final refinement gave R = 0.0497, wR(F
2) = 0.1157 for 2,879 observed reflections with I > 2σ(I). X-ray diffraction analysis reveals that the dihedral angle between the two phenyl rings is 25.9 (2)°. The molecule adopts
a trans configuration about the central C=N functional bond. The crystal structure is stabilized by C–H…O hydrogen bonds and π–π stacking interactions. The title compound possesses moderate antibacterial activity.
相似文献
997.
Introduction Since Tang[1] firstly reported the electroluminescence of 8-hydroxyquinoline aluminium, much attention has been paid to the organic compound as electro-luminescent material. Especially, electron transport materials play an important role in organic light-emitting diode(OLED). 2-(4-Biphenyl)-5-(t-butylphenyl)-1,3,4-oxadiazole(PBD), as a kind of popular electron injection/transport materials, can improve remarkably the injection balance of electrons and holes. As a result, it can amend the properties of OLED[2,3]. 相似文献
998.
Let R be a 2-torsion free prime ring, d1 a nonzero derivation, -γ a generalized derivation associated with a nonzero derivation d2, U a square closed Lie ideal of R. In the present paper,we prove that if [di^2(u), u] ∈ Z(R) or γ acts as a homomorphism (or an antihomomorphism) on U, then U Z(R). 相似文献
999.
1000.
Yu‐An Xiong Tai‐Ting Sha Qiang Pan Xian‐Jiang Song Shu‐Rong Miao Zheng‐Yin Jing Zi‐Jie Feng Yu‐Meng You Ren‐Gen Xiong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(26):8949-8953
The X‐site ion in organic–inorganic hybrid ABX3 perovskites (OHPs) varies from halide ion to bridging linkers like HCOO?, N3?, NO2?, and CN?. However, no nitrite‐based OHP ferroelectrics have been reported so far. Now, based on non‐ferroelectric [(CH3)4N][Ni(NO2)3], through the combined methodologies of quasi‐spherical shape, hydrogen bonding functionality, and H/F substitution, we have successfully synthesized an OHP ferroelectric, [FMeTP][Ni(NO2)3] (FMeTP=N‐fluoromethyl tropine). As an unprecedented nitrite‐based OHP ferroelectric, the well‐designed [FMeTP][Ni(NO2)3] undergoes the ferroelectric phase transition at 400 K with an Aizu notation of 6/mmmFm, showing multiaxial ferroelectric characteristics. This work is a great step towards not only enriching the molecular ferroelectric families but also accelerating the potential practical applications. 相似文献