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1.
Mathematical Notes - Let $$\mathbb N$$ denote the set of all nonnegative integers, and let $$A\subseteq\mathbb N$$ . Let $$h,n\in\mathbb N$$ , $$h\ge 2$$ and $$r_h(A,n)=\#\{(a_1,\dots,a_h)\in... 相似文献
2.
《中国化学快报》2020,31(5):1317-1321
Dipyrrolyldiketone difluoroboron complexes (BONEPYs) were synthesized by condensation of the corresponding pyrroles and malonyl chloride followed by treatment with BF3·OEt2. The aryl-substituted pyrrole is introduced to form a cyclic system in order to investigate anion binding studies. In BONEPYs 1–3 the o-H of the aryl group forms hydrogen bonding with F− to give a more table complex. In contrast, the intramolecular hydrogen-bonded BONEPY endo-4 is more stable than its exo isomer. While adding F−, the hydrogen bonds must be broken first to give 4·(3)F−. Owing to the electron-rich group (-OMe), the o-H of the phenyl group can hardly interact with F− via hydrogen bonding to give the less stable complex 4·(5)F−. The energy differences between the different conformations were calculated using DFT methods, which is consistent to the experimental observations. 相似文献
3.
Novel expanded porphyrinoids with advanced structure features have a wide range of benefits (such as multi-metal coordination and facile tunable aromaticity) not offered by their normal porphyrin analogues. Considering research efforts have been devoted to address their limited synthetic accessibility issue. This review highlights some of these recent synthetic progresses towards these novel expanded porphyrinoids. 相似文献
4.
BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. An overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C-H functionalization of the BODIPY framework have been provided. 相似文献
5.
Dr. Xiu-Du Zhang Dr. Kai Chen Prof. Dr. Wei-Yin Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(16):5107-5119
Cucurbit[n]urils (Q[n]s) are a relatively young family of macrocycles, consisting of glycoluril units bridged by methylene groups, and their unique structures have attracted extensive attention from chemists in recent decades. Due to the presence of a rigid hydrophobic inner cavity and two polar outer portals lined with carbonyl groups, Q[n]s not only encapsulate guest species into the cavity, but also coordinate with metal ions/clusters. Considerable achievements have been obtained in the fields of Q[n]s-based host–guest chemistry, coordination chemistry, as well as the combination of host–guest and coordination chemistry. Furthermore, the outer surface of Q[n]s has been demonstrated to be capable of interacting with definite species to generate supramolecular architectures in recent years. With more in-depth research into Q[n]s, their application studies have also emerged as a hot topic. This Minireview focuses on recent advances in the potential applications of solid-state materials based on Q[n]s and their derivatives for the capture and adsorption of hazardous chemicals from a solution or a gas mixture. 相似文献
6.
NH3–plasma treated multi-walled carbon nanotubes (pn-MWCNTs) with cation traps for the detection of ultratrace quantities of Zn(II), Cd(II), Cu(II), and Hg(II) using square wave anodic stripping voltammetry (SWASV) is described. The pn-MWCNTs use their adsorption performance to enhance the sensitivity. It is found that under optimized conditions Zn(II), Cd(II), Cu(II) and Hg(II) were individually detected at potentials of −1.16, −0.78, −0.268 and 0.108 V, respectively. The detection limit (3σ method) of 0.314, 0.0272, 0.2263, and 0.1439 nM toward Zn(II), Cd(II), Cu(II), and Hg(II) is achievable, respectively. No interference could be seen during the simultaneous detection of Zn(II), Cd(II), Cu(II), and Hg(II). The pn-MWCNTs exhibit excellent selectivity owing to the different ability of adsorption. A study of the ability of pn-MWCNTs in practical application is carried out using a sample of water collected from Dongpu Reservoir in Hefei City, Anhui, China. It is found that the results were favorable when compared against inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis. 相似文献
7.
《中国化学快报》2020,31(11):2897-2902
Directly monitoring mitophagy-specific viscosity dynamic in living cells is of great significance but remains challenging. Herein, this study reported a novel mitochondria-targeted fluorescent probe DPAC-DY based on vibration-induced emission (VIE) for monitoring viscosity changes during mitochondrial autophagy. This probe contained N,N'-diphenyl- dihydrodibenzo[a,c]phenazine (DPAC) as the VIE core and two positively charged pyridinium moieties for mitochondria anchoring. As the ambient viscosity increased, the vibration of DPAC-DY could be hindered, and subsequently resulting in the enhancement of fluorescence emission. In vitro and intracellular experiments indicated that the probe DPAC-DY showed highly sensitive response to viscosity due to VIE mechanism. Importantly, by virtue of this probe, in situ and real-time visualization of the specific viscosity dynamics during the mitochondrial autophagy process was achieved. Thus, this work provides a novel strategy for VIE-based viscosity response sensors applied to specific organelles and offers a platform for in-depth study of mitochondrial viscosity-related diseases. 相似文献
8.
Zhu Hong Zeng Xiangbing Han Tianli Li Xuexue Zhu Shuguang Sun Bai Zhou Ping Liu Jinyun 《Journal of Solid State Electrochemistry》2019,23(7):2173-2180
Journal of Solid State Electrochemistry - Since conventional graphite-based anode possesses a low capacity, seeking for high-capacity anode candidates becomes significant for constructing emerging... 相似文献
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10.
A new polymorph of Bi2(SO4)3 was prepared by reaction of LiBiO2 with H2SO4 and its crystal structure was solved from X-ray powder diffraction. This new polymorph crystallizes in C2/c space group with lattice parameters a = 17.3383(3) Å, b = 6.77803(12) Å, c = 8.30978(13) Å, β = 101.4300(12)°. Bi2(SO4)3 presents a layered structure made of SO4 sulfate groups and signs of stereochemically active Bi3+ lone pairs. The new Bi2(SO4)3 absorbs water to form Bi2(H2O)2(SO4)2(OH)2 through an intermediate Bi2O(OH)2SO4 phase, and the transition is reversible when heated under vacuum. 相似文献