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991.
Importing intramolecular hydrogen bond in phosphorescent transition metal complexes has been considered one of the excellent approaches to improve the electroluminescence performance of organic light-emitting diodes in real applications. However, the relationships between such H-bond structure and phosphorescent properties have not been theoretically revealed yet. In this study, two types of intramolecular hydrogen bonds are introduced into the two classes of traditional materials, that is, Pt(II) and Ir(III) complexes ( 1a and 2a ) to completely elucidate their influence on the structures and properties by comparing with the original phosphors ( 1b and 2b ) using density functional theory/time-dependent density functional theory for the first time. A comprehensive analysis of the geometric structures, molecular orbitals, and luminescence properties (including phosphorescence emission wavelengths and radiative and nonradiative decay processes) has been carried out. Our theoretical model highlights that complexes 1a and 2a embedded with H-bonds significantly promote the phosphorescence emission band blue-shifted and restrict molecular deformations compared with the corresponding 1b and 2b , which can provide helpful guidance to regulate and design several aspects of highly efficient blue phosphorescent emitters. 相似文献
992.
993.
Aequationes mathematicae - In this paper we study estimation, continuous dependence and Hyers–Ulam stability for continuous solutions of a second order iterative equation. First we give an... 相似文献
994.
Two LnIII ions are sandwiched by dinuclear CoII building blocks derived from a tris‐triazamacrocyclic ligand bearing pendant carboxylic acid functionality, 1,3,5‐tris((4,7‐bis(2‐carboxyethyl)‐1,4,7‐triazacyclonon‐1‐yl)methyl)‐benzene (H6L), giving rising to two nanoscale heterometallic metal–organic cages formulated as [Co4Ln2(LH2.5)2(H2O)4]·(ClO4)6·NO3·nH2O [Ln = Dy, n = 12 ( 1 ); Ln = Yb, n = 9 ( 2 )], whose internal cavity accommodates a guest NO3? anion. Their hexanuclear cage‐like architectures are maintained both in solution and solid states as confirmed by mass spectrum as well as X‐ray diffraction experiments. These two cages display ligand‐based fluorescence emissions and therefore both were chosen to be operated as fluorescent chemosensors for the detection of nitroaromatic compounds. Attractively, these metal–organic cages allow highly selective and sensitive detection of picric acid (PA) over other nitroaromatics in solution and suspension, and the fluorescence resonance energy transfer (FRET) between the cage probes and PA is mainly responsible for the remarkable detection efficiency. 相似文献
995.
JPC – Journal of Planar Chromatography – Modern TLC - High-performance thin-layer chromatography, which is a quick qualitative and quantitative method, was used to determine 3 kinds of... 相似文献
996.
Given a planar continuum Gaussian free field h𝒰 in a domain 𝒰 with Dirichlet boundary condition and any δ > 0, we let be a real-valued smooth Gaussian process where is the average of h𝒰 along a circle of radius δ with center v. For γ > 0, we study the Liouville first-passage percolation (in scale δ), i.e., the shortest path distance in 𝒰 where the weight of each path P is given by . We show that the distance between two typical points is for all sufficiently small but fixed γ > 0 and some constant c* > 0. In addition, we obtain similar upper bounds on the Liouville first-passage percolation for discrete Gaussian free fields, as well as the Liouville graph distance, which roughly speaking is the minimal number of euclidean balls with comparable Liouville quantum gravity measure whose union contains a continuous path between two endpoints. Our results contradict some reasonable interpretations of Watabiki's prediction (1993) on the random distance of Liouville quantum gravity at high temperatures.© 2019 Wiley Periodicals, Inc. 相似文献
997.
Dr. Jiong Zhou Dr. Guocan Yu Yang Li Jie Shen Mengbin Wang Dr. Zhengtao Li Dr. Peifa Wei Prof. Dr. Jianbin Tang Prof. Dr. Feihe Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(63):14447-14453
Cyanide is extremely hazardous to living organisms and the environment. Owing to its wide range of applications and high toxicity, the development of functional materials for cyanide detection and sensing is highly desirable. Host–guest complexation between bis(p-phenylene)-34-crown-10 H and N-methylacridinium salt G remarkably decreases the detection limit for cyanide anions compared with that of the guest itself. The [2]pseudorotaxane selectively recognizes the cyanide anion with high optical sensitivity as a result of the nucleophilic addition of the cyanide anion at the 9-position of G . The host–guest complexation is further incorporated into supramolecular materials for the visual detection of cyanide anions, especially the detection of cellular cyanide excretion with a detection limit of 0.6 μm . This supramolecular method provides an extremely distinct strategy for the visual detection of cyanide anions. 相似文献
998.
Jian Wang Jinjin Zhou Yu Xu Bingqi Zhu Huiyi Li 《Rapid communications in mass spectrometry : RCM》2019,33(17):1410-1419
999.
Dr. Wenyan Hao Yuchen Sha Dr. Yi Deng Yi Luo Li Zeng Shan Tang Dr. Yue Weng Prof. Dr. Chien-Wei Chiang Prof. Dr. Aiwen Lei 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(19):4931-4934
An in situ generated oxidation species of nickel quinolinylpropioamide intermediate was produced. Characterization by X-ray absorption near edge structure (XANES) and EPR provides complementary insights into this oxidized nickel species. With aliphatic amides and isocyanides as substrates, a nickel-catalyzed facile synthesis of structurally diverse five-membered lactams could be achieved. 相似文献
1000.
Na-Na Jiang Shu-Zong Du Yan-Song Ye Hui Yan Xing-Wei Yang Jian Yang Yin Nian Gang Xu 《Tetrahedron letters》2019,60(45):151220
Hyphenone A (1), a new type of bicyclic polyprenylated acylphloroglucinols (BPAPs) featured with an unprecedented 3,3-diisoprenylated 1,3,5-trione core, were characterized from the roots of Hypericum henryi together with two new congeners (hyphenones B–C, 2–3) and five known biosynthetic related PPAPs. Biogenetically, 1 should be derived from a novel 3,3,5,5-tetraisoprenylated MPAPs precursor. Their structures were elucidated by comprehensive spectroscopic data and X-ray diffraction. Moreover, 1–3 were identified as the first PPAPs type Cav3.1 T-type calcium channel (TTCC) inhibitors, with IC50 values of 7.07, 6.19, and 5.47 μM, respectively. 相似文献