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961.
Inside Cover: Peripheral Templation‐Modulated Interconversion between an A4L6 Tetrahedral Anion Cage and A2L3 Triple Helicate with Guest Capture/Release (Angew. Chem. Int. Ed. 7/2018)
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962.
One three-dimensional Sr(II) coordination polymer [C6(MIm)2][Sr3(1,4-NDC)4] (I) (C6(MIm)2 = 1,3-bis(3-methylimidazolium-1-yl)hexyl, 1,4-H2NDC = 1,4-naphthalenedicarboxylate acid) has been synthesized using an ionothermal method and structurally characterized by IR spectroscopy, UV-Vis spectroscopy, XRPD, and X-ray single-crystal structure analysis (СIF file CCDC 1033958). Two types of strontium centers are bridged by two coordination modes of 1,4-H2NDC ligands to form a Sr(II) chain. Each Sr(II) chain is crossconnected to four other chains to generate a 3D coordination polymer, in which C6(MIm) 2 2+ cations as charge balancing species are filled in the channels of the anionic framework. The polymeric solid of I exhibits strong luminescent emission at room temperature. 相似文献
963.
Yuanyuan Lu Sílvia Alujas-Burgos Cristina Oliveras-González Laura Vázquez-Jiménez Pep Rojo Ángel Álvarez-Larena Pau Bayón Marta Figueredo 《Tetrahedron》2018,74(1):104-116
An enantioselective approach to substituted indolizidine and quinolizidine frameworks has been developed. Key steps of the synthesis are the enantioselective, palladium-catalyzed N-allylation of an imide, the nucleophilic allylation of an acyliminium ion and a ring closing metathesis. This general strategy has been applied to the synthesis of indolizidine peptide mimics, starting from a chiral imide derived from l-aspartic acid. It was observed that the preexisting stereogenic center of this substrate has a moderate influence on the stereoselectivity of the electrophilic allylation, which is mainly determined by the sense of chirality of the catalyst. 相似文献
964.
965.
Fei Ding Quanbing Mou Yuan Ma Gaifang Pan Yuanyuan Guo Prof. Gangsheng Tong Prof. Chung Hang Jonathan Choi Prof. Xinyuan Zhu Prof. Chuan Zhang 《Angewandte Chemie (International ed. in English)》2018,57(12):3064-3068
Functional siRNAs are employed as cross‐linkers to direct the self‐assembly of DNA‐grafted polycaprolactone (DNA‐g‐PCL) brushes to form spherical and nanosized hydrogels via nucleic acid hybridization in which small interfering RNAs (siRNAs) are fully embedded and protected for systemic delivery. Owing to the existence of multivalent mutual crosslinking events inside, the crosslinked nanogels with tunable size exhibit not only good thermostability, but also remarkable physiological stability that can resist the enzymatic degradation. As a novel siRNA delivery system with spherical nucleic acid (SNA) architecture, the crosslinked nanogels can assist the delivery of siRNAs into different cells without any transfection agents and achieve the gene silencing effectively both in vitro and in vivo, through which a significant inhibition of tumor growth is realized in the anticancer treatment. 相似文献
966.
Peripheral Templation‐Modulated Interconversion between an A4L6 Tetrahedral Anion Cage and A2L3 Triple Helicate with Guest Capture/Release
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Xuemin Bai Prof. Chuandong Jia Prof. Yanxia Zhao Dr. Dong Yang Shi‐Cheng Wang Prof. Anyang Li Prof. Yi‐Tsu Chan Prof. Yao‐Yu Wang Prof. Xiao‐Juan Yang Prof. Biao Wu 《Angewandte Chemie (International ed. in English)》2018,57(7):1851-1855
An anion‐coordination‐based A4L6 (“A” denotes anion and “L” is ligand) tetrahedral cage was constructed by a C2‐symmetric bis‐bis(urea) ligand and phosphate anion, which showed reversible interconversion with the A2L3 triple helicate as a response to the template, concentration, or solvent. Notably, an unusual “peripheral” templation was found to be critical to stabilize the tetrahedral structure. This peripheral effect was utilized to assemble an “empty” A4L6 cage that allows the multi‐stimuli‐controlled capture/release of biologically important species such as choline and acetylcholine. 相似文献
967.
High-efficiency nonvolatile holographic storage with two-step recording in praseodymium-doped lithium niobate by use of continuous-wave lasers 总被引:1,自引:0,他引:1
We have observed efficient two-photon, two-step recording in a praseodymium-doped lithium niobate crystal by use of cw lasers. Single-photon erasure during the readout at near-infrared wavelengths was found to be negligible. Nonvolatile holographic image storage was demonstrated. This progress is an important step in the realization of an economically feasible nonvolatile read-write holographic recording system based on low-cost semiconductor diode lasers. 相似文献
968.
Bai LP Cai Z Zhao ZZ Nakatani K Jiang ZH 《Analytical and bioanalytical chemistry》2008,392(4):709-716
Spectrofluorometric titration, electrospray ionization time-of-flight mass spectrometric and UV melting methods were employed
to study the binding of chelerythrine and sanguinarine to bulged DNA. The results showed that both alkaloids bind specifically
to single pyrimidine (C, T) bulge sites. The ability of sanguinarine to bind to both regular and bulged hairpins was found
to be stronger than that of chelerythrine, but the binding selectivity of chelerythrine toward single-base bulges was much
larger than that of sanguinarine.
Figure Association constants for chelerythrine and sanguinarine toward regular and single-base bulged hairpins obtained from fluorometric
analysis 相似文献
969.
A water-compatible Pd(ii) pincer with a hybrid [SNS]-donor set, [L(1)PdCl]Cl.2H(2)O [L(1) = bis-(2-(i-butylsulfanyl)-ethyl)-amine] has been isolated and crystallographically characterized; its solid lattice at 223 K contains a ladder-like water polymer of tetramers and extensive H-bonding exists among the cation, anion and water cluster, and this water-soluble complex is active in Suzuki-Miyaura coupling of phenylboronic acid and selected aryl bromides in water at 75 degrees C. 相似文献
970.
Jian-Po Zhang Xin Zhou Tao Liu Fu-Quan Bai Hong-Xing Zhang Au-Chin Tang 《Theoretical chemistry accounts》2008,121(3-4):123-134
A series of Osmium(II) complexes [Os (trpy-R)2]2+(trpy=2,2′,6′,2′′-terpyridine and R=H (1), OH (2), and C6H5(3)) have been investigated by the density functional (DF) and ab initio calculations. The structures of 1–3 in the ground and excited states were fully optimized at the B3LYP and CIS level, respectively, and their absorption and emission spectra in the acetonitrile solution were obtained using the TD-DFT (B3LYP) method associated with the PCM model. The calculations indicated that, for 1–3, the variation of the substituents on the terpyridine ligand only slightly changes their geometrical structures in the ground and excited states but leads to a sizable difference in the electronic structures. The results show that the low-lying MLCT/ILCT transitions (at 446 (1), 465 (2), and 499 nm (3)) are red-shifted according to the electron-donating ability of substituents on the terpyridine ligand, but blue-shift trend of the high-lying ILCT transitions (at 301 (1), 297 (2), and 272 nm (3)). It also reveals that the lowest energy emissions of 1–3 at 649 nm, 656 nm, and 676 nm have the character of mixing 3[π*(trpy) → d(Os)] and 3 ππ* (3MLCT/3ILCT) transitions localized on the terpyridine ligand, which are identical to the transition properties of the lowest-energy absorptions. 相似文献