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1.
Mi-Young Song En-Young Kim Kyung Il Kim Hong-Seok Kim Chang-Hee Lee 《Tetrahedron letters》2004,45(2):299-301
Furans, thiazoles, fluorene or thiophene incorporated calix[4]pyrrole analogues were synthesized and characterized. The synthesis was achieved by utilization of various building blocks such as 7, 13, 14, 18 and 21. Acid catalyzed condensation of those building blocks with acetone or meso-disubstituted dipyrromethanes afforded desired macrocycles. 相似文献
2.
Tetrel bond, a weak noncovalent interaction between the σ-hole of a Group IV element (silicon in our case) and the cloud of an electronegative element (oxygen in our case) is the focus of this work. The percentage strengthening of tetrel bond has been investigated by optimizing 16 binary complexes of halogenated silane and water of general formula SiXnH4−n−H2O and 16 ternary complexes, of general formula NaX−SiXnH4−n−H2O, where X=F, Cl, Br and I and n=1, 2, 3 and 4 at various levels of theory defined within the formalism of density functional theory (DFT). With the addition of NaX, tetrel bond between Si and O in SiXnH4−n−H2O gets strengthened up to 49 %, owing to cooperativity effect exerted by hydrogen bonding between X and H in the ternary complex NaX−SiXnH4−n−H2O. In the series of complexes studied here, overall stabilization due to cooperativity lies between 10 kJ/mol to 170 kJ/mol. This large extent of reinforcement due to cooperativity has never been showcased before. The exceptional stabilization and reinforcement owe its genesis to the transformation of the ternary complex into a cluster orchestrated by the H-bonding in most of the cases and covalent bonding in few of the cases. 相似文献
3.
Analysis of the bisignate circular dichroism spectra of bilirubin-IXα bis-propionate salts of (S)-(-)-N, N, N-trimethyl α-phenethylammonium hydroxide reveals a preference in CHC13, (CH3)2 CO and CH3 CN solvents for folded conformations in which the propionate groups are intramolecularly H-bonded to the opposing pyrromethenone units. 相似文献
4.
Linjun Qi Ming Dong Jinlong Qian Shuling Yu Prof. Xiaofeng Tong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202215397
Reductive elimination of alkyl−PdII−O is a synthetically useful yet underdeveloped elementary reaction. Here we report that the combination of an H-bonding donor [PyH][BF4] and AgNO3 additive under toluene/H2O biphasic system can enable such elementary step to form alkyl nitrate. This results in the Pd0-catalyzed asymmetric carbonitratations of (Z)-1-iodo-1,6-dienes with (R)-BINAP as the chiral ligand, affording alkyl nitrates up to 96 % ee. Mechanistic studies disclose that the reaction consists of oxidative addition of Pd0 catalyst to vinyl iodide, anion ligand exchange between I− and NO3−, alkene insertion and SN2-type alkyl−PdII−ONO2 reductive elimination. Evidences suggest that H-bonding interaction of PyH⋅⋅⋅ONO2 can facilitate dissociation of O2NO− ligand from the alkyl−PdII−ONO2 species, thus enabling the challenging alkyl−PdII−ONO2 reductive elimination to be feasible. 相似文献
5.
Dr. Thangavel Vijayakanth Supriya Sahoo Premkumar Kothavade Vijay Bhan Sharma Prof. Dr. Dinesh Kabra Dr. Jan K. Zaręba Dr. Kadhiravan Shanmuganathan Prof. Dr. Ramamoorthy Boomishankar 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(3):e202214984
Hybrid materials possessing piezo- and ferroelectric properties emerge as excellent alternatives to conventional piezoceramics due to their merits of facile synthesis, lightweight nature, ease of fabrication and mechanical flexibility. Inspired by the structural stability of aminophosphonium compounds, here we report the first A3BX6 type cyanometallate [Ph2(iPrNH)2P]3[Fe(CN)6] ( 1 ), which shows a ferroelectric saturation polarization (Ps) of 3.71 μC cm−2. Compound 1 exhibits a high electrostrictive coefficient (Q33) of 0.73 m4 C−2, far exceeding those of piezoceramics (0.034–0.096 m4 C−2). Piezoresponse force microscopy (PFM) analysis demonstrates the polarization switching and domain structure of 1 further confirming its ferroelectric nature. Furthermore, thermoplastic polyurethane (TPU) polymer composite films of 1 were prepared and employed as piezoelectric nanogenerators. Notably, the 15 wt % 1 -TPU device gave a maximum output voltage of 13.57 V and a power density of 6.03 μW cm−2. 相似文献
6.
Dr. Sourav Sarkar Anushree Shil Suman Maity Dr. Yun Lim Jung Dr. Mingchong Dai Prof. Atanu Acharya Prof. Kyo Han Ahn 《Angewandte Chemie (International ed. in English)》2023,62(43):e202311168
Aryl alcohol-type or phenolic fluorophores offer diverse opportunities for developing bioimaging agents and fluorescence probes. Due to the inherently acidic hydroxyl functionality, phenolic fluorophores provide pH-dependent emission signals. Therefore, except for developing pH probes, the pH-dependent nature of phenolic fluorophores should be considered in bioimaging applications but has been neglected. Here we show that a simple structural remedy converts conventional phenolic fluorophores into pH-resistant derivatives, which also offer “medium-resistant” emission properties. The structural modification involves a single-step introduction of a hydrogen-bonding acceptor such as morpholine nearby the phenolic hydroxyl group, which also leads to emission bathochromic shift, increased Stokes shift, enhanced photo-stability and stronger emission for several dyes. The strategy greatly expands the current fluorophores’ repertoire for reliable bioimaging applications, as demonstrated here with ratiometric imaging of cells and tissues. 相似文献
7.
Homopolymerization of N-pyrimidinyl acrylamide(NPA)was reported for the first time.The polymer(polyNPA)was soluble only in acidic media and fluoroalcohols,and only in fluoroalcohol was homogeneous polymerization of NPA feasible.~1H NMR analysis proved that a 1:1 H-bonding complex could be formed between NPA andα,α-bis(trifluoromethyl)phenyl propan-2-ol (BTMP).Cumyl dithiobenzoate mediated reversible addition-fragmentation chain transfer(RAFT)polymerization of NPA in BTMP was carried out.~1H NMR analyses proved that the molecular weight increased linearly with the monomer conversion.The polymer prepared in conventional solvents was atactic while in protic media the syndiotacticity was slightly enhanced. 相似文献
8.
1 The single stranded-helicate Vanadium(IV) complex [V2O2Cl4(L)(H2O)2] (1) involving heterocyclic bis-bidentate ligand viz. 3,3/-dipyridine-2-yl-[1.1/]bi[imidazo[1,5-a]pyridineyl] (L) with biological relevance is prepared and characterized by X-ray diffraction analysis. The compound lacks molecular center of symmetry where coordination environments around V(1) and V(2) centres are distorted octahedral (V···V# separation of 5.827 Å). Structure of the compound in the solid state structure shows anion?π interactions, classical and Carene-H---anion non-classical H-bonding interactions. These interactions play significant roles in shaping the extended structure of this molecule. 相似文献
9.
Qi Jin Ruichun Du Hao Tang Yan Zhao Wansu Peng Yanyan Li Jing Zhang Tangsong Zhu Xinxin Huang Prof. Deshuo Kong Yucheng He Tianwei Bao Desheng Kong Prof. Xiaoliang Wang Prof. Rong Wang Prof. Qiuhong Zhang Prof. Xudong Jia 《Angewandte Chemie (International ed. in English)》2023,62(26):e202305282
Tough and self-healable substrates can enable stretchable electronics long service life. However, for substrates, it still remains a challenge to achieve both high toughness and autonomous self-healing ability at room temperature. Herein, a strategy by using the combined effects between quadruple H-bonding and slidable cross-links is proposed to solve the above issues in the elastomer. The elastomer exhibits high toughness (77.3 MJ m−3), fracture energy (≈127.2 kJ m−2), and good healing efficiency (91 %) at room temperature. The superior performance is ascribed to the inter and intra crosslinking structures of quadruple H-bonding and polyrotaxanes in the dual crosslinking system. Strain-induced crystallization of PEG in polyrotaxanes also contributes to the high fracture energy of the elastomers. Furthermore, based on the dual cross-linked supramolecular elastomer, a highly stretchable and self-healable electrode containing liquid metal is also fabricated, retaining resistance stability (0.16–0.26 Ω) even at the strain of 1600 %. 相似文献
10.
Khashayar Rajabimoghadam Yousef Darwish Umyeena Bashir Dylan Pitman Sidney Eichelberger Maxime A. Siegler 《Journal of Coordination Chemistry》2019,72(8):1346-1357
AbstractIn this research article, we report the synthesis and structural characterization of a family of first-row metal complexes bearing redox-active ligands with tunable H-bonding donors. We observed that these coordination complexes can adopt three different geometries and that they are stabilized by intramolecular multicenter H-bonding interactions, which are systematically modified by changing the metal ion (Co, Ni, Cu, Zn), the ligand scaffold (variations in the diamine and ureanyl substituents used) and the solvent of crystallization. 相似文献