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1.
Tai Ning LIANG Xiang Yu ZHANG Xiao Zhen YANG* State Key Laboratory of Polymer Physics Chemistry Center for Molecular Science Institute of Chemistry Chinese Academy of Sciences Beijing Institute of Chemistry & Engineering Heilongjian 《中国化学快报》2001,(9)
The prediction of glass transition temperature from chemical structure has a great significance to select and design new high-properties materials. However, for the estimation and correlation methods, the deficiency of parameters for newer groups will lead to invalidity of Tg prediction or greater deviation from experiment. In the present work, we predicted Tg for a polyimide (PI) ensemble with rigid moieties, and analyzed structural factor that regards to the rotation barrier of the bridging… 相似文献
2.
JingLinCHEN LiYiZHANG ZhongNingCHEN 《中国化学快报》2005,16(3):372-374
A novel dimeric complex [Ru3^111,111,11(μ3-O)(μ-CH3COO)(CO)]2(μ-dppf)(μ-odppf) (dppf=1, 1‘-bis(diphenylphosphio)ferrocene, odppf = 1, 1‘-bis(oxodiphenylphosphoranyl)ferrocene) (1) of oxo-centered triruthenium-aectate cluster units was synthesized and characterized by X-ray crystallography. Compound 1 exhibits a cyclic structure formed by linkages of two triruthenium cluster units Ru3^111,111,11(μ3-O)(μ-CH3COO)6(CO) through dppf and odppf ligands, respectively. The diameter of the molecular loop is ca. 1.0 rim. 相似文献
3.
《中国化学快报》1997,(6)
Asanessentialfeatureofbiochemicalsystems,molecularrecognitionplaysplvotalroleinlifeprocesses.['.'1Duringthepasttwodecades,researchonthedesign,synthesisandevaluationofvarioustroesofsyntheticreceptorshasreachedanewdimension-Therigidhydrophobicskeletonandinherentasymmetryofsteroidnucleiposethernasidealbuildingblocksfortheconstructionofsynthetichostmolecules.Therefore,thedesignandsynthesisofrecept0rsderivlngfromster0idshavecurrentlyarousedwldespreadinterest.ThemacrocycIicreceptorsbasedonandrogenh… 相似文献
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5.
Yu Liu Yan-Li Zhao En-Cui Yang Heng-Yi Zhang 《Journal of inclusion phenomena and macrocyclic chemistry》2004,50(1-2):3-11
Three -cyclodextrin (-CD) derivatives bearing anthracene group (2–4) were synthesized by the condensation of 9-anthracenecarboxylic acid with the corresponding oligo(aminoethylamino)--CDs in 33–36% yields and their original conformations and binding behavior with steroid molecules were investigated by using spectroscopic techniques and isothermal calorimeter. The combination of induced circular dichroism (ICD) and 2D NMR spectra reveals that the anthryl group attached to -CD is itself included in cavity and the chain length of oligo(aminoethylamino) decides the orientation of the anthryl located in the cavity to some extent, directly affecting the binding ability with guest molecules. Calorimetric titration has been performed at buffer aqueous solution (pH 7.2) at 25 °C to give the binding constants (K_S) and thermodynamic parameters for 11 inclusion complexation of modified -CDs 2–4 and representative steroids, i.e., cholate, deoxycholate, glycocholate, and taurocholate. Possessing the sidearm with appropriate length, 3 gives the highest stability constant of 22485± 15 M–1 for the complexation with deoxycholate molecule, which may be ascribed to the co-inclusion interactions between the host and guest. As compared with parent -CD 1 upon complexation with steroids, hosts 2–4 with different chain lengths enhanced the binding ability and significant molecular discrimination, which are discussed comparatively and globally from the viewpoint of thermodynamics. Furthermore, we establish the correlation between the conformation of the resulting complexes and the thermodynamic parameters obtained. 相似文献
6.
A variety of fluorinated compounds of β‐amino ketones could be obtained in good to excellent yields at room temperature through a three‐component Mannich reaction of aldehydes, anilines, and acetones catalyzed by iodine. 相似文献
7.
With the rapid developments in the field of information technology, the material research society is looking for an alternate scientific route to the traditional methods of trial and error in material research and process development. Machine learning emerges as a new research paradigm to accelerate the application‐oriented material discovery. Quantum dots are expanded as functional nanomaterials to enhance cutting‐edge photonic technology. However, they suffer from uncertainty in industrial fabrication and application. Here, we discuss how machine learning accelerates the development of quantum dots. The basic principles and operation procedures of machine learning are described with a few representative examples of quantum dots. We emphasize how machine learning contributes to the optimization of synthesis and the analysis of material characterizations. To conclude, we give a short perspective discussing the problems of combining machine learning and quantum dots. 相似文献
8.
The active site of 3CL proteinase (3CL^por) for coronavirus was identified by comparing the crystal structures of human and porcine coronavirus. The inhibitor of the main protein of rhinovirus (Ag7088) could bind with 3CL^pro of human coronavirus, then it was selected as the reference for molecular docking and database screening. The ligands from two databases were used to search potential lead structures with molecular docking. Several structures from natural products and ACD-SC databases were found to have lower binding free energy with 3CL^pro than that of Ag7088. These structures have similar hydrophobicity to Ag7088. They have complementary electrostatic potential and hydrogen bond aeceptor and donor with 3CL^pro, showing that the strategy of anti-SARS drug design based on molecular docking and database screening is feasible. 相似文献
9.
Xin Li Dr. Shuo-Qing Zhang Li-Cheng Xu Prof. Dr. Xin Hong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13355-13361
Radical C−H bond functionalization provides a versatile approach for elaborating heterocyclic compounds. The synthetic design of this transformation relies heavily on the knowledge of regioselectivity, while a quantified and efficient regioselectivity prediction approach is still elusive. Herein, we report the feasibility of using a machine learning model to predict the transition state barrier from the computed properties of isolated reactants. This enables rapid and reliable regioselectivity prediction for radical C−H bond functionalization of heterocycles. The Random Forest model with physical organic features achieved 94.2 % site accuracy and 89.9 % selectivity accuracy in the out-of-sample test set. The prediction performance was further validated by comparing the machine learning results with additional substituents, heteroarene scaffolds and experimental observations. This work revealed that the combination of mechanism-based computational statistics and machine learning model can serve as a useful strategy for selectivity prediction of organic transformations. 相似文献
10.
Molecular modeling of interactions of four 7- or 8-substituted benzolactam-V8 (BLV) molecules with the cys2 activator-binding domain of protein kinase C (PKCδ) was carried out using molecular docking program Autodock. The docked models reveal that the hydroxymethyl group at the C(5) atom of the eight-membered ring of each BLV is bound at the bottom of the binding groove of the cys2 domain of PKCδ The BLV molecules make hydrogen bonds and hydrophobic interactions with PKCδ, which are similar to those in the crystal structure of the cys2 domain of PKCδ in complex with phorbol 13-acetate. BLV-1 does not contain a long side chain that is hydrophobic and necessary for membrane insertion, so that it would not be a potent modulator of PKCδ. The other three BLV molecules have long side chains substituted at C(7) or C(8) atoms, and it was predicted, based on the docking results, that they had the PKCδ-binding affinity in the order of BLV-2〉BLV-4〉BLV-3, and BLV-2 would be a potent activator of PKCδ. 相似文献
11.
ZhiGangZHAO QiMingMU ShuHuaCHEN 《中国化学快报》2004,15(11):1285-1288
A novel type of chiral molecular tweezers has been designed and synthesized by usingchenodeoxy cholic acid as spacer and the aromatic compounds as arm. Their structures werecharacterized by 1HNMR, IR, MS spectra and elemental analysis. These chiral molecular tweezersshowed good enantioselectivity for D-amino acid methyl esters. 相似文献
12.
Synthesis of Calix[4]pyrroles: A Class of New Molecular Receptor 总被引:1,自引:0,他引:1
RecentlySesslerandco-workersdiscoveredthatthemeso-octaalkylporphyrinogensshowedinterestinganionandneutralsubstratebindingpropertiesandmightserveasaclassofneweasy-to-makemolecularreceptorintheareaofsupramolecularchemistry'.However,themeso-octaalkylpor... 相似文献
13.
Dr. Jun Heuk Park Dr. Jan Paczesny Namhun Kim Prof. Bartosz A. Grzybowski 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10387-10391
When components of a metal–organic framework (MOF) and a crystal growth modulator diffuse through a gel medium, they can form arrays of regularly-spaced precipitation bands containing MOF crystals of different morphologies. With time, slow variations in the local concentrations of the growth modulator cause the crystals to change their shapes, ultimately resulting in unusual concave microcrystallites not available via solution-based methods. The reaction–diffusion and periodic precipitation phenomena 1) extend to various types of MOFs and also MOPs (metal–organic polyhedra), and 2) can be multiplexed to realize within one gel multiple growth conditions, in effect leading to various crystalline phases or polycrystalline formations. 相似文献
14.
XiuMeiTAI HongXiaWANG XiuQiSHI 《中国化学快报》2005,16(6):843-845
Using glycerol, glycol and water as solvent, cetyltrimethylammonium bromide (CTAB) as template, tetraethyl orthosilicate (TEOS) as silica source, ethylenediamine (EDA) as base source, mesoporous molecular sieve MCM-41 has been synthesized at room temperature, characterized by X-ray power diffraction and N2 adsorption. Compared with the samples synthesized by glycol and water, the samples synthesized by glycerol have larger pore diameter and high surface areas. Thus glycerol is an efficient solvent for preparing larger pore mesoporous MCM-41. 相似文献
15.
Inverse chromatography (IC) has been widely applied to characterize surface, interface, and bulk characteristics of technologically important materials. Probe molecules with known properties are injected into an isothermal chromatographic system with the material of interest as 相似文献
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A one-pot procedure has been developed for the synthesis of β-phosphonomalonates via P-C bond formation through tandem Knoevenagel–phospha–Michael reaction catalyzed by iodine as a new, inexpensive, nonmetallic, and commercially available catalyst. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
17.
Jing XIN Ji Shuan SUO* Xiao Ming ZHANG State Key Laboratory for Oxo Synthesis Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 《中国化学快报》2001,(8)
Although titanium silicate-1 (denoted TS-1) is an effective catalyst for the selective oxidation of organic substrates1,2, the substrates that can be oxidized by TS-1 are limited to species having kinetic diameters ( 6 ?. However, the recently discovered silica-based mesoporous molecular sieve offers new opportunities for the preparation of large-pore TS-1 analogs capable of transforming larger organic molecules. The Ti-containing mesoporous molecular sieve catalysts thus obtained, are promi… 相似文献
18.
Dr. Sanil E. Sivan Minhui Lee Su-Kyung Lee Dr. Ji Woong Yoon Dr. Kiwoong Kim Dr. Do-Young Hong Kyung-Ho Cho Dr. U-Hwang Lee Prof. Jong-San Chang Dr. Jaehoon Jung Prof. Young Kyu Hwang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(56):12889-12894
Oxo-bridged trimeric chromium acetate clusters [Cr3O(OOCCH3)6(H2O)3]NO3 have been encapsulated for the first time in the mesoporous cages of the chromium terephthalate MIL-101(Cr). The isolated clusters in MIL-101(Cr) have increased affinity towards propylene compared to propane, due to generation of a new kind of pocket-based propylene-binding site, as supported by DFT calculations. 相似文献
19.
Phthalocyaninesaresyntheticsubstancesrelatedtothenaturallyoccurringporphyrins.Itsthermalandchemicalstabilitymakesitveryusefulinmolecularelectronicsl.TheLBfilmsofphthalocyaninehavebeenwidelystudiedinthepastdecade.ButfewreportsonthemixedLBfilmsofphthalocyanineandporphyrinhavebeenpublished"'HerewereportanovelmixedLBfilmfabricatedbydepositingporphyrinandphthalocyaineinonelayerbasedonmolecularrecognition.Figure1.ThestructureofcompoundAandBAsymmetricallysubstitutedphthalocyanineAandporphyrinBa… 相似文献
20.
Shao Jun CHEN Jing Cang SU Peng Sheng LIU 《中国化学快报》2005,16(9):1241-1244
A novel method of controlling the shape memory properties of shape memory polyurethane (SMPU) by addition of micro-phase separation promoters including 1-octadecanol (ODO) and liquid paraffin (LP) is reported. The results indicate that the strain recovery temperature and the strain modulus rate (Eg/Er) were increased significantly with addition of small amount of micro-phase separation promoters. Thus it can increase the shape memory fixity rate and other shape memory behaviors of SMPU. 相似文献