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1.
Yike Li Chao Liu Xuan Bai Fei Tian Guoqing Hu Jiashu Sun 《Angewandte Chemie (International ed. in English)》2020,59(9):3486-3490
Chiral analysis of bioactive molecules is of increasing significance in chemical and life sciences. However, the quantitative detection of a racemic mixture of enantiomers is a challenging task, which relies on complicated and time‐consuming multiple steps of chiral derivatization, chiral separation, and spectroscopic measurement. Herein, we show that, without the use of chiral molecules or pretreatment steps, the co‐assembly of amino acids with achiral TPPS4 monomers controlled by enantiomorphic microvortices allows quantitative detection of racemic or enantiomeric amino acids, through analysis of the sign and magnitude of supramolecular chirality in different outlets of a microfluidic platform. A model demonstrates that chiral microvortices can induce an initial chiral bias by bending the sheet structure, resulting in supramolecular self‐assembly of TPPS4 and amino acids of compatible chirality by the self‐sorting. This sensing system may find versatile applications in chiral sensing. 相似文献
2.
Tianxiang Chen Bolong Huang Sarah Day Chiu Chung Tang Shik Chi Edman Tsang Kwok-yin Wong Tsz Woon Benedict Lo 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1109-1113
Reported here is the first crystallographic observation of stereospecific bindings of l - and d -lysine (Lys) in achiral MFI zeolites. The MFI structure offers inherent geometric and internal confinement effects for the enantiomeric difference in l - and d -Lys adsorption. Notable differences have been observed by circular dichroism (CD) spectroscopy and thermogravimetric analysis (TGA). Distinct l - and d -Lys adsorption behaviours on the H-ZSM-5 framework have been revealed by the Rietveld refinement of high-resolution synchrotron X-ray powder diffraction (SXRD) data and the density-functional theory (DFT) calculations. Despite demonstrating the approach for l - and d -Lys over MFI zeolites at an atomistic resolution, the differential adsorption study sheds light on the rational engineering of molecular interaction(s) with achiral microporous materials for chiral separation purposes. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(27):7905-7910
The aggregation of (pro)chiral/achiral molecules into crystalline structures at interfaces forms conglomerates, racemates, and solid solutions, comparable to known bulk phases. Scanning tunneling microscopy and Monte Carlo simulations were employed to uncover a distinct racemic phase, expressing 1D disordered chiral sorting through random tiling in surface‐confined supramolecularly assembled achiral 4,4′′‐diethynyl‐1,1′:4′,1′′‐terphenyl molecules. The configurational entropy of the 1D disordered racemic tiling phase was verified by analytical modeling, and found to lie between that of a perfectly ordered 2D racemate and a racemic solid solution. 相似文献
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Dr. Myriam Roy Dr. Veronika Berezhnaia Dr. Marco Villa Dr. Nicolas Vanthuyne Dr. Michel Giorgi Dr. Jean-Valère Naubron Dr. Salomé Poyer Dr. Valérie Monnier Prof. Dr. Laurence Charles Dr. Yannick Carissan Dr. Denis Hagebaum-Reignier Prof. Dr. Jean Rodriguez Prof. Dr. Marc Gingras Dr. Yoann Coquerel 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(8):3290-3297
We report a molecular design and concept using π-system elongation and steric effects from helicenes surrounding a triphenylene core toward stable chiral polycyclic aromatic hydrocarbons (PAHs) with a maximal π-distortion to tackle their aromaticity, supramolecular and molecular properties. The selective syntheses, and the structural, conformational and chiroptical properties of two diastereomeric large multi-helicenes of formula C90H48 having a triphenylene core and embedding three [5]helicene units on their inner edges and three [7]helicene units at their periphery are reported based on diastereoselective and, when applicable, enantiospecific Yamamoto-type cyclotrimerizations of racemic or enantiopure 9,10-dibromo[7]helicene. Both molecules have an extremely distorted triphenylene core, and one of them exhibits the largest torsion angle recorded so far for a benzene ring (twist=36.9°). 相似文献
5.
Jindřich Nejedlý Dr. Michal Šámal Dr. Jiří Rybáček Miroslava Tobrmanová Dr. Florence Szydlo Dr. Christophe Coudret Maria Neumeier Dr. Jaroslav Vacek Dr. Jana Vacek Chocholoušová Miloš Buděšínský Dr. David Šaman Dr. Lucie Bednárová Dr. Ladislav Sieger Dr. Irena G. Stará Dr. Ivo Starý 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(21):5933-5937
A series of oxahelicenes composed of ortho/meta-annulated benzene/pyridine and 2H-pyran rings were synthesized on the basis of the cobalt(I)-mediated (or rhodium(I)- or nickel(0)-mediated) double, triple, or quadruple [2+2+2] cycloisomerization of branched aromatic hexa-, nona-, or dodecaynes, thus allowing the construction of 6, 9, or 12 rings in a single operation. The use of a flow reactor was found to be beneficial for the multicyclization reactions. The stereogenic centers present in some of the oligoynes steered the helical folding in such a way that the final oxa[9]-, [13]-, [17]- and [19]helicenes were obtained in both enantiomerically and diastereomerically pure form. Specifically, the oxa[19]helicenes beat the current record in the length of a helicene backbone. Single-molecule conductivity was studied by the mechanically controllable break-junction method with a pyridooxa[9]helicene. 相似文献
6.
Dr. Yi-Qi Zhang Dr. Tao Lin Borja Cirera Raphael Hellwig Dr. Carlos-Andres Palma Zhi Chen Prof. Dr. Mario Ruben Prof. Dr. Johannes V. Barth Prof. Dr. Florian Klappenberger 《Angewandte Chemie (International ed. in English)》2017,56(27):7797-7802
The aggregation of (pro)chiral/achiral molecules into crystalline structures at interfaces forms conglomerates, racemates, and solid solutions, comparable to known bulk phases. Scanning tunneling microscopy and Monte Carlo simulations were employed to uncover a distinct racemic phase, expressing 1D disordered chiral sorting through random tiling in surface-confined supramolecularly assembled achiral 4,4′′-diethynyl-1,1′:4′,1′′-terphenyl molecules. The configurational entropy of the 1D disordered racemic tiling phase was verified by analytical modeling, and found to lie between that of a perfectly ordered 2D racemate and a racemic solid solution. 相似文献
7.
Žiga Jakopin 《合成通讯》2013,43(20):3422-3438
We present a useful route for the preparation of saccharin derivatives of amino acids. Sixteen new compounds, saccharin-derived amino acids, were synthesized, all of them bearing additional functional groups either at the 5- or 6-position of the saccharin skeleton, thus rendering the compounds more amenable to functionalization. 相似文献
8.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(4):1075-1078
Strecker synthesis has long been considered one of the prebiotic reactions for the synthesis of α‐amino acids. However, the correlation between the origin of chirality and highly enantioenriched α‐amino acids through this method remains a puzzle. In the reaction, it may be conceivable that the handedness of amino acids has been determined at the formation stage of the chiral intermediate α‐aminonitrile, that is, the enantioselective addition of hydrogen cyanide to an imine. Herein, an enantiotopic crystal surface of an achiral imine acted as an origin of chirality for the enantioselective formation of α‐aminonitriles by the addition of HCN. In conjunction with the amplification of the enantiomeric excess and multiplication of enantioenriched aminonitrile, a large amount of near enantiopure α‐amino acids, with the l ‐ and d ‐handedness corresponding to the molecular orientation of the imine, is reported. 相似文献
9.
Jia-Yi Li Dr. Li Wang Li-Ping Yin Xin-Meng Jiang Dr. Kai Guo Dr. Chun Zhang Dr. Shan-Shan Yu Prof. Dr. Xiao-Qi Yu Prof. Dr. Qin Wang 《ChemistryOpen》2022,11(6):e202200088
A new racemic naphthyl-coumarin-based probe was found to bind covalently with amino acids in MeOH-KOH system and thereby generates distinct CD responses. The induced strong CD signals allowed quantitative enantiomeric excess analysis of amino acids and enantioselective sensing of amines and amino alcohols. The mechanism for the reaction of the coumarin-aldehyde probe with an amino acid was investigated by CD, UV-Vis, NMR, ESI-MS analyses and ECD calculation. 相似文献
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Geert C. van Almen Hanna Talacua Bastiaan D. Ippel Björne B. Mollet Mellany Ramaekers Marc Simonet Anthal I. P. M. Smits Carlijn V. C. Bouten Jolanda Kluin Patricia Y. W. Dankers 《Macromolecular bioscience》2016,16(3):350-362
Cell‐free approaches to in situ tissue engineering require materials that are mechanically stable and are able to control cell‐adhesive behavior upon implantation. Here, the development of mechanically stable grafts with non‐cell adhesive properties via a mix‐and‐match approach using ureido‐pyrimidinone (UPy)‐modified supramolecular polymers is reported. Cell adhesion is prevented in vitro through mixing of end‐functionalized or chain‐extended UPy‐polycaprolactone (UPy‐PCL or CE‐UPy‐PCL, respectively) with end‐functionalized UPy‐poly(ethylene glycol) (UPy‐PEG) at a ratio of 90:10. Further characterization reveals intimate mixing behavior of UPy‐PCL with UPy‐PEG, but poor mechanical properties, whereas CE‐UPy‐PCL scaffolds are mechanically stable. As a proof‐of‐concept for the use of non‐cell adhesive supramolecular materials in vivo, electrospun vascular scaffolds are applied in an aortic interposition rat model, showing reduced cell infiltration in the presence of only 10% of UPy‐PEG. Together, these results provide the first steps toward advanced supramolecular biomaterials for in situ vascular tissue engineering with control over selective cell capturing.
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Vijaykumar Ijeri Francis Vocanson Claude Martelet Nicole Jaffrezic‐Renault 《Electroanalysis》2007,19(4):510-514
The possibility of using capacitance and flat band voltage as measurable quantities for determining amino acids that are neither electroactive nor with strong UV‐vis absorption has been explored. The sensors were fabricated by immobilizing calixarene derivatives on Si/SiO2/Si3N4 transducers. The measurements were made in sulfuric acid media of ca. pH 1 and in physiological buffer of pH 7.4. The different calixarene derivatives showed varying sensitivities to the amino acids ranging from 8 to 137 mV/decade. 相似文献
14.
Dr. Zhen Chen Prof. Dr. Vivian Wing-Wah Yam 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(12):4870-4875
The development of size-selective membranes with well-defined nanopores towards the precise separation of nanometer-sized substances is a challenging task to achieve. Here a supramolecular membrane is presented that comprises a highly oriented, honeycomb-like, 2D supramolecular polymer on a polycarbonate filter support. It enables precise size-selective sieving of colloidal nanoparticles (NPs). Owing to the uniform parallel-aligned nanocavities within the 2D supramolecular polymers, the composite membrane shows a high size-selectivity with a sub-nanometer accuracy in the cutoff size of about 4.0 nm. In principle, the species of size-separable particles are unlimited, as demonstrated by quantum dots, noble metal, and metal oxide NPs. This supramolecular membrane combined with filtration advances the potential of NPs in terms of their monochromatic emission and size monodispersity, and also enables rapid removal of small magnetic NP adsorbents that are otherwise difficult to capture. 相似文献
15.
Jing Zhang Yun‐Yun Xi Qing Li Qing Tang Ruibing Wang Ying Huang Zhu Tao Sai‐Feng Xue Leonard F. Lindoy Gang Wei 《化学:亚洲杂志》2016,11(16):2250-2254
Binding interactions between twisted cucurbit[14]uril (tQ[14]) and twenty standard amino acids (AAs) have been investigated by NMR spectroscopy and isothermal titration calorimetry (ITC) in aqueous HCl solutions and in DMSO. The results showed that tQ[14] displays clear binding affinity for AAs with a positively charged side chain or containing an aromatic ring, but weaker binding affinity for AAs with hydrophobic or polar side chains, with the binding mode depending on the type of side chain present in the AAs. 相似文献
16.
Highly Stereoselective Recognition and Deracemization of Amino Acids by Supramolecular Self‐Assembly 下载免费PDF全文
Dr. Soon Mog So Kimia Moozeh Dr. Alan J. Lough Prof. Jik Chin 《Angewandte Chemie (International ed. in English)》2014,53(3):829-832
The highly stereoselective supramolecular self‐assembly of α‐amino acids with a chiral aldehyde derived from binol and a chiral guanidine derived from diphenylethylenediamine (dpen) to form the imino acid salt is reported. This system can be used to cleanly convert D ‐amino acids into L ‐amino acids or vice versa at ambient temperature. It can also be used to synthesize α‐deuterated D ‐ or L ‐amino acids. A crystal structure of the ternary complex together with DFT computation provided detailed insight into the origin of the stereoselective recognition of amino acids. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(8):2101-2105
The first catalytic synthesis of cyclic diarylborinic acids is developed using a dihydroaminoborane reagent as the boron source. Unlike previously reported methods that use organolithium reagents, this method allows the easy synthesis of cyclic diarylborinic acids bearing a range of functionalities including CN, CO2Et, CONEt2 and NMeCO2t Bu. Furthermore, these cyclic diarylborinic acids provide rapid access to skeletal diversity, in particular they enable the synthesis of six‐ to nine‐membered π‐extended heteroarenes through simple cross‐coupling reactions, which are important synthetic targets in both advanced materials and pharmaceuticals. 相似文献
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Anna L. Vagstad Takefumi Kuranaga Salome Püntener Vijaya R. Pattabiraman Jeffrey W. Bode Jrn Piel 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(8):2268-2272
Post‐translational modifying enzymes from the S‐adenosyl‐l ‐methionine (AdoMet) radical superfamily garner attention due to their ability to accomplish challenging biochemical reactions. Among them, a family of AdoMet radical epimerases catalyze irreversible l ‐ to d ‐amino acid transformations of diverse residues, including 18 sites in the complex sponge‐derived polytheonamide toxins. Herein, the in vitro activity of the model epimerase OspD is reported and its catalytic mechanism and substrate flexibility is investigated. The wild‐type enzyme was capable of leader‐independent epimerization of not only the stand‐alone core peptide, but also truncated and cyclic core variants. Introduction of d ‐amino acids can drastically alter the stability, structure, and activity of peptides; thus, epimerases offer opportunities in peptide bioengineering. 相似文献