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1.
Yao‐Rong Zheng Hai‐Bo Yang Prof. Dr. Koushik Ghosh Liang Zhao Dr. Peter J. Stang Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(29):7203-7214
The self‐organization of multicomponent supramolecular systems involving a variety of two‐dimensional (2 D) polygons and three‐dimensional (3 D) cages is presented. Nine self‐organizing systems, SS1 – SS9 , have been studied. Each involves the simultaneous mixing of organoplatinum acceptors and pyridyl donors of varying geometry and their selective self‐assembly into three to four specific 2 D (rectangular, triangular, and rhomboid) and/or 3 D (triangular prism and distorted and nondistorted trigonal bipyramidal) supramolecules. The formation of these discrete structures is characterized using NMR spectroscopy and electrospray ionization mass spectrometry (ESI‐MS). In all cases, the self‐organization process is directed by: 1) the geometric information encoded within the molecular subunits and 2) a thermodynamically driven dynamic self‐correction process. The result is the selective self‐assembly of multiple discrete products from a randomly formed complex. The influence of key experimental variables ‐ temperature and solvent ‐ on the self‐correction process and the fidelity of the resulting self‐organization systems is also described. 相似文献
2.
《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(1):164-173
This paper presents results from a series of pulsed field gradient (PFG) NMR studies on lipophilic guanosine nucleosides that undergo cation‐templated assembly in organic solvents. The use of PFG‐NMR to measure diffusion coefficients for the different aggregates allowed us to observe the influences of cation, solvent and anion on the self‐assembly process. Three case studies are presented. In the first study, diffusion NMR confirmed formation of a hexadecameric G‐quadruplex [G 1 ]16 ? 4 K+ ? 4 pic? in CD3CN. Furthermore, hexadecamer formation from 5′‐TBDMS‐2′,3′‐isopropylidene G 1 and K+ picrate was shown to be a cooperative process in CD3CN. In the second study, diffusion NMR studies on 5′‐(3,5‐bis(methoxy)benzoyl)‐2′,3′‐isopropylidene G 4 showed that hierarchical self‐association of G8‐octamers is controlled by the K+ cation. Evidence for formation of both discrete G8‐octamers and G16‐hexadecamers in CD2Cl2 was obtained. The position of this octamer–hexadecamer equilibrium was shown to depend on the K+ concentration. In the third case, diffusion NMR was used to determine the size of a guanosine self‐assembly where NMR signal integration was ambiguous. Thus, both diffusion NMR and ESI‐MS show that 5′‐O‐acetyl‐2′,3′‐O‐isopropylidene G 7 and Na+ picrate form a doubly charged octamer [G 7 ]8 ? 2 Na+ ? 2 pic? 9 in CD2Cl2. The anion's role in stabilizing this particular complex is discussed. In all three cases the information gained from the diffusion NMR technique enabled us to better understand the self‐assembly processes, especially regarding the roles of cation, anion and solvent. 相似文献
3.
One Ligand in Dual Roles: Self‐Assembly of a Bis‐Rhomboidal‐Shaped,Three‐Dimensional Molecular Wheel
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Kai Guo Jing Wang Mingjun Huang Prof. Jin‐Liang Wang Dr. Ting‐Zheng Xie Dr. Charles N. Moorefield Prof. Stephen Z. D. Cheng Prof. Chrys Wesdemiotis Prof. George R. Newkome 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(41):13094-13098
A facile high yield, self‐assembly process that leads to a terpyridine‐based, three‐dimensional, bis‐rhomboidal‐shaped, molecular wheel is reported. The desired coordination‐driven supramolecular wheel involves eight structurally distorted tristerpyridine (tpy) ligands possessing a 60° angle between the adjacent tpy units and twelve Zn2+ ions. The tpy ligand plays dual roles in the self‐assembly process: two are staggered at 180° to create the internal hub, while six produce the external rim. The wheel can be readily generated by mixing the tpy ligand and Zn2+ in a stoichiometric ratio of 2:3; full characterization is provided by ESI‐MS, NMR spectroscopy, and TEM imaging. 相似文献
4.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(38):11608-11613
Three generations of metalated trigonal supramolecular architectures, so‐called metallo‐triangles, were assembled from terpyridine (tpy) complexes. The first generation (G1) metallo‐triangles were directly obtained by reacting a bis(terpyridinyl) ligand with a 60° bite angle and ZnII ions. The direct self‐assembly of G2 and G3 triangles by mixing organic ligands and ZnII, however, only generated a mixture of G1 and G2, as well as a trace amount of insoluble polymer‐like precipitate. Therefore, a modular strategy based on the connectivity of ⟨tpy−Ru2+−tpy⟩ was employed to construct two metallo‐organic ligands for the assembly of G2 and G3 Sierpiński triangles. The metallo‐organic ligands LA and LB with multiple free terpyridines were obtained through Suzuki cross‐coupling of the RuII complexes, and then assembled with ZnII or CdII to obtain high‐generation metallo‐triangular architectures in nearly quantitative yield. The G1–G3 architectures were characterized by NOESY and DOSY NMR spectroscopy, ESI‐MS, TWIM‐MS, and transmission electron microscopy. 相似文献
5.
Metal‐Directed Self‐Assembly of a Polyoxometalate‐Based Molecular Triangle: Using Powerful Analytical Tools to Probe the Chemical Structure of Complex Supramolecular Assemblies
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Dr. Guillaume Izzet Dr. Andrew Macdonell Dr. Corentin Rinfray Madeleine Piot Séverine Renaudineau Dr. Etienne Derat Dr. Benjamin Abécassis Prof. Dr. Carlos Afonso Prof. Dr. Anna Proust 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19010-19015
A polyoxometalate‐based molecular triangle has been synthesized through the metal‐driven self‐assembly of covalent organic/inorganic hybrid oxo‐clusters with remote pyridyl binding sites. The new metallomacrocycle was unambiguously characterized by using a combination of 1H NMR spectroscopy, 2D diffusion NMR spectroscopy (DOSY), electrospray ionization travelling wave ion mobility mass spectrometry (ESI‐TWIM‐MS), small‐angle X‐ray scattering (SAXS) and molecular modelling. The collision cross‐sections obtained from TWIM‐MS and the hydrodynamic radii derived from DOSY are in good agreement with the geometry‐optimized structures obtained by using theoretical calculations. Furthermore, SAXS was successfully employed and proved to be a powerful technique for characterizing such large supramolecular assemblies. 相似文献
6.
Dr. Christoph Gütz Rainer Hovorka Dr. Gregor Schnakenburg Prof. Dr. Arne Lützen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(33):10890-10894
A 1,1′‐binaphthyl‐based bis(pyridine) ligand ( 1 ) was prepared in racemic and enantiomerically pure form to study the formation of [Pd2( 1 )4] complexes upon coordination to palladium(II) ions with regard to the degree of chiral self‐sorting. The self‐assembly process proceeds in a highly selective narcissistic self‐recognition manner to give only homochiral supramolecular M2L4 cages, which were characterized by ESI‐MS, NMR, and electronic circular dichroism (ECD) spectroscopy, as well as by single‐crystal XRD analysis. 相似文献
7.
Alexander Filosa Heng Wang Wei‐Jian Li Wenjing Zhang Ellie Ngo Jonathan E. Piccolo Hai‐Bo Yang Xiaopeng Li 《中国化学》2019,37(11):1167-1173
Porphyrins have been widely used in the self‐assembly of metallo‐supramolecules. In this study, we introduced 2,2':6,2"‐terpyridine (tpy) into a porphyrin core to synthesize a tetratopic building block with multiple conformers. During the self‐assembly with Zn(II), such a mixture of conformers was able to form a discrete nanoprism with all building blocks in one conformation. Detailed characterizations, including NMR, ESI‐MS and traveling‐wave ion mobility‐mass spectrometry (TWIM‐MS), all supported the formation of the desired assemblies. AFM and TEM further confirmed the dimensions of assembled nanoprisms. Moreover, the photophysical properties of the ligands and complexes were noticeably different depending upon size and metal ion center. 相似文献
8.
Structural varieties of selectively mixed G‐ and C‐rich short DNA sequences studied with electrospray ionization mass spectrometry
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Yanwei Cao Shang Gao Caijin Li Yuting Yan Bing Wang Xinhua Guo 《Journal of mass spectrometry : JMS》2016,51(10):931-937
Short guanine(G)‐repeat and cytosine(C)‐repeat DNA strands can self‐assemble to form four‐stranded G‐quadruplexes and i‐motifs, respectively. Herein, G‐rich and C‐rich strands with non‐G or non‐C terminal bases and different lengths of G‐ or C‐repeats are mixed selectively in pH 4.5 and 6.7 ammonium acetate buffer solutions and studied by electrospray ionization mass spectrometry (ESI‐MS). Various strand associations corresponding to bi‐, tri‐ and tetramolecular ions are observed in mass spectra, indicating that the formation of quadruplex structures is a random strand by strand association process. However, with increasing incubation time for the mixtures, initially associated hybrid tetramers will transform into self‐assembled conformations, which is mainly driven by the structural stability. The melting temperature values of self‐assembled quadruplexes suggest that the length of G‐repeats or C‐repeats shows more significant effect on the stability of quadruplex structures than that of terminal residues. Accordingly, we can obtain the self‐associated tetrameric species generated from the mixtures of various homologous G‐ or C‐strands efficiently by altering the length of G‐ or C‐repeats. Our studies demonstrate that ESI‐MS is a very direct, fast and sensitive tool to provide significant information on DNA strand associations and stoichiometric transitions, particularly for complex mixtures. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
9.
《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(1):298-307
The self‐assembly and characterization of water‐soluble calix[4]arene‐based molecular capsules ( 1?2 ) is reported. The assemblies are the result of ionic interactions between negatively charged calix[4]arenes 1 a and 1 b , functionalized at the upper rim with amino acid moieties, and a positively charged tetraamidiniumcalix[4]arene 2 . The formation of the molecular capsules is studied by 1H NMR spectroscopy, ESI mass spectrometry (ESI‐MS), and isothermal titration calorimetry (ITC). A molecular docking protocol was used to identify potential guest molecules for the self‐assembled capsule 1 a?2 . Experimental guest encapsulation studies indicate that capsule 1 a?2 is an effective host for both charged (N‐methylquinuclidinium cation) and neutral molecules (6‐amino‐2‐methylquinoline) in water. 相似文献
10.
Susanne C. Solleder Deniz Zengel Katharina S. Wetzel Prof. Dr. Michael A. R. Meier 《Angewandte Chemie (International ed. in English)》2016,55(3):1204-1207
The efficient synthesis of a sequence‐defined decamer, its characterization, and its straightforward dimerization through self‐metathesis are described. For this purpose, a monoprotected AB monomer was designed and used to synthesize a decamer bearing ten different and selectable side chains by iterative Passerini three‐component reaction (P‐3CR) and subsequent deprotection. The highly efficient procedure provided excellent yields and allows for the multigram‐scale synthesis of such perfectly defined macromolecules. An olefin was introduced at the end of the synthesis, allowing the self‐metathesis reaction of the resulting decamer to provide a sequence‐defined 20‐mer with a molecular weight of 7046.40 g mol?1. The obtained oligomers were carefully characterized by NMR and IR spectroscopy, GPC and GPC coupled to ESI‐MS, and mass spectrometry (FAB and orbitrap ESI‐MS). 相似文献
11.
Cristian Peptu Alina Nicolescu Catalina A. Peptu Valeria Harabagiu Bogdan C. Simionescu Marek Kowalczuk 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5581-5592
Oligo(3‐OH butyrate)‐β‐cyclodextrin esters (PHB‐CD) were obtained through ring opening of β‐butyrolactone (β‐BL) in the presence of β‐cyclodextrin (CD) and (‐)‐sparteine (SP) as nucleophilic activator. The resulted reaction mixture was first separated in two fractions and then investigated through a deep mass spectrometry (MS) study performed on a liquid chromatography‐electrospray ionization‐quadrupole time of flight (LC‐ESI‐QTOF) instrument. LC MS and tandem MS structural assignment of the reaction products was completed by NMR. The performed analysis revealed that poly(3‐OH butyrate) homopolymers (PHB) are formed together with the PHB‐CD products. Secondary reactions resulting in the formation of crotonates were also proved to occur. A comparison between MS and NMR results demonstrated that more than one PHB oligomer is attached to the CD in the PHB‐CD product. The tandem MS fragmentation studies validated the proposed structure of CD derivatives. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
12.
Min CHEN Rong QIAN Hai‐Yan JIANG Xiang ZHANG Jing ZHOU Wei‐Guo CAO Yin‐Long GUO 《中国化学》2008,26(5):923-928
Electrospray ionization mass spectrometry (ESI‐MS) was utilized to perform monitoring of the intermediates in the reaction of 1,2,3‐trisubstituted electron‐deficient cyclopropane derivatives, cis‐1‐thien‐2′‐oyl‐2‐(p‐subustituted phenyl‐6,6‐dimethyl)‐5,7‐dioxaspiro[2.5]‐4,8‐octadiones, with methanol. Key intermediates, either cationic or protonated forms of neutral species, were intercepted and characterized by ESI‐MS and its tandem version (ESI‐MS/MS). Therefore, the mechanism of the ring‐opening process for electron‐deficient cyclopropane derivatives was fully confirmed by the intermediates monitored. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(19):5342-5346
Two‐ and three‐dimensional metallosupramolecules shaped like a Star of David were synthesized by the self‐assembly of a tetratopic pyridyl ligand with a 180° diplatinum(II) motif and PdII ions, respectively. In contrast to other strategies, such as template‐directed synthesis and stepwise self‐assembly, this design enables the formation of 2D and 3D structures in one step and high yield. The structures were characterized by both one‐dimensional (1H, 13C, 31P) and two‐dimensional (COSY, NOESY, DOSY) NMR spectroscopy, ESI‐MS, ion‐mobility mass spectrometry (IM–MS), AFM, and TEM. The stabilities of the 2D and 3D structures were measured and compared by gradient tandem mass spectrometry (gMS2). The high stability of the 3D Star of David was correlated to its high density of coordination sites (DOCS). 相似文献
14.
Ting Feng Xin Li Yuan‐Yuan An Sha Bai Li‐Ying Sun Yang Li Yao‐Yu Wang Ying‐Feng Han 《Angewandte Chemie (International ed. in English)》2020,59(32):13516-13520
The efficient backbone‐directed self‐assembly of cyclic metalla[3]catenanes by the combination of tetrachloroperylenediimide (TCPDI)‐based dinuclear rhodium(III) clips and 4,4′‐diazopyridine or 4,4′‐dipyridylethylene ligands is realized in a single‐step strategy. The topology and coordination geometry of the cyclic metalla[3]catenanes are characterized by NMR spectroscopy, ESI‐TOF‐MS spectrometry, UV/Vis‐NIR spectroscopy, and X‐ray diffraction studies. The most remarkable feature of the formed cyclic metalla[3]catenane is that it contains π‐aggregates (ca. 2.6 nm) incorporating six TCPDIs. Further studies revealed that cyclic metalla[3]catenanes can be converted reversibly to their corresponding sodium adducts and precursor building blocks, respectively. This strategy opens the possibility of generating unique supramolecular structures from discrete functional π‐aggregates with precise arrangements. 相似文献
15.
In order to search for novel agrochemicals with high activity and low toxicity, a series of phosphonate derivatives containing 1,2,3-triazole and thiazole rings were designed and synthesized using 2-chloro-5-(chloromethyl)- thiazole as the starting material. Their structures were confirmed by IR, ^1H NMR, ^31p NMR, EI-MS or ESI-MS and elemental analyses. The crystal structure of 7a was determined by single crystal X-ray diffraction. Preliminary bioassays indicated that most of the target compounds did not display insecticidal activities, but a fraction of them possessed herbicidal and fungicidal activities to some extent. 相似文献
16.
Two new trijugin‐type limonoids, cipatrijugins G and H ( 1 and 2 , resp.) along with four known limonoids, were isolated from the leaves of Cipadessa cinerascens. All structures were elucidated on the basis of spectroscopic analyses, including IR, 1D‐ and 2D‐NMR, and ESI‐MS and HR‐ESI‐MS techniques. 相似文献
17.
《Journal of heterocyclic chemistry》2017,54(6):3065-3070
A convenient method for the preparation of symmetric and unsymmetric bisimidazole derivatives was established. The symmetric bisimidazolylmethane derivatives 1a–9a was prepared with 2‐substituted imidazole derivatives 1–9 as reaction materials. However, the symmetric and unsymmetric bisimidazolylmethane derivatives 10a–12a and 10b–12b was obtained, respectively. With 4‐position with the azo‐groups imidazole derivatives 10–12 were used as reaction materials. All these compounds have been structurally characterized by the NMR, ESI‐MS, and EA. And 8a and 12a were also characterized by the X‐ray single crystal diffusion. 相似文献
18.
Avi Weissberg Maor Elgarisi Moran Madmon Avital Shifrovich Merav Blanca Shai Dagan 《Journal of mass spectrometry : JMS》2019,54(3):274-280
The chromatograms obtained from the gas chromatography‐electron ionization mass spectrometric (GC‐EI‐MS) analysis of extracts containing G‐nerve agents in the presence of diesel, gasoline, etc., are dominated by hydrocarbon backgrounds that “mask” the G‐nerve agents, leading to severe difficulties in identification. This paper presents a practical solution for this challenge by transferring the G‐nerve agents from the organic phase into the aqueous phase using liquid‐liquid extraction (LLE), followed by derivatization with 2‐[(dimethylamino)methyl]phenol (2‐DMAMP), allowing ultrasensitive LC‐ESI‐MS/MS analysis of the G‐derivatives. The proposed approach enables rapid identification of trace amounts of G‐nerve agents with limits of identification (LOIs) at the pg/mL scale. 相似文献
19.
Dr. Ana Pérez Dr. Diana de Saá Prof. Alfredo Ballesteros Prof. José Luis Serrano Dr. Teresa Sierra Dr. Pilar Romero 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(31):10271-10279
The self‐assembly of polycatenar molecules derived from 1,6‐diphenyl‐3,4‐dipropyl‐3‐hexen‐1,5‐diyne has been studied in detail by solution NMR spectroscopy. The analysis of the concentration‐ and temperature‐dependent evolution of the chemical shifts and the diffusion coefficients in [D12]cyclohexane agrees well with an isodesmic model of association in this solvent. The association constants for the stacking and entropy and enthalpy of the process have been obtained. The driving force for the aggregation process is provided by a negative enthalpy (ΔH), which is partially compensated by a negative entropy (ΔS). A structural study of the self‐assembly in solution has been carried out with the help of NOESY NMR spectroscopic experiments. 相似文献
20.
Gan Zhou Shuyun Shi Wei Zhang Zhirong Tan Yao Chen Dong Guo Honghao Zhou Haitang Hu Jin Tan 《Biomedical chromatography : BMC》2010,24(10):1130-1135
Ilaprazole is a new proton pump inhibitor designed for the treatment of gastric ulcers, and limited data is available on the metabolism of the drug. In this article, the structural elucidation of urinary metabolites of ilaprazole in human was described by HPLC‐ESI‐MS/MS and stopped‐flow HPLC‐NMR experiments. Urinary samples were precipitated by sodium carbonate solution, and then extracted by liquid–liquid extraction after adding ammonium acetate buffer solution. The enriched sample was separated using a C18 reversed‐phase column with the mobile phase composed of acetonitrile and 0.05 mol/L ammonium acetate buffer solution in a gradient solution, and then directly coupled to ESI‐MS/MS detection in an on‐line mode or 1H‐NMR (500 MHz) spectroscopic detection in a stopped‐flow mode. As a result, four sulfide metabolites, ilaprazole sulfide (M1), 12‐hydroxy‐ilaprazole sulfide (M2), 11,12‐dihydroxy‐ilaprazole sulfide (M3) and ilaprazole sulfide A (M4), were identified by comparing their MS/MS and NMR data with those of the parent drug and available standard compounds. The main biotransformation reactions of ilaprazole were reduction and the aromatic hydroxylation of the parent drug and its relative metabolites. The result testified that HPLC‐ESI‐MS/MS and HPLC‐NMR could be widely applied in detection and identification of novel metabolites. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献