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Search for "nanostructures" in Full Text gives 61 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis and anion recognition properties of shape-persistent binaphthyl-containing chiral macrocyclic amides
- Marco Caricato,
- Nerea Jordana Leza,
- Claudia Gargiulli,
- Giuseppe Gattuso,
- Daniele Dondi and
- Dario Pasini
Beilstein J. Org. Chem. 2012, 8, 967–976, doi:10.3762/bjoc.8.109
- stabilization of nanostructures. Noticeable examples can be found in the field of foldamers [13][14] or in the design of assembled architectures functioning as artificial ion-channel mimics [15]. Amide functionalities are also widely used for their hydrogen bonding capability in the context of anion
Graphical Abstract
Figure 1: Structure of the macrocycle (R,R)-1 (top), and synthetic strategies for the production of novel ami...
Scheme 1: Reagents and conditions: (i) SOCl2, CHCl3 or (COCl)2, DMF, CH2Cl2 then amine, Et3N, CH2Cl2 or (ii) ...
Scheme 2: Structure and synthesis of the macrocycles discussed in this paper.
Figure 2: UV and CD (EtOH) spectra of macrocycles (R,R)-10, (R,R)-11 and (R,R)-12 in the range 220–400 nm.
Figure 3: Minimized molecular structures of (from top left to bottom left, clockwise): (R,R)-10, (R,R)-11, (R,...
Figure 4: Aromatic region of the 1H NMR (CDCl3, 500 MHz, 25 °C) spectra of macrocycle (R,R)-12 (2.8 mM, botto...
Diarylethene-modified nucleotides for switching optical properties in DNA
- Sebastian Barrois and
- Hans-Achim Wagenknecht
Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103
- environments. The sequence independent photochromic behavior represents an important result for the future application of this type of switch in DNA-based nanostructures. Representatively, we performed switching experiments with the double strand (ds) of the most critical candidate (DNA2). The kinetic behavior
- photoreactive and self-assembled nanostructures and materials based on nucleic acids. Experimental Materials and methods Chemicals were purchased from Sigma Aldrich, Fluka, ABCR, Alfa Aesar and Acros. Unmodified oligonucleotides were purchased from Metabion. TLC was performed on Merck silica gel 60 F254 coated
Graphical Abstract
Scheme 1: Spiropyran as DNA base surrogate 1, DNA base modifications 2 and 3, and diarylethene-modified nucle...
Scheme 2: Synthesis of diarylethene-modified 2’-deoxyuridines 4 [30], 5 and 6.
Figure 1: Photoswitching properties of nucleosides 4–6 (each 20 mM in MeCN, rt). Top: Irradiation of 4 at 242...
Scheme 3: Synthesis of DNA building block 17 [30] and sequences of diarylethene-modified DNA1–DNA4.
Figure 2: Irradiation of dsDNA2 at 310 nm (A, left) and plot of kinetic trace of absorption changes at 450 nm...
Figure 3: UV–vis absorption spectra of ssDNA1–ssDNA4 (2.5 μM in 50 mM Na–Pi buffer, pH 7, 250 mM NaCl, rt).
Cyanoethylation of the glucans dextran and pullulan: Substitution pattern and formation of nanostructures and entrapment of magnetic nanoparticles
- Kathrin Fiege,
- Heinrich Lünsdorf,
- Sevil Atarijabarzadeh and
- Petra Mischnick
Beilstein J. Org. Chem. 2012, 8, 551–566, doi:10.3762/bjoc.8.63
- spectroscopy (PEELS). Keywords: cyanoethyldextran; cyanoethylpullulan; ferromagnetic nanoparticles; glycan nanostructures; substitution pattern; Introduction Cyanoethylation has been widely applied to polysaccharides, e.g., to cellulose [1], inulin [2], and starch [3]. Onda reported on cyanoethylation of
- NMR measurements (1H and 13C). A homopolymerization of acrylonitrile could be excluded since the DSEA from N and C/N were very close and only moderately enhanced compared to the DSGC. Nanostructures of cyanoethylglucans In the next step the ability of cyanoethylglucans to form nanoparticles was
- units, which is typical for reversible reactions and always favored in aqueous systems. High cyanoethylated glucans form regularly shaped nanostructures with diameters in the range of 260 to 613 nm. When dialysis was performed in the presence of ferromagnetic nanoparticles, glucan-coated multicore
Graphical Abstract
Figure 1: Polysaccharide structures of pullulan and dextran cyanoethylation with acrylonitrile and NaOH as ca...
Figure 2: ATR–IR spectra of (a) dextran, 6 kDa, and cyanoethyldextrans (b–d) CED-1–3.
Figure 3: ATR–IR spectra of (a) pullulan, 100 kDa, and cyanoethylpullulans (b–d) CEP-1–3.
Figure 4: 1H NMR spectra (300 MHz) of (a) CED-2 (DSNMR(1) = 1.81) in D2O; (b) dextran, native in D2O; (c) CED...
Figure 5: 1H NMR spectra (400 MHz) of (a) CEP-2 (DSNMR(3) = 1.31) in D2O; (b) pullulan, native in D2O; (c) CE...
Figure 6: Gas chromatogram of hydrolyzed and trimethylsilylated cyanoethylglucans; (a) CED-1 (DSGC = 0.74); (...
Figure 7: Experimentally determined substituent distribution in the glucosyl units (glc) of cyanoethyldextran...
Figure 8: Experimentally determined substituent distribution in the glucosyl units (glc) of cyanoethylpullula...
Figure 9: TEM micrograph of iron oxide nanoparticles prepared from an aqueous dispersion.
Figure 10: SEM micrographs of CEP-3 with iron oxide nanoparticles, (Table 3, entry 2).
Figure 11: TEM micrograph of (a) uncoated iron oxide nanoparticles; (b) of CEP-3 + iron oxide nanoparticles (n...
Figure 12: ESI Fe distribution maps of CEP-3 with iron oxide nanoparticle (Table 3, entry 1). (A) Net Fe, shown in re...
Liquid-crystalline nanoparticles: Hybrid design and mesophase structures
- Gareth L. Nealon,
- Romain Greget,
- Cristina Dominguez,
- Zsuzsanna T. Nagy,
- Daniel Guillon,
- Jean-Louis Gallani and
- Bertrand Donnio
Beilstein J. Org. Chem. 2012, 8, 349–370, doi:10.3762/bjoc.8.39
Graphical Abstract
Figure 1: Three of the common molecular and supramolecular structural motifs in liquid crystal chemistry: rod...
Figure 2: Schematic representation of the solvent-mediated ligand exchange process, illustrated for the parti...
Figure 3: Chemical structures and LC properties of the rodlike ligands discussed in the text.
Figure 4: Schematic representation of pseudospherical Au NPs coated exclusively with mesogenic rodlike ligand...
Figure 5: TEM images of Au@612 (a) before and (b) after thermal treatment. Below: Proposed model of the nanop...
Figure 6: Ligand deformation at the surface of the gold NPs giving rigid "poles" and a soft equator. Such def...
Figure 7: A simplified illustration of the local rectangular arrangement of nanoparticles in a condensed mixe...
Figure 8: Chemical structures and LC properties of the rodlike ligands discussed in the text.
Figure 9: Schematic drawing of the arrangement of nanoparticles in the columnar phase, as viewed from above (...
Figure 10: The proposed structural models resulting from ligand migration at the NP surface: (a) Smectic (Au@C6...
Figure 11: Reversible migration of the surface ligands as a function of temperature (and phase). Only the blue...
Figure 12: Photochromic and photo-mesogenic rodlike ligands.
Figure 13: Chemical structures and LC properties of side-on mesogens used to coat NPs.
Figure 14: Left: POM image of ligand 12. Right: POM image of Schlieren texture of the hybrid Au@12. Reprinted ...
Figure 15: Threaded nematic texture of Au@ C12/13 as observed by POM at RT. Scale bar = 10 μm. Reprinted with ...
Figure 16: Schematic representation of the gold NP columnar structures. (a) Rhombohedral phase in Au@C12/13 an...
Figure 17:
TEM images of thin films of the ![[Graphic 5]](/bjoc/content/inline/1860-5397-8-39-i5.png?max-width=637&scale=1.18182)
phase of Au@C12/13 recorded with the beam (a) parallel to the ![[Graphic 6]](/bjoc/content/inline/1860-5397-8-39-i6.png?max-width=637&scale=1.18182)
pla...
Figure 18: Chemical structures and mesogenic properties of bent-core proto-mesogenic ligands used to coat NPs.
Figure 19: Chemical structures and mesogenic properties of dendritic and proto-dendritic ligands used to coat ...
Figure 20: TEM image showing the arrangement of the hybrid NPs Au@16 into regularly spaced rows. Reprinted wit...
Figure 21: Chemical structures and mesogenic properties of dendritic and proto-dendritic ligands used to coat ...
Figure 22:
Top left: Body-centred (I) cubic lattice of ![[Graphic 8]](/bjoc/content/inline/1860-5397-8-39-i8.png?max-width=637&scale=1.18182)
symmetry composed of truncated octahedrons. Top right:...
Figure 23: Model proposed for the organisation of the hybrids within the quasi-nematic mesophase. Reprinted wi...
Figure 24: Mesogenic dendrons used to coat Au NPs.
Figure 25: Chemical structures of the discotic mesogenic ligands used to coat NPs.
Figure 26: TEM images of Au@235,12 prepared from aged solutions stood for 10 days in solutions of (a) 1:1 MeOH...
Figure 27: Some of the various hybrid geometries and packing motifs possible upon ligand grafting to the surfa...
Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal
- Baoxiang Gao,
- Hongxia Li,
- Defang Xia,
- Sufang Sun and
- Xinwu Ba
Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26
- ; liquid crystal; organogels; Introduction Peptide self-assembly has drawn a significant attention due to potential applications, especially in the fields of biomedicine and bionanotechnology [1][2][3]. Programmed self-assembly of peptides into highly ordered nanostructures creates biomaterials that
- display a wide range of physical properties often exceeding those of synthetic polymers [4][5]. Peptide-amphiphiles (PAs) represent an attractive class of bioactive molecules as they self-assemble into a variety of nanostructures, many of which have promising biological activity due to the exposed peptide
- regions on their outer surface [6][7]. The self-assembly of amphiphilic oligopeptide systems is thus emerging as a particularly powerful strategy to direct the self-assembly of relatively simple peptide building blocks toward sophisticated nanostructures [8]. Furthermore, the natural amino acid based
Graphical Abstract
Scheme 1: Synthetic sequence of amphiphilic dendritic peptides: (i) 1-dodecanol, EDCI, DMAP, dichoromethane, ...
Figure 1: (A) SEM images of the xerogels of G3 from n-hexane (B) magnification of the xerogels structure.
Figure 2: X-ray diffraction patterns of G3 as an organogelator and liquid crystal.
Figure 3: FT-IR of G3 as an organogelator and liquid crystal.
Figure 4: Differential scanning thermograms of ADPs registered during the second heating–cooling cycle with s...
Figure 5: Temperature dependent FT-IR of G3.
Figure 6: . Polarized optical micrographs of G3 at 145 °C (A), 140 °C (B), and 50 °C (C).
Figure 7: X-ray diffraction patterns of G3 at 50 °C.
The intriguing modeling of cis–trans selectivity in ruthenium-catalyzed olefin metathesis
- Naeimeh Bahri-Laleh,
- Raffaele Credendino and
- Luigi Cavallo
Beilstein J. Org. Chem. 2011, 7, 40–45, doi:10.3762/bjoc.7.7
- Naeimeh Bahri-Laleh Raffaele Credendino Luigi Cavallo MoLNaC - Modeling Lab for Nanostructures and Catalysis (http://www.molnac.unisa.it), Dipartimento di Chimica, Università di Salerno, Via Ponte don Melillo, I-84084 Fisciano (SA), Italy Polymerization Engineering Department, Iran Polymer and
Graphical Abstract
Scheme 1: Possible products resulting from the CM of terminal olefins.
Scheme 2: Representation of the reactions investigated.
Figure 1: Reaction profile for the formation of cis- and trans-2-butene.
Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems
- Gernot U. Marten,
- Thorsten Gelbrich and
- Annette M. Schmidt
Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98
- energy to heat energy due to relaxation processes and hysteresis losses [40][41][42]. Here, we report the investigation of a biocatalytically active carrier system that can be tuned by temperature or external magnetic fields. The hybrid nanostructures are obtained by the combination of magnetic
- , the immobilization of trypsin as a serine protease introduces biocatalytic activity. These components result in hybrid nanostructures, which serve as a recoverable reaction system that can be activated reversely by external ac magnetic fields, by using the thermal energy developed by magnetic heating
- -type shell. Synthesis of functional core–shell nanostructures In the first step, Fe3O4 nanoparticles are prepared by alkaline precipitation based on a method of Cabuil and Massart [43] and surface-functionalized with (p-chloromethyl)phenyltrimethoxysilane (CTS) [44] in order to introduce benzylic
Graphical Abstract
Scheme 1: Synthesis of magnetic biocatalyst particles.
Figure 1: Structures of comonomers employed in the synthesis of functional core–shell particles.
Figure 2: TEM images of a) Fe3O4 nanoparticles electrostatically stabilized by citric acid; b) Fe3O4@P(M100) ...
Figure 3: a) Cloud point temperature Tc of Fe3O4@P(OxMy) in water in relation to molar fraction of MEMA χM,ex...
Figure 4: a) Normalized magnetization loops of dispersions based on Fe3O4@CA in water (solid line), Fe3O4@CPS...
Scheme 2:
Reaction scheme of the enzymatic digestion of BAPNA catalyzed by magnetically labeled trypsin (![[Graphic 1]](/bjoc/content/inline/1860-5397-6-98-i6.png?max-width=637&scale=0.1536366)
).
Figure 5: a) Cornish-Bowden diagram for the temperature-dependent kinetic data of trypsin activity, and b) Ea...
Scheme 3: Proposed mechanism of catalytic activity after heating magnetic biocatalyst particles above Tc.
Figure 6: a) Turnover number kcat and b) Michaelis constant Km of particle- immobilized trypsin vs free tryps...
Preparation of pyridine-3,4-diols, their crystal packing and their use as precursors for palladium-catalyzed cross-coupling reactions
- Tilman Lechel,
- Irene Brüdgam and
- Hans-Ulrich Reissig
Beilstein J. Org. Chem. 2010, 6, No. 42, doi:10.3762/bjoc.6.42
- numerous naturally occurring compounds and are also frequently used in functional materials [1][2][3][4]. Pyridindiol derivatives are of particular interest as building blocks for the construction of dendritic nanostructures in supramolecular chemistry [5], whereas N-protected pyridine-3,4-diols find
Graphical Abstract
Scheme 1: Deprotection of 3-alkoxypyridinols 1 to pyridine-3,4-diols 2. aMethod a: Pd/C, H2, MeOH, rt, 1 d; b...
Figure 1: X-ray crystal structure of compound 2c/2c′.
Scheme 2: Conversion of pyridine-3,4-diols 2 into pyridinediyl bistriflates or -nonaflates 3. a) Et3N, Rf2O, ...
Scheme 3: Sonogashira couplings of pyridinediyl bis(perfluoroalkanesulfonates) 3. a) Pd(PPh3)4 [or Pd(OAc)2/P...
Figure 2: Absorption and fluorescence spectra of compounds 4b and 4c.
Molecular recognition of organic ammonium ions in solution using synthetic receptors
- Andreas Späth and
- Burkhard König
Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32
- potential use of these peptide nanostructures is as pro-drugs that may be activated by a specific proteolytic enzyme to target selectively and destroy undesirable cells [190]. Kim et al. reported two bis(azacrown)anthracene derivatives 48a and 48b (Figure 30) for the recognition and detection of
Graphical Abstract
Figure 1: Biologically important amines and quaternary ammonium salts: histamine (1), dopamine (2) and acetyl...
Figure 2: Crown ether 18-crown-6.
Figure 3: Conformations of 18-crown-6 (4) in solvents of different polarity.
Figure 4: Binding topologies of the ammonium ion depending on the crown ring size.
Figure 5: A “pseudorotaxane” structure consisting of 24-crown-8 and a secondary ammonium ion (5); R = Ph.
Figure 6: Typical examples of azacrown ethers, cryptands and related aza macrocycles.
Figure 7: Binding of ammonium to azacrown ethers and cryptands [111-113].
Figure 8: A 19-crown-6-ether with decalino blocking groups (11) and a thiazole-dibenzo-18-crown-6-ether (12).
Figure 9: 1,3-Bis(6-oxopyridazin-1-yl)propane derivatives 13 and 14 by Campayo et al.
Figure 10: Fluorescent azacrown-PET-sensors based on coumarin.
Figure 11: Two different pyridino-cryptands (17 and 18) compared to a pyridino-crown (19); chiral ammonium ion...
Figure 12: Pyridino-18-crown-6 ligand (21), a similar acridino-18-crown-6 ligand (22) and a structurally relat...
Figure 13: Ciral pyridine-azacrown ether receptors 24.
Figure 14: Chiral 15-crown-5 receptors 26 and an analogue 18-crown-6 ligand 27 derived from amino alcohols.
Figure 15: C2-symmetric chiral 18-crown-6 amino alcohol derivatives 28 and related macrocycles.
Figure 16: Macrocycles with diamide-diester groups (30).
Figure 17: C2-symmetric chiral aza-18-crown-6 ethers (31) with phenethylamine residues.
Figure 18: Chiral C-pivot p-methoxy-phenoxy-lariat ethers.
Figure 19: Chiral lariat crown ether 34.
Figure 20: Sucrose-based chiral crown ether receptors 36.
Figure 21: Permethylated fructooligosaccharide 37 showing induced-fit chiral recognition.
Figure 22: Biphenanthryl-18-crown-6 derivative 38.
Figure 23: Chiral lariat crown ethers derived from binol by Fuji et al.
Figure 24: Chiral phenolic crown ether 41 with “aryl chiral barriers” and guest amines.
Figure 25: Chiral bis-crown receptor 43 with a meso-ternaphthalene backbone.
Figure 26: Chromogenic pH-dependent bis-crown chemosensor 44 for diamines.
Figure 27: Triamine guests for binding to receptor 44.
Figure 28: Chiral bis-crown phenolphthalein chemosensors 46.
Figure 29: Crown ether amino acid 47.
Figure 30: Luminescent receptor 48 for bis-alkylammonium guests.
Figure 31: Luminescent CEAA (49a), a bis-CEAA receptor for amino acids (49b) and the structure of lysine bindi...
Figure 32: Luminescent CEAA tripeptide for binding small peptides.
Figure 33: Bis crown ether 51a self assembles co-operatively with C60-ammonium ion 51b.
Figure 34: Triptycene-based macrotricyclic dibenzo-[24]-crown-8 ether host 52 and guests.
Figure 35: Copper imido diacetic acid azacrown receptor 53a and the suggested His-Lys binding motif; a copper ...
Figure 36: Urea (54) and thiourea (55) benzo crown receptor for transport and extraction of amino acids.
Figure 37: Crown pyryliums ion receptors 56 for amino acids.
Figure 38: Ditopic sulfonamide bridged crown ether receptor 57.
Figure 39: Luminescent peptide receptor 58.
Figure 40: Luminescent receptor 59 for the detection of D-glucosamine hydrochloride in water/ethanol and lumin...
Figure 41: Guanidinium azacrown receptor 61 for simple amino acids and ditopic receptor 62 with crown ether an...
Figure 42: Chiral bicyclic guanidinium azacrown receptor 63 and similar receptor 64 for the enantioselective t...
Figure 43: Receptors for zwitterionic species based on luminescent CEAAs.
Figure 44: 1,10-Azacrown ethers with sugar podand arms and the anticancer agent busulfan.
Figure 45: Benzo-18-crown-6 modified β-cyclodextrin 69 and β-cyclodextrin functionalized with diaza-18-crown-6...
Figure 46: Receptors for colorimetric detection of primary and secondary ammonium ions.
Figure 47: Porphyrine-crown-receptors 72.
Figure 48: Porphyrin-crown ether conjugate 73 and fullerene-ammonium ion guest 74.
Figure 49: Calix[4]arene (75a), homooxocalix[4]arene (75b) and resorcin[4]arene (75c) compared (R = H, alkyl c...
Figure 50: Calix[4]arene and ammonium ion guest (R = H, alkyl, OAcyl etc.), possible binding sites; A: co-ordi...
Figure 51: Typical guests for studies with calixarenes and related molecules.
Figure 52: Lower rim modified p-tert-butylcalix[5]arenes 82.
Figure 53: The first example of a water soluble calixarene.
Figure 54: Sulfonated water soluble calix[n]arenes that bind ammonium ions.
Figure 55: Displacement assay for acetylcholine (3) with a sulfonato-calix[6]arene (84b).
Figure 56: Amino acid inclusion in p-sulfonatocalix[4]arene (84a).
Figure 57: Calixarene receptor family 86 with upper and lower rim functionalization.
Figure 58: Calix[6]arenes 87 with one carboxylic acid functionality.
Figure 59: Sulfonated calix[n]arenes with mono-substitution at the lower rim systematically studied on their r...
Figure 60: Cyclotetrachromotropylene host (91) and its binding to lysine (81c).
Figure 61: Calixarenes 92 and 93 with phosphonic acids groups.
Figure 62: Calix[4]arene tetraphosphonic acid (94a) and a double bridged analogue (94b).
Figure 63: Calix[4]arene tetraphosphonic acid ester (92c) for surface recognition experiments.
Figure 64: Calixarene receptors 95 with α-aminophosphonate groups.
Figure 65: A bridged homocalix[3]arene 95 and a distally bridged homocalix[4]crown 96.
Figure 66: Homocalix[3]arene ammonium ion receptor 97a and the Reichardt’s dye (97b) for colorimetric assays.
Figure 67: Chromogenic diazo-bridged calix[4]arene 98.
Figure 68: Calixarene receptor 99 by Huang et al.
Figure 69: Calixarenes 100 reported by Parisi et al.
Figure 70: Guest molecules for inclusion in calixarenes 100: DAP × 2 HCl (101a), APA (101b) and Lys-OMe × 2 HC...
Figure 71: Different N-linked peptido-calixarenes open and with glycol chain bridges.
Figure 72: (S)-1,1′-Bi-2-naphthol calixarene derivative 104 published by Kubo et al.
Figure 73: A chiral ammonium-ion receptor 105 based on the calix[4]arene skeleton.
Figure 74: R-/S-phenylalaninol functionalized calix[6]arenes 106a and 106b.
Figure 75: Capped homocalix[3]arene ammonium ion receptor 107.
Figure 76: Two C3 symmetric capped calix[6]arenes 108 and 109.
Figure 77: Phosphorous-containing rigidified calix[6]arene 110.
Figure 78: Calix[6]azacryptand 111.
Figure 79: Further substituted calix[6]azacryptands 112.
Figure 80: Resorcin[4]arene (75c) and the cavitands (113).
Figure 81: Tetrasulfonatomethylcalix[4]resorcinarene (114).
Figure 82: Resorcin[4]arenes (115a/b) and pyrogallo[4]arenes (115c, 116).
Figure 83: Displacement assay for acetylcholine (3) with tetracyanoresorcin[4]arene (117).
Figure 84: Tetramethoxy resorcinarene mono-crown-5 (118).
Figure 85: Components of a resorcinarene based displacement assay for ammonium ions.
Figure 86: Chiral basket resorcin[4]arenas 121.
Figure 87: Resorcinarenes with deeper cavitand structure (122).
Figure 88: Resorcinarene with partially open deeper cavitand structure (123).
Figure 89: Water-stabilized deep cavitands with partially structure (124, 125).
Figure 90: Charged cavitands 126 for tetralkylammonium ions.
Figure 91: Ditopic calix[4]arene receptor 127 capped with glycol chains.
Figure 92: A calix[5]arene dimer for diammonium salt recognition.
Figure 93: Calixarene parts 92c and 129 for the formation molecular capsules.
Figure 94: Encapsulation of a quaternary ammonium cation by two resorcin[4]arene molecules (NMe4+@[75c]2 × Cl−...
Figure 95: Encapsulation of a quaternary ammonium cation by six resorcin[4]arene molecules (NMe3D+@[130]6 × Cl−...
Figure 96: Structure and schematic of cucurbit[6]uril (CB[6], 131a).
Figure 97: Cyclohexanocucurbit[6]uril (CB′[6], 132) and the guest molecule spermine (133).
Figure 98: α,α,δ,δ-Tetramethylcucurbit[6]uril (134).
Figure 99: Structure of the cucurbituril-phthalhydrazide analogue 135.
Figure 100: Organic cavities for the displacement assay for amine differentiation.
Figure 101: Displacement assay methodology for diammonium- and related guests involving cucurbiturils and some ...
Figure 102: Nor-seco-Cucurbituril (±)-bis-ns-CB[6] (140) and guest molecules.
Figure 103: The cucurbit[6]uril based complexes 141 for chiral discrimination.
Figure 104: Cucurbit[7]uril (131c) and its ferrocene guests (142) opposed.
Figure 105: Cucurbit[7]uril (131c) guest inclusion and representative guests.
Figure 106: Cucurbit[7]uril (131c) binding to succinylcholine (145) and different bis-ammonium and bis-phosphon...
Figure 107: Paraquat-cucurbit[8]uril complex 149.
Figure 108: Gluconuril-based ammonium receptors 150.
Figure 109: Examples of clefts (151a), tweezers (151b, 151c, 151d) and clips (151e).
Figure 110: Kemp’s triacid (152a), on example of Rebek’s receptors (152b) and guests.
Figure 111: Amino acid receptor (154) by Rebek et al.
Figure 112: Hexagonal lattice designed hosts by Bell et al.
Figure 113: Bell’s amidinium receptor (156) and the amidinium ion (157).
Figure 114: Aromatic phosphonic acids.
Figure 115: Xylene phosphonates 159 and 160a/b for recognition of amines and amino alcohols.
Figure 116: Bisphosphonate recognition motif 161 for a colorimetric assay with alizarin complexone (163) for ca...
Figure 117: Bisphosphonate/phosphate clip 164 and bisphosphonate cleft 165.
Figure 118: N-Methylpyrazine 166a, N-methylnicotinamide iodide (166b) and NAD+ (166c).
Figure 119: Bisphosphate cavitands.
Figure 120: Bisphosphonate 167 of Schrader and Finocchiaro.
Figure 121: Tweezer 168 for noradrenaline (80b).
Figure 122: Different tripods and heparin (170).
Figure 123: Squaramide based receptors 172.
Figure 124: Cage like NH4+ receptor 173 of Kim et al.
Figure 125: Ammonium receptors 174 of Chin et al.
Figure 126: 2-Oxazolin-based ammonium receptors 175a–d and 176 by Ahn et al.
Figure 127: Racemic guest molecules 177.
Figure 128: Tripods based on a imidazole containing macrocycle (178) and the guest molecules employed in the st...
Figure 129: Ammonium ion receptor 180.
Figure 130: Tetraoxa[3.3.3.3]paracyclophanes 181 and a cyclophanic tetraester (182).
Figure 131: Peptidic bridged paraquat-cyclophane.
Figure 132: Shape-selective noradrenaline host.
Figure 133: Receptor 185 for binding of noradrenaline on surface layers from Schrader et al.
Figure 134: Tetraphosphonate receptor for binding of noradrenaline.
Figure 135: Tetraphosphonate 187 of Schrader and Finocchiaro.
Figure 136: Zinc-Porphyrin ammonium-ion receptors 188 and 189 of Mizutani et al.
Figure 137: Zinc porphyrin receptor 190.
Figure 138: Zinc porphyrin receptors 191 capable of amino acid binding.
Figure 139: Zinc-porphyrins with amino acid side chains for stereoinduction.
Figure 140: Bis-zinc-bis-porphyrin based on Tröger’s base 193.
Figure 141: BINAP-zinc-prophyrin derivative 194 and it’s guests.
Figure 142: Bisaryl-linked-zinc-porphyrin receptors.
Figure 143: Bis-zinc-porphyrin 199 for diamine recognition and guests.
Figure 144: Bis-zinc-porphyrin crown ether 201.
Figure 145: Bis-zinc-porphyrin 202 for stereodiscrimination (L = large substituent; S = small substituent).
Figure 146: Bis-zinc-porphyrin[3]rotaxane and its copper complex and guests.
Figure 147: Dien-bipyridyl ligand 206 for co-ordination of two metal atoms.
Figure 148: The ligand and corresponding tetradentate co-complex 207 serving as enantioselective receptor for a...
Figure 149: Bis(oxazoline)–copper(II) complex 208 for the recognition of amino acids in aqueous solution.
Figure 150: Zinc-salen-complexes 209 for the recognition tertiary amines.
Figure 151: Bis(oxazoline)–copper(II) 211 for the recognition of amino acids in aqueous solution.
Figure 152: Zn(II)-complex of a C2 terpyridine crown ether.
Figure 153: Displacement assay and receptor for aspartate over glutamate.
Figure 154: Chiral complex 214 for a colorimetric displacement assay for amino acids.
Figure 155: Metal complex receptor 215 with tripeptide side arms.
Figure 156: A sandwich complex 216 and its displaceable dye 217.
Figure 157: Lanthanide complexes 218–220 for amino acid recognition.
Figure 158: Nonactin (221), valinomycin (222) and vancomycin (223).
Figure 159: Monesin (224a) and a chiral analogue for enantiodiscrimination of ammonium guests (224b).
Figure 160: Chiral podands (226) compared to pentaglyme-dimethylether (225) and 18-crown-6 (4).
Figure 161: Lasalocid A (228).
Figure 162: Lasalocid derivatives (230) of Sessler et al.
Figure 163: The Coporphyrin I tetraanion (231).
Figure 164: Linear and cyclic peptides for ammonium ion recognition.
Figure 165: Cyclic and bicyclic depsipeptides for ammonium ion recognition.
Figure 166: α-Cyclodextrin (136a) and novocaine (236).
Figure 167: Helical diol receptor 237 by Reetz and Sostmann.
Figure 168: Ammonium binding spherand by Cram et al. (238a) and the cyclic[6]metaphenylacetylene 238b in compar...
Figure 169: Receptor for peptide backbone and ammonium binding (239).
Figure 170: Anion sensor principle with 3-hydroxy-2-naphthanilide of Jiang et al.
Figure 171: 7-bromo-3-hydroxy-N-(2-hydroxyphenyl)naphthalene 2-carboxamide (241) and its amine binding.
Figure 172: Naturally occurring catechins with affinity to quaternary ammonium ions.
Figure 173: Spiropyran (244) and merocyanine form (244a) of the amino acid receptors of Fuji et al.
Figure 174: Coumarin aldehyde (245) and its iminium species with amino acid bound (245a) by Glass et al.
Figure 175: Coumarin aldehyde appended with boronic acid.
Figure 176: Quinolone aldehyde dimers by Glass et al.
Figure 177: Chromogenic ammonium ion receptors with trifluoroacetophenone recognition motifs.
Figure 178: Chromogenic ammonium ion receptor with trifluoroacetophenone recognition motif bound on different m...
Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state
- Carolin Rether,
- Wilhelm Sicking,
- Roland Boese and
- Carsten Schmuck
Beilstein J. Org. Chem. 2010, 6, No. 3, doi:10.3762/bjoc.6.3
- aromatic scaffolds such as benzene or furan instead of pyrrole or with an amidinium cation instead of a guanidinium cation was also confirmed by DFT calculations [14]. Zwitterion 1 has thus found widespread application in the formation of self-assembled nanostructures such as vesicles or supramolecular
Graphical Abstract
Figure 1: Self-assembly of zwitterion 1 to give dimer 1·1 and self-assembly of zwitterion 2 to give dimer 2·2...
Scheme 1: Synthesis of zwitterion 2.
Scheme 2: Synthesis of compound 2·H+.
Figure 2: 1H NMR spectra of zwitterion 2 (bottom) and its protonated form 2·H+ (top).
Figure 3: Part of the 1H NMR spectrum of 2 in [D6]DMSO showing the complexation-induced shifts of the indole ...
Figure 4: Representative binding isotherm of the aromatic proton d (left) and the indole NH proton (right).
Figure 5: Binding isotherm of the guanidinium NH2 protons.
Figure 6: Crystal structure of dimer 2·2 with hydrogen bond distances (Å) and dihedral angles.
Figure 7: Side view of dimer 2·2 in the solid state.
Figure 8: Part of the crystal lattice of zwitterion 2.
Scheme 3: An attractive H-bond in 1 (left) is replaced by a repulsive steric interaction in 2 (right).
Figure 9: Energy-minimized structure for dimer 2·2 with hydrogen bond distances (Å) and dihedral angles.
Synthesis of deep- cavity fluorous calix[4]arenes as molecular recognition scaffolds
- Maksim Osipov,
- Qianli Chu,
- Steven J. Geib,
- Dennis P. Curran and
- Stephen G. Weber
Beilstein J. Org. Chem. 2008, 4, No. 36, doi:10.3762/bjoc.4.36
- have included nanowires [3], self organized nanostructures [4] chiral supramolecular assemblies [5], as well as sensors for cations [6][7], anions [8] and neutral organic molecules [9]. The versatility of the calixarene scaffold is a result of its preorganized cavity [10], which consists of four
Graphical Abstract
Figure 1: Calix[4]arene in cone conformation.
Scheme 1: Preparation of 3a and 3b.
Scheme 2: Preparation of 4 and 5.
Scheme 3: Preparation of 6.
Scheme 4: Preparation of 8 and 9.
Figure 2: Full (top), top (bottom left)a, and side (bottom right)a views of 5; afluorous chains omitted for c...
