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Search for "solvent polarity" in Full Text gives 85 result(s) in Beilstein Journal of Organic Chemistry.
Valence isomerization of cyclohepta-1,3,5-triene and its heteroelement analogues
- Helen Jansen,
- J. Chris Slootweg and
- Koop Lammertsma
Beilstein J. Org. Chem. 2011, 7, 1713–1721, doi:10.3762/bjoc.7.201
- methyl groups in benzene oxide (4) [38][40][51]. Thus, in contrast to the cycloheptatriene–norcaradiene (1–2) pair, the equilibrium constant for oxepine (3) and bicyclic benzene oxide (4) varies widely with solvent polarity and to some extent with temperature and substituents, making it possible to work
Graphical Abstract
Scheme 1: Valence isomerization of cyclohepta-1,3,5-triene (1) and its heteroelement analogues.
Scheme 2: Conformational ring inversions.
Scheme 3: Rearrangements of the parent cycloheptatriene 1 and norcaradiene 2.
Figure 1: NICS(0) values of fluorinated heteropines.
Scheme 4: Reactivity of oxepine (3) and benzene oxide (4).
Figure 2: Stabilized thiepines 15–18.
Scheme 5: Valence isomerization of 1H-azepines.
Scheme 6: Reactivity of 1H-azepine.
Figure 3: Benzannulated azepines 27 and 28.
Figure 4: Reported phosphepines 29–32.
Scheme 7: Phosphinidene generation from metal-complexed benzophosphepine 33.
Synthesis of dye/fluorescent functionalized dendrons based on cyclotriphosphazene
- Aurélien Hameau,
- Sabine Fuchs,
- Régis Laurent,
- Jean-Pierre Majoral and
- Anne-Marie Caminade
Beilstein J. Org. Chem. 2011, 7, 1577–1583, doi:10.3762/bjoc.7.186
- or in pyridine, and was ascribed to the solvent polarity, which modifies the interactions between both parts of the molecule [17]. In our case, we may consider that the structure of dendron 10 in solution in dioxane is more expanded than in water, which should bring the hydrophobic moieties (the
Graphical Abstract
Scheme 1: Synthesis of functionalized phenols. Reagents and conditions: a) Boc2O, 1.0 equiv, THF, 0 °C → rt, ...
Scheme 2: Single substitution of hexachlorocyclotriphosphazene. Reagents and conditions: a) Cs2CO3, 1.67 equi...
Scheme 3: Synthesis of dansylated dendrons. Reagents and conditions: a) Cs2CO3, 11 equiv, THF, rt, 48 h. b) Cs...
Scheme 4: Synthesis of dabsylated dendrons. Reagents and conditions: a) Cs2CO3, 11 equiv, THF, rt, 48 h. b) T...
Figure 1: UV–vis spectra of compounds 8–10.
Figure 2: UV–vis spectra of compounds 4, 11 and 12 in dioxane.
Figure 3: Excitation (left) and emission (right) spectra of compounds 8–10 in 1,4-dioxane (the excitation spe...
Figure 4: Emission spectra (λexc = 347 nm) of compound 10 in mixtures water/dioxane with different molar frac...
Figure 5: λem,max of 10 in mixture water/dioxane vs molar fraction of water in dioxane (filled squares) and v...
Predicting the UV–vis spectra of oxazine dyes
- Scott Fleming,
- Andrew Mills and
- Tell Tuttle
Beilstein J. Org. Chem. 2011, 7, 432–441, doi:10.3762/bjoc.7.56
- been observed and the mechanism(s) explored in previous studies by various authors [9][10][11]. Most of these investigations have involved measuring experimentally the spectroscopic features of oxazine dyes, upon varying the solvent polarity. However, some attempt has been made to rationalize these
- observations by a computational study of the solvatochromism of the oxazine dye Nile red [12]. In the investigation, TD-DFT was applied in order to try and explore the contributing factors in the solvatochromism observed with Nile red, upon gradually increasing the solvent polarity from benzene to acetonitrile
Graphical Abstract
Figure 1: Quinone imine structural relationships.
Figure 2: Numbering and structure of oxazine dyes studied in this work (counterions not shown).
Figure 3: Directions of solvated (a) dipole moments and (b) transition moments from origin (0,0,0).
Figure 4: Error between experimental and calculated λmax values for each dye at the different levels of theor...
Figure 5: The orbital overlaps (Λ) for each dye at the different levels of theory investigated. All structure...
Formation of macrocyclic lactones in the Paternò–Büchi dimerization reaction
- Junya Arimura,
- Tsutomu Mizuta,
- Yoshikazu Hiraga and
- Manabu Abe
Beilstein J. Org. Chem. 2011, 7, 265–269, doi:10.3762/bjoc.7.35
- detected by 1H NMR (500 MHz). To investigate the medium effect on the formation of 2a, the photochemical reaction of 1a was performed in several solvents (entries 4–6). The yield of 2a decreased with increasing solvent polarity; 16% in toluene (entry 4) and 10% in CH3CN (entry 6). Temperature had no effect
Graphical Abstract
Scheme 1: Reaction of furan with triplet excited carbonyls, regioselectivity.
Scheme 2: Possible pathways for the photochemical reaction of furan derivatives 1a–c.
Scheme 3: Synthesis and the photochemical reaction of furan-2-ylmethyl 2-oxoacetates 1a,b.
Figure 1: X-ray crystal structure of the macrocyclic lactone 2a.
Figure 2: 1H NMR spectra (500 MHz) for (a) the photolysate of 1a after 4 h irradiation in degassed and dried C...
Fluorometric recognition of both dihydrogen phosphate and iodide by a new flexible anthracene linked benzimidazolium-based receptor
- Kumaresh Ghosh and
- Debasis Kar
Beilstein J. Org. Chem. 2011, 7, 254–264, doi:10.3762/bjoc.7.34
- in emission in CHCl3 containing 0.1% CH3CN (Supporting Information File 1). These observations thus intimate that solvent polarity is an important aspect for monitoring the sensing behavior of benzimidazolium-based receptors. In our opinion, CH3CN in the present case participates in H-bonding with
Graphical Abstract
Figure 1: Synthesized compounds 1 and 2.
Scheme 1: Synthesis of 1 and 2.
Figure 2: Energy optimized geometry of 1 with H2PO4− (E = 92.14 kcal/mol, a = 2.45 Å, b = 1.94 Å, c = 2.34 Å, ...
Figure 3: Change in fluorescence emission of 1 (c = 5.78 × 10−5 M) in the presence of 2 equiv of tetrabutylam...
Figure 4: Change in emission spectra of 1 (c = 5.78 × 10−5 M) in presence of increasing amounts of H2PO4− in ...
Figure 5: Suggested modes of binding of the H2PO4− ion into the cleft of 1.
Figure 6: Plot of change in emission of 1 at 420 nm vs the ratio of guest to host concentration in CH3CN.
Figure 7: Fluorescence Job plot of 1 with H2PO4−.
Figure 8: Change in fluorescence emission of 2 (c = 3.93 × 10−5 M) in the presence of 1 equiv of tetrabutylam...
Figure 9: Stern–Volmer plots for 1 (c = 5.78 × 10−5 M) with H2PO4−, F−, Br− and I− at 420 nm (up to the addit...
Figure 10: Change in UV–vis spectra of 1 (c = 5.78 × 10−5 M) in presence of increasing amounts of H2PO4− in CH3...
Figure 11: Change in fluorescence emission of 1 (c = 5.78 × 10−5 M) in the presence of 2 equiv of tetrabutylam...
Figure 12: Stern–Volmer plots for 1 (c = 5.78 × 10−5 M) with H2PO4−, F−, Br− and I− at 420 nm (up to the addit...
Figure 13: Fluorescence decays (at λmax = 420 nm) of receptor 1 upon the addition of H2PO4− ion ([H] = 5.78 × ...
Figure 14: Fluorescence decays (at λmax = 420 nm) of receptor 1 upon the addition of I− ion ([H] = 5.78 × 10−5...
Figure 15: Partial 1H NMR (300 MHz, CDCl3 containing 4% CD3CN) spectra of (a) 1 (c = 1.38 × 10−3 M), (b) 1:1 a...
Donor-acceptor substituted phenylethynyltriphenylenes – excited state intramolecular charge transfer, solvatochromic absorption and fluorescence emission
- Ritesh Nandy and
- Sethuraman Sankararaman
Beilstein J. Org. Chem. 2010, 6, 992–1001, doi:10.3762/bjoc.6.112
- absorption and fluorescence emission properties of these molecules have been studied in solvents of different polarity. For a given derivative, solvent polarity had minimal effect on the absorption maxima. However, for a given solvent the absorption maxima red shifted with increasing conjugation of the
- substituent. The fluorescence emission of these derivatives was very sensitive to solvent polarity. In the presence of strongly electron withdrawing (–CN) and strongly electron donating (–NMe2) substituents large Stokes shifts (up to 130 nm, 7828 cm−1) were observed in DMSO. In the presence of carbonyl
- whose fluorescence emission is sensitive to environment and solvent polarity are of significant interest due to their versatile applications in chemistry, biology and environmental science [1][2][3][4]. Considerable effort has been expended into shifting the fluorescence emission of organic molecules
Graphical Abstract
Scheme 1: Structures of 2-phenylethynyltriphenylene derivatives.
Scheme 2: Synthesis of 2-ethynyltriphenylene (4).
Scheme 3: Synthesis of phenylethynyltriphenylene derivatives 1a–g.
Figure 1: Absorption spectra of 1a–g in cyclohexane and acetonitrile (10−5 M).
Figure 2: Fluorescence emission spectra of 1a–g in cyclohexane and DMSO (10−5 M), λex = 335 nm.
Figure 3: Fluorescence emission spectra of 1e and 1g in various solvents (10−5 M). CH – cyclohexane (λex = 33...
Figure 4: Effect of binary solvent system (cyclohexane-isopropyl alcohol) on the fluorescence emission of 1g ...
Figure 5: Lippert–Mataga plot showing Stokes shift as a function of solvent orientation polarizibility (Δf).
Figure 6: Correlation of Stokes shift with ET(30) scale.
Figure 7: HOMO and LUMO surfaces of 1c and 1g according to DFT calculations.
Synthesis of the fluorescent amino acid rac-(7-hydroxycoumarin-4-yl)ethylglycine
- Manfred Braun and
- Torsten Dittrich
Beilstein J. Org. Chem. 2010, 6, No. 69, doi:10.3762/bjoc.6.69
- ), which not only displays a relatively large Stokes shift but also a fluorescence that is sensitive to both pH and solvent polarity [10][11]. Although a straightforward, short approach to the L-amino acid 1 has been reported [10], its isolation and purification was found to be difficult and tedious
Graphical Abstract
Figure 1: Fluorescent amino acid (7-hydroxycoumarin-4-yl)ethylglycine (1).
Scheme 1: Synthetic route to racemic amino acid 1·HCl. Reagents and conditions: a) BH3·SMe2, THF, 0 °C to r. ...
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
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...
Recognition properties of receptors consisting of imidazole and indole recognition units towards carbohydrates
- Monika Mazik and
- André Hartmann
Beilstein J. Org. Chem. 2010, 6, No. 9, doi:10.3762/bjoc.6.9
- the limitations of the NMR method, see ref. [55]). After the addition of 5% DMSO-d6 the binding constants for 4•6a were determined to be 35000 (K11) and 1000 M−1 (K12). Thus, the affinity of 4 significantly decreases as solvent polarity increases (the addition of dimethyl sulfoxide also caused the
Graphical Abstract
Figure 1: Examples of hydrogen bonds in the complex of a) galactose-binding protein with D-glucose [3], b) Amara...
Figure 2: Structures of receptors 1–5.
Figure 3: Structures of sugars investigated in this study.
Scheme 1: Reaction conditions: a) AlCl3, CH3CH2Br, 0 °C to r. t., 12 h (85%) [47]; b) 33% HBr in CH3COOH, ZnBr2, ...
Figure 4: Structures of the recently described phenanthroline/aminopyridine-based receptors showing α- vs. β-...
Figure 5: Partial 1H NMR spectra (400 MHz; CDCl3) of receptor 4 (a), 5 (b), 1 (c), and 3 (d) before (bottom) ...
Figure 6: Partial 1H NMR spectra (400 MHz, CDCl3) of 5 after addition of (from bottom to top) 0.00–1.63 equiv...
Figure 7: Energy-minimized structure of the 1:1 a) and 2:1 complex b) formed between receptor 4 and β-galacto...
Figure 8: Examples of hydrogen bonding motifs indicated by molecular modeling studies in the 1:1 complex betw...
Quinoline based receptor in fluorometric discrimination of carboxylic acids
- Kumaresh Ghosh,
- Suman Adhikari,
- Asoke P. Chattopadhyay and
- Purnendu Roy Chowdhury
Beilstein J. Org. Chem. 2008, 4, No. 52, doi:10.3762/bjoc.4.52
- behaviors of the receptors 1 and 2 were noticed in solvents of different polarities. In the ground state the absorption peak at 289 nm for quinoline of 1 and at 290 nm for naphthalene of 2 in CHCl3 are considerably affected in intensities as well as positions (red shift; ~18 nm) as the solvent polarity is
Graphical Abstract
Figure 1: Structures of compounds 1 and 2.
Scheme 1: Syntheses of receptors 1 and 2.
Figure 2: UV-vis spectra of 1 (c = 5.05 × 10−5 M) in different solvents.
Figure 3: UV-vis spectra of 2 (c = 5.05 × 10−5 M) in different solvents.
Figure 4: UV spectra of the complex of 1 with citric acid (c = 1.67 × 10−5 M) and its change of absorbance on...
Figure 5: UV spectra of the complex of 1 with D-(−)-tartaric acid (c = 1.67 × 10−5 M) and its change of absor...
Figure 6: UV spectra of the complex of 2 with citric acid (c = 1.67 × 10−5 M) and its change of absorbance on...
Figure 7: UV spectra of the complex of 2 with D-(−)-tartaric acid (c = 1.67 × 10−5 M) and its change of absor...
Figure 8: Fluorescence change of 1 in CHCl3 in the presence of carboxylic acids (λex = 290 nm).
Figure 9: Plot of the ratio of excimer to monomer emission vs concentration of the complex of 1 with citric a...
Figure 10: Fluorescence change of 1 in CHCl3 (c = 1.67 × 10−5 M) upon addition of citric acid dissolved in CHCl...
Figure 11: Fluorescence change of 1 in CHCl3 (c = 1.67 × 10−5 M) upon addition of D-(−)-tartaric acid dissolve...
Figure 12: Fluorescence change of 2 in CHCl3 in the presence of carboxylic acids (λex = 290 nm).
Figure 13: Fluorescence change of 2 in CHCl3 (c = 1.67 × 10−5 M) upon addition citric acid dissolved in CHCl3 ...
Figure 14: 1H NMR (in CDCl3) spectra of receptor 1 (c = 3.57 × 10−3 M; bottom) and the 1:1 complex with citric...
Figure 15: AM1 optimized geometries of the complexes of 1 with (a) citric acid, hydrogen bond distances: a = 2...
Figure 16: AM1 optimized geometry of the complex of 2 with citric acid, hydrogen bond distances: a = 2.12 Å, b...
