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Search for "host–guest systems" in Full Text gives 20 result(s) in Beilstein Journal of Organic Chemistry.
Switchable molecular tweezers: design and applications
- Pablo Msellem,
- Maksym Dekthiarenko,
- Nihal Hadj Seyd and
- Guillaume Vives
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
- allosterically regulated host–guest systems to catalysis or magnetic properties. Redox switchable molecular tweezers One of the cleanest stimuli for supramolecular switching is electron transfer. Besides photoswitching, the undeniable advantages of redox switching are the absence of chemical waste and the fact
Graphical Abstract
Figure 1: Principle of switchable molecular tweezers.
Figure 2: Principle of pH-switchable molecular tweezers 1 [19].
Figure 3: a) pH-Switchable tweezers 2 substituted with alkyl chains as switchable lipids. b) Schematic depict...
Figure 4: Modification of spectral properties of 3 by controlled induction of Pt–Pt interactions.
Figure 5: Conformational switching of di(hydroxyphenyl)pyrimidine-based tweezer 4 upon alkylation or fluoride...
Figure 6: Hydrazone-based pH-responsive tweezers 5 for mesogenic modulation.
Figure 7: pH-Switchable molecular tweezers 6 bearing acridinium moieties.
Figure 8: a) Terpyridine and pyridine-hydrazone-pyridine analogs molecular tweezers and b) extended pyridine ...
Figure 9: Terpyridine-based molecular tweezers with M–salphen arms and their field of application. Figure 9 was adapt...
Figure 10: a) Terpyridine-based molecular tweezers for diphosphate recognition [48]; b) bishelicene chiroptical te...
Figure 11: Terpyridine-based molecular tweezers with allosteric cooperative binding.
Figure 12: Terpyridine-based molecular tweezers presenting closed by default conformation.
Figure 13: Pyridine-pyrimidine-pyridine-based molecular tweezers.
Figure 14: Coordination-responsive molecular tweezers based on nitrogen-containing ligands.
Figure 15: Molecular tweezers exploiting the remote bipyridine or pyridine binding to trigger the conformation...
Figure 16: Bipyridine-based molecular tweezers exploiting the direct s-trans to s-cis-switching for a) anion b...
Figure 17: a) Podand-based molecular tweezers [66,67]. b) Application of tweezers 32 for the catalytic allosteric reg...
Figure 18: Anion-triggered molecular tweezers based on calix[4]pyrrole.
Figure 19: Anion-triggered molecular tweezers.
Figure 20: a) Principle of the weak link approach (WLA) developed by Mirkin and its application to b) symmetri...
Figure 21: Molecular tweezers as allosteric catalyst in asymmetric epoxide opening [80].
Figure 22: Allosteric regulation of catalytic activity in ring-opening polymerization with double tweezers 41.
Figure 23: a) Conformational switching of 42 by intramolecular –S–S– bridge formation. b) Shift of conformatio...
Figure 24: a) Redox-active glycoluril-TTF tweezers 44. b) Mechanism of stepwise oxidation of said tweezers wit...
Figure 25: Mechanism of formation of the mixed-valence dimers of tweezers 45.
Figure 26: Mechanism of carbohydrate liberation upon redox-mediated conformation switching of 46.
Figure 27: a) The encapsulation properties of 47 as well as the DCTNF release process from its host–guest comp...
Figure 28: Redox-active bipyridinium-based tweezers. a) With a ferrocenyl hinge 49, b) with a propyl hinge 50 ...
Figure 29: Redox-active calix[4]arene porphyrin molecular tweezers.
Figure 30: a) Mechanism of the three orthogonal stimuli. b) Cubic scheme showing the eight different states of ...
Figure 31: Redox-controlled molecular gripper based on a diquinone resorcin[4]arene.
Figure 32: a) Shinkai's butterfly tweezers and their different host–guest properties depending on the isomer. ...
Figure 33: Cyclam-tethered tweezers and their different host–guest complexes depending on their configuration.
Figure 34: Azobenzene-based catalytic tweezers.
Figure 35: Photoswitchable PIEZO channel mimic.
Figure 36: Stilbene-based porphyrin tweezers for fullerene recognition.
Figure 37: Stiff-stilbene-based tweezers with urea or thiourea functional units for a) anion binding, b) anion...
Figure 38: Feringa’s photoswitchable organocatalyst (a) and different catalyzed reactions with that system (b)....
Figure 39: a) Irie and Takeshita’s thioindigo-based molecular tweezers. b) Family of hemithioindigo-based mole...
Figure 40: Dithienylethylene crown ether-bearing molecular tweezers reported by Irie and co-workers.
Insight into functionalized-macrocycles-guided supramolecular photocatalysis
- Minzan Zuo,
- Krishnasamy Velmurugan,
- Kaiya Wang,
- Xueqi Tian and
- Xiao-Yu Hu
Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15
- of the host and guest as well as the degree of geometric complementarity [21][22]. CDs can recognize guests in both aqueous and solid environments, so that they can be used as an excellent host for the construction of photocatalytic systems. CD-based host–guest systems can realize various types of
Graphical Abstract
Figure 1: Chemical structures of representative macrocycles.
Figure 2: Ba2+-induced intermolecular [2 + 2]-photocycloaddition of crown ether-functionalized substrates 1 a...
Figure 3: Energy transfer system constructed of a BODIPY–zinc porphyrin–crown ether triad assembly bound to a...
Figure 4: The sensitizer 5 was prepared by a flavin–zinc(II)–cyclen complex for the photooxidation of benzyl ...
Figure 5: Enantiodifferentiating Z–E photoisomerization of cyclooctene sensitized by a chiral sensitizer as t...
Figure 6: Structures of the modified CDs as chiral sensitizing hosts. Adapted with permission from [24], Copyrigh...
Figure 7: Supramolecular 1:1 and 2:2 complexations of AC with the cationic β-CD derivatives 16–21 and subsequ...
Figure 8: Construction of the TiO2–AuNCs@β-CD photocatalyst. Republished with permission of The Royal Society...
Figure 9: Visible-light-driven conversion of benzyl alcohol to H2 and a vicinal diol or to H2 and benzaldehyd...
Figure 10: (a) Structures of CDs, (b) CoPyS, and (c) EY. Republished with permission of The Royal Society of C...
Figure 11: Conversion of CO2 to CO by ReP/HO-TPA–TiO2. Republished with permission of The Royal Society of Che...
Figure 12: Thiacalix[4]arene-protected TiO2 clusters for H2 evolution. Reprinted with permission from [37], Copyri...
Figure 13: 4-Methoxycalix[7]arene film-based TiO2 photocatalytic system. Reprinted from [38], Materials Today Chem...
Figure 14: (a) Photodimerization of 6-methylcoumarin (22). (b) Catalytic cycle for the photodimerization of 22...
Figure 15: Formation of a supramolecular PDI–CB[7] complex and structures of monomers and the chain transfer a...
Figure 16: Ternary self-assembled system for photocatalytic H2 evolution (a) and structure of 27 (b). Figure 16 reprodu...
Figure 17: Structures of COP-1, CMP-1, and their substrate S-1 and S-2.
Figure 18: Supramolecular self-assembly of the light-harvesting system formed by WP5, β-CAR, and Chl-b. Reprod...
Figure 19: Photocyclodimerization of AC based on WP5 and WP6.
Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres
- Si-Yuan Liu,
- Xin-Rui Wang,
- Man-Ping Li,
- Wen-Rong Xu and
- Dietmar Kuck
Beilstein J. Org. Chem. 2020, 16, 2551–2561, doi:10.3762/bjoc.16.207
- : fullerenes; host–guest systems; microspheres; supramolecular chemistry; tribenzotriquinacene; Introduction In the field of supramolecular chemistry, host–guest association through noncovalent interactions is an interesting and exciting topic, especially for the encapsulation of various fullerenes, such as
- of 0.3–3.5 μm were observed for the complex TBTQ-(OG)6 C60. Obviously, these aggregates form by further assembly of the supra-amphiphilic host–guest systems, as suggested in Figure 6c, due to the hydrophobic interactions governing the association behavior of TBTQ-(OG)6 C60 in water. Conclusion In
Graphical Abstract
Figure 1: Selected TBTQ derivatives 1–5 that bind fullerenes in host–guest complexes.
Scheme 1: Synthetic route to TBTQ-(OG)6.
Figure 2: Fluorescence spectra of TBTQ-(OG)6 (5.0 × 10−6 M) with varying concentrations of (a) C60 and (b) C70...
Figure 3:
Absorption spectra of (a) TBTQ-(OG)6 ![[Graphic 2]](/bjoc/content/inline/1860-5397-16-207-i3.svg?max-width=637&scale=1.18182)
C60 [TBTQ-(OG)6: 50 μM; C60: 50 μM] and (b) TBTQ-(OG)6 C70 [...
Figure 4:
Absorption spectra of (a) TBTQ-(OG)6 C60 [TBTQ-(OG)6: 50 μM; C60: 50 μM] and (b) TBTQ-(OG)6 C70 [...
Figure 5:
Raman spectra of TBTQ-G6, C60 and TBTQ-G6 C60. Sample solutions of TBTQ-(OG)6 (50 μM) and TBTQ-(OG)...
Figure 6:
Molecular model of the complex TBTQ-(OG)6 C60 in water, as generated by DFT calculations. (a) Side...
Figure 7:
SEM images of (a) C60; (b) TBTQ-(OG)6; (c) and (d) TBTQ-(OG)6 C60 (C60: 1.4 mM; TBTQ-(OG)6: 1.4 mM...
1,2,3-Triazolium macrocycles in supramolecular chemistry
- Mastaneh Safarnejad Shad,
- Pulikkal Veettil Santhini and
- Wim Dehaen
Beilstein J. Org. Chem. 2019, 15, 2142–2155, doi:10.3762/bjoc.15.211
- interactions, compared to monovalent receptor–ligand interactions offer the advantage of multiple and sequential binding within the host–guest systems. These noncovalent interactions which can be controlled in a chemical or physical manner depend on the binding sites in the multivalent assembly [67
Graphical Abstract
Figure 1: Hydrogen, halogen or chalcogen bonding to anions within a bistriazolium macrocycle.
Figure 2: Main synthetic strategies towards macrocyclic triazoliums.
Figure 3: Chemical structure of compound 1 (1a, 1b and 1c) and 2.
Figure 4: Chemical structure of compound 3 and 4.
Figure 5: Chemical structure of compound 5.
Figure 6: Chemical structure of compound 6.
Figure 7: Chemical structure of compound 7.
Figure 8: Chemical structure of compound 8.
Figure 9: Chemical structures of compound 9.
Figure 10: Chemical structures of compound 10, 11 and 12.
Figure 11: Chemical structure of compound 13.
Figure 12: Chemical structure of compound 15 including the sigma-connected TCNQ dimer.
Figure 13: Chemical structure of compound 16 for the kinetic resolution of epoxides.
Figure 14: Chemical structure of compound 17a (bisnaphtho crown ether shown).
Figure 15: Jump rope in molecular double-lasso compounds 18.
Figure 16: Chemical structure of compound 19 and acid–base triggered motions.
Host–guest interactions in nor-seco-cucurbit[10]uril: novel guest-dependent molecular recognition and stereoisomerism
- Xiaodong Zhang,
- Wei Wu,
- Zhu Tao and
- Xin-Long Ni
Beilstein J. Org. Chem. 2019, 15, 1705–1711, doi:10.3762/bjoc.15.166
- of G2·host-2 are derived not only from the ion–dipole interactions between the host and guest, but also in the assistant of the hydrophobic effect. Notably, the entropic gain achieved with the G2·host-2 system was higher than that obtained with other host–guest systems, indicating that the large
Graphical Abstract
Scheme 1: Chemical structures of host-1, host-2, G1, and G2.
Figure 1: 1H NMR spectra of G1 (1.0 mmol, D2O, pD = 2.0) in the presence of host-1 at different concentration...
Figure 2: 1H NMR spectra of G1 (1.0 mmol, D2O, pD = 2.0) in the presence of host-2 at different concentration...
Scheme 2: Plausible diastereomers showing the fluorescence response of G2 with host-1.
Figure 3: Fluorescence spectral changes of G2 (10.0 μM) in the presence of host-1 (a) and host-2 (b) at diffe...
Figure 4: 1H NMR spectra of G2 (1.0 mmol, D2O, pD = 2.0) in the presence of different concentrations of host-1...
Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies
- Rakesh Puttreddy,
- Ngong Kodiah Beyeh,
- S. Maryamdokht Taimoory,
- Daniel Meister,
- John F. Trant and
- Kari Rissanen
Beilstein J. Org. Chem. 2018, 14, 1723–1733, doi:10.3762/bjoc.14.146
- host–guest interactions persist even in these very competitive environments (Table 3, Figures S5 and S9, Supporting Information File 1). Conclusion Host–guest systems formed between C-hexyl-2-bromoresorcinarene (BrC6) and twelve aromatic N-oxides have been characterised using solid-state X-ray
Graphical Abstract
Figure 1: The chemical structures of C-ethyl-2-bromoresorcinarene (BrC2), C-propyl-2-bromoresorcinarene (BrC3...
Figure 2: X-ray crystal structures of (a) 3@BrC6, (b) 4@BrC6, (c) 5@BrC6, (d) 6@BrC6, (e) 7@BrC6, (f) 8@BrC6,...
Figure 3: Comparison of X-ray crystal structures (a) 3@BrC2, (c) 3@BrC3, and (e) 3@BrC6 and their DFT-based o...
Figure 4: (a) The negative potential localised on the N-oxide oxygen in 3@BrC6 and, (b) the positive charge d...
Figure 5: An expansion of the 1H NMR (6.6 mM at 298 K, 500 MHz) of BrC6 complexes with 3. Spectra are produce...
Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy
- Monica Ferro,
- Franca Castiglione,
- Nadia Pastori,
- Carlo Punta,
- Lucio Melone,
- Walter Panzeri,
- Barbara Rossi,
- Francesco Trotta and
- Andrea Mele
Beilstein J. Org. Chem. 2017, 13, 182–194, doi:10.3762/bjoc.13.21
- host–guest systems. Experimental Materials and measurements The detailed procedures for the synthesis of CDNS and the preparation of the corresponding hydrogels containing IbuNa can be found and seen in [34]. In the following, we report the essential information on the synthesis and the experimental
Graphical Abstract
Figure 1: Schematic thermodynamic description of the CP process and time constants. The I-S model (left), the ...
Figure 2: 1H MAS NMR spectra of a) CDNS(1:8)-IbuNa and b) CDNS(1:8). The inset (top right) shows the expansio...
Figure 3: The effect of the spinning speed on the spectral features. 1H MAS NMR spectra of a) CDNS(1:4)-IbuNa...
Figure 4: 13C CP-MAS NMR spectra for samples of β-CD (top), CDNS(1:4) (middle) and CDNS(1:8) polymers (bottom...
Figure 5: 13C CP-MAS NMR spectrum of: a) CDNS(1:4) polymer; b) CDNS(1:4)-IbuNa system; c) CDNS(1:8)-IbuNa sys...
Figure 6: 13C CP-MAS NMR spectra of CDNS(1:4) acquired with CP variable contact time in the range 50 μs–7 ms.
Figure 7: Time dependence of 13C magnetization for CDNS(1:4) (left) and CDNS(1:8) (right) polymers.
Figure 8: 1H-13C CP oscillatory kinetics for the carbon C(1) and C(4) of CDNS(1:4)-IbuNa sample (left) and CD...
Figure 9: 1H-13C CP oscillatory kinetics for the ibuprofen aromatic carbon atoms C(6,8) in samples CDNS(1:4)-...
Figure 10: PXRD patterns of: a) CDNS(1:8), b) CDNS(1:4), c) CDNS(1:8)-IbuNa loaded, d) CDNS(1:4)-IbuNa loaded,...
Interactions of cyclodextrins and their derivatives with toxic organophosphorus compounds
- Sophie Letort,
- Sébastien Balieu,
- William Erb,
- Géraldine Gouhier and
- François Estour
Beilstein J. Org. Chem. 2016, 12, 204–228, doi:10.3762/bjoc.12.23
- expand the size of the cavities, resulting in a better hydrolysis inhibition of the pesticides through its deeper inclusion. The formation of inclusion complexes can also modulate the organophosphorus photodegradation rates, but the results strongly depend on the host–guest systems [59][60] (Table 5
- ions in the solvent. Acting as the active site, the substitution of secondary hydroxy groups might impact the hydrolysis rate. This was investigated comparing the effect of β-CD, DIMEB and TRIMEB on the alkaline hydrolysis of parathion, methyl parathion, and fenitrothion [53][54]. In all host–guest
- systems, the rate of alkaline hydrolysis is reduced with the the inclusion of the organophosphorothioate pesticides into the CDs (kc/kun < 1, Table 3). However it appears clearly that the three studied CDs do not share the same pesticide hydrolysis inhibition level as in all cases, fenitrothion is
Graphical Abstract
Figure 1: Structure of NOPs.
Figure 2: Examples of structures of NOPs.
Figure 3: Structures of pesticides studied in the literature as guest to form an inclusion complex with CDs.
Figure 4: Structures of pesticides sensitive to the presence of CDs.
Scheme 1: The hydrolysis mechanism of substrate (S) in presence of a cyclodextrin (CD).
Figure 5: Structures of the different stereoisomers of G agents.
Scheme 2: Reaction mechanism of CD accelerated decomposition of organophosphorus compound (PX).
Scheme 3: Proposed degradation mechanism of cyclosarin by β-CD [72].
Figure 6: Schematic representations of β-CD and TRIMEB.
Scheme 4: Synthetic pathways to 6-monosubstituted CD derivatives.
Scheme 5: Synthetic pathways to 2-monosubstituted CD by an iodosobenzoate group.
Scheme 6: Synthetic pathways to 2-monosubstituted CDs with N–OH derivatives.
Scheme 7: Synthetic pathways to 3-monosubstituted CDs.
Scheme 8: Synthetic pathways to 3-homodisubstituted CDs.
Scheme 9: Synthetic pathways to 2,3-heterodisubstituted CDs.
Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy
- Manuel Gensler,
- Christian Eidamshaus,
- Maurice Taszarek,
- Hans-Ulrich Reissig and
- Jürgen P. Rabe
Beilstein J. Org. Chem. 2015, 11, 817–827, doi:10.3762/bjoc.11.91
- the β2-adrenergic receptor [24] and rhodopsin [25]. On the field of supramolecular model systems DFS revealed the mechanical stability of coordination bonds [26][27][28], host–guest systems [29][30][31][32], and rotaxanes [33]. In 2008 Guzman et al. analyzed hydrogen bonds of 4H, 6H and 8H chains in
Graphical Abstract
Figure 1: Expected coordination complexes of monovalent and bivalent structures (1 and 2a–c, respectively) wi...
Scheme 1: Synthesis of pyridine-PEG conjugate 5.
Scheme 2: Synthesis of pyridine-PEG conjugate 10.
Figure 2: Principle of the SMFS experiment. During retraction of the sample, possible interactions are probed...
Figure 3: Potential energy diagrams according to the KBE model for simultaneous and successive bond rupture a...
Figure 4: Most probable rupture forces plotted over their corresponding loading rate. Each point denotes for ...
Figure 5: Possible rupture mechanism describing the extraordinary long rupture length of system 2c. Starting ...
Figure 6: Most probable rupture forces at a logarithmic loading rate of 8.5 in relation to the corresponding ...
Inclusion of trans-resveratrol in methylated cyclodextrins: synthesis and solid-state structures
- Lee Trollope,
- Dyanne L. Cruickshank,
- Terence Noonan,
- Susan A. Bourne,
- Milena Sorrenti,
- Laura Catenacci and
- Mino R. Caira
Beilstein J. Org. Chem. 2014, 10, 3136–3151, doi:10.3762/bjoc.10.331
- reported above clearly indicate a mutual induced fit when TMA forms an inclusion complex with RSV. This phenomenon of mutual induced fit has recently been cited as a frequent occurrence in biological systems, but a rare one for synthetic host–guest systems [13]. However, its occurrence in CD inclusion
Graphical Abstract
Figure 1: Chemical structure of trans-resveratrol (1).
Figure 2: DSC traces of RSV (a), TMA (b), TMA–RSV physical mixture (PM) (c), TMA–RSV preparation by kneading ...
Figure 3: TG (red) and DSC (blue) traces for the hydrated TMA·RSV complex (top), and hot stage micrographs sh...
Figure 4: The two symmetry-independent complex units of TMA·RSV·6.25H2O (A and B), with only the major compon...
Figure 5: Representative atomic labelling for the ordered RSV molecule A (blue) present in host A and the two...
Figure 6: Space-filling representations of the two independent complex units A (a) and B (b) of the complex T...
Figure 7: Crystal packing for the complex TMA·RSV·6.25H2O projected down [010].
Figure 8: The components of the disorder model for RSV in its inclusion complex with TMB (s.o.f. = 0.73 for t...
Figure 9: The asymmetric unit in the crystal of TMB·RSV·5.6H2O (a), and the non-H atom and methylglucose ring...
Figure 10: Space-filling model of the inclusion complex TMB·RSV·5.6H2O showing the inclusion of the RSV molecu...
Figure 11: Packing arrangement in the crystal of TMB·RSV·5.6H2O viewed down [010] (a) and [100] (b). Hydrogen ...
Figure 12: Structure of the host–guest complex DMB·RSV·4.0H2O (a), ring and atomic nomenclature for the host m...
Figure 13: Space-filling model of the inclusion complex DMB·RSV·4.0H2O showing the encapsulation of part of th...
Figure 14: Stereoview of two DMB·RSV·4.0H2O complex units related by a unit translation along the crystal a-ax...
Figure 15: Projections of the crystal structure of the complex DMB·RSV·4H2O along [100] (a) and [010] (b). Hyd...
Figure 16: Solubility of RSV as a function of [β-CD] (blue) and [γ-CD] (red) at 25 °C.
Figure 17: Solubility of RSV as a function of the concentrations of TMB (light blue), DMB (red), HP-β-CD (gree...
Synthesis and characterization of a new photoinduced switchable β-cyclodextrin dimer
- Florian Hamon,
- Claire Blaszkiewicz,
- Marie Buchotte,
- Estelle Banaszak-Léonard,
- Hervé Bricout,
- Sébastien Tilloy,
- Eric Monflier,
- Christine Cézard,
- Laurent Bouteiller,
- Christophe Len and
- Florence Djedaini-Pilard
Beilstein J. Org. Chem. 2014, 10, 2874–2885, doi:10.3762/bjoc.10.304
- –guest systems studied (temperature 298 K in water). Acknowledgements The authors would like to acknowledge financial support from the Agence Nationale de la Recherche ANR, France (CP2D program, CYCLOCAT project). Mathilde Bellot and Dr David Mathiron are thanked for their help with ITC and NMR
- modeling methods: (a) 1:1 chelate-type complex with AZO-CDim 1 in its cis configuration; linear (b) and cyclic (c) supramolecular polymers with AZO-CDim 1 in its trans configuration. Synthesis pathway of the dimer AZO-CDim 1. Thermodynamic parameters deduced from ITC experiments for the different host
Graphical Abstract
Scheme 1: Synthesis pathway of the dimer AZO-CDim 1.
Figure 1: Overlaid UV spectra of the irradiation of AZO-CDim 1 (a) from 0 to 120 min at 365 nm and then (b) f...
Figure 2: HPLC quantification of the cis/trans ratio of AZO-CDim 1 before irradiation (left) and after irradi...
Figure 3: Percentage of cis isomer of AZO-CDim 1 produced during photoisomerization cycles (c = 10−4 M, water...
Figure 4: Representation of the most stable structures obtained for the azobenzene linker (a) for the trans c...
Figure 5: Structure of the ditopic guest ADAdim 4.
Figure 6: Titration of (a) β-CD (c = 0.8 mM) and (b) β-CD-NH2 (c = 0.8 mM) by ADAdim 4 (c = 4 mM). (c) Diluti...
Figure 7: (a) 1H NMR spectra of AZO-CDim 1 (500 MHz, D2O, 2.5 mM) in the absence (bottom) and presence of ADA...
Figure 8: Proposed structures of inclusion complexes with the ditopic host AZO-CDim 1 and the ditopic guest A...
Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers
- Michael Kurlemann and
- Bart Jan Ravoo
Beilstein J. Org. Chem. 2014, 10, 2428–2440, doi:10.3762/bjoc.10.253
- -complementary cyclodextrin trimers host–guest systems of higher stoichiometry are formed. Based on these results further development of the guest strands can be done to create even heteromultivalent systems which show highly selective molecular recognition and can be used for the defined self-assembly of
- polymerization is possible, depending on the concentrations of the host and the guest strand (Figure 8B). The homodivalent guest strand 8 with two adamantane moieties shows an alternating complexation behavior towards the complementary CD dimer 3. The ITC data suggest that instead of 1:1 adducts 2:1 host–guest
- systems are formed. Therefore, the analysis was done using a 2:1 binding model, assuming two non-cooperative and independent complexations. This method gives intrinsic thermodynamic parameters (Table 2). The intrinsic binding constant is ca. 2 × 105 M−1. This value is 4-fold higher than the binding
Graphical Abstract
Figure 1: Chemical structures of the di- (A) and trivalent (B) CD sequences, the di- (C) and trivalent (D) gu...
Figure 2: Synthesis of the di- and trivalent CD sequences 1–7 (for detailed reaction conditions see Supporting Information File 1).
Figure 3: Solid phase peptide synthesis of the di- and trivalent guest strands 8 – 14 (for detailed reaction ...
Figure 4: 1H NMR spectra of 17 (B) and its inclusion complexes with β- (A) and α-CD (C), measured in D2O (600...
Figure 5: Schematic drawing of the complexation of the serine derivatives 17 (A) and 18 (B) with α- and β-CD....
Figure 6: 1H NMR spectra of 18 (B) and its inclusion complexes with β- (A) and α-CD (C), measured in D2O (600...
Figure 7: Selected binding models for the analysis of ITC data. (A) Monovalent receptor (R)-ligand (L) intera...
Figure 8: Schematic drawing of the interactions of the divalent guest molecules 8 (A), 9 (B) and 10 (C) with ...
Figure 9: Schematic drawing of the interactions of the trivalent guest molecules 11 (A), 12 (B), 13 (C) and 14...
Structure elucidation of β-cyclodextrin–xylazine complex by a combination of quantitative 1H–1H ROESY and molecular dynamics studies
- Syed Mashhood Ali,
- Kehkeshan Fatma and
- Snehal Dhokale
Beilstein J. Org. Chem. 2013, 9, 1917–1924, doi:10.3762/bjoc.9.226
- science and is the basis for most of the vital biological processes [1]. The basis of supramolecular chemistry is molecular recognition where host and guest species interact with each other and exist as a single system. These host–guest systems symbolize simplest examples of supramolecular systems in
Graphical Abstract
Figure 1: Structure of xylazine.
Figure 2: Comparative 1H NMR spectra of pure β-CD and a 1:1 β-CD–xylazine mixture showing β-CD regions.
Figure 3: Scott’s plot of the chemical shift changes of β-CD cavity protons during titration with xylazine in...
Figure 4: Full ROESY spectrum of a β-CD-xylazine 1:1 mixture showing intermolecular crosspeaks.
Figure 5: Two probable modes of the inclusion of xylazine into the β-CD cavity.
Figure 6: Coordinate system used to define the complexation process.
Figure 7: The time evolution of the potential energy calculated from the MD run in vacuum from (a) wide side ...
Figure 8: Snapshots showing the inclusion of xylazine into the β-CD cavity as obtained in the MD trajectory f...
Figure 9: Snapshots showing the inclusion of xylazine into the β-CD cavity as obtained in the MD trajectory f...
Figure 10: Side and front views of the proposed conformation of the β-CD-xylazine complex.
Linkage of α-cyclodextrin-terminated poly(dimethylsiloxanes) by inclusion of quasi bifunctional ferrocene
- Helmut Ritter,
- Berit Knudsen and
- Valerij Durnev
Beilstein J. Org. Chem. 2013, 9, 1278–1284, doi:10.3762/bjoc.9.144
- verified by the shifts of the protons in the 1H NMR spectra and in the correlation signals of the 2D ROESY NMR spectra. Keywords: cyclodextrins; ferrocene; host–guest systems; polysiloxanes; supramolecular chemistry; Introduction Polymers containing cyclodextrins (CD) covalently or supramolecularly
Graphical Abstract
Scheme 1: Hydrosilylation of Si–H terminated poly(dimethylsiloxanes) 1 and 2 with mono-((6-N-(allylamino)-6-d...
Figure 1: IR spectra of (a) H-terminated disiloxane (1), (b) α-CD-terminated disiloxane (α-CD-disiloxane) (4)...
Figure 2: 1H NMR spectra of ferrocene (A), complex of α-CD-disiloxane (α-CD-DS) 4 with ferrocene (B) and comp...
Figure 3: 2D ROESY NMR spectra of the complex of α-CD-disiloxane (α-CD-DS) 4 with ferrocene.
Figure 4: 2D ROESY NMR spectra of the complex of α-CD-polydimethylsiloxane (α-CD-PDMS) 5 with ferrocene.
Figure 5: TEM images of α-CD-disiloxane 4 (A) and the supramolecular formation of α-CD-disiloxane 4 with ferr...
Figure 6: DLS measurements of α-CD-disiloxane 4 (A) (dashed line) and the supramolecular formation of α-CD-di...
Host–guest complexes of mixed glycol-bipyridine cryptands: prediction of ion selectivity by quantum chemical calculations, part V
- Svetlana Begel,
- Ralph Puchta and
- Rudi van Eldik
Beilstein J. Org. Chem. 2013, 9, 1252–1268, doi:10.3762/bjoc.9.142
- the widest range in both host–guest systems, see Table 9. The illustrated occurrence evidences the importance of the possible alteration of the angles between the CH2 groups and the Nsp3 bridgehead for optimal matching between the host and the guest molecules. The stereochemistry of all investigated
Graphical Abstract
Figure 1: Structure of [2.2.2] also known as 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane or Kr...
Figure 2: Structures of [2.2.bpy] and [2.bpy.bpy].
Figure 3:
Calculated (RB3LYP/LANL2DZp) structure (C2) for [K ![[Graphic 2]](/bjoc/content/inline/1860-5397-9-142-i3.png?max-width=637&scale=0.295455)
2.2.bpy]+.
Figure 4:
Calculated (RB3LYP/LANL2DZp) structure (C2) for [K 2.bpy.bpy]+.
Figure 5:
Calculated (RB3LYP/LANL2DZp) transition state structures (C2) for [Mg 2.2.bpy]2+ and [Ga 2.2.bpy]...
Figure 6: Comparison of the calculated (RB3LYP/LANL2DZp) M–Npyridine/M–Nsp2 and M–NH3/M–Nsp3 coordinating dis...
Figure 7: Comparison of the calculated (RB3LYP/LANL2DZp) M–OH2 and M–O coordinating distances for [2.2.bpy] (...
Figure 8: Comparison of the calculated (RB3LYP/LANL2DZp) M–Npyridine/M–Nsp2 and M–NH3/M–Nsp3 coordinating dis...
Figure 9: Comparison of the calculated (RB3LYP/LANL2DZp) M–OH2 and M–O coordinating distances for [2.bpy.bpy]...
Scheme 1: Model reaction.
Figure 10:
RB3LYP/LANL2DZp complexation energies for [M 2.2.bpy]m+ according to Scheme 1, plotted against the ionic r...
Figure 11:
RB3LYP/LANL2DZp complexation energies for [M 2.bpy.bpy]m+ according to Scheme 1, plotted against the ionic...
Figure 12:
RB3LYP/LANL2DZp torsion angles CH2–Nsp3–Nsp3–CH2 (a) and (CH2)2–Nsp3–Nsp3–(CH2)2 (b) for [M 2.2.bp...
Figure 13:
RB3LYP/LANL2DZp torsion angle Nsp2–C–C–Nsp2 for [M 2.2.bpy]m+ and [M 2.bpy.bpy]m+ plotted against...
Figure 14:
RB3LYP/LANL2DZp torsion angle O–C–C–O for [M 2.2.bpy]m+ and [M 2.bpy.bpy]m+ plotted against the i...
Figure 15: Reverse development of the calculated torsion angles on the respective cryptate sides for [2.2.bpy]....
Figure 16: Reverse development of the calculated torsion angles on the respective cryptate sides for [2.bpy.bp...
Figure 17: Trend in the preferred ion selectivity of the studied cryptands. Every cryptand family is distingui...
Enantioselective supramolecular devices in the gas phase. Resorcin[4]arene as a model system
- Caterina Fraschetti,
- Matthias C. Letzel,
- Antonello Filippi,
- Maurizio Speranza and
- Jochen Mattay
Beilstein J. Org. Chem. 2012, 8, 539–550, doi:10.3762/bjoc.8.62
- of tunable macrocycles largely studied in the context of host–guest chemistry, as cavitands [5] and capsules [6]. The great ability of resorcin[4]arenes to trap several classes of compounds makes them very suitable for the subtle study of the chemicophysical properties of their host–guest systems
Graphical Abstract
Figure 1: Examples of monoexponential decay: The slope of the line directly provides the reaction pseudo-firs...
Figure 2: Example of biexponential decay.
Figure 3: Amidoresorcin[4]arene YS.
Scheme 1: Studied (a) peptidoresorcin[4]arenes and (b) dipeptidic guests.
Figure 4: Catharanthine and vindoline, monomers constituting the anticancer vinblastine and the analogous vin...
Figure 5: Stable conformers of catharanthine.
Figure 6: Global minima of (a) [VS∙H∙T]+ and (b) [VR∙H∙T]+ complexes.
Figure 7: Guests studied in [47].
Figure 8: Selected nucleosides.
Figure 9: Example of molecular logic gate.
Figure 10: Cyclochiral resorcin[4]arenes.
Binding of group 15 and group 16 oxides by a concave host containing an isophthalamide unit
- Jens Eckelmann,
- Vittorio Saggiomo,
- Svenja Fischmann and
- Ulrich Lüning
Beilstein J. Org. Chem. 2012, 8, 11–17, doi:10.3762/bjoc.8.2
- to be obtained by curve fitting, which adds to the overall error. In our host–guest systems, saturation was not reached even when 20 equivalents of guests were used. An even larger excess of guest changed the polarity of the solvent to such an extent that all signals were affected, not only those
Graphical Abstract
Figure 1: Bi-macrocyclic concave host 1 and its non-macrocyclic model 2.
Scheme 1: Synthetic scheme for the syntheses of concave host 1 and non-macrocyclic derivative 2. a) Et3N, THF...
Figure 2: Expansion of a part of the 1H NMR spectra (200 MHz, 298 K) of pure 1 and 2 in CD2Cl2 (bottom) and a...
Figure 3: Normalized 1H NMR CIS (see text) for concave host 1 with different anionic and neutral guests. The ...
Figure 4: Normalized 1H NMR CIS (see text) for concave host 2 with different anionic and neutral guests. The ...
NMR studies of anion-induced conformational changes in diindolylureas and diindolylthioureas
- Damjan Makuc,
- Jennifer R. Hiscock,
- Mark E. Light,
- Philip A. Gale and
- Janez Plavec
Beilstein J. Org. Chem. 2011, 7, 1205–1214, doi:10.3762/bjoc.7.140
- along the C7–N7α bonds and the syn–syn conformer was preferred for anion–receptor complexes. The conformational changes upon anion binding are in good agreement with energetic preferences established by ab initio calculations. Keywords: anion recognition; conformation analysis; host–guest systems; NMR
Graphical Abstract
Figure 1: Anion receptors 1–4 together with their atomic numbering scheme.
Figure 2: 1H NMR spectra of 1 in the absence of anions (a) and upon addition of one equivalent of the followi...
Figure 3: Three representative conformational families of rotamers of 1. Notations refer to the orientations ...
Figure 4: NOE enhancements of 1 in the absence of anions (a) and upon addition of one equivalent of acetate a...
Figure 5: Surface plot of the relative potential energy of 1 as a function of the two constitutive [C6–C7–N7α...
Figure 6: Freely optimized structure at the B3LYP/6-311+G(d,p) level of theory and side view showing deviatio...
Figure 7: 1H NMR chemical shift changes, Δδ = δ (in the presence of anions) – δ (in the absence of anions), i...
Figure 8: Freely optimized structures at the B3LYP/6-311+G(d,p) level of theory and side view showing deviati...
Figure 9: Conformational preferences and proposed binding mode for the 3·AcO− 1:1 complex.
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...
Progress in liquid crystal chemistry
- Sabine Laschat
Beilstein J. Org. Chem. 2009, 5, No. 48, doi:10.3762/bjoc.5.48
- smectic phases, nematic phase engineering by using V-shaped molecules, saddle-shaped columnar systems displaying anomalous odd-even effects, theoretical studies on the origin of chirality transfer in liquid crystalline host-guest systems, liquid crystalline carboranes and dyes and discotic phenanthrene
