Complexation of molecular clips containing fragments of diphenylglycoluril and benzocrown ethers with paraquat and its derivatives

• Leonid S. Kikot',
• Catherine Yu. Kulygina,
• Alexander Yu. Lyapunov,
• Svetlana V. Shishkina,
• Roman I. Zubatyuk,
• Tatiana Yu. Bogaschenko and
• Tatiana I. Kirichenko

Beilstein J. Org. Chem. 2017, 13, 2056–2067, doi:10.3762/bjoc.13.203

• with clips 1–6. Complex stability constants of molecular clips 1–5 with guests 7–10 in acetonitrile at 20 °C. Contribution of polyether oxygen atoms of molecular clips 1–5 to the binding of paraquat. The host–guest interaction energies are estimated by quantum chemical calculations (b97-D3/def2-tzvp

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• efficient push–pull tendency existing in the host–guest interaction mechanism. The appearance of a clear isosbestic point at 500 nm clearly indicates the formation of the new complex. The complete disappearance of the absorbance at 459 nm at higher concentrations of fluoride and acetate ions is suggestive

• from 0.96 Å to 1.47 Å and 1.55 Å reflects the host–guest interaction. Mulliken charge distribution calculations showed a change of the atomic charge on the oxygen atom of receptors R1 and R2 from less negative to more negative values which are indicative for an intramolecular charge transfer process

A self-assembled cyclodextrin nanocarrier for photoreactive squaraine

• Ulrike Kauscher and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2016, 12, 2535–2542, doi:10.3762/bjoc.12.248

• squaraines can also be immobilized onto CDVs. For this purpose, the squaraines are equipped with two adamantane functions that bind into the cavities of cyclodextrin on the surface of the CDVs (Figure 1). The resulting divalent host–guest interaction should lead to a higher binding affinity of the squaraine

• was stored in the dark for 10 min. In this case, the absorption spectra show no decrease indicating that again no decomposition is obtained (Figure 2, bottom). Thus, AdSq is stable in solution if stored in the dark. Next, we investigated the immobilization of AdSq by host–guest interaction with CDVs

• any influence on solubility of AdSq, stability of CDVs or host guest interaction can be neglected. Fluorescence spectra were taken 20 min after addition of AdSq to assure the complete equilibration of the CDV dispersion. The fluorescence spectrum of AdSq without CDV shows no fluorescence, while

Hydroxy-functionalized hyper-cross-linked ultra-microporous organic polymers for selective CO₂ capture at room temperature

• Partha Samanta,
• Priyanshu Chandra and
• Sujit K. Ghosh

Beilstein J. Org. Chem. 2016, 12, 1981–1986, doi:10.3762/bjoc.12.185

• ]. In terms of surface area, tuneable porosity and feasible host–guest interaction, MOFs have scored over other above mentioned porous materials [6]. But the less hydrolytic stability of metal-organic frameworks limits their real time application [7][8]. So the search for new materials having high

Interactions between 4-thiothymidine and water-soluble cyclodextrins: Evidence for supramolecular structures in aqueous solutions

• Vito Rizzi,
• Sergio Matera,
• Paola Semeraro,
• Paola Fini and
• Pinalysa Cosma

Beilstein J. Org. Chem. 2016, 12, 549–563, doi:10.3762/bjoc.12.54

• previously existing bonds of the OH groups of CDs. In fact, when a CD and a guest molecule interact with each other, the electron cloud of the guest is perturbed leading to the observed increasing of the wavenumbers [46]. On the other hand, during the host–guest interaction processes, also a decrease in

• -mediated hydrogen bonds, involving the thiol moiety [61]. In other words when DIMEB CD was used, the presence of both CH3 and OH moieties induced a tight host–guest interaction in which the C=S group is coordinated outside the cavity through hydroxy groups via H bonds. Conclusions With the prospect to

Supramolecular structures based on regioisomers of cinnamyl-α-cyclodextrins – new media for capillary separation techniques

• Gabor Benkovics,
• Ondrej Hodek,
• Martina Havlikova,
• Zuzana Bosakova,
• Pavel Coufal,
• Milo Malanga,
• Eva Fenyvesi,
• Andras Darcsi,
• Szabolcs Beni and
• Jindrich Jindrich

Beilstein J. Org. Chem. 2016, 12, 97–109, doi:10.3762/bjoc.12.11

• proximity of the cavity and therefore contributing to the host−guest interaction. More detailed study of the ROESY spectra (see Figure 3) provided relevant information about the mode of the host–guest interaction. Important differences can be observed between the interactions of the two double bond protons

• back the solutions to a room temperature led to the formation of large particles with Dh comparable to the size of the initial particles. The large aggregate sizes observed in water also indicate the formation of supramolecular structures, although it must be noted that only the host–guest interaction

• -assembling monomer: DPmax = (K × c)0.5. The highest stability constants reported for the trans-cinnamyl derivatives with α-CD are on the order of 2 × 103 M−1 [16]. If only this host–guest interaction would be involved in the intermolecular interaction, the degree of polymerization according to Boutellier’s

Supramolecular polymer assembly in aqueous solution arising from cyclodextrin host–guest complexation

• Jie Wang,
• Zhiqiang Qiu,
• Yiming Wang,
• Li Li,
• Xuhong Guo,
• Duc-Truc Pham,
• Stephen F. Lincoln and
• Robert K. Prud’homme

Beilstein J. Org. Chem. 2016, 12, 50–72, doi:10.3762/bjoc.12.7

• . Subsequently, Tian et al. reported the formation of a self-healing polymeric hydrogel based on the host–guest interaction between the β-CD substituents of an acrylamide-based polymer, poly-β-CD, and the α-bromonaphthalene substituents of a second acrylamide-based polymer, poly-α-BrNp (Figure 22) [109]. A

Synthesis and surface grafting of a β-cyclodextrin dimer facilitating cooperative inclusion of 2,6-ANS

• Lars W. Städe,
• Thorbjørn T. Nielsen,
• Laurent Duroux,
• Reinhard Wimmer,
• Kyoko Shimizu and
• Kim L. Larsen

Beilstein J. Org. Chem. 2015, 11, 514–523, doi:10.3762/bjoc.11.58

• voltage of 700 V. MS spectra (2440–2500 Da) of the purified β-CD dimer. Structure of fluorescent guest molecule, 2,6-ANS, used to probe host–guest interaction and two derivatives thereof with methyl substitutions at the anilino moiety. Illustration of potential 1:1 inclusion complexes of the β-CD dimer

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

• TMA·RSV complex, the major stabilising host–guest interaction is that between the phenolic group of the 4-hydroxyphenyl ring and the primary rim of the host TMA molecule, which is mediated by a bridging water molecule. In ordered complex unit A, for example, the linkage is RSV(4-OH)···O(water)···O6

Binding mode and free energy prediction of fisetin/β-cyclodextrin inclusion complexes

• Bodee Nutho,
• Wasinee Khuntawee,
• Chompoonut Rungnim,
• Piamsook Pongsawasdi,
• Peter Wolschann,
• Alfred Karpfen,
• Nawee Kungwan and
• Thanyada Rungrotmongkol

Beilstein J. Org. Chem. 2014, 10, 2789–2799, doi:10.3762/bjoc.10.296

• inclusion complex. The ligand binding mode and water accessibility, host–guest interaction, and binding free energy of the inclusion complex were analyzed. The MM-PBSA/GBSA and M06-2X/6-31G(d,p)//MM-PBSA/GBSA approaches were used to predict the binding affinity of fisetin/β-CD complexes. The M06-2X/6-31G(d

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

• artificial amino acids no significant selectivity was observed [40]. In this work we present an alternative approach to realize the hybridization of complementary strands mediated by multivalent host–guest interaction. We used α- and β-CD because of their well-known and regiospecific modifiability for the

End-group-functionalized poly(N,N-diethylacrylamide) via free-radical chain transfer polymerization: Influence of sulfur oxidation and cyclodextrin on self-organization and cloud points in water

• Sebastian Reinelt,
• Daniel Steinke and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 680–691, doi:10.3762/bjoc.10.61

• functionalization is supported by 1H NMR-, SEC-, FTIR- and MALDI–TOF measurements. Keywords: chain-transfer polymerization; cyclodextrins; end-group functionalization; host–guest interaction; lower critical solution temperature (LCST); poly(N,N-diethylacrylamide); Introduction Supramolecular chemistry was first

Superstructures of fluorescent cyclodextrin via click-reaction

• Arkadius Maciollek,
• Helmut Ritter and
• Rainer Beckert

Beilstein J. Org. Chem. 2013, 9, 827–831, doi:10.3762/bjoc.9.94

• the elongated noncovalent polymeric structures collapse. Keywords: fluorescent dye; cyclodextrins; host–guest interaction; supramolecular polymer; Introduction Most small heterocyclic molecules show low fluorescence. However, as we reported earlier, substituted 4-hydroxythiazoles have a high

Spin state switching in iron coordination compounds

• Philipp Gütlich,
• Ana B. Gaspar and
• Yann Garcia

Beilstein J. Org. Chem. 2013, 9, 342–391, doi:10.3762/bjoc.9.39

Cyclodextrin-induced host–guest effects of classically prepared poly(NIPAM) bearing azo-dye end groups

• Gero Maatz,
• Arkadius Maciollek and
• Helmut Ritter

Beilstein J. Org. Chem. 2012, 8, 1929–1935, doi:10.3762/bjoc.8.224

• observed. Additionally, this azo-dye-end-group-labeled polymer was complexed with hyperbranched polyglycerol (HPG) decorated with β-CD to generate hedgehog-like superstructures. Keywords: azo-dye; cyclodextrins; end-group functionalization; host–guest interaction; supramolecular aggregation; Introduction

• functionalization by condensation with an azo dye. We also investigated the host–guest interaction of the azo-dye-labeled end group with randomly methylated β-cyclodextrin (RAMEB-CD), and with HPG bearing β-CD on top. Thus, the focus of the present study was directed towards the preparation and superstructure

Continuous proline catalysis via leaching of solid proline

• Suzanne M. Opalka,
• Ashley R. Longstreet and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2011, 7, 1671–1679, doi:10.3762/bjoc.7.197

• been suggested. Initially, researchers gathered 1H NMR, UV, and fluorescence data to show that ureas enhance the solubility of proline through a host–guest interaction between the urea and proline carboxylate: A substrate-independent model [49][50]. However, it has been proposed that substrate–urea

Chiral recognition of ephedrine: Hydrophilic polymers bearing β-cyclodextrin moieties as chiral sensitive host molecules

• Sabrina Gingter and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1516–1519, doi:10.3762/bjoc.7.177

• -containing polymer. The supramolecular structures obtained by complexation of ephedrine and cyclodextrin were verified by 2-D ROESY NMR measurements. Dynamic light scattering showed clear differences in the mean coil size. Keywords: chiral recognition; cyclodextrins; ephedrine; host–guest interaction

Chiral recognition of macromolecules with cyclodextrins: pH- and thermosensitive copolymers from N-isopropylacrylamide and N-acryloyl-D/L-phenylalanine and their inclusion complexes with cyclodextrins

• Sabrina Gingter,
• Ella Bezdushna and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 204–209, doi:10.3762/bjoc.7.27

• soluble stimuli-responsive polymers bearing phenylalanine moieties via host-guest interaction with β-cyclodextrin and randomly-methylated-β-cyclodextrin (RAMEB-CD). We synthesised N-acryloyl-D/L-phenylalanine monomers (2D, 2L) which were then copolymerised under free radical conditions with N

• 3D, 3L (1:20) copolymer, whereas the 3D, 3L (1:10) copolymer is relatively hydrophobic and not water-soluble. Surprisingly, the polymers 3D, 3L (1:10) become water-soluble due to host–guest interaction with RAMEB-CD yielding 4D and 4L. To confirm the formation of the proposed inclusion complexes

• In this work, we have succeeded in showing enantioselective recognition of copolymers containing D- or L-phenylalanine moieties by use of DLS and NMR spectroscopy. The results clearly indicate that enantioselective recognition of the polymeric attached chiral amino acid takes place due to host–guest

Free radical homopolymerization of a vinylferrocene/cyclodextrin complex in water

• Helmut Ritter,
• Beate E. Mondrzik,
• Matthias Rehahn and
• Markus Gallei

Beilstein J. Org. Chem. 2010, 6, No. 60, doi:10.3762/bjoc.6.60

• polymerization in water at 50 °C. During the reaction an increase in viscosity was observed, due to the formation of complexed polyvinylferrocene 3, which did not precipitate during the chain growth as a consequence of a strong host-guest interaction (Scheme 1). The complex remains in solution. The ratio of

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