Determination of formation constants and structural characterization of cyclodextrin inclusion complexes with two phenolic isomers: carvacrol and thymol

• Miriana Kfoury,
• David Landy,
• Steven Ruellan,
• Lizette Auezova,
• Hélène Greige-Gerges and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2016, 12, 29–42, doi:10.3762/bjoc.12.5

• shifts (Δδ) and diffusion coefficients (ΔD) were plotted as a function of CD concentration for both guests (Figure 4). A global analysis was applied to determine the host/guest affinity. A unique Kf, together with the maximum shifts of each signal, were used to fit simultaneously theoretical and

Synthesis and photophysical characteristics of polyfluorene polyrotaxanes

• Aurica Farcas,
• Giulia Tregnago,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert and
• Franco Cacialli

Beilstein J. Org. Chem. 2015, 11, 2677–2688, doi:10.3762/bjoc.11.288

• synthesis of 1·TM-βCD or 1·TM-γCD in polar protic solvents is driven by hydrophobic interactions in combination with electrostatic, van der Waals or π–π interactions. In comparison, in polar aprotic solvents such as DMF, THF relies mostly on host–guest specific interactions, such as dispersion or dipole

Inclusion complexes of 2-methoxyestradiol with dimethylated and permethylated β-cyclodextrins: models for cyclodextrin–steroid interaction

• Mino R. Caira,
• Susan A. Bourne,
• Halima Samsodien and
• Vincent J. Smith

Beilstein J. Org. Chem. 2015, 11, 2616–2630, doi:10.3762/bjoc.11.281

• host–guest β-CD inclusion complex, prepared by two methods, yielded very rapid dissolution in water at 37 °C relative to untreated 2ME, attaining complete dissolution within 15 minutes (co-precipitated complex) and 45 minutes (complex from kneading). Keywords: complexation; cyclodextrin; 2

• complexes, some of them having host–guest stoichiometric ratios of 2:1 and 3:2 with β-CD and γ-CD, respectively. An early attempt to acquire basic structural information from PXRD data for crystalline inclusion complexes of β-CD with a series of pregnanes as guests led to the estimation of crystal unit cell

• ). Further routine characterization of the β-CD complex of 2ME by UV spectrophotometry (at λ = 198.5 nm in MeOH/water 50:50 v/v) coupled with thermogravimetric anlysis (TGA) data (8.8 ± 0.4% one-step mass loss in the range 30–150 °C, n = 3) yielded the host–guest stoichiometry (2:1) and crystal water content

Smart molecules for imaging, sensing and health (SMITH)

• Bradley D. Smith

Beilstein J. Org. Chem. 2015, 11, 2540–2548, doi:10.3762/bjoc.11.274

• ”. In 2003, Houk and coworkers published a survey of all known natural and synthetic host/guest binding systems and concluded that the best predictor of strong affinity is the amount of solvent accessible surface area that is buried upon binding [48]. Typically, this surface area is amphiphilic; that is

Size-controlled and redox-responsive supramolecular nanoparticles

• Raquel Mejia-Ariza,
• Gavin A. Kronig and
• Jurriaan Huskens

Beilstein J. Org. Chem. 2015, 11, 2388–2399, doi:10.3762/bjoc.11.260

• their use as drug delivery vehicles. Here, we aim to form supramolecular nanoparticles (SNPs) by combining advantages of the reversible assembly properties of SNPs using host–guest interactions and of a stimulus-responsive moiety. The SNPs are composed of a core of positively charged poly(ethylene imine

• core of the SNPs. Keywords: host–guest interactions; nanoparticles; self-assembly; stimulus-responsive; supramolecular chemistry; Introduction Self-assembly and molecular recognition are two core concepts underlying supramolecular chemistry. These offer convenient and versatile pathways to

• these SNPs using host–guest interactions between CD and Ad. Tseng et al. studied the formation of SNPs that are assembled solely by host–guest interactions [11][12]. Here, the core is composed of multivalent interactions between positively charged CD-grafted polymers and positively charged poly

Life lessons

• Jonathan R. Nitschke

Beilstein J. Org. Chem. 2015, 11, 2350–2354, doi:10.3762/bjoc.11.256

• Learner Keywords: autobiography; host–guest; self-assembly; supramolecular; Review I was raised in Syracuse, New York (USA), and went to a series of state schools of varying quality. Only the faces of the bad teachers stick with me, but I remember the names, too, of a few of the good ones – Karen Curry

Co-solvation effect on the binding mode of the α-mangostin/β-cyclodextrin inclusion complex

• Chompoonut Rungnim,
• Sarunya Phunpee,
• Manaschai Kunaseth,
• Supawadee Namuangruk,
• Kanin Rungsardthong,
• Thanyada Rungrotmongkol and
• Uracha Ruktanonchai

Beilstein J. Org. Chem. 2015, 11, 2306–2317, doi:10.3762/bjoc.11.251

• addition with complexation [2][3][6] have demonstrated that the thermodynamics underlying the interactions between host–guest molecules can be significantly changed in these instances. In these cases, the co-solvent can also occupy the CD cavity in conjunction with the guest (drug) molecules to form CD

• anion affinity and selectivity of a neutral anion receptor, bis(cyclopeptide) [17]. Molecular dynamics (MD) simulations can give important insights into the energetics of structural interactions. The hydrated structure of β-CD in aqueous solution [18] and those showing host–guest interactions between

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

• (s) between the aromatic rings and also provide flexibility to the overall structure. Cyclophanes play an important role in “host–guest” chemistry [39][40][41][42][43] and supramolecular assembly [44][45][46][47]. “Phane”-containing molecules show interactions with π-systems, and they can also bind

Donor–acceptor type co-crystals of arylthio-substituted tetrathiafulvalenes and fullerenes

• Xiaofeng Lu,
• Jibin Sun,
• Shangxi Zhang,
• Longfei Ma,
• Lei Liu,
• Hui Qi,
• Yongliang Shao and
• Xiangfeng Shao

Beilstein J. Org. Chem. 2015, 11, 1043–1051, doi:10.3762/bjoc.11.117

• ) connection of two components through covalent bonds [23][24][25][26][27] or (2) supramolecular assembly between TTFs (as host) and fullerene (as guest) [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. For the formation of the host–guest type supramolecular system, the shape and size complementarity

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• checked the influence of the redox properties towards binding ability by studying the strong electrodeficient acceptor F4-TCNQ. Interaction with 1,3-dinitrobenzene (m-DNB) The host–guest affinity was detected by UV–visible spectroscopy upon titration of clip 3 (10−3 M in o-C6H4Cl2) with addition of m-DNB

• could not observe any host–guest binding interaction. These results suggest that electronic and spatial properties of the cavity constitute fundamental parameters for binding the m-DNB guest. The binding of such a weak electron acceptor was successful for molecular clip 3 presenting the most suitable

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

Discrete multiporphyrin pseudorotaxane assemblies from di- and tetravalent porphyrin building blocks

• Mirko Lohse,
• Larissa K. S. von Krbek,
• Sebastian Radunz,
• Suresh Moorthy,
• Christoph A. Schalley and
• Stefan Hecht

Beilstein J. Org. Chem. 2015, 11, 748–762, doi:10.3762/bjoc.11.85

• proving the desired host–guest ratio in the supramolecular structure. Similar results are obtained for the other [3]- and [5]pseudorotaxanes (Figure 3b and Figure 4a,b). However, it should be noted that despite extensive titration experiments (see Supporting Information File 1 for details) a detailed

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

• grafting onto azide-functionalized quartz surfaces. Host–guest interactions with the fluorescent guest molecule 2-anilinonaphthalene-6-sulfonic acid (2,6-ANS) were investigated by NMR and fluorescence spectroscopy. Further, we probe the complex formation of the surface-grafted β-CD dimer with 2,6-ANS by

• negligible. Inclusion complex with free β-CD dimer in solution Host–guest interactions with the fluorescent probe 2,6-ANS were evaluated for the β-CD dimer by steady-state fluorescence spectroscopy and compared to that of the parent β-CD and 2,6-ANS. In water, 2,6-ANS displays only weak fluorescence

• contribution from the linker and the inversion of the host–guest concentration ratio as compared to fluorescence measurements of the free β-CD dimer in solution. In solution, the concentration of the β-CD dimer is kept in excess of the 2,6-ANS. On the surface, the fixed concentration of the β-CD dimer is lower

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

• high-quality single crystals of each of the three inclusion complexes. The host–guest stoichiometries of the inclusion complexes between RSV and the three methylated CDs were all found to be 1:1 from 1H NMR spectra of solutions of single crystals of the respective complexes (Supporting Information File

• molecules and 12.5 water molecules, is shown in Figure 4a. In both 1:1 host–guest complex units the guest phenyl ring bearing one phenolic group (the 4-hydroxyphenyl residue) is fully immersed in the host cavity, being located at the primary side, while the ring bearing two phenolic groups (the 1,3

• 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

Release of β-galactosidase from poloxamine/α-cyclodextrin hydrogels

• César A. Estévez,
• José Ramón Isasi,
• Eneko Larrañeta and
• Itziar Vélaz

Beilstein J. Org. Chem. 2014, 10, 3127–3135, doi:10.3762/bjoc.10.330

• are able to form host–guest complexes by the inclusion of hydrophobic molecules. Cyclodextrins also act as hosts in the formation of inclusion compounds with polymer chains through non-covalent interactions [10]. For instance, incorporation of 5% α-CD transforms dilute Tetronic solutions into gels

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

• 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

• –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

Synthesis of an organic-soluble π-conjugated [3]rotaxane via rotation of glucopyranose units in permethylated β-cyclodextrin

• Jun Terao,
• Yohei Konoshima,
• Akitoshi Matono,
• Hiroshi Masai,
• Tetsuaki Fujihara and
• Yasushi Tsuji

Beilstein J. Org. Chem. 2014, 10, 2800–2808, doi:10.3762/bjoc.10.297

• prepared organic-soluble host–guest-linked PMCD derivatives that can undergo intramolecular self-inclusion to form an insulated molecule with an [1]rotaxane structure in methanolic aqueous solutions, where PMCD derivatives are soluble in. We recently developed a new method for synthesizing π-conjugated

• -phenylene) as backbone units by polymerization of these linked [3]rotaxanes as monomers. Synthesis of [1]rotaxane by self-inclusion of a host–guest-linked molecule: a) short molecular length, b) appropriate molecular length, c) long molecular length. Synthesis of an insulated molecule via flipping

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

• applications, β-CD has been mostly used as a drug carrier, stabilizer and additive by the formation of host–guest complexes with increased solubility and consequently better bioavailability of low water soluble organic compounds (i.e., drugs) [20][21][22][23]. The inclusion complex can also improve ligand

• these two previous studies, the fisetin/β-CD inclusion complex was optimized in gas phase, the A- or B-rings of fisetin were not well inserted, but only partially occupied in the cavity, while the other ring entirely stayed outside of the β-CD moiety. Herein, the host–guest inclusion complexation

• 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

Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments

• Eléonore Bertaut and
• David Landy

Beilstein J. Org. Chem. 2014, 10, 2630–2641, doi:10.3762/bjoc.10.275

• designing the experimental strategies which achieve the highest quality in the characterization of host–guest supramolecules. Results and Discussion Non-competitive experiments In the first part of this work, we consider the study of inclusion compounds in non-competitive conditions, i.e., with one host and

• be designed to study the complexation phenomenon. Concerning the host, guest, and host–guest solutions to be prepared, some theoretical and experimental facts have to be considered. Firstly, as cyclodextrins are often used to solubilize hydrophobic guests, titration experiments generally employ the

• as the release protocol; it has been introduced by Heerklotz [14] for vesicles and then applied to cyclodextrins [30][31]. Protocol D (called “dilution”) corresponds to the reverse of protocol C: buffer injections within the host–guest mixture induce weak dilutions, thus dissociating a weak part of

Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

• Véronique Nardello-Rataj and
• Loïc Leclercq

Beilstein J. Org. Chem. 2014, 10, 2603–2622, doi:10.3762/bjoc.10.273

• Veronique Nardello-Rataj Loic Leclercq Université de Lille, Sciences et Technologies, EA 4478, Chimie Moléculaire et Formulation, F-59655 Villeneuve d’Ascq Cedex, France 10.3762/bjoc.10.273 Abstract Host–guest chemistry is useful for the construction of nanosized objects. Some of the widely used

• : cyclodextrin; biocide; encapsulation; host–guest chemistry; pathogen; textile; Introduction Since the first reference to cyclodextrins (CDs) in 1891 by Villiers, CD has been of great interest to researchers [1]. Cyclodextrins are composed of several α-D-glucopyranose units linked 1→4 and arranged in a conical

Synthesis and characterization of a hyper-branched water-soluble β-cyclodextrin polymer

• Francesco Trotta,
• Fabrizio Caldera,
• Roberta Cavalli,
• Andrea Mele,
• Carlo Punta,
• Lucio Melone,
• Franca Castiglione,
• Barbara Rossi,
• Monica Ferro,
• Vincenza Crupi,
• Domenico Majolino,
• Valentina Venuti and
• Dominique Scalarone

Beilstein J. Org. Chem. 2014, 10, 2586–2593, doi:10.3762/bjoc.10.271

• -shielding in the presence of the polymer, consistent with the formation of a host–guest association. The analysis of the polymer induced chemical shift variations on SF (Δδ values, Table 1) points out that the largest de-shielding is experienced by the protons of the benzofuranone ring system, H3 and H4 in

Host–guest-driven color change in water: influence of cyclodextrin on the structure of a copper complex of poly((4-hydroxy-3-(pyridin-3-yldiazenyl)phenethyl)methacrylamide-co-dimethylacrylamide)

• Nils Retzmann,
• Gero Maatz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 2480–2483, doi:10.3762/bjoc.10.259

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

• realize sequence-specific molecular recognition by the use of host–guest chemistry, but the recognition motifs as well as the linkages have to be chosen very carefully. In the case of trivalent systems one adamantane moiety must be included to induce preferred formation of 1:1 adducts. Due to the too weak

• toxins or viruses and for imaging and targeted drug delivery [3]. Hydrogels which are built up by multivalent host–guest interactions and vesicles of amphiphilic host molecules have been intensively studied for their ability to function as drug delivery systems as well [4][5][6][7][8][9]. Additionally

• biofunctional materials [21][22][23][24][25][26][27]. Even the molecular recognition of macroscopic gel blocks by multivalent host–guest interactions has been realized [28][29][30][31][32]. Besides the number of receptor–ligand interactions their spatial distribution is crucial for the highly selective

Derivatives of the triaminoguanidinium ion, 3. Multiple N-functionalization of the triaminoguanidinium ion with isocyanates and isothiocyanates

• Jan Szabo,
• Kerstin Karger,
• Nicolas Bucher and
• Gerhard Maas

Beilstein J. Org. Chem. 2014, 10, 2255–2262, doi:10.3762/bjoc.10.234

• transformations using heterocumulenes as reagents. Due to their particular molecular shape and the presence of hydrogen-bond donor and acceptor groups, the obtained 1,2,3-tris(ureido)guanidinium salts 7 and the derived neutral guanidine 8 may become of interest as host components in host–guest complexes, for

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• -CD, respectively. Changes in the absorption spectra of the monomer 1 upon the addition of increasing amounts of TMS-γ-CD in CHCl3. The inset shows the fitted binding constant curve based on a 1:1 host–guest complexation stoichiometry. 1H NMR spectrum of the polyrotaxane 4a copolymer in toluene-d8

• accurately due to the strong UV absorbance of this solvent. Thus, Ks measurements were performed in CHCl3. The Ks was determined by measuring the change in the absolute optical density (OD) at 314 nm with an increasing concentration of TMS-β-CD or TMS-γ-CD macrocycles and the fitting according to a 1:1 host

• –guest complexation stoichiometry. Thus, the Ks in CHCl3 was determined to be approximately 205 and 150 (±30) M−1, respectively (see the determined Ks of 1b in Figure 2). Concerning the binding affinity of molecule 1 to the TMS-β-CD and TMS-γ-CD cavities, it should be mentioned that the values toward