Selective detection of DABCO using a supramolecular interconversion as fluorescence reporter

• Indrajit Paul,
• Debabrata Samanta,
• Sudhakar Gaikwad and
• Michael Schmittel

Beilstein J. Org. Chem. 2019, 15, 1371–1378, doi:10.3762/bjoc.15.137

• porphyrin edge capsules to cone-shaped inclusion complexes depending on the presence of C60/C70, however, a process that was not selective for one of the guests [24]. A spectacular case of guest sensing, but not guest-induced recognition, was demonstrated by Clever in a supramolecular cage-to-cage

Efficient resolution of racemic crown-shaped cyclotriveratrylene derivatives and isolation and characterization of the intermediate saddle isomer

• Sven Götz,
• Andreas Schneider and
• Arne Lützen

Beilstein J. Org. Chem. 2019, 15, 1339–1346, doi:10.3762/bjoc.15.133

• are Xe inclusion complexes that are of special interest as they help to establish laser-polarized 129Xe NMR spectroscopy for the imaging in biological systems [22][23][24][25]. For the formation of Xe cryptophane complexes, cryptophane-1.1.1 has proven to be a very suitable host as it still shows the

Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• medicine. The binding affinities and thermodynamics of p-sulfonato-calix[4]arene upon complexation with different inorganic and organic cations in water have been investigated experimentally by Bonal et al. [30] and Morel et al. [31]. The experiments indicated 1:1 stoichiometry of the inclusion complexes

Precious metal-free molecular machines for solar thermal energy storage

• Meglena I. Kandinska,
• Snejana M. Kitova,
• Vladimira S. Videva,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• Stanislav B. Baluschev,
• Silvia E. Angelova and
• Aleksey A. Vasilev

Beilstein J. Org. Chem. 2019, 15, 1096–1106, doi:10.3762/bjoc.15.106

• reactions. Real-time E/Z-photoisomerization of dyes 4a–d and their complexes The photoisomerization of free dyes 4a–d and dye–Ba2+ inclusion complexes were investigated in real time mode upon irradiation with visible light (λ = 488 nm) close to their absorption maxima. Figure 3a illustrates the

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• engineering [6], energy storage [7], biosensors [8], catalysis [9], and environmental engineering [10]. Various supramolecular host molecules such as cyclodextrins (CDs), calix[n]arenes, and pillar[n]arenes can form host–guest inclusion complexes (ICs) with numerous compounds due to their unique cavity

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

• Iveta Chena Tichá,
• Simona Hybelbauerová and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2019, 15, 830–839, doi:10.3762/bjoc.15.80

• others [24]. Hence, combining cinchona alkaloids with CDs has the potential to widen the applications of CD derivatives in asymmetric organocatalysis. The combination of cinchona alkaloids with CDs was first reported by Liu et al. [25] who prepared inclusion complexes of cinchona alkaloids and

• organoselenium-bridged bis-β-CDs. Subsequently, the same research group [26] investigated the performance of inclusion complexes of native and permethylated β-CDs and cinchona alkaloids as pH-responsive binding systems. Nevertheless, to the best of our knowledge, CD derivatives with covalently bonded cinchona

• ; cinchona alkaloids; CuAAC click reaction; cyclodextrin; organocatalysts; Introduction Cyclodextrins (CDs) [1], cyclic oligosaccharides consisting of α-D-glucopyranoside units, and their derivatives are widely used in many industrial and research areas for their ability to form supramolecular inclusion

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• -difunctionalization; regioselectivity; Introduction Cyclodextrins (CDs) are cyclic oligomers of α-D-glucopyranose (Figure 1 illustrates the heptamer, β-CD) that have attracted worldwide interest in various fields of applied supramolecular chemistry due to their ability to form host–guest inclusion complexes [1]. A

• ditosyl (but not the diazido) compounds in deuterated water: the departure from C7 molecular symmetry that lifts the chemical equivalence of the glucopyranose units and the ability of the tosyl group to form intra- or intermolecular inclusion complexes, as documented for 6-monotosyl-β-CD [28] and the

• the cavity is preferred. In all cases, however, the tosyl groups display ROESY cross-peaks with the CD cavity protons (Supporting Information File 1, Figure S11). The cross-peaks indicate the formation of intermolecular as well as intramolecular (self-inclusion) complexes in situ in D2O. This

Fabrication of supramolecular cyclodextrin–fullerene nonwovens by electrospinning

• Hiroaki Yoshida,
• Ken Kikuta and
• Toshiyuki Kida

Beilstein J. Org. Chem. 2019, 15, 89–95, doi:10.3762/bjoc.15.10

• supramolecular fiber materials composed of cyclodextrin (CD)–fullerene inclusion complexes by electrospinning. Similar to the molecular state of fullerenes in solution, the resulting fibers include molecularly-dispersed fullerenes. We believe such a concept could be expanded to diverse host–guest complexes

• functionalize such fibers is to use host–guest inclusion complexes in CD electrospinning. To date, Uyar and Celebioglu have reported electrospinning of two different inclusion complexes: hydroxypropyl-β-CD (HP-β-CD)–tricosan [16] and HP-β-CD–azobenzene inclusion complexes [17]. Although such complexes are

• promising as an approach for fiber functionalization, the scope is limited to cases with 1:1 inclusion complexes and chemically modified CD. Fullerenes have been widely studied in the fields of chemistry and materials science because they have attractive chemical structures and good electron acceptor

Synthesis of a water-soluble 2,2′-biphen[4]arene and its efficient complexation and sensitive fluorescence enhancement towards palmatine and berberine

• Xiayang Huang,
• Xinghua Zhang,
• Tianxin Qian,
• Junwei Ma,
• Lei Cui and
• Chunju Li

Beilstein J. Org. Chem. 2018, 14, 2236–2241, doi:10.3762/bjoc.14.198

• 1H NMR spectroscopy in aqueous phosphate buffer solution (pH 7.4). In the presence of 2,2’-CBP4, 1H NMR signals of P and B displayed very large upfield shifts, indicating the formation of inclusion complexes with strong binding affinities. Fluorescence titration experiments showed that P and B

• was included by 2,2’-CBP4; the guest emits stronger fluorescence in a more hydrophobic microenvironment [48]. Combined with NMR results, we can unambiguously conclude the alkaloid molecules must insert into the hydrophobic cavity of 2,2’-CBP4 to form inclusion complexes. Interestingly, the emission

• ’-CBP4, for the first time and studied its complexation towards two alkaloid guests, P and B. 1H NMR and fluorescence results indicate the formation of inclusion complexes with strong stability. The association constants are in the magnitude of 105–106 M−1. Upon complexation with 2,2’-CBP4, both alkaloid

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• derivatives I and J [55][56][57]. The incorporation of these symmetric species into MIMs often circumvents complex isomeric mixtures. 3. Pseudorotaxanes and inclusion complexes: on the way to TTF-based MIMs Pseudorotaxanes have the general form of a molecular thread encircled by a macrocycle. The difference

• rotaxanes is achieved by stoppering reactions, while catenanes can be made by macrocyclization of the pseudorotaxane thread. Therefore, we discuss in the following section reports of important pseudorotaxanes and inclusion complexes that contributed to major developments of TTF-based MIMs and AMMs. The

• , extended π-surfaces [64] of TTF derivatives can have a stabilizing effect upon complexation. TTF (1) also forms inclusion complexes with neutral host molecules such as cyclodextrins (Figure 6). This complexation is mainly driven by the hydrophobic effect. α-Cyclodextrin (6) molecules encapsulate the

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• , or the design of self-inclusion complexes, in which an outer cavity-attached rhodamine was intramolecularly bound in the CB7 cavity. As an alternative, it has been previously suggested that host-assisted protonation of a cavity-binding functional moiety (an “anchor group”) and a suitably attached

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

• along with the M06-2X/6-31G(d,p)//ωB97X-D/6-311G(d,p) calculated relative energies of complexes with respect to the most stable complex 3@BrC6 by following isodesmic reaction schemes (see Supporting Information File 1, Table S3) are shown in Figure 3. In the optimised structures, the inclusion complexes

Hyper-reticulated calixarene polymers: a new example of entirely synthetic nanosponge materials

• Alberto Spinella,
• Marco Russo,
• Antonella Di Vincenzo,
• Delia Chillura Martino and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2018, 14, 1498–1507, doi:10.3762/bjoc.14.127

• substrates, indeed, have been considered a class of probe guests of choice for investigating the formation of host–guest inclusion complexes with cyclodextrins [38][39][40][41] and calixresorcinarenes [42], because of both their easy accessibility and the fact that their molecular properties can be largely

Mechanochemistry of nucleosides, nucleotides and related materials

• Olga Eguaogie,
• Joseph S. Vyle,
• Patrick F. Conlon,
• Manuela A. Gîlea and
• Yipei Liang

Beilstein J. Org. Chem. 2018, 14, 955–970, doi:10.3762/bjoc.14.81

• carbon nanotubes [93]. In the presence of guanosine-5′-monophosphate, 78% of the SWNT (0.78 mg mL−1) was dissolved but attempted removal of iron contamination from this material by treatment with acid gave a "viscous precipitate". Formation of cyclodextrin–drug inclusion complexes can be accelerated

Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

• Elias Christoforides,
• Andreas Papaioannou and
• Kostas Bethanis

Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69

• inclusion complexes with the cholesterol molecule. β-CD and its modified derivatives (2,6-di-O-methyl-β-CD or DM-β-CD, randomly methylated β-CD or RAMEB and 2-hydroxypropyl-β-CD or HP-β-CD) comprise a class of pharmacological agents commonly used to remove membrane cholesterol from cells [5][6][7][8

• dimeric structure is characterized as IM (Figure 2d). According to the classification of dimeric β-CD inclusion complexes [31], the dimers crystallizing in the P1 space group stack either according to the channel (CH) packing mode, if their cell dimensions are all about 15.5 Å, or to the IM packing mode

• shift is favored by the lack of the crystal contacts between the hydroxy group of the guest and vicinal inclusion complexes occurring in the crystalline state (Figure 2c). In Figure 5a, the plot of the distance between the O1 atom of the guest and the centroid of the O4n atoms of host A during the

An uracil-linked hydroxyflavone probe for the recognition of ATP

• Márton Bojtár,
• Péter Zoltán Janzsó-Berend,
• Dávid Mester,
• Dóra Hessz,
• Mihály Kállay,
• Miklós Kubinyi and
• István Bitter

Beilstein J. Org. Chem. 2018, 14, 747–755, doi:10.3762/bjoc.14.63

• that they form any type of inclusion complexes disturbing the recognition of ATP. Association constant determination The association constant has been obtained from the emission spectra using standard methods for non-linear curve fitting [65]. The best fit was obtained using 1:1 stoichiometry which

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• derivatives, obtained by anchoring suitable polyammonium or imidazolium pendant groups onto the main macrocycle scaffold [23][24][25][26][27][28]. The latter example is interesting, because of the well-known ability of these macrocycles to form inclusion complexes with diverse organic guest molecules [29][30

Binding abilities of a chiral calix[4]resorcinarene: a polarimetric investigation on a complex case of study

• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2698–2709, doi:10.3762/bjoc.13.268

• Polarimetry was used to investigate the binding abilities of a chiral calix[4]resorcinarene derivative, bearing L-proline subunits, towards a set of suitably selected organic guests. The simultaneous formation of 1:1 and 2:1 host–guest inclusion complexes was observed in several cases, depending on both the

Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of γ-cyclodextrin

• Markéta Bláhová,
• Sergey K. Filippov,
• Lubomír Kováčik,
• Jiří Horský,
• Simona Hybelbauerová,
• Zdenka Syrová,
• Tomáš Křížek and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2017, 13, 2509–2520, doi:10.3762/bjoc.13.248

• reasons. Compared to α- or β-CD, the number of publications dealing with γ-CD is quite small, e.g., [14][15]. The naphthyl group is well known for its ability to make inclusion complexes with CDs [16]. The allyl connecting linker is relatively rigid and should support the formation of supramolecular

• as a ditopic monomer of the AB type with groups A and B undergoing an association of 1:1. However, a number of alternate or competing interactions may occur, as mentioned above, γ-CD is known to form also inclusion complexes of 2:1 stoichiometry and formation of cyclic supramolecular structures my

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• equivalent – methyl α-D-glucopyranoside – was investigated for a deeper understanding of the type of host–guest interactions. Solid state studies of PTX/CDs were performed using FTIR–ATR and Raman spectroscopy techniques. Keywords: antifolate; cyclodextrin; hydrophobic interactions; inclusion complexes

• various sizes (4.7–8.3 Å) into which distinct compounds may enter and form inclusion complexes, an ability that is thoroughly used by the pharmaceutical industry for the formation of drug delivery systems [1][2][3][4][5]. The formation of an inclusion complex often results in a favorable change of

• stabilities of these noncovalent complexes. From the previous studies it is known that collision-induced dissociation (CID) experiments may be helpful in distinguishing between exclusion and inclusion complexes via comparison of the relative complex stabilities. For example, inclusion complexes of folic acid

Solid-state studies and antioxidant properties of the γ-cyclodextrin·fisetin inclusion compound

• Joana M. Pais,
• Maria João Barroca,
• Maria Paula M. Marques,
• Filipe A. Almeida Paz and
• Susana S. Braga

Beilstein J. Org. Chem. 2017, 13, 2138–2145, doi:10.3762/bjoc.13.212

• are liposome derivatives) [20], and cyclodextrin inclusion complexes [21][22][23]. Cyclodextrins (CDs) are naturally occurring cyclic oligosaccharides produced by bacterial degradation of starch. Native CDs have six to eight α-D-glucose units linked by α-1,4 bonds, being called α-, β- and γ-CDs

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

• its analogues 8–10 (Figure 1). Results and Discussion Complexation studies Paraquat (7) and its derivatives are among the most studied electron-acceptor guests that can form stable inclusion complexes with electron-donating molecules. Stabilization of such inclusion complexes is mainly realized due to

• π–π stacking and C–H∙∙∙X (X = N, O, F ...) interactions. The stability of inclusion complexes based on molecular clips and paraquat derivatives depends on two factors: 1) the value of the positive charge on the dipyridinium fragment of paraquat derivatives, the distribution of which is well

• observed for other complexes of the clips 1–5 with paraquat derivatives 8–10. This is typical for most pseudorotaxanes and catenanes and an evidence of the fairly stable host–guest inclusion complexes [33][34]. The ability of the obtained clips 1–5 to act as receptors for the guests 7–10 in solution was

Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• effect on the nucleophilic reaction. Keywords: cyclodextrins; milling parameters; nucleophilic substitution; planetary ball mill; Introduction Their hollow structures make cyclodextrins (CDs) a class of carbohydrates that can form inclusion complexes with organic molecules, inorganic salts and complex

Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

• Spyros D. Chatziefthimiou,
• Mario Inclán,
• Petros Giastas,
• Athanasios Papakyriakou,
• Konstantina Yannakopoulou and
• Irene M. Mavridis

Beilstein J. Org. Chem. 2017, 13, 1572–1582, doi:10.3762/bjoc.13.157

• structure; Introduction Cyclodextrins (CDs) are cyclic, water-soluble carbohydrates with a rather non-polar cavity that can host a variety of organic molecules (guests) and form inclusion complexes [1]. The guest molecules may be completely or partly enclosed inside the cavity depending on their size and

• the enhancement of solubility, bioavailability and stability of drugs [2][3][4][5]. Moreover, being oligomers of α-D-glucopyranose, CDs possess an intrinsic chirality, thus they form diastereomeric inclusion complexes with enantiomeric pairs and frequently they exhibit enantioselectivity in aqueous

Interactions between shape-persistent macromolecules as probed by AFM

• Johanna Blass,
• Jessica Brunke,
• Franziska Emmerich,
• Cédric Przybylski,
• Vasil M. Garamus,
• Artem Feoktystov,
• Roland Bennewitz,
• Gerhard Wenz and
• Marcel Albrecht

Beilstein J. Org. Chem. 2017, 13, 938–951, doi:10.3762/bjoc.13.95

• of the CD polymer and a reactive isothiocyanate–silane monolayer. Atomic force measurements of CD polymer decorated surfaces show enhanced supramolecular interaction energies which can be attributed to multiple inclusion complexes based on the rigidity of the polymer backbone and the regular

• configuration of the CD moieties. Depending on the geometrical configuration of attachment anisotropic adhesion characteristics of the polymer system can be distinguished between a peeling and a shearing mechanism. Keywords: AFM; cyclodextrin; inclusion complexes; molecular recognition; polyconjugated polymers

• polymers have been reported so far, including CD-modified conjugated oligomers and polymers composed of rigid phenylene ethynylene (PPE) structure units which are able to form self-inclusion complexes with tunable electrochemical properties [29][30][31][32][33][34][35]. The synthesis of PPE, in which two β