Enhanced single-isomer separation and pseudoenantiomer resolution of new primary rim heterobifunctionalized α-cyclodextrin derivatives

• Iveta Tichá,
• Gábor Benkovics,
• Milo Malanga and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2018, 14, 2829–2837, doi:10.3762/bjoc.14.261

• ; heterobifunctionalized alpha-cyclodextrin; homobifunctionalized alpha-cyclodextrin; regioisomers; regioselectivity; Introduction Cyclodextrins, cyclic cone-shaped oligosaccharides [1], have long attracted interest for their properties in host–guest complexes both in research and in pharmaceutical and food industry

Coordination-driven self-assembly of discrete Ru₆–Pt₆ prismatic cages

• Aderonke Ajibola Adeyemo and
• Partha Sarathi Mukherjee

Beilstein J. Org. Chem. 2018, 14, 2242–2249, doi:10.3762/bjoc.14.199

• [47][48][49][50][51] and host–guest chemistry [52][53][54][55][56] among others. The cardinal prerequisites to obtain these self-assembled supramolecular architectures include stoichiometry and conformational complementarity on the binding sites of the building blocks [57][58][59][60][61]. However

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

• = (2.29 ± 0.27) × 106 M−1) is 3.9 times larger than that of P (Ka = (5.87 ± 0.24) × 105 M−1). Keywords: berberine; biphenarenes; host–guest complexes; molecular recognition; palmatine; Introduction Host–guest chemistry in water is significantly important due to its extensive applications in biology

• specific structures and interesting host–guest properties [21][22][23][24][25][26][27][28][29][30][31][32]. Water-soluble pillar[n]arene derivatives, especially those containing carboxylato moieties, showed low cell toxicity and good biocompatibility, and have been applied in biomedical applications such

• as bioimaging and self-assembled drug delivery systems [33][34][35][36][37][38][39][40]. For example, our group demonstrated a direct host–guest complexation-based drug delivery system for oxaliplatin by carboxylatopillar[6]arene [36]. The encapsulation could not only improve the drug‘s stability in

Dynamic light scattering studies of the effects of salts on the diffusivity of cationic and anionic cavitands

• Anthony Wishard and
• Bruce C. Gibb

Beilstein J. Org. Chem. 2018, 14, 2212–2219, doi:10.3762/bjoc.14.195

• regards to the former, we have shown how poorly solvated anions such as SCN− have an affinity for non-polar surfaces. Because of this, they can compete with the interactions between two non-polar surfaces in a host–guest complexation event and can induce an apparent weakening of the hydrophobic effect

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

• first TTF-based pseudorotaxane was reported by Stoddart and Williams in 1991 (Figure 5) [33]. At this time, they investigated the host–guest properties of the π-electron-poor cyclophane cyclobis(paraquat-p-phenylene) (3) in form of the tetrakis(hexafluorophosphate) salt [58]. The square-shaped host

• breakthroughs for the construction of TTF-based supramolecular architectures: (b) Stepwise deprotection/alkylation, (c) phosphite-mediated heterocoupling, and (d) pyrrolo-annulated TTF derivatives I and J. (a) Host–guest equilibrium between π-electron-poor cyclophane 3 and different TTFs with their

• corresponding association constants in CH3CN. (b) Crystal structure of host–guest complex 13 [33]. Solvent molecules and counterions are omitted for clarity. TTF complexes with different host molecules. Stable TTF (a) radical-cation and (b) mixed-valence dimers in confined molecular spaces. A “three-pole

A switchable [2]rotaxane with two active alkenyl groups

• Xiu-Li Zheng,
• Rong-Rong Tao,
• Rui-Rui Gu,
• Wen-Zhi Wang and
• Da-Hui Qu

Beilstein J. Org. Chem. 2018, 14, 2074–2081, doi:10.3762/bjoc.14.181

• +) containing intermediate compound 5 were assembled in dichloromethane through host–guest interaction and capped with compound 8 under Cu(I)-catalyzed azide–alkyne cycloaddition to get the final [2]rotaxane with two distinguishable recognition sites. The target [2]rotaxane R1 was then characterized by 1H NMR

Coordination-driven self-assembly vs dynamic covalent chemistry: versatile methods for the synthesis of molecular metallarectangles

• Li-Li Ma,
• Jia-Qin Han,
• Wei-Guo Jia and
• Ying-Feng Han

Beilstein J. Org. Chem. 2018, 14, 2027–2034, doi:10.3762/bjoc.14.178

• metallarectangles, metallacages and Borromean-type rings. Moreover, many of these structures have been utilized for various applications, such as catalysts, host–guest chemistry and others [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Through the use of a range of diverse functional ligands, the

A self-assembled photoresponsive gel consisting of chiral nanofibers

• Lei Zou,
• Dan Han,
• Zhiyi Yuan,
• Dongdong Chang and
• Xiang Ma

Beilstein J. Org. Chem. 2018, 14, 1994–2001, doi:10.3762/bjoc.14.174

• by three-dimensional networks through self-assembly have drawn significant attention in the past decades. They are normally fabricated by means of noncovalent intermolecular interactions [3], such as π–π stacking, hydrogen bonding, van der Waals forces, hydrophobic, electrostatic, host–guest and

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• surfactants having a host–guest recognition site [23]. So, they are able to form nanoaggregates in aqueous solutions, thus providing the concentration of the active binding sites into nanoaggregate for multivalent binding with the substrate [24]. We recently synthesized a series of cationic receptors based on

• determined by the isomolar series method at two concentrations: below and above the CAC values, measured with EY as the probe (Table 3). At concentrations below the CAC (1 µM), the monomeric molecules of the macrocycles 10a,b form with EY a discrete 1:1 host–guest complex [X2−calix2+], where X2− and calix2

• seen ADP more effectively embeds into the molecular cleft formed by two ammonium moieties due to a good host–guest geometric size and/or shape complementarity (Figure 4a and c). The three phosphate groups of ATP have a larger size and cannot realize a similar supramolecular motif in the complex. For

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

• -dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding

• pKa values from the direct titration and from the global fitting agreed reasonably well, and the complexation-induced pKa shifts were in the typical range reported for CB7 host–guest complexes [58]. Application of BODIPY-CB7 complexes The availability of BODIPY dyes, which respond towards complexation

• specific host–guest binding of 5 to CB7 on the surface, which suggests the use of 5 for straightforward surface functionalization to create nanophotonic devices as well as for multimodal surface group quantifications, e.g., using their optical properties for fluorescence and their fluorine heteroatom for X

An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

• Tomoki Ogoshi,
• Tomohiro Akutsu and
• Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

• aggregation of the hydrophobic alkyl chain rings, which induced insolubilization of the bicyclic compound in aqueous media at 20 °C and a decrease in its clouding point. Keywords: amphiphilic molecules; host–guest complexes; lower critical solution temperature; pillar[n]arenes; pseudo[1]catenane

• component because of their high functionality and superior host–guest properties with neutral guests [12][13][14][15][16]. The amphiphilic pillar[n]arenes 1 and 2 exhibit clouding points at 41 and 42 °C, respectively [5][6]. The oligo(ethylene oxide) moieties are solvated with water molecules at room

• in the clouding point. The clouding point of 1 increased upon addition of a cationic guest as the hydrophilic ratio in the molecule increased by formation of the complex with the hydrophilic cationic guest [5]. We also demonstrated photoresponsive LCST behavior by using a photoresponsive host–guest

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• nitrostyrene 7a lacking substituents has minimal steric hindrance and tends to bind with the calixarene cavity by supramolecular host–guest interactions which could further improve the enantioselectivity. In addition, electronic effects of the substituents on the aromatic ring showed a significant influence on

• supramolecular host–guest interaction with the calixarene to form a stable transition state A. Then, another hydrogen bond is formed between the nitrogen atom of the tertiary amine group in A and acetylacetone in its enol form, leading to the formation of a ternary complex B. Finally, nucleophilic attack of

Strong binding and fluorescence sensing of bisphosphonates by guanidinium-modified calix[5]arene

• Jie Gao,
• Zhe Zheng,
• Lin Shi,
• Si-Qi Wu,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2018, 14, 1840–1845, doi:10.3762/bjoc.14.157

• in view of low cost, ease of use and high sensitivity of optical sensing modalities, but remains a challenge since BPs are considered as unlabeled analytes. With the development of the host–guest concept in supramolecular chemistry, the indicator displacement assay (IDA), pioneered by Prof. Anslyn

• recovery, offers the opportunity for fluorescence “switch-on” sensing of BPs. In general, fluorescent IDA could be operated at low μM or even nM concentrations, which is desirable with respect to sensing sensitivity. We tested the host–guest complexation of GC5A with a total number of 9 BP drugs clinically

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

• Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, N9B 3P4, Canada 10.3762/bjoc.14.146 Abstract Host–guest complexes of C-hexyl-2-bromoresorcinarene (BrC6) with twelve potential aromatic N-oxide guests were studied using single crystal X-ray diffraction analysis and

• , aiding in the binding of polar guests such as N-oxides. Keywords: aromatic N-oxides; C–H···π Interactions; ditopic receptors; endo/exo complexation; host–guest chemistry; resorcinarenes; Introduction Resorcinarenes are macrocyclic compounds with a bowl-shaped cavity stabilised by circular

• ], coordination chemistry [12][13], biological systems [14] and especially for host–guest (H–G) chemistry [15]. Resorcinarenes can be modified at either the upper rim 2-position, lower rim, or both, to deliver supramolecular structures with the required structure for a given function [16][17][18]. We have shown

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• host–guest complexes by non-covalent bonding [64]. This mode of catalysis is similar to the way enzymes mediate biochemical reactions [64]. The use of water as a solvent and the non-toxicity of the cyclodextrin catalyst make the method attractive. This method, like the previously reported protocols, is

A conformationally adaptive macrocycle: conformational complexity and host–guest chemistry of zorb[4]arene

• Liu-Pan Yang,
• Song-Bo Lu,
• Arto Valkonen,
• Fangfang Pan,
• Kari Rissanen and
• Wei Jiang

Beilstein J. Org. Chem. 2018, 14, 1570–1577, doi:10.3762/bjoc.14.134

• changes are rare. In this article, we present a thorough study on the host–guest chemistry of a conformationally adaptive macrocycle, namely per-O-ethoxyzorb[4]arene (ZB4). Similar to per-O-ethoxyoxatub[4]arene, ZB4 is capable of accommodating a wide range of organic cations. However, ZB4 does not show

• binding behavior of ZB4 and lays the basis for the construction of stimuli-responsive materials with ZB4 as a major component. Keywords: conformations; host–guest chemistry; macrocycles; supramolecular chemistry; zorb[4]arene; Introduction Macrocyclic receptors are the principal workhorses used in

• 1:1 mixture of ZB4 with 4+ or 5+ (Figures S1 and S2 in Supporting Information File 1). This indicates the importance of the core quaternary ammonium ions in the host−guest complexation. All other guests can be encapsulated in the cavity of ZB4, and significant chemical shifts on both the guests and

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

A three-armed cryptand with triazine and pyridine units: synthesis, structure and complexation with polycyclic aromatic compounds

• Claudia Lar,
• Adrian Woiczechowski-Pop,
• Attila Bende,
• Ioana Georgeta Grosu,
• Natalia Miklášová,
• Elena Bogdan,
• Niculina Daniela Hădade,
• Anamaria Terec and
• Ion Grosu

Beilstein J. Org. Chem. 2018, 14, 1370–1377, doi:10.3762/bjoc.14.115

• are reported. Appropriate NMR and molecular modelling investigations proved the formation of 1:1 host–guest assemblies between the investigated cryptand and some polynuclear aromatic hydrocarbons or their derivatives. Keywords: aromatic guests; aromatic nucleophilic substitution; cryptand; NMR

• reported cage-box [11] is able to complex a plethora of aromatic compounds (e.g., anthracene, pyrene, perylene), while in the cases of several metallo-based cryptands the formation of layered host–guest supramolecular structures (with many guests in the cavity of the host) were reported [12][13][14][15

• libraries [2][25][34][35]) allowed accessing of more sophisticated architectures. In a previous work [32] we reported the formation of a host–guest complex between a cryptand having pyridine units in the bridges and 1,3,5-triphenylbenzene caps (1, Figure 1). Surprisingly, no complexation ability of cryptand

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

• coordinates was based on the asymmetric unit of the determined structure and the dynamic behavior of the inclusion complex was monitored at two different temperatures (300 and 340 K) to gain some insight on the evolution of the host–guest interactions and to estimate the host–guest binding affinity in aqueous

• numerous van der Waals and C–H···O interactions mainly between the guest and the inner dimeric host cavity. The observed host–guest interactions along with the extended hydrogen bond network between water molecules, hosts and guest are listed analytically in Supporting Information File 1, Table S1. In

• XAMDEX [35]) are found to have a 2:1 host/guest stoichiometry. In all these cases, the shift between two successive dimers along the c-axis is 6.017, 6.22 and 6.27 Å, respectively. Thus they crystallize also in the IM packing mode. The first case (ANAXAP), concerns the inclusion of a small molecule model

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• catalysts are entrapped and physically separated in an isolated compartment has appeared to be an excellent facile approach to enhance performance of reactions in water [31][32][33][34]. Pioneering examples in this field include small molecule host–guest containers such as cavitands [35][36][37], and

From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• derivatives were prepared from 3 in order to examine their host–guest properties by ESI mass spectrometry and NMR spectroscopy. Some tetraoxaadamantanes were also examined in this way. For example, compound 30 (Figure 1) was found to have a particular affinity for complexation with choline [26][36], and the

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

• possible occurrence of two different behaviours (Figure 4). With the neutral guest 1 at any pH and with the anionic guests 2–4 at the highest pH values, data trends account for the exclusive formation of a 1:1 host–guest inclusion complex. By contrast, with guests 2–4 at the lowest pH values, i.e

• significantly affected. The latter consideration may also justify the possible formation of higher order host–guest aggregates with anionic guests mentioned previously. In fact, due to molecular size, modelling considerations rule out the accommodation of more than one guest unit into the host cavity. Thus, we

• 1:1 host–guest complexes are present in the samples. Otherwise, deviations from the expected trend give evidence of the formation of higher order aggregates. In order to study the interaction between AmCDs and Alg, a stock alginate solution 25 mN was first prepared as follows. The proper amount of

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

• charge status of the host and the structure of the guest. Thus, the use of the polarimetric method was thoroughly revisited, in order to keep into account the occurrence of multiple equilibria. Our data indicate that the stability of the host–guest complexes is affected by an interplay between Coulomb

• : calix[4]resorcinarene; host–guest complexes; p-nitroanilines; polarimetry; supramolecular chemistry; Introduction During the last decades calix[n]arenes and calix[n]resorcinarenes (CAs) have emerged as versatile supramolecular host systems for various applications [1][2][3][4][5], spanning from sensors

Exploring mechanochemistry to turn organic bio-relevant molecules into metal-organic frameworks: a short review

• Vânia André,
• Sílvia Quaresma,
• João Luís Ferreira da Silva and
• M. Teresa Duarte

Beilstein J. Org. Chem. 2017, 13, 2416–2427, doi:10.3762/bjoc.13.239

• field of supramolecular chemistry [27][28][29], for solvent-free preparation of co-crystals, and adducts [30][31][32][33][34][35][36][37][38], polymorphs [12], supramolecular aggregates [4][30][39][40][41][42], host–guest complexes [5][43][44][45], metal-organic frameworks (MOFs) [8][28][44][46][47][48

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

• /bjoc.13.222 Abstract The complexation of the antifolate pemetrexed (PTX) with native cyclodextrins was studied. This process, along with the findings gathered for the structurally related folic acid was treated as a model for exploiting host–guest interactions of this class of guest molecules in the

• 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

• ; pemetrexed; supramolecular chemistry; Introduction Herein, supramolecular host–guest complexes of the potent folic acid inhibitor pemetrexed (PTX, Figure 1a) with native cyclodextrins (α-, β- and γ-CDs, Figure 1b) in the gas phase (MS), in solution (NMR, UV–vis) and in the solid state (Raman, FTIR–ATR) were