Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• cucurbit[6]uril (TMeQ[6]) and 1,2-bis(4-pyridyl)ethene (G) were used to construct a supramolecular fluorescent probe G@TMeQ[6]. The host–guest interaction between TMeQ[6] and G was investigated using 1H NMR spectroscopy, single-crystal X-ray diffraction and various experimental techniques. The results show

• that a G and TMeQ[6] inclusion complex is formed with a 1:1 stoichiometry. Isothermal titration calorimetry (ITC) analysis The association constant and thermodynamic parameters of the host–guest interaction between G and TMeQ[6] can be obtained using ITC. At 25 °C, a neutral aqueous solution of TMeQ[6

• the G molecule will split, indicating that the TMeQ[6] also affects it. Conclusion We studied the host–guest interaction between G and TMeQ[6] and the specific recognition of Hg2+ ions by the G@TMeQ[6] fluorescent probe. The interaction ratio of G to TMeQ[6] was 1:1 and the association constant was

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• interaction was observed. In 2010, the same group also reported the construction of a well-defined porphyrin nanowire [70] in water using Zn(II) porphyrin-CD conjugate 174 and free-base porphyrin-adamantane conjugate 176b through a robust 1:1 β-CD/adamantane host–guest interaction. First, porphyrin 176b was

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• hydrophobic cavity inside the molecule, while all hydrophilic hydroxy groups are arranged outside the cavity. This feature determines the main practical application of CDs as supramolecular hosts for host–guest interaction. Due to their low cost, low toxicity, and good complexation ability, they are

Synthesis of a new water-soluble hexacarboxylated tribenzotriquinacene derivative and its competitive host–guest interaction for drug delivery

• Man-Ping Li,
• Nan Yang and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56

• host. These results suggested that MV could be effectively released from the cavity of TBTQ-CB6 by the competitive host–guest interaction of SM, since the binding affinity between TBTQ-CB6 and SM was about seven times higher than that between TBTQ-CB6 and MV. Competitive replacement of DOX from the

Tetraphenylethylene-embedded pillar[5]arene-based orthogonal self-assembly for efficient photocatalysis in water

• Zhihang Bai,
• Krishnasamy Velmurugan,
• Xueqi Tian,
• Minzan Zuo,
• Kaiya Wang and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2022, 18, 429–437, doi:10.3762/bjoc.18.45

• photosynthesis and exhibited a high catalytic efficiency for the photocatalytic dehalogenation reaction of various bromoketone derivatives with good yields in short reaction time in water. Keywords: aggregation-induced emission; Förster resonance energy transfer; host–guest interaction; photocatalysis

• . Product yields were obtained from 1H NMR spectra. 2-Bromo-1-phenylethanone dehalogenation reaction under various reaction conditions.a Supporting Information Supporting Information File 124: Experimental details, NMR spectra, host–guest interaction, FRET, and other materials. Funding This work was

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• TBT through outer-surface interaction than the host–guest interaction between the benzene ring or the melamine group of TBT. The host–guest interaction of Q[7]-TBT Using the same method of 1H NMR titration as above. The interaction between Q[7] and TBT is studied and is proved to be different from

• that of TMeQ[6]. It is found that their interaction is the classical host–guest interaction instead of the outer-surface interaction because of the larger cavity of Q[7]. As shown in Figure 2, the proton signals of the entire TBT are shifted upfield with the increasing amount of Q[7]. For example, the

• with strong host–guest interaction. In addition, we also used the UV–vis spectrum to verify the above inference and to further investigate their molar ratio in detail. Q[7] has a larger cavity than TMeQ[6], giving it the ability to bind TBT. Therefore, the absorbance of TBT gradually decreases and

Synthesis of a novel aminobenzene-containing hemicucurbituril and its fluorescence spectral properties with ions

• Qingkai Zeng,
• Qiumeng Long,
• Jihong Lu,
• Li Wang,
• Yuting You,
• Xiaoting Yuan,
• Qianjun Zhang,
• Qingmei Ge,
• Hang Cong and
• Mao Liu

Beilstein J. Org. Chem. 2021, 17, 2840–2847, doi:10.3762/bjoc.17.195

• association constant up to (2.1 ± 0.3) × 104 M−1. Meanwhile, this macrocycle showed no obvious or only slight enhancement of the fluorescence intensity with selected anions. Keywords: amidobenzene-containing macrocycle; hemicucurbituril; host–guest interaction; macrocycle; modification; Introduction

• constants for 1:1 complexation between the host 4 and the guest cations were calculated by Equation 1 [47], where Ka is the association constant of the host–guest interaction, while ΔI is the change in the fluorescence intensity of the host upon gradual addition of the guest, and Δa refers to the different

• on host–guest interaction and supramolecular systems. Its applications and modifications are being pursued in our laboratory, and the results will be reported in due course. The X-ray structure of nitrobenzene-containing hemicucurbituril 9 (CCDC 2094879). Fluorescence emission spectra (λmax = 349 nm

Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• inhibitory activity of CPE against E. coli. Keywords: antibacterial activity; chloramphenicol; cucurbit[8]uril; host–guest interaction; in vitro cumulative release; stability; Introduction Chloramphenicol (CPE, Figure 1A) is a broad-spectrum antibiotic resulting from the metabolism of chorismic acid in

• sustained-release ability of drug molecules [31][33][34]. However, previous studies rarely reported the interaction between Q[8] and antibiotics, and did not explore the effect of Q[8] on antibacterial activity of antibiotics. Herein, Q[8] was selected as the host and the host–guest interaction between Q[8

• ] and CPE was studied using single-crystal X-ray diffraction, UV–vis and 1H NMR spectroscopy, and the effects of Q[8] on the stability, in vitro release rate and antibacterial activity of CPE were investigated. Results and Discussion The host–guest interaction between Q[8] and CPE Single-crystal

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

• , this hybrid material rapidly degraded MO (≈98%) within 10 min, whereas freshly prepared TiO2 reached a value of ≈47%. This may be due to the synergic effect of β-CD and the AuNCs, which relies on two aspects: i) the host–guest interaction between β-CD and MO could lead to the Au cores being directly

Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

• Zhishu Zeng,
• Jun Xie,
• Guangyan Luo,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194

• the inclusion compound with Q[8]. Keywords: cucurbit[8]uril; host–guest interaction; inclusion complex; oroxin A; properties; Introduction Cucurbit[n]urils (Q[n]s) are a family of macrocyclic cage compounds synthesized by the condensation of glycoluril and formaldehyde in a strong acidic solution [1

• that the molecular size of the flavonoids and the length of the sugar chains have a greater impact on the assembly mode of supramolecular systems. Results and Discussion Host–guest interactions The host–guest interaction can be effectively observed using 1H NMR spectroscopy, and the mode of action of

Highly selective Diels–Alder and Heck arylation reactions in a divergent synthesis of isoindolo- and pyrrolo-fused polycyclic indoles from 2-formylpyrrole

• Carlos H. Escalante,
• Eder I. Martínez-Mora,
• Carlos Espinoza-Hicks,
• Alejandro A. Camacho-Dávila,
• Fernando R. Ramos-Morales,
• Francisco Delgado and
• Joaquín Tamariz

Beilstein J. Org. Chem. 2020, 16, 1320–1334, doi:10.3762/bjoc.16.113

• stereoselective approaches of substrates and reagents or catalysts in a variety of processes. Examples include the substrate–enzyme recognition (the host–guest interaction) responsible for inducing pharmacological activity, the DNA-intercalation capable of generating biomolecular activity, molecular dynamics [63

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• corresponding properties of the inclusion complex were studied using 1H NMR, IR and UV–vis spectroscopy and DTA. The results showed that BALE forms an inclusion compound (1:1) with Q[8], and the properties of baicalein are changed by cucurbit[8]uril. Keywords: baicalein; cucurbit[8]uril; host–guest interaction

• the host–guest interaction packing and pattern are shown in Figure 2. 1H NMR spectroscopy is usually one of the most effective methods to characterize host–guest interactions and can be used to deduce the mode of action of the cucurbit[n]uril–guest according to the chemical shift of the proton

• formation of a 1:1 host–guest inclusion complex. Q[8] and BALE in the host–guest interaction package and pattern are shown in Figure 2. The mass spectrum of the BALE–Q[8] inclusion complex (Supporting Information File 1, Figure S2) features the parent-ion peak at m/z 1599.4534 (M+), supporting the formation

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• . Upon complexation with a halide, the planar aromatic ring adopted a heavily pinched boat conformation, a result consistent with theoretical prediction [49]. We also examined the host–guest interaction in solution phase employing NMR and UV–vis spectroscopy and fluorescence technology. Unfortunately

Morphology-tunable and pH-responsive supramolecular self-assemblies based on AB₂-type host–guest-conjugated amphiphilic molecules for controlled drug delivery

• Yang Bai,
• Cai-ping Liu,
• Di Chen,
• Long-hai Zhuo,
• Huai-tian Bu and
• Wei Tian

Beilstein J. Org. Chem. 2019, 15, 1925–1932, doi:10.3762/bjoc.15.188

• varied morphology could inhibit cancer cell proliferation, indicating their potential application in the field of drug delivery. Keywords: β-cyclodextrin; controlled drug delivery; host–guest interaction; stimuli-responsive; supramolecular self-assemblies; Introduction Supramolecular self-assemblies

• based on noncovalent interactions with dynamic nature and reversible property have attracted increasing attention in the fields of biomedicine [1][2][3][4][5][6][7], smart materials [8][9][10], etc. As one common noncovalent interaction [11], host–guest interaction has been used to effectively create

• transition mechanism of β-CD-BM2-based supramolecular self-assemblies in different pH solutions was proposed. In neutral aqueous solution, the host–guest interaction between β-CD and BM in β-CD-BM2 were enhanced, and further driven by β-CD-BM2 to form the FSSAs. While the BM could be protonated in the acidic

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

• ]. Keywords: fluorescent; host–guest interaction; macrocycles; molecular recognition; nor-seco-cucurbit[10]uril; pyrene; Introduction Host–guest interactions that trigger molecular recognition are a current topic of interest. For example, understanding the protein–ligand molecular recognition is of paramount

• structure of host-1, which has the ability to expand its cavity to accommodate larger guests. This effect makes it selective toward small guests [12]. As mentioned previously, Isaacs and co-workers reported their pioneering work on the host–guest interaction properties of host-1 and -2. Several

• fluorescence spectral changes of G2 (Figure 3b) suggest that a similar host–guest interaction triggered monomer-to-excimer binding response between G2 and host 2, similar to host 1 with G2, when we attempted to add host-2 to the G2 solution under the same conditions. Both of the complexes of G2 with the host-1

Reversible end-to-end assembly of selectively functionalized gold nanorods by light-responsive arylazopyrazole–cyclodextrin interaction

• Maximilian Niehues,
• Patricia Tegeder and
• Bart Jan Ravoo

Beilstein J. Org. Chem. 2019, 15, 1407–1415, doi:10.3762/bjoc.15.140

• assembly and disassembly of the AuNR could be induced by host–guest interaction of CD on the nanorods and a photoswitchable arylazopyrazole cross-linker in aqueous solution. The end-to-end assembly of AuNR could be effectively controlled by irradiation with UV and visible light, respectively, over four

• nanoparticle systems [18][19][20][21][22][23][24]. The host–guest interaction can be responsive to external stimuli such as redox, pH or light, with the latter being the most desirable for assembling nanoparticles by virtue of its noninvasive nature [25]. Prominent light-responsive guest molecules are

• -to-end aggregates. Ma et al. suggested that the host–guest interaction is not strong enough to assemble the particles if not preformed. Yet, this is not consistent with publications that report photoswitchable azobenzene–CD interaction on surfaces [28], in hydrogels [29], the assembly of CD vesicles

Aqueous olefin metathesis: recent developments and applications

• Valerio Sabatino and
• Thomas R. Ward

Beilstein J. Org. Chem. 2019, 15, 445–468, doi:10.3762/bjoc.15.39

• through host–guest interaction with silica-gel-supported β-cyclodextrin. Selection of artificial metathases reported by Ward and co-workers (ArM 1 based on biotin–(strept)avidin technology and ArM 2 based on dative anchoring to hCAII). Artificial metathase based on covalent anchoring approach. α

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

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

• 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

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

• –guest interaction in the case of the dihydroxylated guest leads to a weaker host–guest interaction and consequently to a lower association constant. This may explain the different results obtained from the experimental and theoretical data. Indeed, the recalculation including the influence of the

• solvent environment afforded more realistic results for the complexation of the three guest molecules. Namely, the strongest binding was found for anthracene, followed by pyrene, whereas the weakest host–guest interaction was calculated for the cryptand–1,5-dihydroxynaphthalene complex. We consider that

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

• and 1617 cm−1 and for the γ-CD/PTX complex two vibrations at 1537 and 1617 cm−1 are observed. A small host–guest interaction, in the form of band shifts is evident in all obtained spectra of CD/PTX complexes when compared with the spectrum of the free PTX. However, for α-CD/PTX, this shifting is the

• of new bands, may allow for the classification of which particular host–guest interaction is taking place in each analyzed case. Finally, we showed that results from gas-phase, solution and solid state studies are complementary to each other proving that such comprehensive study employing different

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