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In this work, the combination of cucurbit[6]uril (Q[6]) with various naphthalene disulfonates and alkaline-earth metal ions allows for successful isolation of 9 novel Q[6]-based coordination complexes with the formulas [Ca(H2O)4(Q[6])0.5(1,5-NDA)0.5]·(1,5-NDA)0.5·3H2O (1), [Sr(H2O)4(Q[6])0.5(1,5-NDA)0.5]·(1,5-NDA)0.5·4H2O (2), [Ba(H2O)4(Q[6])0.5(1,5-NDA)0.5]·(1,5-NDA)0.5·4H2O (3), [Ca(H2O)5(Q[6])0.5](2,6-NDA)·9H2O (4), [Sr(H2O)5(Q[6])0.5]·(2,6-NDA)·6H2O (5), [Ba2(H2O)7(Q[6])(2,6-NDA)2]·11H2O (6), [Sr(H2O)4(Q[6])0.5(2,6-NDA)0.5]·(2,6-NDA)0.5·5H2O (7), [Ca2(H2O)10(Q[6])](2,7-NDA)·14H2O (8) and [Sr(H2O)5(Q[6])(2,7-NDA)]·4H2O (9) (H2NDA = naphthalenedisulfonic acid). Structural analysis revealed that the carbonyl groups of Q[6] bind directly to the alkaline-earth metal ions to form 1D coordination chains. Moreover, the metal ions are also linked to the disulfonate substituents of the naphthalenes, which, in the case of 9, resulted in a simple coordination complex, for 6, a 1D Q[6]–NDA–M2+ chain, and in the case of 1–3 and 7, 2D networks. By contrast, for 4, 5 and 8, the disulfonate ligands do not bind to the metals, and instead, act as supramolecular linkers. The resultant 3D supramolecular architecture of these compounds was constructed through various noncovalent interactions, particularly involving outer-surface interactions of the Q[6]s. Furthermore, the fluorescence properties of species 2 and 7 were investigated, and sensing experiments indicated that both were capable of functioning as fluorescent sensors for Fe3+ with high sensitivity and selectivity.

We have strategically incorporated three different fluorophores at tren to construct a multi-energy donor/acceptor “smart” probe L. This probe operates by using three-dimensional scales (response time, wavelength and fluorescence intensity) which allows for the selective recognition and discrimination of the Cu2+, Hg2+, Fe3+ and F− ions.

The supramolecular interaction between hemicucurbit[6]uril (HemiQ[6]) and ferrocene is investigated using 1 H and 13 C NMR spectroscopy, cyclic voltammetry (CV), isothermal titration calorimetry (ITC) and quantum chemistry. By means of the 1 H NMR and 13 C NMR spectra, the host-guest interaction is confirmed by the slight shift in the resonance peaks of ferrocene. Cyclic voltammetry shows the diffusion current of ferrocene was enhanced with a slight improvement in the voltammetric behavior in the presence of HemiQ[6]. Isothermal titration calorimetry provides thermodynamic data for the host-guest interaction and an association constant of K a = 4.9 × 10 4 L mol −1 in a 1:1 ratio has been obtained. Quantum chemistry suggests the encapsulation complex was stabilized by the formation of hydrogen bonding between the aromatic protons on the ferrocene guest molecule and the carbonyl groups on hemicucurbit[6]uril, and the electron transfer of the interaction complex is more easy than in free ferrocene.

Herein, we report the synthesis of two novel coordination polymers using a combination of imidazole-containing ligands, namely 1,3,5-tris((1H-imidazol-1-yl)methyl)benzene (L1) and 3,3′,5,5′-tetra(1H-imidazol-1-yl)-1,1′-biphenyl (L2) and a carboxylate ligand derived from 4,4′-biphenyldicarboxylic acid (H2BPDC). The structures of the two coordination polymers [Ni(L1)(BPDC)]·2H2O (1·2H2O), which exhibits a 2-fold interpenetrated 3D → 3D architecture, and {[Co(CH3OH)2(L2)0.5(BPDC)] (2) possessing a 2D framework, have been determined. Moreover, the gas adsorption properties of 1 and 2 have been investigated.

A series of anthracene-containing derivatives have been synthesised and characterised. The photochemical behaviour of these derivatives have been investigated by 1 H NMR spectroscopy. An unprecedented photolysis reaction for anthracene-containing derivatives was observed in the case of anthracenes directly armed with a -CH 2 O-R group upon UV irradiation. The photolysis reaction process has been demonstrated to occur in three steps. Firstly, the anthracene-containing derivatives are converted into the corresponding endoperoxide intermediate upon UV irradiation in the presence of air; then, the endoperoxide intermediate is decomposed to the corresponding starting compound and 9-anthraldehyde; finally, 9-anthraldehyde is further oxidised to anthraquinone. Additionally, the photolysis reaction of anthracene-containing derivatives is significantly promoted in the presence of a thiacalix[4]arene platform.

A new type of chemosensor-based approach to the detection of 2,4,6-trinitrophenol (TNP) is described in this paper. Two hexahomotrioxacalix[3]arene-based chemosensors 1 and 2 were synthesized through click chemistry, which exhibited high binding affinity and selectivity toward TNP as evidenced by UV-vis and fluorescence spectroscopy studies. (1)H NMR titration analysis verified that CH⋯O hydrogen bonding is demonstrated as the mode of interaction, which possibly facilitates effective charge-transfer.

A novel type of selective and sensitive fluorescent sensor having triazole rings as the binding sites on the lower rim of a hexahomotrioxacalix[3]arene scaffold in a cone conformation is reported. This sensor has desirable properties for practical applications, including selectivity for detecting Zn 2+ and Cd 2+ in the presence of excess competing metal ions at low ion concentration or as a fluorescence enhancement type chemosensor due to the cavity of calixarene changing from a ‘flattened-cone’ to a more-upright form and inhibition of PET. In contrast, the results suggested that receptor 1 is highly sensitive and selective for Cu 2+ and Fe 3+ as a fluorescence quenching type chemosensor due to the photoinduced electron transfer (PET) or heavy atom effect.

A new pyrenyl appended hexahomotrioxacalix[3]arene L featuring 1,2,3-triazole linkers was synthesized as a fluorescent chemosensor for Zn2+ in mixed aqueous media. It exhibited high affinity toward Zn2+, and the monomer and excimer emission of the pyrene moieties could be adjusted. The binding stoichiometry of the L·Zn2+ complex was determined to be 1:1, and the association constant (Ka) was found to be 7.05 × 104 M−1. The binding behavior with Zn2+ has been confirmed by 1H NMR spectroscopic analysis.

Two novel receptors 5,11,17,23-tetra-tert-butyl-25,27-bis[(ethoxycarbonyl)methoxy]-26,28-bis-[1-methyl-(imidazole)meth-oxy]-2,8,14,20-tetra-thiacalix[4]arene (L1) and 5,11,17,23-tetra-tert-butyl-25,27-bis-[(benzyl)methoxy]-26,28-bis-[1-methyl-(imidazole)-methoxy]-2,8,14,20-tetrathiacalix[4]arene (L2) possessing imidazole moieties based on thiacalix[4]arene in the 1,3-alternate conformation have been synthesized and characterized. The crystal structures of L1 and L2 have been determined. The binding behaviour towards Li+, Na+, K+ and Ag+ ions has been examined by 1H NMR titration experiments in (CDCl3/CD3CN; 10:1, v/v) solution. The exclusive formation of mononuclear complexes of L1 with metal cations is of particular interest revealing a negative allosteric effect in the thiacalix[4]arene family. Liquid-liquid extraction experiments indicate that synthesized L2 can be utilized as an efficient reusable extractant for dichromate anion by controlling the pH of the aqueous solution.

A rare and exclusive endoperoxide photoproduct was quantitatively obtained from a thiacalix[4]arene crown-shaped derivative upon irradiation at λ=365 nm; the structure was unambiguously confirmed by (1) H/(13) C NMR spectroscopy and X-ray crystallography. The prerequisites for the formation of the endoperoxide photoproduct have also been discussed. Furthermore, the photochemical reaction rate could be greatly enhanced in the presence of the thiacalix[4]arene platform because it served as a host to capture oxygen.

Three novel thiacalix[4]arene receptors 4a–c each with a 1,3-alternate conformation and possessing two urea moieties linking various phenyl groups substituted with either para electron-donating or -withdrawing groups have been synthesized. The binding properties of these receptors were investigated by means of 1H NMR spectroscopy and UV-vis absorption titration experiments using various anions. The structures and complexation energies were also studied by density functional theory (DFT) methods. The results suggested that receptor 4c, which possesses two p-(trifluoromethyl)phenyl ureido moieties, can complex most efficiently in the urea cavity and exhibits high selectivity towards F− and AcO− ions.

A new thiacalix[4]arene based fluorescent chemosensor L bearing two pyrenyl groups in a 1,3-alternate conformation has been synthesized, and its metal ion-binding and fluorescence-sensing properties were investigated in ethanol. The designed chemosensor L exhibited high selectivity toward Cu²⁺ ions versus the other tested metal ions with a detection limit of up to 1.44 × 10⁻⁷ M. The chemosensor L was capable of acting an efficient ratiometric fluorescent chemosensor at low ion concentration or as a fluorescence quenching type chemosensor due to the PET and heavy atom effects operating in high ionic strength solution. Further studies revealed that chemosensor L acted as a reversible sensor in the presence of Cu²⁺ and ethylenediamine.

The tripodal probe L was readily prepared via introducing rhodamine and azobenzene groups in a two-step procedure. Studies of the recognition properties indicated that probe L exhibited high sensitivity and selectivity towards F−, AcO− and H2PO4− through a ratiometric colorimetric response with low detection limits of the order of 10−7 M. The complexation behaviour was fully investigated by spectral titration, 1H NMR spectroscopic titration and mass spectrometry. Probe L not only recognizes F−, AcO− and H2PO4−, but can also distinguish between these three anions via the different ratiometric behaviour in their UV–vis spectra (387/505 nm for L-H2PO4−, 387/530 nm for L-AcO− and 387/575 nm for L-F− complex) or via different colour changes (light coral for L-H2PO4−, light pink for L-AcO− and violet for the L-F− complex). Additionally, given the presence of NH and OH groups in probe L, which can be protonated and deprotonated, probe L further exhibited an excellent pH response over a wide pH range (pH 3 to pH 12).

Heteroditopic receptors (4a–e) based on a thiacalix[4]arene in the 1,3-alternate conformation, which have two urea moieties linking various phenyl groups substituted with either electron-donating or -withdrawing groups at their m-, or p-positions with a crown-ether moiety at the opposite side of the thiacalix[4]arene cavity, have been synthesized. The two examples with p-CH3– (4b) and p-NO2-substituted (4e) phenyl groups have been characterized by X-ray crystallography. The binding properties of receptor 4e were investigated by means of 1H NMR spectroscopic and absorption titration experiments in CHCl3–DMSO (10 : 1, v/v) solution in the presence of K+ ions and various anions. Interestingly, it was found that receptor 4e, which possesses two p-nitrophenyl ureido moieties, can complex most efficiently in the urea cavity or the crown-ether moiety; and the plausible allosteric effect of receptor 4e was also studied.

Three organic ionophores (2-4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing two pyridyl coordinating moieties (ortho for 2, meta for 3 and para for 4), have been synthesized and characterized in the solid state. The solvent extraction experiments with the metal ions showed that the ability of these derivatives to complex with Ag(+) appeared to be largely dependent on the position of the nitrogen atoms of the pyridyl ring. Two different complexation modes have been confirmed by 1H NMR titration. Ionophore 2 armed with two pyridyl moieties, complexed with Ag(+) cation through N···Ag(+)···S interactions; however, ionophore 3 and ionophore 4 complexed with Ag(+) through metal-nitrogen (N···Ag(+)) interactions. The DFT computational studies were consistent with the experimental findings. These findings will provide us with an important rule to design an appropriate thiacalix[4]arene ionophore in the future. Another study on the possibility for application of ionophores 2-4 for the treatment of waste water containing Cr(VI) and Cr(III), showed that ionophore 3 was useful in the application of the solvent extraction method in selective treatment of waste water containing Cr(VI) and Cr(III) prior to discharge.

A diffusive predator-prey model with modified Leslie-Gower and Holling type IV schemes is considered in detail. By the upper solution, we ensure the priori bound of solution. Furthermore, the stability of positive equilibrium is obtained by means of local analysis. All these results are of significance in complexity of ecosystems.

O-Alkylation of the flexible thiacalix[4]arene 1 with 2-chloromethyl-1-methyl-1H-imidazole 2 in the presence of Na2CO3 or K2CO3 afforded mono-O-alkylation product 3 in 29–51% yield, along with recovery of the starting compound. In contrast, the same reaction in the presence of Cs2CO3 gave only one pure stereoisomer, namely 1,3-alternate-4; other possible isomers were not observed. Alkali metal salts such as Na2CO3 and Cs2CO3 can play an important role in the conformer distribution via a template effect. The conformations of the receptors, mono-O-alkylation product 3 and that of 1,3-alternate-4, have been confirmed by X-ray crystallography. Furthermore, the complexation properties of the receptor 1,3-alternate-4 toward selected alkali/transition metal cations are reported. The two-phase solvent extraction data indicated that 1,3-alternate-4 exhibited a stronger extraction efficiency for transition metals over alkali metals. The dichromate anion extraction ability of 1,3-alternate-4 showed that it could serve as an efficient extractor of HCr2O7−/Cr2O72− anions at low pH.

Upper rim pyrene-functionalized hexahomotrioxacalix[3]arene L was synthesized via Click chemistry, and its fluorescence behaviors toward several common metal cations were investigated. L exhibited a significant fluorescence quenching response to Hg(2+) in CH3CN solution, which was unaffected by the coexistence of other competitive metal cations. Thus, L can be utilized as a highly selective and sensitive fluorescent chemosensor for Hg(2+) with a detection limit in the nM level. Interestingly, the quenched fluorescence emission can be successfully revived upon the addition of water. In this process, the heavy atom effect of Hg(2+) can be blocked by further coordination of a water molecule and resulted in the revival of the fluorescence emission of L/Hg(2+) complex. Particularly, other polar solvents such as CH3OH and CH3CH2OH also have the ability to revive the fluorescence emission of the L/Hg(2+) complex, but on a much smaller scale than observed for H2O. The heavy atom effect and blocking thereof were demonstrated within the same system by the use of a C3-symmetric homooxacalix[3]arene scaffold. The present studies provided further evidence for the blocking heavy atom effect.

A diffusive predator-prey model with modified Leslie-Gower and Holling type IV schemes is investigated analytically and numerically. Mathematical theoretical works mainly focus on the existence of traveling wave solutions. Numerical simulations are performed to confirm the feasibility of traveling wave solutions. All these results are significant in exploration of the dynamic complexity of ecosystems.

The [2 + 2] Schiff-base macrocycles [2,2'-(CH2CH2)(C6H4N[double bond, length as m-dash]CH)2-2,6-(4-RC6H2OH)]2 ((R)H2), upon reaction with MnCl2 (two equivalents) afforded the bimetallic complex [Cl3Mn(μ-Cl)Mn((Me)H2)] (1) or the salt complex [Cl3Mn(NCMe)][MnCl((tBu)H2)] (2). Under similar conditions, use of the related [2 + 2] oxy-bridged macrocycle [2,2'-O(C6H4N[double bond, length as m-dash]CH)2-4-RC6H2OH] (II(R)H2), afforded the bimetallic complexes [(MnCl)2II(R)] (R = Me 3, tBu 4), whilst the macrocycle derived from 1,2-diaminobenzene and 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-methylenedibenzaldehyde (H4) afforded the complex [(MnCl)2(III)]·2MeCN (5·2MeCN). For comparative studies, the salt complexes [2,6-(ArNHCH)2-4-MeC6H2O][MnCl3(NCMe)] (Ar = 2,4-Me2C6H3, 6) and {[(2-ArN[double bond, length as m-dash]CH),6-(ArNHCH)-4-Me-C6H2O]MnCl}2[MnCl4]7·8CH2Cl2 (Ar = 4-MeC6H4, ·8CH2Cl2) were prepared. The crystal structures of 1 - 7 are reported (synchrotron radiation was necessary for complexes 1, 3 and 5). Complexes 1 - 7 (not 5) were screened for their potential to act as pre-catalysts for the ring opening polymerization (ROP) of e-caprolactone; 3, 4 and 6, 7 were inactive, whilst 1 and 2 exhibited only poor activity with low conversion (

The fluorescent sensor (3) based on the 1,3-alternate conformation of the thiacalix[4]arene bearing the coumarin fluorophore, appended via an imino group, has been synthesised. Sensing properties were evaluated in terms of a colorimetric and fluorescence sensor for Zn2+ and F−. High selectivity and excellent sensitivity were exhibited, and ‘off-on’ optical behaviour in different media was observed. All changes were visible to the naked eye, whilst the presence of the Zn2+ and F− induces fluorescence enhancement and the formation of a 1:1 complex with 3. In addition, 3 exhibits low cytotoxicity and good cell permeability and can readily be employed for assessing the change of intracellular levels of Zn2+ and F−.

Purpose : To isolate and identify the fungal endophytes of Fagopyrum tataricum and assess their antimicrobial activity. Methods : The fungal isolates were identified according to their morphological characters and internal transcribed spacer (ITS) sequence analysis. Both broth-dilution-colorimetric assay and spore germination test were employed to assess the antimicrobial activity of fungal mycelia extracts.. Results : A total of 72 endophytic fungal isolates were successfully obtained from the healthy tissues of F. tataricum. On the basis of their morphological and molecular characteristics, thirteen distinct fungal isolates were identified, and belonged to Alternaria, Bionectria, Botryosphaeria, Fusarium, Guignardia, Nectria, Neonectria, Phomopsis, Pseudocercospora and Verticillium spp. Of these, Pseudocercospora owned the maximum colonization frequency (15.3 %), next for Alternaria (12.5 %) and Neonectria (11.1 %). Through antimicrobial screening assays, six endophytes (Fataf-4, 6, 9, 11, 12 and 15) were active against Bacillus subtilis, Staphylococcus aureus, Agrobacterium tumefaciens, Escherichia coli and Pseudomonas lachrymans , and their minimal inhibitory concentration (MIC) ranged from 0.125 to 2.00 mg/mL. Furthermore, the endophytes, Fataf-9 and Fataf-11, also displayed strong inhibitory activity on the spore germination of F. oxysporum f. sp. vasinfectum and F. oxysporum f. sp. cucumerinum , and their median effective inhibitory concentration (IC50) was 0.356, 0.463, 0.451 and 0.489 mg/mL, respectively. Conclusion : The endophytic fungi of F. tataricum appear to be diverse and promising in their antimicrobial activity, and may represent a potential source of antibiotics for agriculture and/or pharmaceutical applications. Keywords : Endophytic fungi, Fagopyrum tataricum, Diversity, Antimicrobial activity, Antibiotics, Pseudocercospora