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The binding properties of pyrenyl-appended calix[4]arenes 2–4 towards lanthanide and transition metal cations were investigated by spectrophotometric data processing, which indicated that 2 forms mononuclear species with all the cations studied. The extraction power decreased toward ligands 2–3 except Co2+, then increased for ligand 4, which reflect the better ability of ligands 2 and 4 to complex and extract at the interface. Derivative 3 formed mono and binuclear species simultaneously with the trivalent cations from La3+ to Er3+ but only M2L species with Yb3+. In the case of 4, only M3L was detected for Yb3+ and only ML for La3+, with the complexation of the other cations tending to form mono-, bi- and tri-nuclear species.

In addition to a variety of viral-glycoprotein receptors (e.g., heparan sulfate, Niemann-Pick C1, etc.), dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN), from the C-type lectin receptor family, plays one of the most important pathogenic functions for a wide range of viruses (e.g., Ebola, human cytomegalovirus (HCMV), HIV-1, severe acute respiratory syndrome coronavirus 2, etc.) that invade host cells before replication; thus, its inhibition represents a relevant extracellular antiviral therapy. We report two novel p-tBu-calixarene glycoclusters 1 and 2, bearing tetrahydroxamic acid groups, which exhibit micromolar inhibition of soluble DC-SIGN binding and provide nanomolar IC50 inhibition of both DC-SIGN-dependent Jurkat cis-cell infection by viral particle pseudotyped with Ebola virus glycoprotein and the HCMV-gB-recombinant glycoprotein interaction with monocyte-derived dendritic cells expressing DC-SIGN. A unique cooperative involvement of sugar, linker, and calixarene core is likely behind the strong avidity of DC-SIGN for these low-valent systems. We claim herein new promising candidates for the rational development of a large spectrum of antiviral therapeutics.

Despite strong indications of antimycobacterial activities for clitocybins reported since 1945, no reports linking chemical structure and activity have been reported in the literature since then. In this study, we synthesized some clitocybin derivatives (also called 2-substituted-isoindolinones), and tested their activities and carried out some chemical derivations. Isoindolinones were prepared from methyl 2-formyl-3,5-dimethoxybenzoate and various primary aromatic amines. Compounds were evaluated for in vitro activity against Mycobacterium tuberculosis H37Rv, as well as for cytotoxicity (CC50) on the Vero cell line. 4,6-dihydroxy-2-(4-hydroxyphenyl)isoindolin-1-one, 7, and 4-hydroxy-2-(4-hydroxyphenyl)-6-methoxy-isoindol-1-one, 5, exhibited the highest antimycobacterial activities (minimum inhibitory concentration = 19.45 µM and 18.45 µM, respectively) and were non-toxic (CC50 = 30 µM and 29 µM, respectively).

A series of six new p-tert-butylcalix [4]arene-1,3-N,N′-diacylhydrazone derivatives 1–6 have been synthesized starting from β-chloro-α,β-unsaturated aldehydes and p-tert-butylcalix [4]arene hydrazide. They were characterized by IR, (1H, 13C, 19F) NMR and HRMS. In addition of the E/Z isomers around the C C bond of the starting aldehydes, the NMR data showed three conformers due to N C(O) bond rotation: transamid/transamid; Cisamid/transamid and Cisamid/Cisamid resulting from the disubstitution of calix [4]arenes. The rotational barriers around N C(O) bond for most compounds were measured in dimethylsulfoxide using dynamic NMR spectroscopy (DNMR). The results are discussed and compared with those previously reported for related β-chloro-α,β-unsaturated acylhydrazones.

In this study, we report the synthesis and characterization of novel nanocomposite namely doubly functionalized chloromethyl-calix[4]arene-methoxy grafted silylated clay (SC-C[4]). The silylation of nanoclay (thickness of the sheets ≈ 1 nm) was performed using (3-aminopropyl)trimethoxysilane (APTMS) (height ≈ 4.55 A) coupling agent. The resulting organoclay was characterized by various techniques such as X-ray diffraction (XRD), infrared spectroscopy (IR), thermal gravimetric analysis (TGA), and 29Si and 13C solid-state NMR. The XRD results suggested the presence of a double layer of silanes molecules into the clay galleries of nanoclay minerals by increasing in the basal spacing. While the IR, 29Si and 13C solid-state NMR, and TGA analysis demonstrated the successful silylation of clay by the appearance of novel absorption bands, the changes in the chemical environment and the peaks degradation in the range 200 to 500 ° C related to aminosilane molecules, respectively. The calix[4]arenes derivatives were synthesized and characterized by IR spectroscopy and 1HNMR. The results showed that calix[4]arene was functionalized at the lower and upper rim. The grafting of the doubly functionalized calix[4]arene onto clay surfaces was performed through nucleophilic reaction. Structure, thermal properties of the nanocomposite SC-C[4] were also investigated. All data approved the successful grafting of para-chloromethyl-calix[4]arene-OMe onto clay surfaces.

The recycling of Risidu Pet-Al (a laminated foil made from polyethylene and aluminum foil in food brike packaging) continues to be a challenge. Despite the fact that previous studies proposed green solutions for the recycling of the Pet-Al composite, the handicaps linked to the increase of the cost of the reagents involved in the recycling mechanism, the complexity of the steps, resulting in products with a critical aspect, really reflect a problem. The growing concern about environmental impacts such as greenhouse gas emissions from inceneration treatment is distinctly clear to the scientific community. This article involves chemical treatment by adding a strong base NaOH or KOH as the dissolving reagent, Followed by the addition of the strong acid HCl . The birth of a neutral environment promotes the recovery of aluminum salts as well as sodium (or potassium). The released H2, polyethylene and cardboard are also products regenerated by this recycling.The study contributes to the optimal conditions of time concentration temperature as well as the mode of separation. The recovered salts are identified, however their purity remains an important factor of quality before adapting their use.

Hybrid nanocomposites were obtained in this study by solid–solid reaction based on calixarenic derivatives and natural Tunisian clay: clay-calixarene. For this purpose, two calixarenic derivatives were synthesized and their properties were studied. Results show their affinity towards bivalent mercury and lithium by complexation in a homogeneous medium and vis-a-vis the rubidium by extraction of water to dichloromethane. The clay was purified and characterized by means of X-ray diffraction, X-ray fluorescence, cation exchange capacity and BET techniques. Intercalation of the calixarenes in the interfoliar space of the clay has been demonstrated by the spacing of the basal space after reaction and the comparison of infrared spectra confirms that the reaction has taken place. In addition, these hybrids have developed important specific surfaces area. Both nanocomposites prepared are among the first synthesis of clay-calixarenic hybrids in solid state. According to the calixarenic structures, it is assumed that these materials were of class II hybrids.

The four new multivalent ligands 5-8 derived from calix[4]arene and thiacalix[4]arene backbones in 1,3-Alternate conformation bearing ortho-imino- and ortho-amino-methylpyridine chelating sites have been designed, prepared and characterized. Owing to the imposed 1,3-Alternate conformation of the backbone, ligands 5-8 offer two coordinating pockets composed of two sets of chelates located above and below the mean place of the macrocyclic framework. Ligands 6-8, independent of the nature of the anion associated with Ag+ cation, form binuclear silver complexes (AgX, X = BF4-, PF6-, SbF6-, AsF6-, NO3-) in solution and in the solid state. Ligand 7, in the presence of an excess of Ag+, also forms tetranuclear silver complexes 7-(AgBF4)4, and 7-(AgNO3)4 in presence of two different auxiliary ligands (H2O or NO3-) that have been characterized in the solid state. Due to a rather short Ag-Ag distance of ca 2.89 A, the tetranuclear complex 7-(AgBF4)4 is emissive in the solid state, at 298 K (λexc = 295 nm, λem = 425 nm) resulting from argentophilic interactions between the closely positioned silver cations.

Opportunistic Gram-negative

International audience; Opportunistic Gram-negative Pseudomonas aeruginosa uses adhesins (e.g., LecA and LecB lectins, type VI pili and flagella) and iron to invade host cells with the formation of a biofilm, a thick barrier that protects bacteria from drugs and host immune system. Hindering iron uptake and disrupting adhesins’ function could be a relevant antipseudomonal strategy. To test this hypothesis, we designed an iron-chelating glycocluster incorporating a tetrahydroxamic acid and α-l-fucose bearing linker to interfere with both iron uptake and the glycan recognition process involving the LecB lectin. Iron depletion led to increased production of the siderophore pyoverdine by P. aeruginosa to counteract the loss of iron uptake, and strong biofilm inhibition was observed not only with the α-l-fucocluster (72%), but also with its α-d-manno (84%), and α-d-gluco (92%) counterparts used as negative controls. This unprecedented finding suggests that both LecB and biofilm inhibition are closely related to the presence of hydroxamic acid groups.

International audience; Glycan-protein interactions control numerous biological events from cell-cell recognition and signaling to pathogen host cell attachment for infections. To infect cells, some viruses bind to immune cells with the help of DC-SIGN (dendritic cell [DC]-specific ICAM3-grabbing nonintegrin) C-type lectin expressed on dendritic and macrophage cell membranes, via their envelope protein. Prevention of this infectious interaction is a serious therapeutic option. Here, we describe the synthesis of the first water-soluble tetravalent fucocluster pseudopeptide-based 1,3-alternate thiacalixarenes as viral antigen mimics designed for the inhibition of DC-SIGN, to prevent viral particle uptake. Their preparation exploits straightforward convergent strategies involving one-pot Ugi four-component (Ugi-4CR) and azido-alkyne click chemistry reactions as key steps. Surface plasmon resonance showed strong inhibition of DC-SIGN interaction properties by tetravalent ligands designed with high relative potencies and β avidity factors. All ligands block DC-SIGN active sites at nanomolar IC50 preventing cis-cell infection by Ebola viral particles pseudotyped with EBOV glycoprotein (Zaire species of Ebola virus) on Jurkat cells that express DC-SIGN. In addition, we observed strong inhibition of DC-SIGN/human cytomegalovirus (HCMV)-gB recombinant glycoprotein interaction. This finding opens the way to the simple development of new models of water-soluble glycocluster-based thia-calixarenes with wide-ranging antimicrobial activities.

International audience; 25,27-bis(methoxycarboxylic acid)-26,28-dihydroxycalix[4]arene (calixH2), so call here calix[4]arene dimethoxycarboxylic acid, was investigated for its ability to build metal–organic frameworks. When reacted with zinc or manganese chloride in DMF and deprotonated with trimethylamine it gives Zn (1) and Mn (2) coordination compounds. These crystallize in the triclinic P-1 space group and are isostructural as shown by X-ray diffraction on single crystals. The crystal structures evidence the coordination of calix[4]arenedimethoxycarboxylic acid through the carboxylate groups. This makes a 1D coordination polymer running along the c axis direction in which [MII2(calix)2(H2O)3(DMF)2] (M = Zn or Mn) neutral units are connected. Last step refinements of the crystal structure reveal a lot of residual electron density which was ascribed to uncoordinated disordered water and DMF molecules. This was treated with the SQUEEZE routine of the program PLATON from which the solvent accessible voids per unit cell volume was calculated to be 24.5% for compound 1 (Zn) and 24.9% for compound 2 (Mn). Complementary differential thermal analyses (DTA) combined with thermogravimety analysis (TGA) and mass spectrometry (MS) are in agreement with large amount of incorporated and non-coordinated water and DMF molecules. Adsorption isotherms of N2 measured for compound 1 do not show any significant porosity. The temperature dependence of the magnetic susceptibility (χ) of compound 2 evidences antiferromagnetic interactions and was best fitted with a weak antiferromagnetic exchange coupling between the manganese(II) ions J = − 1.5 cm−1 and small antiferromagnetic inter-dinuclear interactions zJ = − 1.2 cm−1 (g = 2.02).

International audience

The binding of lanthanide(III) cations with p-isopropylcalix[n]arenes (n = 4, 6, 8) after partial deprotonation has been investigated using UV-Vis absorption spectrophotometry. The ease and degree of deprotonation of the calixarenes closely parallels the behaviour of their t-butyl analogues in the same solvents. The conditional stability constants of the praseodymium, europium, ytterbium and yttrium complexes were determined in DMF and in acetonitrile. The effect of water on the stability of lanthanide complexes in DMF was also treated. The results show that the cation binding selectivity, stoichiometry and stability of the complexes depend on various factors such as the degree of condensation (n) and the consequent number of O-donor atoms as well as the nature of the cation solvation. The stability of the Y(III), Pr(III), Eu(III) and Yb(III) complexes in DMF increased in all cases with increase of the ring size. DFT calculations were used to estimate the influence of the solvent on both the acidity and the conformations of the calixarene anions.

We optimized Origanum majorana (OM) extraction for mild steel corrosion inhibition in neutral 0.5 M chloride medium. The inhibition mechanism evolved in presence of the optimal extract was discussed when calculating the activation energy (Ea), the activation enthalpy (ΔaH) as well as the activation entropy (ΔaS). The OM extract molecules were investigated using the density functional theory (DFT) at B3LYP/6-31G(d,p) basis set level. 1-methyl-4-propan-2-ylcyclohexa-1,3-diene alpha-terpinene was predicted exhibiting the most inhibition capabilities.

The synthesis and catalytic activity of a series of tris-half sandwich cyclopentadienyl nickel (II) N-heterocyclic carbene (NHC) complexes, that have approximate C3 symmetry, is described. The molecules consist of [Ni(NHC)BrCp] groups (Cp = η-C5H5) in which the NHC ligand is grafted on to the lower rim of a 1,3,5 trimethoxy p-tert butylcalix [6] arene via methylene spacers. These species are all synthesized from 1,3,5-trimethoxy-2,4,6 tris-substituted imidazolium tribromide salts via reactions with nickelocene. All complexes were fully characterized by 1H and 13C NMR spectroscopy and by mass spectrometry. Their catalytic activity in the Suzuki-Miyaura cross coupling reaction was probed.

International audience; A series of novel 6-amino-2-aryl-3H-indolone-N-oxides were synthesized at yields of up to 65% and characterized; onewas further characterized using X-ray crystallographic analysis.Synthesized compounds were evaluated for their in vitro activity against a chloroquine-resistant (FcB1) strain of Plasmodium falciparum, as well as for the 50% cytotoxic concentration (CC50) on Vero cell lines. The most promising activities were observed for the fluorinated compounds, the most active in vitro being 6-(2-morpholinoacetamido)-2-(4-(trifluoromethoxy)phenyl)-3H-indolone-N-oxide (IC50: 15.5 nM). In addition, these compounds showed weak cytotoxicity leading to selectivity index values of >170, thus warranting further in vitro and in vivo studies.

Two new multivalent ligands 1 and 2, based on calix[4]arene and thiacalix[4]arene backbones in 1,3-Alternate conformation, bearing four iminocatechol coordinating units have been prepared and structurally characterized both in solution and in the crystalline phase. Combinations of compounds 1 and 2 with Cu(II) afford neutral binuclear complexes 1-Cu2 and 2-Cu2, characterized in the solid state. In both cases, the metal centre, surrounded by a O3N set of heteroatoms, adopts a deformed square planar coordination geometry. In solution, the propensity of ligands 1 and 2 to bind M2+ cations ((M = Co, Ni, Cu and Zn) was also demonstrated. In 1/1 MeOH/CHCl3 mixture and at room temperature, the following stability sequence Ni2+

Described herein is a convenient, odorless, metal-free, one-pot strategy for the synthesis of unsymmetrical thioethers. The key step in this new strategy is a base-catalyzed 1,5-thiol transfer reaction via a pseudointramolecular mechanism of a 1-bromo-2-alkylthiolcarbonate, which is itself obtained through a straightforward microwave-assisted thioalkylation of a 1,2-cyclic-thionocarbonate precursor with an appropriate alkyl bromide. The starting 1,2-cyclic-thionocarbonates are easily obtained from the corresponding diols. When a propargylthiolcarbonate constitutes the key alkylthiolcarbonate 1,5-shift precursor, a copper-mediated dipolar cycloaddition reaction ("click") with azide partners is rendered possible. This increases the versatility of the approach, as a very large variety of complex triazole-tethered substrates can potentially be integrated into the target unsymmetrical thioether final products. As an example of the scope of the reaction, four 1,5-shift reactions have been triggered simultaneously from a sugar-derived tetrathiolcarbonate precursor using base catalysis, to allow four 6-thioglucose moieties to be installed (78% yield for each sugar unit) onto a 1,3-alternate thiacalix[4]arene scaffold in a one-pot transformation.

International audience; A sophisticated photoactive molecular device hasbeen prepared by combining recent concepts for the preparationof multifunctional nanomolecules (click chemistry onmultifunctional scaffolds) with supramolecular chemistry(self-assembly to prepare rotaxanes). Specifically, a clickable[2]rotaxane scaffold incorporating a free-base porphyrinstopper has been prepared and functionalized with ten peripheralZn(II)-porphyrin moieties. Electrochemical investigationsof the final compound revealed a peculiar behavior resultingfrom the intramolecular coordination of the Zn(II)porphyrin moieties to 1,2,3-triazole units. Finally, steadystate investigations of the compound combining Zn(II) andfree-base porphyrin moieties have shown that this compoundis a light-harvesting device capable of channeling thelight energy from the peripheral Zn(II)-porphyrin subunits tothe core by singlet–singlet energy transfer.

International audience; Five new multivalent ligands based on either p-tert-butylthiacalix[4]arene (TCA) 1 or p-tertbutylcalix[4]arene (CA) 2 backbones in 1,3-Alternate conformation bearing four oxamate coordinating groups at their lower rim were designed and synthesized by a multistep strategy. These ligands differ either by the nature of the calix[4]arene backbone (CA or TCA) or by the nature of the spacer ((CH2)n) connecting the oxamate binding units to the backbone.

Pillar[5]arene derivatives bearing peripheral porphyrin subunits have been efficiently prepared from a deca-azide pillar[5]arene building block (17) and Zn

Dedicated to Professor Vincenzo Balzani on the occasion of his 80th birthday; International audience; Pillar[5]arene derivatives bearing peripheral porphyrin subunits have been efficiently prepared from a decaazide pillar[5]arene building block (17) and ZnII-porphyrin derivatives bearing a terminal alkyne function (9 and 16). For the resulting deca-ZnII-porphyrin arrays (18 and 20), variable temperature NMR studies revealed an intramolecular complexation of the peripheral ZnII-porphyrin moieties by 1,2,3-triazole subunits. As a result, the molecules adopt a folded conformation. This was further confirmed by UV/Visspectroscopy and cyclic voltammetry. In addition, we have also demonstrated that the coordination-driven unfolding of 18 and 20 can be controlled by an external chemical stimulus.Specifically, addition of an imidazole derivative (22) to solution of 18 or 20 breaks the intramolecular coordination at the origin of the folding. The resulting molecular motions triggered by the addition of the imidazole ligand mimic the blooming of a flower.

Herein, the multistep synthesis of eight new ligands based on either calix[4]arene or thiacalix[4]arene backbone blocked in a 1,3-alternate conformation was achieved. Both types of backbones were functionalized with pyridyl coordinating units using either imino or amino junctions. The introduction of the pyridyl units was achieved using either the position 3 (meta) or 4 (para) of the aromatic moiety. Moreover, four out of the eight ligands were structurally investigated in the solid state via X-ray diffraction methods on single crystals.

Experimental and quantum chemical investigations have been coupled in order to determine anticorrosion potential of Malva sylvestris extract molecules. The plant extract is a mixture of chemicals of which only four are abundant. Two groups of molecules are evidenced using quantum chemical parameters. The electrochemical investigation has classified the plant extract as a mixed-type inhibitor. The %EI has been only 54.5% due to antagonistic effects of the extract molecules.

International audience; Combinations of six new coordinating tectons (3-8) tetrakis-pyrazolyl appended calix[4]arenes, blocked in 1,3-A conformation, based on 1 (tetrathiacalix[4]arene) and 2 (tetrathiatetramercaptocalix[4]arene) derivatives, with AgX salts (X = NO3-, BF4-, XF6-(X = P, As and Sb)) lead to nine new silver coordination networks. The flexible nature of tectons 3-8 (length of the spacer between the macrocycle and the pyrazolyl coordinating unit), their high number of potential coordinating sites and the loose coordination demand of Ag + cation lead to the formation of a large variety of networks with different dimensionality: from 1D (5-AgSbF6, 5-AgBF4, 7-AgSbF6 and 8-AgNO3) to extended 2D (6-AgBF4 and 8-AgSbF6) and to a series of three isostructural porous diamond-like 3D architectures (6-AgXF6 (X = P, As and Sb)).

The synthesis and complexation properties of three new derivatives, one spirobiscalix[4]azacrown (1) and two calix[4]azacrown (2 and 3), are reported. Complexation studies of the three ligands toward transition and heavy metal cations have been carried out and monitored by UV absorption spectrophotometry in acetonitrile. Mononuclear complexes were detected for all complexes, whereas binuclear species (M2L) were also formed in the case of ligand 1 with Cu2+ and Pb2+. The extraction properties of 1, 2 and 3 toward Cu2+, Zn2+, Pb2+, Ag2+ and Cd2+ are also reported. The results showed that complexation is the main factor affecting extraction with ligands 2 and 3, while with ligand 1 it is not.

The binding properties of four amido derivatives of p-tetraphenyl tetrahomodioxacalix[4]arene towards alkali and alkaline-earth metal cations using UV-absorption spectrophotometry, 1H NMR and ESI-mass spectrometry techniques are reported.

The binding properties of ethylester derivative of p-tetraphenyl tetrahomodioxacalix[4]arenes (1) towards alkali, alkaline-earth, transition and heavy metal cations using UV-absorption spectrophotometry and 1H-NMR spectroscopy are reported.

A new fluorogenic calix[4]tetraaza-crown-6 (4) bearing two pyrene amide groups has been prepared. It was shown to be selective for Mg2+. When Mg2+ is bound to 4, the pyrene monomer emission increased while the excimer emission declined in a ratiometric manner. It is shown by 1H NMR that this ratiometric change is due to the conformational changes of the pyrenes during the chelation of Mg2+ by the amide functions to form a 1:1 complex.

The synthesis and complexation properties of a novel type of calix[4]azacrown, in which two cone calix[4]arenes are linked via a spiro C-atom incorporated into polyaminoalkylene chains are presented.

Calixarenes 2–4, 6 and 7 in the cone conformation variously substituted by acid or amido functions, glycolic chains and hydroxyl groups were synthesised. They have been used in extraction of native amino acid and amino acid esters.

The synthesis of a new di-imidazolyl-di-methoxy acetamido p-tert-butylcalix[4]arene 4 is reported. 4 has been prepared by reacting the corresponding di-methyl ester di-methoxy derivative with histamine in 1:1 mixture of methanol: toluene. The binding properties of 4 towards alkali, alkaline earth, transition (Zn2+, Co2+) and heavy (Pb2+, Cd2+) metals have been investigated along with the complexes stoichiometries. The 1H-NMR spectra of complexes show the location of cations in receptor 4. Partial cone conformation is observed only with strontium and calcium whereas the cone conformation is detected with most of the cations. Comparison of the complexation results with those obtained for di-imidazolyl acetamido p-tert-butylcalix[4]arene 3 missing the methyl groups is also reported.

Hyperbranched molecules, 4–8, based on calixarenes attached to newly synthesised cores 2 and 3 have been prepared. Preliminary complexation studies of the complexation of Zn(Pic)2 by 8 showed that the ligand prefers to bind the picrate anions.

Four imidazolyl acetamido p-tert-butylcalix[4]arenes 5–8 have been prepared by reacting the corresponding methyl esters derivatives 1–4 with histamine in 1:1 mixture of methanol:toluene. The yields ranged from 56 to 68%. 5–8 have been shown to be in cone conformation. The complexation behaviour of 5–8 towards monovalent metal picrates M+Pic− with M+ = Li+, Na+, K+, Rb+ and Cs+ and divalent metal picrates M2+(Pic−)2 with M2+ = Mg2+, Ca2+, Sr2+, Ba2+, Pb2+, Cd2+, Zn2+ and Co2+ are given. Tentative localisation of the metal cations in the receptors is given. The binding properties towards these cations have been determined along with stoichiometries of the complexes.

In acetonitrile, the tren - N -tricalix[4]arene 4 with three appended pyrenyl groups showed an enhanced fluorescence in the presence of Al 3+ and, to a lesser extent, of In 3+ . Compound 4 was shown to form a 1:1 complex with Al 3+ , the metal cation being located in the tren part. The association constant ( K a ) of 4 for the Al 3+ cation was calculated to be 8.7×10 3 M −1 in acetonitrile.

The binding properties of 1,2,3,4-amido derivatives of p-tert-butyl calix[4]arene (4–6) towards various anions (spherical halides, planar trigonal nitrate and tetrahedral hydrogen sulphate) as their tetrabutyl ammonium (TBA) salts have been studied by 1H NMR technique and using Equi Chem program. The stability constants, log K ass, varying from 0.76 ± 0.10 to 2.13 ± 0.04 have been determined for the mononuclear complexes. Anion complexation by amido derivatives of p-tert-butyl calix[4]arene Abdelwaheb Hamdi, Rym Abidi and Jacques Vicens 1 R = R′ = CH2COOCH3 2 R = H ; R′ = CH2CONH-benzyl 3 R = R′ = CH2CONH-benzyl 4 R = R′ = CH2CONHCH2-furane 5 R = R′ = CH2CONHCH2-thiophene 6 R = R′ = CH2CONH(CH2)2O(CH2)2OH

Both the consequences of 1,3-cyclization of calix[4]arenes by diamide formation, and the effect of 2- and 2,4-alkoxycarbonylmethylation of two 1,3-bridged calix[4]azacrowns on their metal ion-binding capacities have been studied by synthesis of the derivatives in their cone conformation and measurement of the stability constants for their complexation in a range of alkaline earth and transition metal cations. In these two cases, the conformation of the ligand in the solid state has been defined in detail by a crystal structure determination. In the first case, a tubular architecture performing methanol channels is displayed, however, in the second case a zigzag architecture generated by a chloroform network connecting calixarene molecules is present. Speciation in solution appears to be limited to the formation of 1:2 and/or 1:1 and/or 2:1 (M–L) complexes, depending on the system, with values of the stability constants determined by absorption spectroscopy in acetonitrile, lying in the ranges log β12 ca. 10, log β11 ca. 2–5, and log β21 ca. 7–9. There is evidence for selectivity toward Cu(II) and for some unexpected anion effects. None of these ligands appear to be an efficient extractant for the metals as their picrate.

This mini review focuses on the construction of dendrimers from calix[4]arene and thia calix[4]arenes.