A rhodamine-carbazole dyad has been synthesized and electropolymerized to generate thin films. The spectroelectrochemical properties of the resulting polymer are investigated both in absorption and emission. We show that the luminescence of the rhodamine unit is partially quenched by the carbazole moiety and this quenching is strongly enhanced upon oxidation. A reversible switch of the emission intensity between two redox states is demonstrated, but the stability is strongly dependent on the film thickness and proportion of carbazole in the polymerization medium. This luminescence quenching can be used to follow the electropolymerization reaction since a strong decrease of intensity occurs as soon as the oxidative coupling reaction starts.

The antibiotic oxytetracycline (OTC), from the tetracycline family of drugs, is generally used to enhance growth as well as to prevent and cure harmful microorganisms in animals and aquaculture. However, improper OTC use exposes people to trace amounts of antibiotics in the food chain, increasing their risk of health problems. For the first time, a new calix [4] arene functionalized at the upper rim by protected ethylenediamine groups has been successfully synthesized and fully characterized by using elemental analysis H-1 NMR, C-13 NMR, and HRMS. Moreover, indium tin oxide electrode (ITO) modified with the calix [4] arene derivative (EDCA [4]) was successfully prepared using a simple drop-cost method. EDCA [4] film was characterized by static contact angle measurement, cyclic voltammetry measurement, electrochemical impedance spectroscopy, and microscopic surface imaging (SEM). Electrochemical impedance spectroscopy (SIE) measurement showed that the EDCA [4]/ITO exhibited high molecular recognition and consequently displayed a good impedimetric response toward oxytetracycline (OTC). The developed sensor exhibited a wide linear concentration range of 10(-10)M to 10(-5)M and a lower detection limit of 2.3 10(-11) M. Also, the presented sensor has demonstrated great selectivity and reproducibility, and the designed electrochemical platform was successfully used for detecting trace oxytetracycline in spiked milk samples.

New tetrazine derivatives able to be grafted on gold surfaces have been synthesized with either disulfide or thioctic anchoring units, and their electrochemical and photophysical properties are investigated in solution. In parallel, gold nanoparticles have been electrodeposited on indium tin oxide surfaces and then functionalized by the tetrazine compounds. The modified surfaces have been characterized by X-ray photoelectron spectroscopy with a focus on the influence of the deposition potential and immersion time. Tetrazines remain fully electroactive and emissive once grafted. Electrochemical characterization shows that monolayers of tetrazine are formed with high values of the electron transfer rate with the thioctic anchoring group. The photophysical study allows us to estimate the optimal deposition time and shows a gradual bleaching under continuous excitation with a rate depending on the excitation power. The monolayers grafted through the thioctic unit show the best performances from the electrochemical and photophysical point of view, suggesting a better organization than with the disulfide unit.

A series of calix[4]arene supported N-heterocyclic carbene palladium complexes were successfully prepared and characterised. Their X-ray crystal structures were obtained and are discussed. Notably, the dimeric compound b[5-(3-N-4,5-diphenylimidazol-2-yliden-1-yl)-25,26,27,28-tetrapropyloxy calix[4]arene] palladium(II) dibromide (cone) showed pseudo-polymorphism.

The synthesis of N-heterocyclic carbene ( NHC) copper complexes supported by calix[ 4] arene is reported. Mono-substituted calix[ 4] arene was prepared through conventional procedures, followed by the attachment of an imidazolyl group to create the precursor of NHC ligands. Alkylation with two alkyl bromides followed by metalation resulted in fully characterized original complexes. The X-ray structure showed an "out'' conformation for copper. The catalytic activity of the complexes was studied in click chemistry, and revealed good performances. In particular, three new triazoles were synthesized in high yields, under solvent-free conditions and a fast reaction time. The newly synthesized chiral complex was tested in the kinetic resolution of racemic azide.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Nanoparticles made of a polysiloxane matrix and surrounded by 1,4,7,10-tetraazacyclododecane-1-glutaric anhydride-4,7,10-triacetic acid (DOTAGA)[Gd(3+) ] and 2,2'-(7-(1-carboxy-4-((2,5-dioxopyrrolidin-1-yl)oxy)-4-oxobutyl)-1,4,7-triazonane-1,4-diyl)diacetic acid) NODAGA[(68) Ga(3+) ] have been synthesized for positron emission tomography/magnetic resonance (PET/MRI) dual imaging. Characterizations were carried out in order to determine the nature of the ligands available for radiolabelling and to quantify them. High radiolabelling purity (>95%) after (68) Ga labelling was obtained. The MR and PET images demonstrate the possibility of using the nanoparticles for a combined PET/MR imaging scanner. The images show fast renal elimination of the nanoparticles after intravenous injection.

A novel optical sensor for sensitive and selective determination of copper ions in aqueous solution based on a novel calix[4]dicyano-diimidazole ionophore was prepared. The newly synthesized calix[4]dicyano-diimidazole exhibited obvious absorbance enhancement at 284 nm in the presence of copper ions. At pH 6.8, the measuring range of the optode membrane for Cu2+ ions was from 1.0 x 10(-8) to 1.0 x 10(-4) M with a detection limit of 7.0 x 10(-9) M. Furthermore, the response time of the proposed optical device was within 10 min. With the optimum condition described, the optical sensor revealed good selectivity toward Cu2+ ions in comparison with common coexisting cations (Hg2+, pb(2+), cd(2+), Ni2+ and Zn2+). Finally, the reproducibility, regeneration, reversibility and repeatability of this optical sensor were discussed. (C) 2015 Elsevier B.V. All rights reserved.

AbstractThe π‐cationic arylation of methoxy substituted benzoic acids with reactive arenes [e.g. (II)] is developed to provide an optimized synthetic route to phenstatin (V).

A rapid domino π-cationic arylation of aromatic carboxylic acids, mediated by Eaton's reagent, has been developed for the synthesis of Iasi-red polymethoxylated polycyclic aromatic hydrocarbons (PAHs). This route is currently the easiest method to obtain such popular PAH compounds, which bear in addition numerous methoxy groups. The domino process was generalized, the structure of the obtained red products and the mechanism of their formations were elucidated, and some of their photophysical properties were determined. Newly synthesized polymethoxylated-PAHs were tested for their interaction with tubulin polymerization as well as for their cytotoxicity on a panel of NCI-60 human cancer cell lines. Interestingly, one of these rubicene derivatives exhibited remarkable cytotoxicity in vitro, including inhibition of leukemia, colon, melanoma, CNS, and ovarian cancer cell lines with GI50 values in the low nanomolar range (GI50 < 10 nM).

A new series of calix[4]arene supported N-heterocyclic carbene palladium complexes were developed and fully characterized. A mono-substituted calix[4]arene was prepared through conventional procedures, following with the attachment of imidazolyl derivative groups to compose the precursors of novel NHCs ligands. Undergoing the alkylation with n-butylbromide and corresponding metallation with palladium and pyridine, original complexes were obtained. After a full characterization in solution and solid state, the evaluation of catalytic activity was taken out in Suzuki–Miyaura cross-coupling reactions, which revealed good performances.

A new calix[4]dicyano-diimidazole ligand was prepared in two steps from a de-tert-butylated calix[4]arene. The corresponding Cu (I) complex was found to be remarkably stable. The X-ray structure of the latter revealed a mixture of both monomeric–mononuclear and dimeric–dinuclear complexes. Detailed investigations on this copper complex, involving NMR (VT and DOSY), Infra-red, and MS analyses, demonstrated that the dimeric–dinuclear complexe does not exist in solution. Despite the presence of two cyano binding groups on the calixarene platform, every attempts to isolate a stable Cu(II) complex failed.

The ipso-nitration of calix[6]arene-based molecular receptors is a important synthetic pathway for the elaboration of more sophisticated systems. This reaction has been studied for a variety of capped calixarenes, and a general trend for the regioselective nitration of three aromatic units out of six in moderate to high yield has been observed. This selectivity is, in part, attributed to the electronic connection between the protonated cap at the small rim and the reactive sites at the large rim. In addition, this work highlights the fact that subtle conformational properties can drastically influence the outcome of this reaction.

The synthesis of a series of six new per-substituted p-tert-butylcalix[9]arenes derivatives has been achieved. Functions such as ester, nitrile, or carbonate have been grafted on the phenolic oxygens of calix[9]arene: p-tert-butylcalix[9]arene nona-ethyl acetate, p-tert-butylcalix[9]arene nona-carboxylic acid, p-tert-butylcalix[9]arene nona-cyanopropyloxy, p-tert-butylcalix[9]arene nona-tert-butoxycarbonyle, p-tert-butylcalix[9]arene nona-acetyl, and p-tert-butylcalix[9]arene nona-trifluoroacetyl have been obtained in good yields (from 48% to 78%) and fully characterized. The X-ray structures of p-tert-butylcalix[9]arene nona-tert-butoxycarbonyl and p-tert-butylcalix[9]arene nona-ethyl acetate have been determined. A dynamic NMR study has revealed the high conformational mobility of such structures, even at low temperature.

The nuclear industry and the rare earth elements mining need methods in order to separate lanthanides and actinides. Large organic macrocycles have demonstrated their contribution to this domain. Due to the lack of an efficient and reproducible method of synthesis, the chemistry of large p-tert-butylcalix[n] arenes (with 6 < n < 10) has been much less explored than the one of their inferior homologs. Excepted for the p-tert-butylcalix[8]arene which is obtained in good yields, the procedures described in the literature for the preparation of p-tert-butylcalix[7] and [9]arenes involve many steps of purification and lead to, in the very best case, a couple of grams of product, after one month of labor. In this work, a set of experiments with varying parameters has demonstrateed the crucial role of the solvent and of the amount of catalyst in the macrocyclization reaction. Then, a scale-up study was done, the procedure being adapted and realized on a semi industrial scale reactor. Finally, an original purification pathway avoiding the numerous silica-gel chromatographies and recrystallizations was set up and optimized. This simplified procedure opens gateways for the preparation of a few dozen grams of pure p-tertbutylcalix[7] and [9]arenes and should lead to the preparation of new selective complexants.

The alkylation of (dichlorotantala)-p-tert-butylcalix[4]arenes 1 and 3 by two equivalents of NpMgCl (Np = neopentyl) affords the corresponding unreported (bisneopentyltantala)-p-tert-butylcalix[4]arenes 4 and S. These complexes can undergo dealkylation by modest increase of the temperature to yield 6 and 7. The characterization and structural conformation of the complexes 6 and 7 were determined by H-1, C-13, NOESY, and COSY spectroscopic studies and single-crystal X-ray diffraction. 7 exhibits unprecedented use of an intramolecular C H activation of an aromatic ring and simultaneously releases of one equivalent of neopentane. DFT calculation supports a mechanism in which the metal passes through a transition state involving a coplanar arrangement with its three ligands (C-Ar, H-Ar., C-Np).

Numerous studies, many based on statistical analyses of structural data from the Cambridge Structural Database (CSD, have highlighted the importance of halogen•••aryl interactions.Although the exact value of the binding energy is still a subject of debate, it is generally agreed that such interactions can play an important role in crystal packing.For example, previous work by Desiraju and collaborators has shown that Br•••aryl interactions generate characteristic supramolecular motifs, which may be useful for designing molecular solids [2].With this goal in mind, we set out to use 9,9'spirobifluorene (SBF) or tetrabrominated SBF derivatives as tectons [3] and to see if Br•••aryl interactions can be used to build predictable molecular networks.Several features made the SBF core an attractive candidate for this study: 1) SBF has D 2 d symmetry, is rigid and orients its aromatic rings and their substituents in distinct directions of space; 2) the synthesis of SBF derivatives has been described; and 3) derivatives of SBF tend to crystallize readily, frequently as inclusion complexes, which allows the study of interactions between the network and included guests.In the first part of our work, the two different tetrabromo-SBFs (substituted in the meta and para positions, respectively, relative to the spiro center) were synthesized either by a literature procedure or through a new route.Crystals were grown and the structures were solved.Both structures are close packed, and the molecules are linked together by Br•••Ar interactions and also by Br•••Br contacts.In the second part of our work, we co-crystallized un-substituted SBF with small brominated guests that orient 1, 2, 3 or 4 atoms of bromine in distinct directions.The structures of four co-crystals were solved, and analysis reveals the following points: 1) There are at most only a few direct interactions (CH•••) between the SBF units themselves; 2) by engaging in Br•••aryl interactions, the brominated guests play a role of connector between SBF units; iii) in this way, Br•••aryl interactions direct the packing of the crystal structures.

The design of multivalent glycoconjugates has been developed over the past decades to obtain high-affinity ligands for lectin receptors. While multivalency frequently increases the affinity of a ligand for its lectin through the so-called "glycoside cluster effect", the binding profiles towards different lectins have been much less investigated. We have designed a series of multivalent galactosylated glycoconjugates and studied their binding properties towards two lectins, from plant and bacterial origins, to determine their potential selectivity. The synthesis was achieved through copper(I)-catalysed azide-alkyne cycloaddition (CuAAC) under microwave activation between propargylated multivalent scaffolds and an azido-functionalised carbohydrate derivative. The interactions of two galactose-binding lectins from Pseudomonas aeruginosa (PA-IL) and Erythrina cristagalli (ECA) with the synthesized glycoclusters were studied by hemagglutination inhibition assays (HIA), surface plasmon resonance (SPR) and isothermal titration microcalorimetry (ITC). The results obtained illustrate the influence of the scaffold's geometry on the affinity towards the lectin and also on the relative potency in comparison with a monovalent galactoside reference probe.

An efficient and selective method for the monofunctionalization of p-tert-butylcalix[4]arene is described. A mono-de-O-functionalization of disubstituted p-tert-butylcalix[4]arenes using titanium tetrachloride was developed to synthesize a series of monosubstituted p-tert-butylcalix[4]arenes with the pendant functions being ethoxycarbonylmethyloxy, 3-ethoxycarbonylpropyloxy, cyanomethyloxy, 3-cyanopropyloxy, 4-bromobutyloxy, 3-hydroxypropyloxy, propyloxy, 2-methylpropyloxy, 3-butynyloxy, and 3-cyanopropyloxy groups. The reaction mechanism of the formation of 5,11,17,23-tetra-tert-butyl-26,27,28-trihydroxy-25-(3-ethoxycarbonylpropyloxy) calix[4]arene was studied by (1)H NMR and GC/mass spectroscopy monitoring. Reaction of TiCl4 with the disubstituted p-tert-butylcalix[4]arene produced the corresponding dioxocalix[4]arene titanium dichloride complex, which undergoes elimination of ethyl 4-chlorobutyrate, leading to a trioxocalix[4]arene titanium dichloride complex and to monosubstituted calix[4]arene after hydrolysis. These two complexes were also synthesized, isolated, and fully characterized.

Variously substituted titanacalixarenes were synthesised and tested for their performance as catalysts in ethylene polymerisation: p-tert-butylcalix[4]arene was derivatised to afford distal diether p-tert-butylcalix[4]arenes L1-L4, distal dihydroxy-depleted L5, proximal dihydroxy-depleted L6, proximal diether p-tert-butylcalix[4]arene L7, proximal intra-bridged disiloxane L8 and proximal monoether L9. (Dichlorotitana)-p-tert-butylcalix[4]arenes 1-8 and (monochlorotitana)-p-tertbutylcalix[4]arene 9 have been successfully synthesised by reacting L1-L4 with TiCl4 center dot 2THF or L5-L9 with TiCl4. The structural conformation of complexes 1-9 in solution were determined by H-1 NMR, C-13 NMR, NOESY and COSY spectroscopic studies. Compounds 2, 3 and 4 have been structurally characterised by single-crystal X-ray diffraction. Upon activation with methylaluminoxane, compounds 1-8 revealed low to moderate activities for the production of high-density polyethylene (HDPE) to ultra-high-molecular-weight polyethylene (UHMWPE). 6/MAO gave the best activity at 770 kg(PE) (mol Ti)(-1) h(-1).