We present the synthesis and oxoanion-assembling properties of a monomer with a naphthalene ring as a central core decorated with two arms containing iodotriazolium rings as anion binding sites. Interactions with SO, HPO, and HPO anions, via a cooperative mechanism, afforded new supramolecular materials stabilized by a combination of halogen- and hydrogen-bonding interactions. H NMR experiments and solid-state structure provided evidence for the initial formation of a supramolecular linear chain, nucleation step, and then two different supramolecular chains are interpenetrated with each other, elongation steps, involving the formation of hydrogen bonds between two oxygens of the anion from one of the chains and the naphthalene inner protons from the other chain. Scanning electron microscopy studies revealed that the morphology of the crystals changed dramatically with the nature of the anion added.
Microcapsules with a silicone liquid core surrounded by a polymeric shell were synthesised through the controlled phase separation. The dispersed silicone phase consisted of the shell polymer PMMA, a good solvent for the PMMA (dichloromethane, DCM) and a poor solvent (methylhydrosiloxane dimethylsiloxane) for the PMMA. The morphology of the PMMA microcapsules was investigated by ATR‐FTIR and by optical microscopy. Microcapsules were prepared with different emulsifiers and different concentrations of acetone and PMMA in the oil phase. The thermal stability of the PMMA microcapsule and the content of the silicone oil core were assessed by TGA. 1H‐NMR spectroscopy and an extraction method were also used to determine the content of the silicone liquid core in the microcapsules.
Several bis(triazolium)‐based receptors have been synthesized as chemosensors for anion recognition. The central naphthalene core features two aryltriazolium side‐arms. NMR experiments revealed differences between the binding modes of the two triazolium rings: one triazolium ring acts as a hydrogen‐bond donor, the other as an anion–π receptor. Receptors 92+⋅2BF4− (C6H5), 112+⋅2BF4− (4‐NO2C6H4), and 132+⋅2BF4− (ferrocenyl) bind HP2O73− anions in a mixed‐binding mode that features a combination of hydrogen‐bonding and anion–π interactions and results in strong binding. On the other hand, receptor 102+⋅2 BF4− (4‐CH3OC6H4) only displays combined Csp2H/anion–π interactions between the two arms of the receptors and the bound anion rather than triazolium (CH)+⋅⋅⋅anion hydrogen bonding. All receptors undergo a downfield shift of the triazolium protons, as well as the inner naphthalene protons, in the presence of H2PO4− anions. That suggests that only hydrogen‐bonding interactions exist between the binding site and the bound anion, and involve a combination of cationic (triazolium) and neutral (naphthalene) CH donor interactions. Theoretical calculations relate the electronic structure of the substituent on the aromatic group with the interaction energies and provide a minimum‐energy conformation for all the complexes that explains their measured properties.
The synthesis and characterization of novel ionic networks linked by the ammonium salts of poly(propylene imine) (PPI) dendrimers of the first (PPI G1) and second (PPI G2) generation and two short bis carboxymethyl ether terminated poly(ethylene glycol)s (DiCOOH-PEG) with different molecular weights (M n $ 250 and M n $ 600) are reported. Likewise, an ionic network based on PPI G1 and a long ao-dicarboxylic acid functionalized PEG (M n $ 4800) were evaluated. Simpler ionic structures based on tris(2-aminoethyl)amine or hexamethylene diamine and the short DiCOOH-PEGs are also investigated. The ionic structures formed were confirmed by differential scanning calorimetry, Fourier Transform Infrared spectroscopy in the attenuated-totalreflection mode, and 1 H-13 C NMR spectroscopy. A comprehensive 1 H NMR analysis revealed that only the primary amines of the PPI G1 dendrimer residing at the periphery take part in the ionic network formation. In the case of PPI G2, the picture is less clear. A thorough investigation of the thermal degradation of the utilized precursors and all the ionic materials prepared was additionally performed by thermogravimetric analysis.
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