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Two novel mononuclear zinc(II) and copper(II) complexes of tetradentate N 2 O 2 Schiff base ligands generated in situ by the template method were synthesized by the reaction of salicylicaldehyde and o -vanillin, respectively, with 1,3-bis(3-aminopropyl)tetramethyldisiloxane and the corresponding metal salts, in the presence of pyridine. The structures of the metal complexes were determined by elemental and spectral (IR, UV–Vis, ESI-MS) analyses as well as by single crystal X-ray diffraction, revealing a tetrahedral coordination geometry around the copper and zinc atoms ensured by the N 2 O 2 donors of the Schiff bases. The crystalline structures are stabilized by intermolecular π–π stacking and short C–H⋯π interactions, which generate supramolecular polymeric chains. The absorption and emission properties of the complexes were studied in solution. The antimicrobial activity was assayed in vitro against three fungi and two bacteria species. Both complexes are moisture stable, as was proved by vapor sorption (DVS) analysis. The catalytic activity of the complexes was evaluated in the decomposition reaction of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Bis[ N-(4-carboxyphenyl)phtalimidyl]dimethylsilane prepared by the reaction between bis(3,4-dicarboxyphenyl)dimethylsilane anhydride and p-aminobenzoic acid has been used to built three novel hydrogen-bonded supramolecular polymers as a result of cocrystallization with pyridine derivatives: 4,4′-bipyridyl ( SP1), 1,2-bis(4-pyridyl)ethylene ( SP2), and 4,4′-azopyridine ( SP3). The structures of the dianhydride, diacid, and derived supramolecular polymers were investigated by Fourier transform infrared (FTIR) and proton magnetic resonance (1H NMR) spectroscopy. Self-assembling was proved by the presence of the IR absorption bands around 1900 and 2400 cm−1 specific for hydrogen bond. The association constant values were estimated by using FTIR spectroscopy in solid state. According to X-ray diffraction study, the bis(3,4-dicarboxyphenyl)dimethylsilane anhydride ( 1) has an isolated molecular structure. Bis[ N-(4-carboxyphenyl)phtalimidyl]dimethylsilane ( 2) molecules are associated in the crystal structure via dimeric OH ...O hydrogen bonds resulting in the wavy 1D supramolecular chain. The main packing motif for SP1 and SP3 is represented by wavy chain formed by alternating sequences of 4,4′-bipyridyl or 4,4′-azopyridine and bis[ N(4-carboxyphenyl)phtalimidyl]dimethylsilane molecules linked by OH ...N hydrogen bonds. Thermal behavior was studied by differential scanning calorimetry and thermogravimetric analysis. The ability for the structuration in film was emphasized by atomic force microscopy. The molecular transport ability of the reversible associations was estimated by dynamic water vapor sorption (DVS) analysis. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 [ABSTRACT FROM AUTHOR]

Pairs of different substituted 3-mercapto-1,2,4-triazole units are coupled, through thioether bridges, to organic-inorganic substrates consisting in short hydrophobic silicone segment. A library of six compounds are isolated as crystalline solids and structurally characterized by X-ray single crystal diffraction, elemental, spectral and thermal analysis. The flexibility of the silicone spacer makes the small molecular compounds exhibit glass transition in the negative domain. The metal binding capacity is evaluated by quantum mechanics calculations, the results being in line with experimental data obtained by UV–vis spectroscopy titration. The results indicate that the prepared compounds can act as ligands for metal ions with high selectivity for Cu2+, an element of interest in biological processes, forming 1:1 stable mononuclear complexes with an association constant up to 8.87 × 103 M−1. The presence of the highly hydrophobic silicone spacer makes the behavior of bis-triazoles obtained more sensitive to the nature of the environment. The preliminary bioassay indicates lipophilic medium more suitable for biocide action of silicone-bridged bis-triazoles, which in some cases far exceeds that of reference. The mechanism of enzyme inhibition is demonstrated by molecular docking, and the results indicate that, in all docked complexes, the ligands are directly coordinated to the heme ferric iron. Unlabelled Image • A library of silicone spaced bis-triazoles is obtained and structurally characterized. • The silicone motif is inserted as organic-inorganic interface between triazole rings. • Compounds are biologically active agents in lipophilic medium. • An inhibitory activity 55 times greater than the drugs taken as reference is found. • Bis-triazoles act as chemosensors for Cu(II) with which easily form 1:1 stable complexes. [ABSTRACT FROM AUTHOR]