Copper-based hierarchical micro/nanostructures were prepared using a novel electrochemical route on polypyrrole−polystyrene sulfonate (PPy−PSS) thin films. The resulting structures are composed of copper hydroxysulfates, as confirmed by the electrochemical, spectroscopic, and X-ray diffraction characterization. The electrochemistry of the film is a key factor in the overall deposition of the micro/nanostructures. The PPy−PSS films capture cations from the copper sulfate electrolyte solution and facilitate the reduction of dissolved oxygen to hydroxide ions. The system then acts like a nanoreactor as the Cu2+ and OH− ions are concentrated on the polymer surface, which in the presence of the SO4 2− ions from the electrolyte solution results in the electrocrystallization of the copper hydroxysulfates hierarchical structures.

Metallic copper nanoparticles (CuNP) are formed from the reduction of hierarchical copper-based micro/nanostructures previously electrodeposited on polypyrrole-polystyrene sulfonate (PPy-PSS) thin films. The application of a high reduction potential causes the erosion of the micro/nanostructures nanosheets and the formation of CuNP. The CuNP are used in a series of preliminary tests in order to assess their performance in the sensing of nitrate. The sensing performance is improved with the introduction of polyethyleneimine-functionalized multiwall carbon nanotubes (MWNT-PEI) to the PPy-PSS films. Electrochemical impedance spectroscopy studies show that the nanotubes increased the electronic conductivity of the reduced films. The limit of detection of the PPy-PSS-MWNT-PEI-CuNP nanocomposite is 30 mM nitrate. The materials need further development and optimization work in order to be applied as sensors.

First example of glycosyl squaramides that induce the efficient gelation of high polarity solvents and hydroethanolic mixtures.

A series of phenanthroline-oxazine ligands were formed by a cyclisation reaction between L-tyrosine amino acid esters and 1,10-phenanthroline-5,6-dione (phendione). The methyl derivative of the phenanthroline-oxazine ligand 1 was complexed with Ag(I), Mn(II) and Cu(II) to form [Ag(1) 2 ]ClO 4 , [Mn(1) 3 ](ClO 4 ) 2 and [Cu(1) 3 ](ClO 4 ) 2 . The activity of these metal complexes was tested against the bacteria Escherichia coli and Staphylococcus aureus. Each of the metal complexes was more active than 1 against S. aureus and the Mn(II) and Cu(II) complexes also showed greater activity than 1 towards E. coli. The effect of increasing the length of the alkyl moiety on the phenanthroline-oxazine ligands and their corresponding tris homoleptic Cu(II) complexes was investigated. In all cases both the ligands and their complexes were more active against Gram-positive S. aureus than against Gram-negative E. coli. Differences in the lipophilicity of the ligands and their corresponding Cu(II) complexes did alter the antibacterial activity, with the hexyl and octyl derivatives and their complexes showing the greatest activity and comparing well with clinically used antibiotics. The most active Cu(II) complexes and their respective ligands were also active against Methicillin-resistant S. aureus (MRSA). In vivo toxicity studies, conducted using the Galleria mellonella model, showed that all of the compounds were well tolerated by the insect larvae.

The surface electrochemistry of polypyrroleÀ polystyrene sulfonate (PPyÀPSS) thin films is exploited for the fabrication of novel hybrid copper-based microstructures. The electrochemical deposition of the copper-based materials at the PPyÀPSS film is strongly dependent on the electrode potential. This dependence is studied at three different potentials: 0.10, 0.00, and À0.10 V vs SCE. Hierarchical micro/nanostructures made of copper hydroxysulfate salts are only formed at 0.10 V vs SCE and are replaced with branched and single microcrystals of Cu 2 O covered by a thin layer of Cu(OH) 2 at 0.00 and À0.10 V vs SCE, respectively. The different structures can be coupled on the same film through a simple fabrication procedure to give hybrid microstructures. These novel hybrids consist of a central microcrystal (deposited at À0.10 V vs SCE) and a surrounding contour of welded nanosheets (deposited at 0.10 V vs SCE). The mechanism of nucleation and growth of the hierarchical micro/ nanostructures formed at 0.10 V vs SCE is also reported. These structures are made from the assembly of nanoparticles into nanowires, nanosheets, and microclusters. These microclusters have a flowerlike shape within which each nanosheet forms a petal of the flower. The nucleation of the clusters is shown to be progressive.