Versatile coordinating behaviour of bis(acylhydrazone) ligands derived from imino- and methyl-iminodiacetic acid diethyl ester. Antimicrobial properties of their trinuclear copper(II) complexes

The coordinating properties of a new bis(pyridylhydrazone) ligand derived from iminodiacetic acid diethyl ester and 2-pyridinecarboxaldehyde (picolinaldehyde) H₃Imdp and of the bis(salicylhydrazone) H₅Imds and H₄MeImds ligands derived, respectively, from iminodiacetic acid diethyl ester and from methyl-iminodiacetic acid diethyl ester and salicylaldehyde were considered, by means of analytical and spectroscopic methods, towards first row transition metal ions. These ligands showed various coordination modes in complexation with Cu(II), Co(II), Mn(II) and Zn(II) ions. In particular, we have synthesized and characterized, by analytical, ¹H NMR and IR techniques, tri-, di- and mononuclear metal complexes of formula Co₃(HImdp)(NO₃)₄·2H₂O, Cu₃(HImdp)(NO₃)₄·C₂H₅OH·H₂O, Cu₃(HImdp)Cl_4, Zn₂(H₃Imdp)(ClO₄)₄·2H₂O, Co₃(HImds)Cl₂·CH₃OH·H₂O, Zn₂(H₃Imds)Cl₂·2H₂O, Co(H₄Imds)NO₃·2H₂O, Mn(H₄Imds)Cl·CH₃OH·H₂O, Cu(H₃Imds)·CH₃OH·H₂O and Cu(H₂MeImds)^.CH₃OH·3H₂O. Antibacterial, antifungal and antiprotozoal properties of H₅Imds and H₃Imdp together with three copper(II) trinuclear species of H₅Imds of formula Cu₃(HImds)(NO₃)₂^.2CH₃OH·2H₂O, Cu₃(HImds)(ClO₄)₂^.EtOH·2H₂O and Cu₃(HImds)SO₄·4H₂O are also discussed. The H₅Imds ligand and their trinuclear copper(II) complexes showed good activities versus Trichomonas vaginalis, Staphylococcus epidermidis and Acanthamoeba castellanii.     

Waterborne polyurethane-acrylic hybrid nanoparticles by miniemulsion polymerization: applications in pressure-sensitive adhesives

Waterborne polyurethane-acrylic hybrid nanoparticles for application as pressure-sensitive adhesives (PSAs) were prepared by one-step miniemulsion polymerization. The addition of polyurethane to a standard waterborne acrylic formulation results in a large increase in the cohesive strength and hence a much higher shear holding time (greater than seven weeks at room temperature), which is a very desirable characteristic for PSAs. However, with the increase in cohesion, there is a decrease in the relative viscous component, and hence there is a decrease in the tack energy. The presence of a small concentration of methyl methacrylate (MMA) in the acrylic copolymer led to phase separation within the particles and created a hemispherical morphology. The tack energy was particularly low in the hybrid containing MMA because of the effects of lower energy dissipation and greater cross-linking. These results highlight the great sensitivity of the viscoelastic and adhesive properties to the details of the polymer network architecture and hence to the precise composition and synthesis conditions.     

Classification of semisimple Levi-Tanaka algebras

After showing that the partial complex structure is defined by an inner derivation, we give a complete classification of semisimple Levi-Tanaka algebra.     

On conciseness of some commutator words

Archiv der Mathematik - We prove that a commutator of two non-commutator words is a concise word.     

Guidelines for measuring solar radius with Baily beads analysis

By inspection of central eclipses videorecords, data of Baily beads timings are retrievable. Knowing the lunar limb profile at the moment of the eclipse we evaluate the excess or defect of solar limb when the Sun is assumed at its standard radius. Two procedures of data analysis are here presented: one based on limb heights and the other on times. While these methods are based upon Occult 4 software, they can be used with other ephemerides and new lunar profiles. The example of 2006 total eclipse data, with its remarkably negative value of ΔR= − 0.41“± 0.04”, is presented.