Phenylhydrazine–borane adduct—characterized in the solid state and in solution

The 1:1 phenylhydrazine–borane adduct, obtained from phenylhydrazine and sodium borohydride in acidic solution, was investigated by IR, NMR spectroscopy, and MS spectrometry. Ab initio MO calculations indicated the isomer in which the boron center is attached to the primary amino group as the more stable. This forecast was confirmed by solution‐state ¹H, ¹¹B, ¹³C, and ¹⁵N NMR spectroscopy, in agreement with the molecular structure in the solid state determined by X‐ray analysis. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:366–372, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10049     

CFD modelling of a spray deposition process of paint

The paint deposition process by spraying has been studied by means of Computational Fluid Dynamics in order to predict the final thickness of the coating and to determine theoretically the overspraying phenomenon. The VOF model has been used to describe the impact phenomena onto the wall and the Euler-Lagrange approach to simulate droplet trajectories on their way to the surface. Particular attention has been devoted to the prediction of the maximum diameter reached by an impinging droplet at the end of the spreading phase. This diameter is very important in the study of the paint processes because the high viscosity and the small surface tension of paints reduce the impingement practically only to the spreading phase. Two different configurations of atomizers have been considered. The air flux provides a finer atomisation of the liquid, gives to the droplets the necessary velocity to reach the wall, but is also the main cause of overspray since the small droplets tend to follow its deviation near the wall.     

Efficient DNA Extraction and Amplification of Samples from the Archeological Site of Pompei (Italy)

Due to their growth and metabolism, microorganisms can cause severe damage to Cultural Heritage, through mechanical and chemical processes. In this paper we used molecular approaches to study bacterial communities on samples from the archeological site of Pompei (Italy). In particular four DNA extraction methods without prior cultivation of the microflora were compared. In terms of efficiency, the DNA extraction method based on the Tri-Reagent™ kit gave the best results. All extraction protocols coupled with 16S rDNA fragments PCR amplification were satisfactory; but the best results were obtained by Klentaq DNA LA Polymerase™; this enzyme can be considered an effective tool for amplification of DNA from Cultural Heritage and possibly other environmental samples.     

Alternating Diene Metathesis Polycondensation (ALTMET) – A Versatile Tool for the Preparation of Perfectly Alternating AB Copolymers

Perfectly alternating copolymers can be synthesised by reacting diacrylates with terminal dienes using alternating diene metathesis polycondensation (ALTMET). This novel method is very versatile and allows preparation of diverse structures of polymers, including main‐chain liquid crystalline polymers.

Main‐chain liquid crystalline polymer obtained by ALTMET.     

Synthesis and crystal structures of the triphenylstannyl esters of N-phthaloyl-glycine and -leucine

Triphenyltin N-phthaloylglycinate crystallizes from ethanol as a bridged, cyclic hexamer (rhombohedral R3 space group, a = 19.928(3) Å, α = 116.47(2)⁰; Z = 6) and triphenyltin N-phthaloylleucinate as a monomeric molecule (orthorhombic Pbca space group, a = 18.032(6), b = 26.992(7), c = 11.705(4) Å; Z = 8).     

Polymerizable Ester-Type Banana Liquid Crystals: A Comparative Study of Mesophase Behavior

Two families of ester-type banana monomers are presented, 1,3-phenylene bis{4-[4′-(10-undecenyloxy)benzoyloxy]benzoate}s and 1,3-phenylene bis{[4′-(10-undecenyloxy)]-1,1′-biphenyl-4-carboxylate}s, in which the nature of the substituents on the central phenyl ring and the side arms was varied. The mesophase behavior of the monomers, including B₂ and B₇ phases, was correlated with their chemical structure and was compared with that of analogous azomethine-type banana mesogens. It is also shown that the banana monomers can be incorporated into new architectures of liquid crystal polymers.     

New Architecture of Liquid‐Crystalline Polymers from Fluorinated Vinylcyclopropanes

A new class of fluorinated polymers was prepared by radical ring‐opening homopolymerization of vinylcyclopropane monomers with a perfluorinated (CF₂)_nF chain (n = 6, 8, or 10). The polymers were in fact copolymers composed of 1,5‐linear and cyclobutane isomer units, the relative content of which depended on n. Surprisingly, they formed liquid‐crystalline mesophases (SmB_d and/or SmA_d), which was attributed to phase separation of the incompatible fluorocarbon and hydrocarbon components of the repeat unit.     

Thick Coating and Functionalization of Organic Surfaces via ATRP in Water

Atom‐transfer radical polymerization has been used for polymerizing water‐soluble monomers from solid polymeric particles, intended as a model for any polymeric functional surface. Depending on the polarity of substrate and solvent, homogeneous initiation throughout the particles or pure surface initiation could be obtained. In the last case, polymer layers were obtained with thicknesses up to several tens of microns, still active for block copolymerization.