New 4-substituted benzyl esters of 16-mereaptohexadecanoic acid were prepared by developing a practicable synthetic procedure and using readily available starting materials. The compounds synthesized have been characterized by NMR, MS, IR spectra and elemental analysis. The mercapto derivatives are precursors for the formation of self-assembled monolayers on metal substrates. (C) Central European Science Journals. All rights reserved.

In recent years, impressive progress has been made in the development of new chiral ligands and in new methodology for Zn-mediated enantioselective additions to aldehydes. The current report aims to present the recent progress in this field.

The structures of some 2-substituted indan-1,3-diones are investigated in the gas phase and solution using quantum chemical calculations and spectral (NMR, IR, and UV) measurements. The influence of the substituent at the 2-position on the tautomeric equilibrium of 2-substituted indan-1,3-diones in solvents with different polarity is evaluated. It is shown that the equilibrium in 2-formyl-indan-1,3-dione and 2-acetyl-indan-1,3dione is shifted to the 2-hydroxyalkylidene-indan-1,3-dione tautomer, while 2-carboxyamide-indan-1,3-dione exists as a mixture of two tautomers, 2-(hydroxyaminomethylidene)-indan-1,3-dione and 2-carboamide-lhydroxy-3-oxo-indan, with extremely fast proton transfer between them. The situation for 2-carboxy-indan1,3-dione is quite different -on the basis of the analysis of the obtained results, the possible existence of an anionic form of 2-carboxy-indan-1,3-dione in solution can be inferred.

Self-assembled monolayers (SAM) from para-substituted benzyl-16-mercaptohexadecanoates (R = -Cl; -OCH3; -NO2; -CN) were prepared using standard deposition procedures on silver substrates. The substituents were attached to the terminal benzyl group of the SAM precursor molecules in order to modify the properties of the outer film surface and to probe their influence on the organizational order of the monolayers. The SAMs were characterized by infrared spectroscopic ellipsometry and contact angle measurements. The carbonyl stretching as well as the methylene symmetric and antisymmetric stretching vibrations were employed to determine the tilt angle of the methylene chains. The water advancing contact angles implied that the wetting of the film's outermost surface is substantially different from that expected for more polar groups like NO2, CN and OCH3 and is much closer to that reported for aryl terminated SAMs. The flexible methylene linkage can facilitate the free rotation around C-Ph bond that leads to a specific orientation of the terminal phenyl rings in which they are closely exposed to the interface. An attempt was made to qualitatively characterize the phenyl ring orientations of the different SAMs using the IR spectroscopic ellipsometry data and IR absorption spectra of the same molecules. (C) 2007 Elsevier B.V. All rights reserved.

Monolayers from para-substituted benzyl esters of 16-mercaptohexadecanoic acid (R = -Cl; -OCH3) self-assembled on (111)-textured gold films have been studied in detail with infrared and visible spectroscopic ellipsometry and contact angles measurements. The experimental data testify that these monolayers on gold tend to adopt tilt angles smaller than typical for n-alkanethiols, while the orientation of the phenyl rings is almost perpendicular to the surface. The same precursor molecules self-assembled on silver showed arrangement of the aliphatic chains characteristic for long-chain alkanethiols but differently tilted orientation of the terminal phenyl rings. An attempt was made to explain that different behavior with the different surface energetics of gold and silver substrates.

The synthesis and the biological (antioxidant and antiviral) activities of novel hydroxycinnamic acid amides of a thiazole containing TFA.valine-4-carboxylic acid ethyl ester are reported. The amides have been synthesized from p-coumaric, ferulic and sinapic acids with the corresponding TFA.valine-thiazole-4-carboxylic acid ethyl ester using the coupling reagent N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-(dimethylamino) pyridine (DMAP) as a catalyst. The antioxidant properties of the newly synthesized amides have been studied for then antioxidative activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH)* test. The newly synthesized compounds have been tested against the replication in vitro of influenza virus A (H3N2) and human herpes virus 1 and 2 (HSV-1 and HSV-2).

In this work we describe a two-dimensional computer simulation of magnetic field enhanced plasma immersion implantation system. Negative bias voltage of 10.0 kV is applied to a cylindrical target located on the axis of a grounded vacuum chamber filled with uniform nitrogen plasma. A pair of external coils creates a static magnetic field with main vector component along the axial direction. Thus, a system of crossed ExB field is generated inside the vessel forcing plasma electrons to rotate in azimuthal direction. In addition, the axial variation of the magnetic field intensity produces magnetic mirror effect that enables axial particle confinement. It is found that high-density plasma regions are formed around the target due to intense background gas ionization by the trapped electrons. Effect of the magnetic field on the sheath dynamics and the implantation current density of the PIII system is investigated. By changing the magnetic field axial profile (varying coils separation) an enhancement of about 30% of the retained dose can be achieved. The results of the simulation show that the magnetic mirror configuration brings additional benefits to the PIII process, permitting more precise control of the implanted dose.

New acyclovir esters with peptidomimetics were synthesized and evaluated in vitro for their antiviral activity against the replication of Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). The influence of peptidomimetics containing oxazole and thiazolyl-thiazole moieties on the antiviral activity is also reported. The esters were synthesized using the coupling reagents N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N,N-dimethyl-4-aminopyridine (DMAP) as a catalyst.

A new set of aryl-substituted amides of 16-mercaptohexadecanoic acid (R = 4-OCH3; 3,5-di-OCH3) are synthesized using a simple and general procedure. Self-assembled monolayers of these molecules on Au(111) are studied by infrared and visible ellipsometry and contact angle measurements. Model calculations are employed to determine the molecular tilt angle. The SAM methylene chains exist in prevailing all-trans conformation and the tilt of the CCC plane is decreased by approximately 15 degrees in comparison with the correspondent value for n-alkanethiols. Strong hydrogen bonds between the amide proton and the carbonyl oxygen are detected with C=O and N-H dipoles oriented parallel to the gold surface. The wetting of the outermost film surface reveals predominantly OCH3 groups exposed.