Nanoporous gold thin films synthesised via de-alloying of Au-based nanoglass for highly active SERS substrates

Nanoporous gold thin films have been fabricated through chemical de-alloying of Au-based nanoglass with a nanocolumnar structure, with composition Au₄₀Cu₂₈Ag₇Pd₅Si₂₀ (at.%), that had previously been deposited by magnetron sputtering. By varying the de-alloying conditions, gold ligaments ranging from 20 to 100?nm were obtained. The microstructure and chemical composition of the as-prepared films were characterised by various techniques. Surface-enhanced Raman scattering (SERS) of thin films was investigated using rhodamine 6G. The results indicate that the main microstructural features with interconnected ligaments and defects of nanoporous gold result in significant SERS enhancement.     

ROMPgel-supported tris(triphenylphosphine)rhodium(I) chloride: a selective hydrogenation catalyst for parallel synthesis

ROMPgel-supported tris(triphenylphosphine)rhodium(I) chloride has been prepared and the immobilised catalyst has been effectively employed in selective hydrogenations of a variety of alkenes and terminal alkynes.     

Synthesis and antitumor evaluation of novel derivatives of 6-amino-2-phenylbenzothiazoles

Novel derivatives of 6-amino-2-phenylbenzothiazole bearing different substituents (amino, dimethylamino or fluoro) on the phenyl ring were prepared as the corresponding hydrochloride salts. 6-Nitro-2-(substituted-phenyl)benzothiazoles (1-6) were synthesized by condensation reactions of substituted benzaldehydes with 2-amino-5-nitrothiophenol. Nitro derivatives were reduced to the amino derivatives with SnCl(2)/HCl.Water soluble hydrochloride salts of 6-amino-2-(substituted-phenyl)benzothiazole (13-19)were prepared using concentrated or gaseous HCl. Compounds 13-19 were found to exert cytostatic activities against malignant human cell lines: cervical (HeLa), breast (MCF-7),colon (CaCo-2), laryngeal carcinoma (Hep-2), and normal human fibroblast cell lines (WI-38).     

Synthesis and Antiproliferative Activity of Cyano and Amidino Substituted 2-Phenylbenzothiazoles

Series of cyano, dicyano, amidino, and diamidino substituted 2-phenylbenzothiazoles were prepared. Mono- and dicyano substituted benzothiazoles were obtained by condensation of appropriate substituted benzaldehydes with 2-aminothiophenol or 4-amino-3-mercaptobenzonitrile. The appropriate amidines or diamidines were prepared by Pinner reaction. The compounds were tested against breast, prostate, and lung cancer cell lines in a 72 h cytotoxicity assay. Many of the compounds had at 10 μM activity equivalent to 2-(4-aminophenyl)benzothiazole, while four compounds had significantly better activity, particularly in the breast cancer model.     

Synthesis of new amidino-substituted 2-aminothiophenoles: mild basic ring opening of benzothiazole

The efficient synthesis of new amidino, N-isopropylamidino, 2-imidazolinyl substituted benzothiazoles and 2-aminothiophenoles by the Pinner reaction is described. The novel ring opening of benzothiazole with ammonia and ethylenediamine was found, and a plausible reaction mechanism proposed. The ring opening with ethylenediamine is selective and applicable to compounds bearing hydrolytically and amonolytically unstable substituents. Different amidino-substituted 2-aminothiophenoles were isolated in zwitterionic and disulfide form and their structures were determined by X-ray crystal structure analysis.     

Highly accurate determinations of CO(2) line strengths using intensity-stabilized diode laser absorption spectrometry

An intensity-stabilized laser absorption spectrometer, which incorporates a mirror-extended cavity diode laser, a temperature-stabilized gas cell, and a Michelson interferometer, was developed and applied to a highly accurate investigation of line intensity factors within the nu(1)+2nu(2) (0)+nu(3) combination band of carbon dioxide, around 2 microm wavelength, at a temperature of 296.0 K. This relatively complex apparatus enables one to observe the absorption line shape with high precision and accuracy in such a way that it is possible to retrieve the integrated absorbance with a relative uncertainty better than 0.1%. The absorption spectra were interpolated with the uncorrelated strong-collision model of Rautian and Sobel'man in order to take into account Dicke narrowing effects, thus obtaining an agreement at a level of a few parts per 10(-5). We report line strength values for the R(2)-R(18) transitions with an unprecedented level of accuracy, in the range between 0.1% and 0.15%. Finally, we discuss the possibility of providing a first experimental test of the theoretical model for molecular line strengths based on the Herman-Wallis expansion.     

Identification of the IR frequencies of the interstitial carbon atom in some M6C (M = Fe,Ru) carbonyl clusters by13 C-enrichment

¹³C-enriched carbido carbonyl clusters of the type [M₆C(CO) _n ] ^z? (M=Fe,n=16,z=2; M=Ru,n=16 ifz=2 andn=17 ifz=0) have been prepared and their IR spectra observed in the 900?600 cm^?1 region; the band shifts occurring upon¹³ C substitution enable the assignment to the stretching modes of the interstitial C atom. Band patterns reflect the symmetry of the M₆C core, but the frequencies seem dependent on other molecular features.     

Measuring the 13C/12C isotope ratio in atmospheric CO2 by means of laser absorption spectrometry: a new perspective based on a 2.05-microm diode laser

The potential use of high sensitivity laser absorption spectroscopy for measuring the 13C/12C isotope ratio in atmospheric CO2 has been demonstrated, using a GaSb-based diode laser at 2.05 microm. In this spectral region, the overlapping between relatively strong 12CO2 and 13CO2 absorption features gives rise to several line pairs which are well suitable for a spectroscopic determination of the isotope ratio. Preliminary results have demonstrated that a short-term precision better than 1 per thousand can be easily obtained, for a CO2 concentration of 1000 ppm. We extensively discuss the influence of a possible non-linearity in the detectors' response on the delta-value and suggest an instrumental development that would allow to eliminate this effect.     

On the euler equation: Bi-Hamiltonian structure and integrals in involution

We propose a bi-Hamiltonian formulation of the Euler equation for the free n-dimensional rigid body moving about a fixed point. This formulation lives on the physical phase space so(n), and is different from the bi-Hamiltonian formulation on the extended phase space sl(n), considered previously in the literature. Using the bi-Hamiltonian structure on so(n), we construct new recursion schemes for the Mishchenko and Manakov integrals of motion.