Modular syntheses of multidentate ligands with variable N-donors: applications to tri- and tetracopper(I) complexes

A general method for the preparation of multidentate ligands comprised of a multi-imine platform derived from 1,1,1-tris(aminomethyl)ethane or tris(aminoethyl)amine connected to bi- and tridentate N-donor chelates has been developed. The feasibility of the method has been demonstrated through the synthesis and characterization of a large set of these ligand types. Complexation to Cu(I) was accomplished for several cases, yielding tri- and tetracopper(I) complexes that have been characterized in solution by NMR spectroscopy and conductivity, and in the solid state by elemental analysis, mass spectrometry, and/or X-ray crystallography. These complexes are potentially useful for modeling multicopper protein active sites.     

Determination of a series of quinolones in pig plasma using solid-phase extraction and liquid chromatography coupled with mass spectrometric detection Application to pharmacokinetic studies

A simple and sensitive liquid chromatography (LC) method was developed for the simultaneous determination of eight quinolones in pig plasma samples. The following two methods of detection were used: ultraviolet (UV) and mass spectrometry with electrospray ionization (ESI/MS). Sample preparation consisted of solid-phase extraction (SPE) on Strata X cartridges prior to the analysis by LC/UV or LC/ESI/MS. The recovery, linearity, limit of detection (LOD) and limit of quantification (LOQ), precision and accuracy of the method were evaluated using spiked pig plasma samples. The suitability of the method for pharmacokinetic studies was evaluated by determining the concentrations of enrofloxacin (ENR) and ciprofloxacin (CIP) also in pig plasma, after administration of 200mg of enrofloxacin per kilogram of fodder during 5 consecutive days.     

Fluorination-free synthesis of a 4,4-difluoro-3,3-dimethylproline derivative

A Claisen rearrangement/iodolactamization sequence starting from commercially available trifluoroacetaldehyde methyl hemiacetal, followed by a classical chemical resolution, provided enantiomerically pure 4,4-difluoro-3,3-dimethylproline (S)-1. No hazardous fluorination reagents were used, and the overall yield over 12 steps was greater than 28%.     

Mono- and digallane complexes of a tridentate amido-diamine ligand

Bis(2-dimethylaminoethyl)amido gallane, H2GaN(CH2CH2NMe2)2, that melts at 27 degrees C and remains stable upon heating at 55 degrees C for two days, was synthesized either from the reaction of the quinuclidine adduct of monochlorogallane with the lithium salt of the corresponding amine, or from the reaction of trimethylamine gallane and the amine; the latter affords an unusual co-product with both GaH2 and GaH3 bonded to the same amido nitrogen.     

The first three anisotropy constants of nickel

The technique of ferromagnetic resonance at 23 GHz has been used to determine the first three anisotropy constants of pure Ni down to 4.2K. A temperature and orientation dependent linewidth has also been observed.