Jean-Pierre Morizur

XPS analysis of humic and fulvic acids

The composition of humic and fulvic acids is examined using X-ray Photoelectron Spectroscopy (XPS). The XPS results are compared to that of elemental analyses. XPS permits an easy detection of the different chemical forms of carbon and sulfur that exist in these complex compounds.

Synthese totale et stereoselective du dimethyl-6,10 methylidene-9 undecene-5 (e) one-2: un des constituants de l'huile de Costus

Abstract The first total and stereoselective synthesis of (E)-6, 10 dimethyl-9 methylidene undec-5-en-2-one: a constituant of Costus Root oil is reported. It was conducted with an overall yield of 22% from 1-methyl-2-oxo-methylcyclopentane carboxylate (α-methylated Dieckmann-ester) 2 , used as a starting material.

Acetamidine-Mg+(2S) complexes; the performance of different exchange and correlation functionals

Abstract The structures, harmonic vibrational frequencies and bonding characteristics of the different isomers of acetamidine [NH2C(CH3)NH] and of the related complexes formed upon Mg+(2S) association have been investigated using the SVWN, BVWN, BP86, BLYP, B3LYP, B3P86 and B3PW91 density functional approaches at the 6-31G∗ level. The DFT optimized geometries are compared with those obtained at the MP2/6-31G∗ and the QCISD/6-31G∗ levels. All hybrid functionals yield rotational constants which differ by less than 0.3% from the ab initio ones, whereas the deviations for the SVWN, BP86 and BLYP functionals are ten times greater. The corresponding acetamidine-Mg+ binding energies were compared with those obtained at the G2(MP2) level. In general those functionals which include gradient corrections to both the exchange and the correlation parts give binding energies differing from the G2(MP2) values by less than 2.0 kcal/mol, provided that a 6-311 + G(3df, 2p) basis set is used. Our results also show that, as far as binding energies are concerned, all these functionals yield nearly equal results, without privileging the hybrid schemes over the non-hybrid ones. Overall, DFT approaches are a reasonably good alternative to high level ab initio calculations provided a flexible basis set (6-311+G(3df, 2p)) is used for the expansion.