Jean-Louis Pascal

Electrochemical Reactivity of Cu3 P with Lithium

Copper phosphide, Cu 3 P, has been synthesized using a solvothermal route. The electrochemical reaction of this binary phosphide with lithium has been studied to describe the insertion/extraction mechanism. The discharge of the half-cell Cu 3 P/Li up to 0.1 V proceeds by lithium insertion into a Cu 3 P hexagonal structure and then by two successive biphasing processes involving the formation of LiCu 2 P and Li 2 CuP, respectively. Simultaneously, copper metal is extruded from the matrix. During the charge the reversible processes are observed. After 15 cycles a 400 mAh g -1 specific capacity is retained.

Synthesis and structural characterization of some anhydrous Ln(OTf)3 complexes (Ln = Sc, La, Nd, Sm, Gd and Er; OTf = CF3SO3)

Abstract Reacting dilute HOTf (OTf = O3SCF3) (10−3-10−2 M) with oxides or chlorides of ScIII, LaIII, NdIII, SmIII, GdIII and ErIII, followed by thermal dehydration in vacuo, yielded anhydrous trifluoromethanesulphonato (triflato) complexes. X-ray powder diffraction showed that, except for Sc(OTf)3, these complexes are isomorphous. IR and Raman spectroscopies indicate that OTf is a tridentate ligand in M(OTf)3 (M = La, Nd, Sm, Gd and Er) and that the central atom is nine-coordinate, while in Sc(OTf)3 OTf is bidentate and Sc is in an octahedral environment. Strong fluorescence phenomena were observed, particularly with Nd, Sm and Nr complexes.

Synthesis, vibrational spectroscopy and EXAFS analysis of some divalent and trivalent trifluoromethanesulphonato complexes

Abstract The syntheses of trifluoromethanesulphonato (OTf) complexes of Co II , Ni II , Cu II , Fe III and Ga III by the reaction of simple metal salts (Cl − , Br − , CO 3 2− , ClO 4 − or metallic gallium with trifluoromethanesulphonic acid have been systematically investigated. Comparison of the vibrational spectra of coordinated OTf in these complexes with that in simple ionic salts indicates the ligand to be bridging bidentate in M(OTf) 3 , M = Ga, Fe and in M(OTf) 2 , M = Cu and bridging tridentate in M′(OTf) 2 , M′= Co, Ni, Cd. EXAFS spectroscopic data can be interpreted in terms of layered structural arrangements for Co, Ni, Cd and Ga trifluoromethanesulphonato complexes, similar to that of the corresponding anhydrous metal perchlorates studied previously. In Cu(OTf) 2 , however, the copper atom is in a square planar environment. The short metal-oxygen distances, 1.96–2.09 A are consistent with strong interactions between the ligand and metallic centre.

Inorganic perchlorato complexes

Abstract A summary is given of the synthesis of non-solvated inorganic perchlorato complexes and their structural characterization. The synthesis of perchlorato complexes has been extended to many elements of the periodic table by the use of efficient perchlorating reagents such as perchloric acid, HClO 4 –Cl 2 O 7 oleums and chlorine trioxide, Cl 2 O 6 . X-ray diffraction, EXAFS and vibrational spectroscopy show that the perchlorato ligand, [ClO 4 ], can be strongly bonded to metals in various bonding arrangements: monodentate, bridging or chelating bidentate, simply bridging or simultaneously bridging and chelating tridentate. It is mostly an assembling ligand.

Anode materials for lithium ion batteries in the Li-Zn-P system

This paper presents an exhaustive study of the Li-Zn-P system through the synthesis and electrochemical characterisation of several binary and ternary phases: Li9ZnP4, LiZnP, Zn3P2 (α and β), ZnP2 (α and β), LiZn, and LiZn4. Three synthetic routes have been used to prepare these materials: ceramic synthesis and ball milling without and with annealing. Li-Zn-P system phases have been evaluated through X-ray diffraction and electrochemical reactivity towards lithium. Exhibiting high specific capacities at potentials close to 0.7 V vs. Li+/Li, some of these materials are promising as negative electrode materials for lithium ion battery.

A la recherche de Ti(CF3SO3)4. 1. Synthèse et analyse structurale de composés issus des réactions de CF3SO3H avec TiCl4, Ti(NO3)4 et Ti(ClO4)4, de NO2CF3SO3 avec TiCl4 et de (CF3SO2)2O avec Ti(OC2H5)4

Resume By reacting HOTf (OTfCF3SO3) with TiCl4, Ti(NO3)4, and Ti(ClO4)4; NO2OTf with TiCl4; and (CF3SO2)2O with Ti(OEt)4, the following molecules can be prepared: TiCl3OTf, TiCl2(OTf)2, TiCl0.75(OTf)3.25, [(NO2)2Ti(OTf)6] and Ti(OEt)2(OTf)2. Thermal degradation of some of these products leads to oxo complexes such as [(NO2)(NO)][TiO(OTf)4], [NO]0.75[TiO0.625(OTf)3.5] and TiOx(OTf)y. The IR and Raman spectra for TiClx(OTf)y complexes are consistent with previous results. In TiCl3OTf, the OTf group is tridentate whilst it is bidentate and bridging in the two other chloro complexes. TiOx(OTf)y and Ti(OEt)2(OTf)2 are polymeric molecules with monodentate and (or) bridging bidentate OTf groups and TiOTi bridges in the oxo complexes. In the nitryl or (and) nitrosyl salts, OTf is monodentate. [Ti(OTf)62ti−] is monomeric while the other anions are polymeric with TiOTi bridges.