Crystallographic report: Crystal and molecular structure of tetramethylammoniumdiisothiocyanatotriphenyltin(IV), [NMe4SnPh3(NCS)2]

The structure of NMe₄SnPh₃(NCS)₂ is molecular, without any significant intermolecular contacts in the lattice. The trigonal plane around the tin atom is defined by three carbon atoms from the phenyl groups and the axial positions occupied by the NCS groups. Copyright © 2003 John Wiley & Sons, Ltd.     

Electrochemical synthesis and characterization of thiophene conducting polymer in aqueous micellar medium

In opposite with the usually applied synthesis in organic media, the polymerization of bithiophene in aqueous media has been studied. The use of a non-ionic surfactant (polyoxyethylene octyl phenyl ether (Triton X-100)) is useful not only to solubilize the hydrophobic monomer but it is also important to incorporate various—biologically and catalytically active—additives. In this paper, the optimization of the polymerization conditions as well as the characterization of the electrochemical, spectral and mass exchange behavior of these composite films is summarized. The layers have shown imperceptible electroactivity in monomer-free aqueous LiClO₄ solutions, and electrochemical quartz crystal microbalance (EQCM) studies exhibited scarce ion movements, caused assumingly by the fact that the dopant species—moving together with their hydrate shell in the aqueous media—could not penetrate into the hydrophobic film. In contrast, nice reversible redox transformation could be obtained in organic medium such as acetonitrile, where—according to the EQCM results—the charge carrier formation/depletion is accompanied by the incorporation/removal of ClO₄ ^? anions. In this solution, the spectral changes have proved the transformation into the conducting state, connected to both mono- and di-cation forms. The incorporation of the surfactant has been demonstrated by the extraordinary surface morphology of the polybithiophene (pBT) films, characterized by scanning electron microscopy. The elementary composition of the curious shell-shaped objects, monitored by energy dispersive X-ray spectroscopy (EDX), evidenced the presence of Triton X-100 by the increased C/S ratio compared to neat polybithiophene, while the Cl/S data reflected the changes connected to the doping level as a consequence of ClO₄ ^? anion movements. Moreover, ex situ attenuated total reflectance (ATR) FT–IR measurements clearly showed the existence of C―O bonds, also proving the successful functionalization by the surfactant, built permanently into the redox active films.     

Decomposition thermique et etude vibrationnelle de NiNa4(P3O9)2·6H2O

We have studied the dehydration and the calcination under atmospheric pressure of cyclotriphosphate tetrahydrate of nickel and sodium, NiNa₄(P₃O₉)₂·6H₂O, between 25 and 700°C by thermal analyses (TG, DTA) infrared spectrometry and X-ray diffraction. This study allows us the identification and the crystallographic characterization of a new phase, NiNa₄(PO₃)6, obtained between 350 and 450°C. NiNa₄(PO₃)₆ crystallizes in the triclinic system, P_–1, with the following unit cell parameters a=6.157(3) Å, b=6.820(6) Å, c=10.918(6) Å, =80.21(5)°, =97.80(9)°, =113.49(3)°, V=409.8 ų, Z=1, M(19)=25 and F(19)=48 (0.0095; 42). The calcination of NiNa₄(PO₃)₆, between 500 and 600°C, leads to a mixture of long-chain polyphosphates NiNa(PO₃)₃ and NaPO₃. The kinetic characteristics of the dehydration of NiNa₄(P₃O₉)₂·6H₂O were determined and discussed. The vibrational spectrum of the title compound, NiNa₄(P₃O₉)2·6H₂O, was interpreted in the domain of the stretching vibrations of the P₃O₉ rings, on the basis of its crystalline structure and in the light of the calculation of the normal IR frequencies of the P₃O₉ ring with D_3h symmetry.

This revised version was published online in November 2005 with corrections to the Cover Date.