160797-03-5Relevant articles and documents
Mixed valence tungsten (IV,V) compounds with layered structures (Part III)[2]: Synthesis and crystal structure of Ag1-x[W2O 2Cl6] and investigations on the Ag+ ion mobility
Beck, Johannes,Hoffbauer, Wilfried,Kusterer, Christian,Schieweling, Marcel
, p. 1827 - 1833 (2010)
The reaction of metallic silver with tungsten tetrachlorideoxide WOCl4 or the reaction of AgCl with WOCl3, both at 690 K, lead to Ag 1-x[W2O2Cl6] as black lustrous crystal needles. The compound shows a substantial phase field width in the silver content depending on reaction temperature and reaction time and crystals with x = 0, 0.38 and 0.82 were isolated. The crystal structure determinations (monoclinic, C2/m) show the structure to be isotypic to those of Tl[W 2O2Cl6] and K0.84[W 2O2Cl6] with the presence of 1D polymeric [W2O2Cl6]n strands and Ag+ ions with a variety in the occupation of the respective crystallographic site. Ag 1-x[W2O2Cl6] represents a mixed valence compound with a variable ratio of W(IV) and W(V) in the W2 dumbbells with a short W-W separation of 2.85 A. In Fourier maps the electron density of the Ag ion appears smeared over a large area. By structure determinations of stoichiometric Ag1.0[W2O 2Cl6] at temperatures of123, 193, and 293 K a double minimum potential was found with the silver ion dynamically disordered over two flat basins with a thermal activation barrier of 13 meV. No long range ion mobility is present since the Ag+ ions are trapped within a coordinating cage consisting of ten chlorine atoms of the surrounding [W 2O2Cl6] strands forming a distorted bicapped cube. By MAS-NMR spectroscopic measurements on the 109Ag nuclei at different temperatures, the spin lattice relaxation times were determined giving a thermally activated barrier of 15 meV. The electronic conductivity of pressed powder samples of Ag[W2O2Cl6] by a four-probe measurement applying direct current is 1Ω-1·cm -1 at room temperature and 10-3Ω -1·cm-1 at 25 K. For the conduction mechanism at low temperatures a variable range hopping mechanism is suggested, whereas at higher temperatures a standard semi-conductivity with a bandgap of 60 meV is present.
Complexes of WOCl4 and WSCl4 with neutral N- and O-donor ligands: Synthesis, spectroscopy and structures
Greenacre, Victoria K.,Hector, Andrew L.,Levason, William,Reid, Gillian,Smith, Danielle E.,Sutcliffe, Laura
, p. 14 - 19 (2019/02/10)
The complexes [WOCl4(L)] and [WSCl4(L)] (L = OPPh3, OPMe3, pyridine, 2,2′-bipyridyl), [{WOCl4}2(μ-L-L)] and [{WSCl4}2(μ-L-L)] (L-L = Ph2P(O)(CH2)nP(O)Ph2 (n = 1, 2)) have been prepared from WOCl4 or WSCl4 and the ligands in anhydrous CH2Cl2 solution, and characterised by microanalysis, IR and NMR (1H, 31P{1H}) spectroscopy. X-Ray crystal structures are reported for [WOCl4(OPPh3)], [{WOCl4}2(μ-Ph2P(O)(CH2)P(O)Ph2)] and [{WSCl4}2(μ-Ph2P(O)(CH2)2P(O)Ph2)]. All, except those of 2,2′-bipyridyl, are six-coordinate with the neutral donor trans to W[dbnd]O or W[dbnd]S. Spectroscopic data suggest that the [WOCl4(2,2′-bipy)] and [WSCl4(2,2′-bipy)] are seven-coordinate. Comparison of the structural and spectroscopic data for the two series of complexes indicate little difference in Lewis acidity between the two tungsten(VI) moieties. Decomposition of [WOCl4(OPMe3)] in solution gave the cyclic trimer [W3O3(μ-O)3Cl6(OPMe3)3], the structure of which revealed a six-membered W3O3 ring core with very asymmetric oxido-bridges. The structure of the tungsten(V) complex [WOCl3(2,2′-bipy)] is also reported.
Substitution of conventional high-temperature syntheses of inorganic compounds by near-room-temperature syntheses in ionic liquids
Groh, Matthias F.,Muller, Ulrike,Ahmed, Ejaz,Rothenberger, Alexander,Ruck, Michael
, p. 1108 - 1122 (2013/12/04)
The high-temperature syntheses of the low-valent halogenides P2I4, Te2Br, a-Te4I4, Te4(Al2Cl7)2, Te4(Bi6Cl20), Te8(Bi4Cl14), Bi8(AlCl4)2, Bi6Cl7, and Bi6Br7, as well as of WSCl4 andWOCl4 have been replaced by resource-efficient low-temperature syntheses in room temperature ionic liquids (RTILs). The simple one-pot syntheses generally do not require elaborate equipment such as twozone furnaces or evacuated silica ampoules. Compared to the published conventional approaches, reduction of reaction time (up to 80%) and temperature (up to 500 K) and, simultaneously, an increase in yield were achieved. In the majority of cases, the solid products were phase-pure. X-Ray diffraction on single crystals (redetermination of 11 crystal structures) has demonstrated that the quality of the crystals from RTILs is comparable to that of products obtained by chemical transport reactions.
