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A new atomic layer deposition (ALD) process was applied for the uniform coating of carbon nanotubes with a number of transition-metal oxide thin films (vanadium, titanium, and hafnium oxide). The presented approach is adapted from non-aqueous sol-gel chemistry and utilizes metal alkoxides and carboxylic acids as precursors. It allows the coating of the inner and outer surface of the tubes with a highly conformal film of controllable thickness and hence, the production of high surface area hybrid materials. The morphology and the chemical composition as well as the high purity of the films are evidenced through a combination of electron microscopic and electron-energy-loss spectrometric techniques. Furthermore, in order to highlight a possible application of the obtained hybrids, the electrical and sensing properties of resistive gas sensors based on hybrid vanadium oxide-coated carbon nanotubes (V2O4-CNTs) are reported and the effect of thermal treatment on the gas sensing properties is studied.

A nonaqueous route based on the solvothermal reaction of alkaline earth precursors with aluminium isopropoxide in benzyl alcohol is introduced. This simple process leads to crystalline complex nanostructures of alkaline earth aluminates, which, up to now, could only be obtained by solid state reaction at temperatures above 1100 degrees C or by sol-gel and further calcination at temperatures only slightly lower ( approximately 800 degrees C). The approach appears to be rather general since under the same reaction conditions BaAl(2)O(4), CaAl(4)O(7), and SrAl(4)O(7) could be obtained. The as-synthesized materials were characterized by X-ray diffraction, electron microscopy techniques, solid-state NMR and FT-IR spectroscopies. The reaction mechanism, which was studied as well, indicates the in-situ formation of benzoate species. These can preferentially bind to particular crystallographic facets of the aluminates via bridging bonds, thereby stabilizing the surfaces that give rise to the peculiar complex structure of the final material. In order to supplement the synthesis approach and to investigate the formation of impurity phases, pure aluminium oxide hybrid nanostructures were synthesized under similar conditions and fully characterized.

The reaction of Na 3 VO 4 with Ph 3 SnCl in a water/CH 2 Cl 2 mixture leads to the formation of [(Ph 3 Sn) 3 VO 4 ] (1). Recrystallization of 1 from toluene/CH 3 CN gives pale yellow crystals of [(Ph 3 Sn) 3 VO 4 ]·CH 3 CN (2). 2 crystallizes as coordination polymer which consists of infinite chains composed of corner-sharing VO 4 tetrahedra and Ph 3 SnO 2 trigonal bipyramides. Additionally the VO 4 groups are connected to two terminal SnPh 3 -Groups contai-Einleitung Die Umsetzung von Organozinnhalogeniden des Typs R 3 SnX (X ϭ Cl, Br) mit Oxometallaten, z. B. MO 4 2Ϫ (M ϭ Mo, W) oder VO 3 Ϫ führt häufig zu Koordinationspolymeren mit Ketten-, Schicht-oder Raumnetzstrukturen. Beispiele dafür sind [(Me 3 Sn) 2 MoO 4 ] [1], (NBu 4 )[(Ph 3 Sn) 3 (MoO 4 ) 2 ] [2] und (NBu 4 )[(Me 3 Sn)MO 4 ] (M ϭ Mo, W) [3]. Kürzlich berichteten wir über die Synthese von [Me 3 SnVO 3 ], das durch die Umsetzung von Me 3 SnBr mit NH 4 VO 3 in einem Agar-Gel zugänglich ist [4]. Wir interessierten uns nun für Triorganozinn-orthovanadate und untersuchten dazu die Reaktion von Ph 3 SnCl mit Na 3 VO 4 . Ergebnisse und DiskussionZur Synthese von [(Ph 3 Sn) 3 VO 4 ] (1) wird eine Lösung von Ph 3 SnCl in Dichlormethan mit einer wässrigen Lösung von Na 3 VO 4 umgesetzt (Gl. 1). Unter Abspaltung von NaCl, das in der wässrigen Phase gelöst bleibt, entsteht 1 als gelblicher Niederschlag, der abfiltriert und getrocknet wird. Frisch synthetisiertes 1 löst sich in aliphatischen Lösungsmitteln nur wenig, in aromatischen Lösungsmitten und po-

The reaction of Te(OH)6 with Ph3SnOH in ethanol leads to the formation of trans‐[(Ph3SnO)4Te(OH)2] (1). Compound 1 crystallizes triclinic in the space group P\bar{1} with a = 996.6(2) pm, b = 1365.4(3) pm, c = 1368.2(3) pm and α = 71.15(2)°, β = 71.48(2)°, γ = 74.81(3)° (at 220 K). The molecular structure of 1 consists of a tellurium atom, which is coordinated nearly octahedrally by four Ph3SnO units and two hydroxyl groups that are trans to each other. The Te–O bond lengths are in the range of 190.5(2) and 193.7(2) pm. Treatment of 1 with methanol under reflux yields trans‐[(Ph3SnO)2Te(OMe)4] (2). Compound 2 crystallizes triclinic in the space group P\bar{1} with a = 1012.8(1) pm, b = 1422.4(2) pm, c = 1618.1(2) pm, and α = 100.44(1)°, β = 107.92(1)°, γ = 110.66(1)° (at 220 K). 2 forms centrosymmetric molecules in which the tellurium atom is surrounded nearly octahedrally by four methoxy groups and two trans arranged Ph3SnO units. The Te–O bond lengths of 187.9(3)–194.5(3) pm are similar to those observed in 1.