The molecular Sn(iv) complexes, [SnCl{BuS(CH)SBu}] (2), [SnCl(BuS)] (3) and [SnCl(BuSe)] (4) have been prepared in good yield from reaction of SnCl with the appropriate chalcogenoether ligand in anhydrous hexane and, together with the known [SnCl{BuSe(CH)SeBu}] (1), employed as single source precursors for the low pressure chemical vapour deposition of the corresponding tin dichalcogenide thin films. At elevated temperatures the bidentate ligand precursors, (1) and (2), also form the tin monochalcogenides, SnSe and SnS, respectively. In contrast, (3) gave a mixture of phases, SnS, SnS and SnS and (4) gave SnSe only. The morphologies, elemental compositions and crystal structures of the resulting films have been determined by scanning electron microscopy, energy dispersive X-ray spectroscopy, grazing incidence X-ray diffraction and Raman spectroscopy. Van der Pauw measurements on the SnS, SnS and SnSe films confirm their resistivities to be 2.9(9), 266(3) and 4.4(3) Ω cm, respectively.

Here we report the controlled growth of SnSe nanowires by a liquid injection chemical vapor deposition (CVD) method employing a distorted octahedral [SnCl4{ n BuSe(CH2)3Se n Bu}] single source diselenoether precursor. CVD with this single source precursor allows morphological and compositional control of the SnSex structures formed, including the transformation of SnSe2 nanoflakes into SnSe nanowires and again to SnSe nanoflakes with increasing growth temperature. Significantly, highly crystalline SnSe nanowires with an orthorhombic Pnma 62 crystal structure could be controllably synthesized in two growth directions, either <011> or <100>. The ability to tune the growth direction of SnSe will have important implications for devices constructed using these nanocrystals. The SnSe nanowires with a <011> growth direction displayed a reversible polarity dependent memory switching ability, not previously reported for nanoscale SnSe. A resistive switching on/off ratio of 10 3 without the use of a current compliance limit was seen, illustrating the potential use of SnSe nanowires for low power non-volatile memory applications.

The inherently rapid ligand substitution kinetics associated with the novel and chemically compatible precursors, [MCl 3

Reaction of activated germanium with nBu2Te2 in THF solution was shown to be more effective for the preparation of the germanium(iv) tellurolate compound, [Ge(TenBu)4], than reaction of GeCl4 with LiTenBu in THF.

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