Niobium(V) and tantalum(V) halide chalcogenoether complexes--towards single source CVD precursors for ME2 thin films.
Niobium(V) and tantalum(V) halide chalcogenoether complexes--towards single source CVD precursors for ME2 thin films.
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铌 (V) 和钽 (V) 卤化物硫族醚络合物——面向 ME2 薄膜的单一来源 CVD 前驱体。
DOI：
10.1039/c4dt02694b
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Benjamin SL
中科院分区：
文献类型：
--
作者：
Benjamin SL
一系列五价铌和钽卤化物与硫醚、硒醚和碲醚配体的配合物，[MCl5(EnBu2)] (M = Nb, Ta; E = S, Se, Te), [TaX5(TeMe2)] (X = Cl, Br, F) 和双核 [(MCl5)2{o-C6H4(CH2SEt)2}] (M = Nb, Ta) 已通过 IR、 1H、 13C{1H}、 77Se、 93Nb 和 125Te NMR 光谱（视情况而定）和微量分析进行了制备和表征。钽(V)-碲醚配位的确认是根据[TaCl5(TeMe2)]的晶体结构进行的，它代表了结构上经过验证的具有碲醚配位的最高氧化态过渡金属络合物。 Ta(V) 单碲醚络合物比 Nb(V) 类似物稳定得多。在 TaCl5 存在下，二碲醚 CH2(CH2TetBu)2 分解；其中一种产品是脱烷基化的[tBuTe(CH2)3Te][TaCl6]，其结构是通过晶体学确定的。 [(MCl5)2{o-C6H4(CH2SEt)2}] (M = Nb, Ta) 的晶体结构显示配体桥接物质。末端烷基取代基上带有 β-氢原子的配合物也已被研究作为通过低压化学气相沉积沉积 ME2 薄膜的单一来源试剂。虽然钽配合物被证明是不合适的，但 [NbCl5(SnBu2)] 和 [NbCl5(SenBu2)] 分别在 750 °C 和 650 °C 下将 NbS2 和 NbSe2 作为六方片状沉积到 SiO2 基材上。掠入射和面内 X 射线衍射证实两种材料均采用 3R 多型体 (R3mh)，并且硫化物显示出择优取向，微晶主要与垂直于基材的 c 轴对齐。扫描电镜和拉曼光谱与X射线数据一致。
A series of pentavalent niobium and tantalum halide complexes with thio-, seleno- and telluro-ether ligands, [MCl5(EnBu2)] (M = Nb, Ta; E = S, Se, Te), [TaX5(TeMe2)] (X = Cl, Br, F) and the dinuclear [(MCl5)2{o-C6H4(CH2SEt)2}] (M = Nb, Ta), has been prepared and characterised by IR, 1H, 13C{1H}, 77Se, 93Nb and 125Te NMR spectroscopy, as appropriate, and microanalyses. Confirmation of the tantalum(V)–telluroether coordination follows from the crystal structure of [TaCl5(TeMe2)], which represents the highest oxidation state transition metal complex with telluroether coordination structurally authenticated. The Ta(V) monotelluroether complexes are much more stable than the Nb(V) analogues. In the presence of TaCl5 the ditelluroether, CH2(CH2TetBu)2, is decomposed; one of the products is the dealkylated [tBuTe(CH2)3Te][TaCl6], whose structure was determined crystallographically. Crystal structures of [(MCl5)2{o-C6H4(CH2SEt)2}] (M = Nb, Ta) show ligand-bridged species. The complexes bearing β-hydrogen atoms on the terminal alkyl substituents have also been investigated as single source reagents for the deposition of ME2 thin films via low pressure chemical vapour deposition. While the tantalum complexes proved to be unsuitable, the [NbCl5(SnBu2)] and [NbCl5(SenBu2)] deposit NbS2 and NbSe2 as hexagonal platelets onto SiO2 substrates at 750 °C and 650 °C, respectively. Grazing incidence and in-plane X-ray diffraction confirm both materials adopt the 3R-polytype (R3mh), and the sulfide shows preferred orientation with the crystallites aligned predominantly with the c axis perpendicular to the substrate. Scanning electron microscopy and Raman spectra are consistent with the X-ray data.