Dinuclear niobium(III), tantalum(III) and tantalum(IV) complexes with thioether and selenoether ligands

Niobium tetrahalide complexes with neutral diphosphine ligands

“…We have recently been exploring the chemistry of Nb and Ta complexes in oxidation states III-V with thio-or seleno-ether ligands, and their possible use as single source precursors for NbS2 or NbSe2 films via low pressure or aerosol assisted chemical vapour deposition. 14,15 The chemistry of Nb(IV) chloride with bidentate group 16 ligands has also proved to be complicated, and in order to obtain a better understanding of the latter, we explored some chemistry with diphosphine ligands, and describe our results below. Only a few complexes of types [NbCl4(diphosphine) 2] or [NbCl4(diphosphine)] have been described previously, 16,17 and none have been structurally characterised.…”

Niobium tetrachloride complexes with thio-, seleno- and telluro-ether coordination – synthesis and structures

“…As previously noted in investigations of the Nb2 6+ dimer chemistry, 11,14 chalcogenoether ligands can undergo CE bond fission in some reactions and the products may contain sulfide or selenide ligands or RE − groups. Since the isoelectronic Cl  and S 2 ligands are very difficult to distinguish by X-ray crystallography, some erroneous complexes have been reported.…”

“…[Nb2Cl4{RE(CH2)2SER}2(μ-Cl)2] ( E = S or Se), 11 all which contain Nb2 6+ units with Nb=Nb double bonds.…”

“…11,14 Reports of mononuclear niobium(IV) complexes with thioethers are very old and describe [NbX4Ln] ( X = Cl, Br or I; L = Me2S, tetrahydrothiophene; n = 1 or 2) and [NbX4{MeS(CH2)2SMe}2], although with limited spectroscopic and no crystallographic data. [15][16][17] There are no reports of selenoether or telluroether analogues.…”

Chalcogenoether complexes of tantalum(V) sulfide trichloride – Synthesis, properties and structures

“…A very small number of complexes of TaECl3 have inorganic analogues of graphene and their band gaps and other properties for various applications can be tuned by varying the chalcogen or the metal [11], [12]. In recent studies we have examined a range of thio-and seleno-ether complexes of niobium and tantalum halides as potential single source low pressure chemical vapour deposition (LPCVD) reagents for the production of thin films of the transition metal dichalcogenides [13][14][15]. Thus, [NbCl5(E n Bu2)] produced thin films of the 3R-polytype (R3mh) of NbS2 and NbSe2; the butyl-substituents provide a β-hydride decomposition route facilitating cleavage of the ligands in an accessible temperature range.…”