Synthesis and Characterization of Molybdenum(0) and Tungsten(0) Complexes of Tetramethylthiourea: Single-Source Precursors for MoS₂ and WS₂

Abstract

The molybdenum(0) and tungsten(0) carbonyl complexes, [M(CO) n (TMTU) 6−n ] (M = Mo and W; TMTU = tetramethylthiourea; n = 4 and 5), have been prepared by addition of TMTU to the appropriate carbonyl precursors. In the solid state, the compounds are monomeric and feature octahedral coordination geometries about the metal. In the case of [M(CO) 4 (TMTU) 2 ], the TMTU ligands are bound in a cis fashion. Dissolution of cis-[M(CO) 4 (TMTU) 2 ] produces an equilibrium mixture of cis-[M(CO) 4 (TMTU) 2 ], free TMTU, and the putative dimeric species, cis,cis-[M 2 (CO) 8 -(μ-TMTU) 2 ]. Attempts to prepare the tricarbonyl complex, [Mo(CO) 3 (TMTU) 3 ], by addition of TMTU to fac-[Mo-(CO) 3 (η 6 -cycloheptatriene)] results in isolation of cis-[Mo-(CO) 4 (TMTU) 2 ], demonstrating that exchange of CO and TMTU ligands is facile in these compounds. Each of the compounds decomposes readily in the solid state above 110 °C, ultimately forming the tetravalent metal disulfide. Thermolysis reactions of [M(CO) n (TMTU) 6−n ] complexes at 300 °C under an argon atmosphere produces amorphous MS 2 , establishing the utility of these compounds as precursors to molybdenum and tungsten disulfide materials under relatively mild conditions.

Accessing Alkyl- and Alkenylcyclopentanes from Cr-Catalyzed Ethylene Oligomerization Using 2-Phosphinophosphinine Ligands

“…The following starting materials were synthesized according to literature procedures: 1•BH 3 and 1, 37 [M(CO) 4 (NBD)] (M = Cr, Mo), 83 and [W-(CO) 4 (COD)]. 84 Synthesis of 2-(Diphenylphosphine−borane)-3-methylphosphinine (2•BH 3 ). 1•BH 3 37 (1.01 g, 2.65 mmol, 1 equiv) was dissolved in dry CH 2 Cl 2 (15 cm 3 ), and a 1 M solution of HCl in Et 2 O (2.65 cm 3 , 2.65 mmol) was added.…”

“…All calculations were performed as previously described; see the Supporting Information for further details. The following starting materials were synthesized according to literature procedures: 1·BH 3 and 1 , [M­(CO) 4 (NBD)] (M = Cr, Mo), and [W­(CO) 4 (COD)] …”

Scalable Synthesis of Few-Layered 2D Tungsten Diselenide (2H-WSe2) Nanosheets Directly Grown on Tungsten (W) Foil Using Ambient-Pressure Chemical Vapor Deposition for Reversible Li-Ion Storage

“…For example, using H 2 S or H 2 Se as the chalcogen precursor or involving an intermediate process of annealing the substrate with Ar/H 2 or using chalcogen precursors such as thiourea in solvothermal methods gives rise to problems in handling these gases as a byproduct of the reaction because they are hazardous to human health. 34 , 35 …”

Mechanistic insight into the formation of colloidal WS2 nanoflakes in hot alkylamine media

“…Therefore, we hypothesized a tautomerization process leading to the formation of a SH group (7.76 ppm) and a quaternary imine carbon (155.9 ppm). [36][37][38][39] The above results made easier the identication of reaction products in the mixtures containing the amine excess with respect to CS 2 and the metal, as precisely adopted for nanocrystal synthesis in this work ( Fig. 3e and f) and reported more in detail in Fig.…”