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Syntheses and X‐ray Crystal Structures of Dichlorobis(tert‐butylimido) Complexes of Molybdenum(VI); Potential Precursors to Molybdenum Nitride and Molybdenum Carbonitride

1994; Wiley; Volume: 41; Issue: 6 Linguagem: Inglês

10.1002/jccs.199400106

2192-6549

Hsin‐Tien Chiu, Gau‐Banng Chang, Wen‐Yu Ho, Shiow‐Huey Chuang, Gene‐Hsiang Lee, Shie‐Ming Peng,

Ferrocene Chemistry and Applications

Abstract The bistertbutylimido complexes [MoCl(μ‐Cl)(NBu 1 ) 2 (NH 2 Bu 1 )] 2 , 1 , and MoCl 2 (NBu 1 ) 2 (py) 2 , 2 (py = pyridine), were prepared by reacting MoCl 2 (NBu 1 ) 2 (dme) (dme = dimethoxyethane) with excess Bu 1 NH 2 and pyridine, respectively. Their structures were determined by X‐ray crystallography. 1 has a pseudo edge‐shared bioctahedral geometry with two Cl ligands bridging the Mo centers unequally. Pertinent bond distances and angles for 1 , Mo = NBu 1 beut = 1.737(3) Å, ∠Mo = N‐CMe 3 = 154.0(2)°; Mo = NBu 1 linear = 1.725(3) Å, ∠Mo = N‐CMe 3 = 172.4(2)°; Mo‐Bu 1 NH 2 = 2.233(2) Å; Mo‐Cl bridging = 2.575(1) and 2.835(1) Å, and Mo‐Cl terminal = 2.428(1) Å. Crystal data for 1: triclinic, space group P 1, a = 8.897(4) Å, b = 10.518(3) Å, c = 10.663(3) Å, α = 107.68(2)° β = 98.03(3)° γ = 99.26(3)°, V = 919.3(5) Å 3 , Z = 1, D c = 1.381 g/mL. 2 is mononuclear with a distorted octahedral geometry with two trans Cl ligands, two cis ‐oriented Bu 1 N = ligands, and two py ligands trans to the imido groups. Pertinent averaged bond distances and angles for 2 , Mo = NBu t bent = 1.736(4) Å, ∠Mo = N‐CMe 3 = 163.8(4)°; Mo = NBu t linear .= 1.705(5) Å, ∠Mo = N‐CMe 3 = 173.4(4)° Mo‐N(py) = 2.44(1), Mo‐Cl = 2.421(3) Å. Crystal data for 2: orthorhombic, space group P na2 1 a = 16.860(2) Å, b = 8.920(3) Å, c = 15.120(3) Å, V = 2274.1(9) Å 3 , Z = 4, D c = 1.362 g/mL. A potential application of 2 as a single‐source precursor to grow molybdenum nitride and molybdenum carbonitride thin films by low pressure chemical vapor deposition (LPCVD) was explored. Cubic phase thin films (a thin film = 4.16–4.20 Å) were grown at temperatures between 450 °C and 650 °C with hydrogen as carrier gas. At 450 °C, thin films of molybdenum nitride were obtained. With temperature of deposition increased from 450 °C to 650 °C, the ratio C/Mo increased from 0.03 to 0.5 whereas me ratio N/Mo decreased from 0.7 to 0.3. Thus, thin films of molybdenum carbonitride were deposited at 650 °C.