Preparation, Chemical and Structural Characterization of Tungsten(III) Coordination Compounds: WCl3Pic3, WCl3Pic3 · 1/2 Pic, and (Pic)2HWCl4Pic2 (Pic = 4‐methylpyridine)

Abstract(Pic)2HWCl4Pic2 (Pic = 4‐methylpyridine, C5H7N) was prepared by reduction of WCl4Pic2 with NaBH4 in isopropanol. The compound crystallizes in the triclinic P1 space group with: a = 9.931(3), b = 14.127(5), c = 10.010(3) Å, α = 83.71(2), β = 99.35(2), γ = 99.90(2)°, Z = 2. The unit cell contains trans‐WCl4Pic2− octahedra and (Pic)2H+. Hydrogen bond NH…N within the cation is 2.71(2) Å. WCl and WN(Pic) bonds (average) are 2.419(5) and 2.165(10) Å.(Pic)2HWCl4Pic2 is very unstable towards oxidation. The first product is WCl4Pic2. (Pic)2HWCl4Pic2 reacts further with 4‐methylpyridine. The product is WCl3Pic3 which crystallizes from the cooled solutions of the ligand as WCl3Pic3 · 1/2 Pic.WCl3Pic3 and WCl3Pic3 · 1/2 Pic are isostructural with the corresponding molybdenum and chromium compounds with the mer structures. WCl3Pic3 is triclinic and WCl3Pic3 · 1/2 Pic monoclinic. WCl3Pic3 · 1/2 Pic decomposes in the inert atmosphere before 140°C to WCl3Pic3. Both neutral compounds are more stable towards oxidation compared to (Pic)2HWCl4Pic2.