Trimethylsilyl-imido-Vanadiumtrichlorid,Me3Si?NVCl3 Synthese,Eigenschaften und Kristallstruktur

Trimethylsilyl-Imido-Vanadium Trichloride, Me₃Si? N?VCl₃. Synthesis, Properties, and Crystal Structure Me₃Si? N?VCl₃ is prepared from VCl₄ and trimethylsilyl azide, forming volatile orange-red crystals extremely sensitive to moisture. Reactions with 2,2′-dipyridyl and PPh₄Cl, resp., lead to the complexes Me₃SiNVCl₃(dipy)] with six-coordinated vanadium and PPh₄Me₃SiNVCl₄] with five-coordinated vanadium. The i.r. spectra are reported. Me₃SiNVCl₃ was characterized by X-ray crystal structure determination. The compound crystallizes orthorhombic in the space group Pnma with four formula units per unit cell and with the lattice dimensions a = 1628 pm, b = 1041 pm, c = 635 pm at 20°C (440 observed, independent reflexions, R = 0.043). Me₃Si? N?VCl₃ forms monomeric molecules with an almost linear axis SiNV (177.5°); the bond lengths are: Si? N 179 pm and V?N 159 pm, indicating a VN triple bond. The molecular geometry (C_s) deviates slightly from the trigonal prisma (C_3v).