Nitrosyl complexes of molybdenum and tungsten. Part 16. Symmetrical and unsymmetrical bis-alkoxo- and mixed alkoxo-amido-complexes of tris(3,5-dimethylpyrazolyl) boratomolybdenum, related tungsten species, and the structure of bis(ethoxo)-, bis(isopropoxo)-, and ethoxo(isopropoxo)-nitrosyl[tris(3,5-dimethylpyrazolyl)borato]-molybdenum

Abstract

The complex [Mo{HB(Me₂pz)₃}(NO)X(Y)][Me₂pz = 3,5-dimethylpyrazolyl; X = I, Y = OH, OC₆H₁₁, and OCH₂C₂CH₂OH; X = Y = OR (R = H, Me, Et, Prⁱ, and Buⁱ); X = OEt, Y = OPrⁱ; X = OPrⁱ, Y = OBuⁱ; X = OR, Y = NHR′(R = Me, R′= H, Me, and Et; R = Et, R′= H, Me, Et, Prⁿ, C₆H₁₁, and CH₂Ph; R = Prⁱ, R′= H, Me, Et, Prⁱ, and C₆H₁₁)] and [W{HB(Me₂pz)₂(3,5-Me₂-4-BrC₃N₂)}(NO)X(Y)](X = Br, Y = OMe, OEt, and OPrⁱ; X = Y = OEt) have been prepared and characterised spectroscopically. The complexes [Mo{HB(Me₂pz)₃}(NO)(OR)(NH₂)](R = Me, Et, or Prⁱ) react with acetone affording [Mo{HB(Me₂pz)₃}-(NO)(NCMe₂)(OR)]·n(CH₃)₂CO. The structures of [Mo{HB(Me₂pz)₃}(NO)(OR)(OR′)](R = R′= Et or Prⁱ; R = Et, R′= Prⁱ) have been determined crystallographically. For R = Et, R′= Prⁱ, crystals are monoclinic, with a= 14.46(4), b= 21.67(6), c= 8.015(14)Å, β= 96.08(3)°, space group P2₁/n, and R 0.0388; for R = R′= Prⁱ, crystals are triclinic, with a= 11.758(8), b= 14.403(9), c= 8.173(14)Å, α= 97.970(16), β= 77.30(3), γ= 96.523(7)°, space group P, and R 0.0398; for R = R′= Et, crystals are monoclinic, with a= 14.73 b= 21.09, c= 8.00 Å, β= 94.80° and space group P2₁/n. The molecules are six-co-ordinate, with linear Mo–N–O groups and short Mo–O bond lengths (1.90 Å).