Novel oxo-bridged dinuclear molybdenum(II) complexes: reaction of [MO 2(O 32CCH 3) 2(CH 3CN) 6](BF 4) 2with aromatic isocyanides. X-Ray crystal structures of [Mo 2(μ-O)(RN 10](BF 4) 2 (R = 2,6-Me 2C 6H 3) and [Mo(= O)F(RNC) 4](BF 4) (R = 2,4,6-Me 3C 6H 2)

Abstract

Treatment of the dinuclear molybdenum complex [Mo 2(O 2CCH 3) 2(CH 3CN) 6](BF 4) 2 with aromatic isocyanides (RNC) gave an oxo-bridged dinuclear molybdenum(II) complex, [Mo 2(μ-O)(RNC) 10](BF 4) 2 ( 1), and a mononuclear molybdenum(IV) complex, [Mo(= O)F(RNC) 4]BF 4( 2) (R = 2,6-dimethylphenyl (Xyl) or 2,4,6-trimethylphenyl (Mes)), which were characterized by IR, electronic, 1H and 19F NMR spectroscopy and X-ray crystallographic analyses. Complex 1a (R = Xyl) crystallizes in the triclinic form, space group P 1 , with a = 13.431(5) A ̊ , b = 15.548(7) A ̊ , c = 12.616(5) A ̊ , α = 111.74(3)°, β = 92.80(3)°, γ = 101.80(3)° and Z = 1 (R = 0.060 and R w = 0.054 for 2818 independent reflections with I >3 σ( I)) Complex 2b (R = Mes) crystallizes in the triclinic form, space group P 1 , with a = 14.317(4) A ̊ , b = 16.16(1) A ̊ , c = 8.968(8) A ̊ , α = 100.31(4)°, β = 97.54(2)°, γ = 91.69(4)° and Z = 2 (R = 0.059 and R w = 0.059 for 2225 independent reflections with I >3 σ( l)) Complex 1 consists of two molybdenum atoms bridged linearly by an oxygen atom. Each molybdenum atom is octahedrally coordinated by five isocyanides and an oxygen atom. Two equatorial planes, Mo(RNC) 4, mutually adopt an eclipsed form. The MoO bond length is 1.876(2) Å and the MoOMo angle is constrained to 180°. Complex 2 has a distorted octahedral geometry, in which molybdenum atom is occupied by four isocyanides, O and F atoms.