Metathetical Exchange between Metal-Metal Triple Bonds.

The reaction of the molybdenum-molybdenum triple-bonded dimer (CO)2CpMo≡MoCp(CO)2 (Cp = η5-C5H5) with the triple-bonded dimetallynes AriPr4MMAriPr4 or AriPr6MMAriPr6 (AriPr4 = C6H3-2,6-(C6H3-2,6-Pri2)2, AriPr6 = C6H3-2,6-(C6H2-2,4,6-Pri3)2; M = Ge, Sn, or Pb) under mild conditions (≤80 °C, 1 bar) afforded AriPr4M≡MoCp(CO)2 or AriPr6M≡MoCp(CO)2 in moderate to excellent yields. The reactions represent the first isolable products from a metathesis of two metal-metal triple bonds. Analogous exchange reactions with the single-bonded (CO)3CpMo-MoCp(CO)3 gave ArM̈-MoCp(CO)3 (Ar = AriPr4 or AriPr6; M = Sn or Pb). The products were characterized by NMR (1H, 13C, 119Sn, or 207Pb), electronic, and IR spectroscopy and by X-ray crystallography.