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.