Synthesis and Characterization of a Metallabenzyne

Although many metallabenzenes are known, complex 1 appears to be the first well-characterized example of a metallabenzyne. It has been synthesized by treatment of [OsCl2(PPh3)3] with an excess of HC≡CSiMe3 in wet benzene. The structure of the novel complex 1 was confirmed by single-crystal X-ray diffraction, which showed the six-membered ring to be essentially planar with a maximum deviation from the least-squares plane of 0.047 Å.