Reactions of Cyclic Osmacarbyne with Coinage Metal Complexes

The
reactions of the five-membered cyclic osmacarbyne complex,
i.e., osmapentalyne, with a complete set of coinage metal (Cu, Ag,
and Au) complexes have been investigated. Osmapentalyne 1 reacts with CuCl or AuCl­(PPh3) via its metal–carbon
triple bond, leading to the formation of osmapentalyne-copper­(I) chloride
adduct 2 or osmapentalyne-gold­(I)-triphenylphosphine
adduct 3, respectively. Moreover, it can react with AgOTf
in the presence of 1,10-phenanthroline to give osmapentalyne-silver­(I)-phenanthroline
adduct 4. All the compounds have been characterized by
X-ray diffraction analysis. The formation of these bimetallic adducts
can be regarded as the “alkyne-like” interaction of
an osmium–carbon triple bond with the coinage metal center.
The interaction is weak and these adducts can readily dissociate to
regenerate precursor osmapentalyne 1 in essentially quantitative
yield with the assistance of PPh3 or chloride ligands.