Interaction of carbon dioxide with acetylene complexes of titanocene. Synthesis and structure of binuclear σ-alkenylcarboxylate complexes of titanium (III) and unexpected transformation of these complexes into titanafuranone metallacycles under the action of air oxyge.

Article abstract of DOI:10.1016/S0022-328X(97)00288-X

It has been shown that carbon dioxide reacts with acetylene complexes of titanocene Cp₂Ti(RC₂R) (R = Ph, SiMe₃) at room temperature and atmospheric pressure to form binuclear σ-alkenylcarboxylate complexes of trivalent titanium Cp₂TiC(R)=C(R)-COOTiCp₂ containing two fused chelate cycles and a tricoordinated oxygen atom. The interaction of these binuclear carboxylate complexes with air oxygen at 20°C results in rapid formation of titanafuranone metallacycles Cp₂ TiC(R)=C(R)-C(O)-O. X-ray diffraction studies of complexes Cp₂TiC(SiMe₃)=C(SiMe₃)-COOTiCp₂ and Cp₂ TiC(Ph)=C(Ph)-C(O)-O have been carried out.