Recent Advances in the Chemistry of Metal-Carbon Triple Bonds

Abstract

Publisher Summary This chapter discusses the recent advances in the chemistry of metal–carbon triple bonds. The chemistry of metal–carbon triple bonds has developed at an increasing pace since the discovery of the first carbine–metal complexes. The metal atoms in the alkylidyne complexes were found to be less shielded than those in nitrido complexes but more shielded than those in compounds containing metal–metal multiple bonds. Aristov and Armentrout and Freiser derived the bond energies of metal– carbon triple bonds from gas-phase experiments. Metal–carbon triple bonds are generally described as consisting of one σ or two π bonds. The first transition-metal– carbyne complexes were synthesized in Fischer's laboratory by the treatment of alkoxycarbene pentacarbonylmetal complexes of chromium, molybdenum, and tungsten with boron trihalides. Oxalyl halides react directly with the pentacarbonylmetal acyl complexes of chromium, molybdenum, and tungsten to form the trans-alkylidyne (halo) tetracarbonyl complexes. The rearrangement of the silyl-substituted vinyl complexes has been proposed to occur by 1,2-silyl migration steps. Metal alkylidyne complexes undergo a variety of oxidation and reduction reactions as well as redox-induced transformations of the alkylidyne ligands. Addition of electrophiles to electron-rich isocyanide complexes is a proven synthetic method for the synthesis of aminocarbyne complexes. The chemistry of metal–carbon triple bonds has developed considerably during the late 1980s. The discovery of novel indium alkylidyne complexes indicates that the full range of metal–carbon triple bonds is not yet known.