Fe3(CO)9(CCO).

Article abstract of DOI:10.1021/ja00363a017

The acylation of a bridging CO in left bracket Fe//3(CO)//1//1 right bracket **2** minus followed by 33 degree cleavage produces a compound that has the chemical properties of an exposed carbide but possesses the structure of a ketenylidene. This compound reacts with H** plus and CH//3** plus sources to produce a cluster-bound methylene or ethyne, respectively. In both cases the CO that formerly was part of the ketenylidene has migrated onto the metal cluster. The X-ray crystal structures of the methyne, left bracket Fe//3(CO)//1//0(CH) right bracket **2** minus , and ketenylidene, left bracket Fe//3(CO)//9(CCO) right bracket **2** minus , were determined, and the CCO ligand in the latter cluster was found to be tipped by 33 degree relative to a plane vertical to the Fe//3 plane. This structural feature may be related to the facile reaction of the CCO ligand with electrophiles.