“Atmende” cluster: Addition und eliminierung als elementarschritte der ligandensubstitution an (μ3-RP)Fe3(CO)10

Abstract The closed tetrahedral clusters RPFe 3 (CO)( 10- n )L n ( 1 ) (R = alkyl, aryl; L = phosphite, isonitrile; n = 0, 1, 2) add ligands L by opening of metal—metal bonds in a stepwise manner to give RPFe 3 (CO)( 10- n )L( n +1 ), ( 2 ) and RPFe 3 (CO)( 10- n )L( n +2 ) ( 3 ) respectively. By stepwise elimination of L the closed tetrahedral clusters 1 are obtained from the MM bond-opened species 3 and 2 , respectively. Elimination of CO from 3 or 2 yields substituted clusters of type 2 or 1 , respectively, again in a stepwise manner. This reaction sequence, documented by several examples, demonstrates that clusters behave like “breathing objects” which reversibly add substrates to their inner surface and “expire” them under reformation of metal—metal bonds. Hence, ligand substitution does not occur as a dissociatively initiated process on the outer surface of a cluster but involves addition-elimination sequences on the inner surface of the polyhedron.