Synthesis and Characterization of Pentanuclear Fe-Ir Carbonyl Clusters: Solid-State Structures of [N(PPH3)2]2[FEIR4(CO)15] and [PPH4][FE2IR3(CO)14]

The dianion [Felr4( C0)15]2- can be obtained by reduction of an equimolar mixture of [Fe(CO)4] and [Ir4(CO)12] in alcoholic NaOH and under 1 atm of carbon monoxide. Its metal framework consists of a trigonal bipyramid with the equatorial triangle formed by iridium atoms. The monoanion [Fe2lr3(CO)14]- was obtained from [Fe(C0)4]2- and [lr(CO)2Cl2]-. Its metallic framework is comprised of an iridium triangle capped on opposite sides by two iron atoms. In the derivative (1) the trigonal bipyramid is considerably elongated in the direction of the apical atoms, when compared with that in (2). This elongation is consistent with the increased number of cluster valence electrons: 76 in (1) and 72 in (2).