These are especially numerous for rh and in certain

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Unformatted text preview: very high nuclearity have been obtained, often by thermolysis. These are especially numerous for Rh and in certain Rh13, Rhl4 and Rh15 anions have structures conveniently visualized either as polyhedra encapsulating further metal atoms, or alternatively as arrays of metal atoms forming portions of hexagonal close packed or body centred cubic lattices stabilized by CO ligands. [Rhl3H3(C0)24I2- (Fig 26.9a) is typical. The anionic cluster [Ir,j(CO)1,]2- is octahedral and an increasing number of Ir clusters have been reported recently though their preparations are more difficult and yields usually smaller than for rhodium. [1rl4(CO)27]- has the highest nuclearity so far and is obtained as black crystals by oxidizing [Ir6(C0)15l2- with ferricinium ion(40) (Fig 26.9b). The incorporation of interstitial or encapsulated heteroatoms is a common and stabilizing feature. Carbon is the most common and, as is the case in 40 R. D. PERGOLA, L. GARLASCHELLI, M. MANASSERO, N. MASCIOCCHI P. ZANELLO, ngew. Chem. Int. Edn. and A Engl. 32, 1347-9 (1993). 1142 Cobalt, Rhodium and Iridium Ch. 26 Figure 26.9 Schematic representations of the metal cores of some clusters of group 9 metals. (a) [Rh13H3(C0)24]2-;the H atoms migrate within the cluster. (b) [Iri4(CO)27]-.( c) [Rh&(CO),s]*-. (d) [Rh8C(C0)19]; a trigonal prism of 6 Rh atoms has one face capped by a seventh Rh atom and one edge bridged by the eighth Rh atom. (e) [co8c(co)~8]2-;the 8 C o atoms define a distorted bicapped trigonal prism which, alternatively, can be viewed as a distorted square antiprism. ( f) [Rhi 2(C2)(CO)25I. group 8 (p. 1107), ma...
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This note was uploaded on 10/12/2012 for the course CHEMISTRY CHM1040 taught by Professor Jhon during the Spring '12 term at Florida A&M.

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