New High-Nuclearity Carbonyl and Carbonyl-Substituted Rhodium Clusters and Their Relationships with Polyicosahedral Carbonyl-Substituted Palladium- and Gold-Thiolates

A reinvestigation of the synthesis of [H5–nRh13(CO)24]n− (n = 2, 3) led to isolation of a series of Rh19, Rh26, and Rh33 high-nuclearity carbonyl and carbonyl-substituted rhodium clusters. The [Rh19(CO)31]5– (1) is electronically equivalent with [Pt19(CO)22]4–, but poor crystal diffraction data of all salts obtained to date have prevented its geometrical analysis. The structures of Rh26(CO)29(CH3CN)11 (2) as 2·2CH3CN and [Rh33(CO)47]5– (3) as [NEt4]5[3]·Me2CO were determined from complete X-ray diffraction determinations. The latter two species adopt polyicosahedral metal frameworks, and notably, [Rh33(CO)47]5– represents the molecular group 9 metal carbonyl cluster of highest nuclearity so far reported.