The ruthenacarboranes 2-(p-cymene)-2,1,7-closo-RuC2B9H11 (2) (p-cymene = 1-methyl-4-isopropylbenzene) and 2-(p-cymene)-2,1,12-closo-RuC2B9H11 (3) have been synthesised by simple metallation of [7,9-nido-C2B9H11](2-) and [2,9-nido-C2B9H11](2-), respectively. In preparing the known cobaltacarborane 2-(eta-C5H5)-2,1,12-closo-CoC2B9H11 (6), the new bis(dicarbollide) [2,2'-Co(1,12-closo-C2B9H11)(2)](-) (as its [(eta-C5H5)(2)Co](+) salt; 7) was also formed. Molecular structures of 2, 3, 6 and 7 and that of the known compound 2-(eta-C5H5)-2,1,7-closo-CoC2B9H11 (5) have been determined. Patterns in <delta(B-11)>, the weighted average B-11 NMR chemical shift, of these metallacarboranes, together with those in 3-(p-cymene)-3,1,2-closo-RuC2B9H11 (1) and 3-(eta-C5H5)-3,1,2-closo-CoC2B9H11 (4) are discussed in relation to <delta(B-11)> in the parent carboranes 1,2-closo-C2B10H12, 1,7-closo-C2B10H12 and 1,12-closo-C2B10H12. The similarity between the H-1 and B-11 spectra of 6 and 7 confirm the isolobality of the [C5H5](-) and [C2B9H11](2-) ligands. An electrochemical study of 7 confirms that trends in the potential of the Co-III/Co-II couple for the series of isomers of (eta-C5H5)CoC2B9H11 are reproduced for the bis(dicarbollides) [Co(C2B9H11)(2)](-). The molecular structures of compounds 1-3 as a family and 4-6 as a family provide a unique opportunity to consider structural patterns in simple isomeric metallacarboranes.
|Number of pages||17|
|Journal||Collection of czechoslovak chemical communications|
|Publication status||Published - 2010|