The compounds 1-Ph-3-(cod)-3,1,2-PdC2B9H10 1a, 1,2-Ph2-3-(cod)-3,1,2-PdC2B9H9 2a, 1-Ph-3-(cod)-3,1,2-PtC2B9H10 3a, and 1,11-Ph2-3-(cod)-3,1,11-PtC2B9H9 4, have been prepared from the reactions between TI2[7-Ph-nido-7,8-C2B9H10] or TI2[7,8-Ph2-nido-7,8-C2B9H 9] and [PdCl2(cod)] or [PtCl2(cod)] as appropriate (cod = cycloocta-1,5-diene). The platinum reactions are considerably cleaner than the palladium ones. Compound 2a was subjected to a crystallographic study which reveals severe intramolecular overcrowding; the palladium atom is slipped by 0.56 Å away from the C-bound phenyl groups, the co-ordination of the cod ligand to the metal is distorted and the cage is deformed with extended C-B distances in the ligand face. Although 1a and 3a are structural analogues, 2a and 4 are not. Rather, compound 4 is only isolated as the C-separated species defined by a 3,1,11-PtC2B9 architecture, thus illustrating that the nature of the metal atom can influence the ease with which carbametallaboranes undergo polyhedral rearrangement. Compound 1a was recovered unchanged from refluxing toluene, but under the same conditions 2a was converted into 2a', tentatively identified as the rearranged isomer 1,11-Ph2-3-(cod)-3,1,11-PdC2B9H9.
|Number of pages||6|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - 1994|