The Derivative Chemistry of Metallocarboranes Nido-11-Atom Metallocarboranes and Their Lewis Base Adducts.

摘要

The reaction between X(1-(eta-C5H5)-2,4,1-C2CoB8H10) or X(1,2-C2B9H11-3,1'-Co-2',4'-C2B8H10)(-1) and pyridine affords the nido-adducts X(9-(eta-C5H5)-11-C5H5N-7,8,9-C2CoB8H10) and X(1,2-C2B9H11-3,9'-Co-11'-C5H5N-7',8'-C2B8H10)(-1) respectively. Oxidation of these species with FeCl3affords the substituted closo-compounds. Analogous compounds were prepared from X(1-(eta-C5H5)-2,4,1-C2CoB8H10) with piperidine in place of pyridine. The unsubstituted nido-metallocarboranes X(9-(eta-C5H5)-7,8,9-C2CoB8H11)(-1) and X(1,2-C2B9H11-3,9'-Co-7',8'-C2B8H11)(-2) were prepared by degradation of the icosahedral compounds (3-(eta-C5H5)1,2,3-C2CoB9H11) and (1,2-C2B9H11-3,3'-Co-1',2'-C2B9H11)(-1). These compounds could be reversibly protonated to give X(9-(eta-C5H5)-7,8,9-C2CoB8H12) and X(1,2-C2B9H11-3,9'-Co-7',8'-C2CoB8H12)(-1) which eliminate hydrogen on heating. The chemical changes resulting from the replacement of a polyhedral (BH)(+2) moiety by ((eta-C5H5) Co)(+2) or (1,2,3-C2CoB9H11)(+2) are discussed. (Modified author abstract)