Silyl group mediated linkage of closo-C2B10-cage to nido-C2B4-carborane: synthesis of the novel carborane ligand, 1-R-2-[5′-(SiMe2CH2)-2′,3′-(SiMe3)2-2′,3′-C2B4H5]-1,2-C2B10H10 (R=Me, Ph)

The reaction of the sodium salt of the monoanion, nido-[2,3-(Si(CH3)3)2-2,3-C2B4H5]−, with (chloromethyl)dimethylchlorosilane in a 1:1 molar ratio produced the B(cage)-substituted cluster, nido-5-ClCH2Si(CH3)2-2,3-(Si(CH3)3)2-2,3-C2B4H5 (1), in 81% yield. This product (1) was reacted further with the lithium salt of [closo-1-R-1,2-C2B10H10]− monoanion (R=Me, Ph) to give the novel linked and mixed C2B4/C2B10 carborane species, 1-Me-2-[5′-SiMe2CH2-2′,3′-(SiMe3)2-2′,3′-C2B4H5]-1,2-C2B10H10 (2), 1-Ph-2-[5′-SiMe2CH2-2′,3′-(SiMe3)2-2′,3′-C2B4H5]-1,2-C2B10H10 (3), in yields of 76% and 81%, respectively.