Syntheses and catalytic activities of single-wall carbon nanotubes-supported nickel (II) metallacarboranes for olefin polymerization

Single-wall carbon nanotubes (SWCNTs)-supported nickel (II) carborane complex, ([closo-1-Ni(PPh3)2-2-Me-3-((CH2)4NH-)-η5-2,3-C2B9H9][OEt])n(SWCNT) (3) has been synthesized by the reaction of in situ prepared nido-C2B9-carborane-functionalized SWCNTs, ([Na+][1‐Me‐2‐((CH2)4NH‐)‐1,2‐C2B9H10−][OEt])n(SWCNT) (1) with dichlorobis(triphenylphosphine)nickel (II) (2). Reaction of closo-1-Me-1,2-C2B10H11 (4) with n-butyllithium followed by treatment with 1-bromopentane results in the formation of closo-1-Me-2-pentyl-1,2-C2B10H10 (5) in 91% yield. After decapitation of (5) with sodium hydroxide in refluxing ethanol, the salt Na[nido-7-Me-8-pentyl-7,8-C2B9H10] (6) has been obtained in 77% yield. For the purpose of comparison of catalytic activity, homogeneous analogue closo-1-Ni(PPh3)2-2-Me-3-Pentyl-η5-2,3-C2B9H9 (7) has been prepared in 83% from its nido-precursor (6). The above synthesized nickel complexes (3) and (7) have been tested as moderately active catalysts for olefin polymerization in the presence of the co-catalyst MAO.