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

Single-wall carbon nanotubes (SWCNTs)-supported nickel (11) carborane complex, ([closo-l-Ni(PPh3)(2)-2-Me-3-((CH2)(4)NH-)-eta(5)-2,3C(2)B(9)H(9)][OEt])(n)(SWCNT) (3) has been synthesized by the reaction of in situ prepared nido-C2B9-carborane-functionalized SWCNTs, ([Na+][1-Me-2-((CH2)(4)NH-)-1,2-C2B9H10][OEt])(n)(SWCNT) (1) with dichlorobis(triphenylphosphine)nickeI (11) (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-l-Ni(PPh3)(2)-2-Me-3-Pentyl-eta(5)-2,3C(2)B(9)H(9) (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. (c) 2006 Elsevier Ltd. All rights reserved.