Synthesis of isomeric B-methylated tantalum carboranes, (Me₂N)₃TaC₂B₉H₁₀Me

Fox, M.A.; Howard, J.A.K.; Hughes, A.K.; Malget, J.M.; Yufit, D.S.

Abstract

The cage-alkylated metallacarborane complex [4,4,4-(NMe2)(3)-3- Me-4,1,2-closo-TaC2B9H10] 8, is obtained as the only product from the reaction of Ta(NMe2)(5) with nido-11-Me-2,7-C2B9H12 4, which is prone to skeletal rearrangement under basic conditions. That no rearrangement occurs indicates that the hydroamminolysis reaction is a clean synthetic method. The isomeric metallacarboranes [3,3,3-(NMe2)(3)-4-Me-3,1,2-closo- TaC2B9H10] 9 and [2,2,2-(NMe2)(3)-3-Me-2,1,7-closo-TaC2B9H10] 10 are produced from the reaction of Ta(NMe2)(5) with [Me3NH][nido-9-Me-7,8-C2B9H11] 5 and [Me3NH][nido-8-Me-7,9- C2B9H11] 6 respectively. Identities of the metallacarboranes 8, 9 and 10 are deduced by detailed multinuclear (B-11, C-13 and H-1) NMR spectroscopy. These geometries are supported by boron NMR shift predictions based on observed shifts of the known non-methylated analogues [3,3,3-(NMe2)(3)-closo-3,1,2- TaC2B9H10] 1 and [3,3,3-(NMe2)(3)-closo-3,1,2-TaC2B9H10] 2 and calculated shifts (GIAO-B3LYP/6-311G*//MP2/6-31G*) of the B- methyl carboranes, closo-3-Me-1,2-C2B10H11 11, 4-Me-1,2- C2B10H11 12 and 2-Me-1,7-C2B10H11 13. The molecular structure of 8 has been determined by X-ray diffraction.

Citation

Fox, M., Howard, J., Hughes, A., Malget, J., & Yufit, D. (2001). Synthesis of isomeric B-methylated tantalum carboranes, (Me₂N)₃TaC₂B₉H₁₀Me. Dalton Transactions, 2001(15), 2263-2269. https://doi.org/10.1039/b103353k

• Journal Article Type: Article
• Acceptance Date: Jun 5, 2001
• Online Publication Date: Jul 16, 2001
• Publication Date: Jul 16, 2001
• Deposit Date: Apr 20, 2007
• Journal: Dalton Transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 2001
• Issue: 15
• Pages: 2263-2269
• DOI: https://doi.org/10.1039/b103353k
• Public URL: https://durham-repository.worktribe.com/output/1555873