Do the discrete dianions C2B9H112- exist? Characterisation of alkali metal salts of the 11-vertex nido dicarboranes, C2B9H112-, in solution

Fox, M.A.; Hughes, A.K.; Johnson, A.L.; Paterson, M.A.J.

Abstract

Detailed experimental solution-state NMR data are reported for the nine moisture-sensitive salts of M2C2B9H11 (M = Li, Na, K) 1–9 generated by deprotonation of 7,8-C2B9H13, 7,9-C2B9H12− and 2,9-C2B9H13 by butyllithium, sodium hydride and potassium hydride. Indicative of cation–anion interactions, the 11B, 13C and 1H chemical shifts depend on the identity of the cation and, to a lesser degree, the solvent. Computed NMR shifts generated from MP2-optimised geometries of C2B9H112−, LiC2B9H11− and NaC2B9H11− suggest that intimate ion-pair cluster anions MC2B9H11− are present in solutions of M2C2B9H11. As a test of the method of comparing experimental structures and chemical shifts with those from optimised geometries, the optimised geometries of the small carborane alkali metal salts M2C2B4H4(SiR3)2 (M = Li or Na, R = H or Me) were computed and shown to agree well with experimental structures.

Citation

Fox, M., Hughes, A., Johnson, A., & Paterson, M. (2002). Do the discrete dianions C2B9H112- exist? Characterisation of alkali metal salts of the 11-vertex nido dicarboranes, C2B9H112-, in solution. Journal of the Chemical Society. Dalton transactions (2001. Online), 2002(9), 2009-2019. https://doi.org/10.1039/b109804g

• Journal Article Type: Article
• Publication Date: 2002-03
• Journal: Dalton transactions.
• Print ISSN: 1472-7773
• Electronic ISSN: 1364-5447
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 2002
• Issue: 9
• Pages: 2009-2019
• DOI: https://doi.org/10.1039/b109804g