Synthetic routes to carbon substituted cobalt bis(dicarbollide) alkyl halides and aromatic amines along with closely related irregular pathways

0584541 - ÚACH 2025 RIV GB eng J - Journal Article
Nekvinda, Jan - Bavol, Dmytro - Litecká, Miroslava - Tüzün, Ece Zeynep - Dušek, Michal - Grüner, Bohumír
Synthetic routes to carbon substituted cobalt bis(dicarbollide) alkyl halides and aromatic amines along with closely related irregular pathways.
Dalton Transactions. Roč. 53, č. 13 (2024), s. 5816-5826. ISSN 1477-9226. E-ISSN 1477-9234
R&D Projects: GA ČR(CZ) GA21-14409S; GA MŠMT LM2023051
Institutional support: RVO:61388980 ; RVO:68378271
OECD category: Inorganic and nuclear chemistry; Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D)
Impact factor: 4, year: 2022
Method of publishing: Open access

Carbon substituted cobalt bis(dicarbollide) alkyl halides [(1-X-(CH2)n-1,2-C2B9H10)(1,2-C2B9H11)-3,3′-Co]Me4N (X = Br, I, n = 1-3) are prepared in high yields (>90%) from their corresponding alcohols without side skeletal substitutions. These species offer access to the synthesis of aromatic cobalt bis(dicarbollide) amines, however only for particular terminal halogen substitution, the propylene pendant arm, and under appropriately controlled reaction conditions. Thus, the compounds substituted at cage carbon atoms with a propylene linker and terminal aromatic amine groups could be prepared. In other cases, numerous irregular reaction pathways occur, undoubtedly as a consequence of the bulky anionic boron cage in close proximity to the reaction site. Among them, an unusual intramolecular hydroboration forming rigidified carbon-to-boron bridged isomeric anions with an asymmetric structure that correspond to formulae [(1,8′-μ-C2H4)-(1,2-C2B9H10)(1′,2′-C2B9H10)-3,3′-Co]− and [(1,7′-μ-C2H4)-(1,2-C2B9H10)(1′,2′-C2B9H10)-3,3′-Co]− is described herein and the former isomer is structurally characterized. This product with a restrained geometry is widely accessible through nucleophile and/or thermally induced decomposition of (pseudo)halides attached to the cage via an ethylene linker. Surprisingly enough, also doubly bridged isomeric species [(1,8-μ-C2H4-1,2-C2B9H9)2-3,3′-Co]− and [(1,7-μ-C2H4-1,2-C2B9H9)2-3,3′-Co]− are available in good yield using these methods. Furthermore, other more typical side reactions are discussed, i.e. nucleophilic reactions of propyl halides with Me3N formed apparently by disproportionation of Me4N+ at higher temperatures or with pyridine used as a base.
Permanent Link: https://hdl.handle.net/11104/0352638


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