Chlorinated Cubane-1,4-dicarboxylic Acids

0568796 - ÚOCHB 2025 RIV US eng J - Journal Article
Křížková, Adéla - Bastien, Guillaume - Rončević, Igor - Císařová, I. - Rybáček, Jiří - Kašička, Václav - Kaleta, Jiří
Chlorinated Cubane-1,4-dicarboxylic Acids.
Journal of Organic Chemistry. (2024). ISSN 0022-3263. E-ISSN 1520-6904
R&D Projects: GA ČR(CZ) GA20-13745S; GA MŠMT(CZ) LTAUSA19120
Research Infrastructure: e-INFRA CZ - 90140
Institutional support: RVO:61388963
Keywords : basis-sets * cubane * electron
OECD category: Organic chemistry
Impact factor: 3.6, year: 2022
Method of publishing: Open access
https://doi.org/10.1021/acs.joc.2c02872

Herein, we report radical chlorination of cubane-1,4-dicarboxylic acid leading preferentially to one monochlorinated cubane dicarboxylate (ca. 70%) that is accompanied by four dichlorinated derivatives (ca. 20% in total). The exact positions of the chlorine atoms have been confirmed by X-ray diffraction of the corresponding single crystals. The acidity constants of all dicarboxylic acids in water were determined by capillary electrophoresis (3.17 ± 0.04 and 4.09 ± 0.05 for monochlorinated and ca. 2.71 ± 0.05 and 3.75 ± 0.05 for dichlorinated cubanes). All chlorinated derivatives as well as the parent diacid showed high thermal stability (decomposition above 250 °C) as documented by differential scanning calorimetry. The probable reaction pathways leading to individual isomers were proposed, and the energies of individual transition states and intermediates were obtained using density functional theory calculations (B3LYP-D3BJ/6-311+G(d,p)). The relative strain energies for all newly prepared derivatives as well as for hypothetical hexahalogenated (fluorinated, chlorinated, brominated, and iodinated) derivatives of cubane-1,4-dicarboxylic acids were predicted using wavefunction theory methods. The hexafluorinated derivative was identified as the most strained compound (57.5 kcal/mol), and the relative strain decreased as the size of halogen atoms increased (23.7 for hexachloro, 16.7 for hexabromo, and 4.0 kcal/mol for the hexaiodo derivative).
Permanent Link: https://hdl.handle.net/11104/0340070


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