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Updated: Jun 14, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Ring-alkyl connecting group effect on mesogenic properties of p-carborane derivatives and their hydrocarbon analogues
Aleksandra Jankowiak1, Piotr Kaszynski, William R Tilford
1Organic Materials Research Group, Department of Chemistry, Vanderbilt University, Box 1822 Station B, Nashville, TN 37235, USA.
Abstract:
The effect of the phenyl-alkyl connecting group on mesogenic properties of several series of isostructural compounds containing p-carborane (A and B), bicyclo[2.2.2]octane (C), and benzene (D) was investigated using thermal and optical methods. Results demonstrated that mesophase stability in the series containing A-D follows the order (Alk)CH₂CH₂- < (Alk)OOC- < (Alk)CH₂O- < (Alk)COO-. Surprisingly, the connecting groups (Alk)CH₂CH₂- and (Alk)OOC- destabilize the mesophase significantly stronger for carboranes (A and B) than for carbocyclic derivatives (C and D). Analysis indicates that this effect may have quadrupolar and conformational origin.
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