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The effect of carborane, bicyclo[2.2.2]octane and benzene on mesogenic and dielectric properties of laterally fluorinated three-ring mesogens
| Content Provider | Semantic Scholar |
|---|---|
| Author | Januszko, Adam Walerian Glab, Kristin L. Kaszyński, Piotr Patel, Kaushik Lewis, Robert Alden Mehl, Georg H. Wand, Michael |
| Copyright Year | 2006 |
| Abstract | Six series of structurally similar compounds containing 12- and 10-vertex p-carborane (A and B), bicyclo[2.2.2]octane (C), and benzene (D) were prepared and their mesogenic and dielectric properties investigated. Comparative analysis showed that all carborane derivatives form significantly less stable mesophases than their carbocyclic analogs, however they exhibit a relatively high shielding ability for lateral fluorination. Depression of the clearing temperature upon fluorination of series 1, 3, and 5 is approximately constant for each series A–D and correlates with the diameter of the ring (the slope = 14.8 °C A−1 and R2 = 0.997). Compounds in series 2 (X = F) were used as low concentration additives to a nematic host, 6-CHBT. Dielectric parameters were extrapolated to pure additives and analyzed using the Maier–Meier equation. The Kirkwood factors g and apparent order parameters Sapp that are required to reproduce the extrapolated dielectric values follow the trend in the size of ring . The smallest g (0.47) and the largest Sapp (6.3) are obtained for carborane 2A, and the largest g (0.69) and the smallest Sapp (0.7) are obtained for the terphenyl derivative 2D. The increase of Sapp in the series D→A corresponds to the increasing disorder of the nematic solution with increasing size of ring . |
| Starting Page | 3183 |
| Ending Page | 3192 |
| Page Count | 10 |
| File Format | PDF HTM / HTML |
| DOI | 10.1039/B600068A |
| Alternate Webpage(s) | https://www.vanderbilt.edu/AnS/Chemistry/omrg/Articles/JMC_3183_06.pdf |
| Alternate Webpage(s) | http://www.rsc.org/suppdata/jm/b6/b600068a/b600068a.pdf |
| Alternate Webpage(s) | https://doi.org/10.1039/B600068A |
| Volume Number | 16 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
