Hexacyclohexylcyclohexane Synthesized

  • Author: ChemistryViews.org
  • Published: 27 July 2020
  • Copyright: Wiley-VCH Verlag GmbH & Co. KGaA
  • Source / Publisher: Journal of the American Chemical Society/ACS Publications
  • Associated Societies: American Chemical Society (ACS), USA
thumbnail image: Hexacyclohexylcyclohexane Synthesized

Polyphenylenes, i.e., compounds made from several phenyl rings, can have a variety of linear, branched, or even dendritic structures. Much less is known about related saturated structures made from cyclohexyl rings. There are a few studies on linear polycyclohexylene and branched "oligocyclohexyls". However, larger oligocyclohexyls are rare, and 1,2,3,4-tetracyclohexylcyclohexane, i.e., a cyclohexane with four cyclohexyl substituents, had been the largest example reported so far.

Zijie Qiu, Akimitsu Narita, Klaus Müllen, Max Planck Institute for Polymer Research, Mainz, Germany, and colleagues have investigated the hydrogenation of hexaphenylbenzene (HPB) and obtained the partially hydrogenated hexacyclohexylbenzene (HCB), as well as fully hydrogenated 1,2,3,4,5,6-hexacyclohexylcyclohexane (HCC, pictured). The hydrogenation of HPB was carried out with a commercially available Pd/C catalyst in an autoclave at 150 °C and 250 bar. Mass spectrometry and high-performance liquid chromatography (HPLC) were used to monitor the reaction.

The crude product contained several compounds with different degrees of hydrogenation. Due to their similar structures, separation using silica-gel chromatography or large-scale recrystallization proved impossible. However, the team was able to grow two differently shaped types of crystals via a slow vapor diffusion of methanol into a chloroform solution of the crude product. The crystals were sorted and separated by hand. X-ray crystallography showed that these two types of crystals were composed of HCB and HCC, respectively.

According to the researchers, the work could serve as a model study for preparations of other fully saturated polyphenylene counterparts. However, this would require catalyst systems with higher hydrogenation efficiency.





Article Views: 817

Sign in Area

Please sign in below

Additional Sign In options

Please note that to comment on an article you must be registered and logged in.
Registration is for free, you may already be registered to receive, e.g., the newsletter. When you register on this website, please ensure you view our terms and conditions. All comments are subject to moderation.

Article Comments - To add a comment please sign in

Bookmark and Share

If you would like to reuse any content, in print or online, from ChemistryViews.org, please contact us first for permission. more


ChemistryViews.org on Facebook

ChemistryViews.org on Twitter ChemistryViews.org on YouTube ChemistryViews.org on LinkedIn Sign up for our free newsletter

Magazine of Chemistry Europe (16 European Chemical Societies)published by Wiley-VCH