From Hexaphenylbenzene to 1,2,3,4,5,6-Hexacyclohexylcyclohexane.

Dillenburger, Marcel; Qiu, Zijie; Ju, Cheng-Wei; Müller, Beate; Morsbach, Svenja; Schollmeyer, Dieter; Narita, Akimitsu; Müllen, Klaus

The hydrogenation of hexaphenylbenzene was studied, affording novel partially hydrogenated hexacyclohexylbenzene (HCB) as well as fully hydrogenated 1,2,3,4,5,6-hexacyclohexylcyclohexane (HCC) as an unprecedented "oligocyclohexyl" molecule. The reaction process was analyzed by mass spectrometry with atmospheric pressure chemical ionization and high-performance liquid chromatography. From a crude product mixture, two different crystals with flake- and block-shapes could be grown and analyzed by X-ray crystallography, revealing their structures as HCB and HCC. While a geared arrangement of cyclohexyl substitutes was found in HCB, two isomeric structures were identified in HCC crystal with chair and twist-boat conformations of the central cyclohexane.