Centrohexaindane: six benzene rings mutually fixed in three dimensions - solid-state structure and six-fold nitration

• Published in: Physical chemistry chemical physics : PCCP Vol. 18; no. 17; pp. 11722 - 11737
• Main Authors: Kuck, Dietmar, Linke, Jens, Teichmann, Lisa Christin, Barth, Dieter, Tellenbröker, Jörg, Gestmann, Detlef, Neumann, Beate, Stammler, Hans-Georg, Bögge, Hartmut
• Format: Journal Article
• Language: English
• Published: England 28.04.2016
• Subjects: Benzene; Electronics; Isomers; Molecular structure; Neopentane; Nitration; Rings (mathematics); Three dimensional
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c5cp07005h

The solid-state molecular structure of centrohexaindane (), a unique hydrocarbon comprising six benzene rings clamped to each other in three dimensions around a neopentane core, and the molecular packing in crystals of ·CHCl3 are reported. The molecular Td-symmetry and the Cartesian orientation of the six indane wings of in the solid state have been confirmed. The course and limitation of electrophilic aromatic substitution of are demonstrated for the case of nitration. Based on nitration experiments of a lower congener of , tribenzotriquinacene , the six-fold nitrofunctionalisation of has been achieved in excellent yield, giving four constitutional isomers, two nonsymmetrical ( and ) and two C3-symmetrical ones ( and ), all of which contain one single nitro group in each of the six benzene rings. The relative yields of the four isomers (∼3 : 1 : 1 : 3) point to a random electrophilic attack of the electrophiles at the twelve formally equivalent outer positions of the aromatic periphery of , suggesting electronic independence of its six aromatic π-electron systems. In turn, the pronounced conformational rigidity of the centrohexacyclic framework of enables the unequivocal structural identification of the isomeric hexanitrocentrohexaindanes by (1)H NMR spectroscopy.