title: Electron Density Analysis of the "O-O" Charge-Shift Bonding in Rubrene Endoperoxide.
abstract: Rubrene endoperoxide p-xylene (1) has been obtained in crystalline form from recrystallization and purification of the organic semiconductor, rubrene, and for the first time characterized by single-crystal X-ray diffraction methods. 1 is produced by reaction of rubrene with molecular oxygen to create rubrene endoperoxide, C42H28O2, in which an O2-bridge is joining the two phenyl-substituted C atoms opposite each other in the second of the four aromatic rings in tetracene thereby breaking the resonance along the tetracene moiety. The electron density distribution of 1 reveals that the intramolecular O-O bond is best characterized as charge-shift bonding with loss of electronic concentration in the interatomic region evidenced by the Laplacian. Likewise the ELI-D indicates little electron localization in this region. Furthermore, source function and ELI-D analysis of 1 clearly quantifies the lack of electronic delocalization across the six-membered ring that carries the peroxide-bridge.
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.|Division of Physics, Faculty of Pure and Applied Sciences, University of Tsukuba , 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.
authors: Venkatesha R
authors: VR
authors: Hathwar
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors: Maja K
authors: MK
authors: Thomsen
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors: Mohammad Aref H
authors: MA
authors: Mamakhel
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors: Mette Ø
authors: MØ
authors: Filsø
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors: Jacob
authors: J
authors: Overgaard
authors: Center for Materials Crystallography and Department of Chemistry, Aarhus University , Langelandsgade 140, DK-8000 Aarhus C, Denmark.
authors: Bo B
authors: BB
authors: Iversen