Richtlinien für die Präsentation der Methoden bei der Publikation von Rechenergebnissen – Teil A: Ab‐initio‐Berechnung der elektronischen Struktur von Molekülen

Die Übersetzung basiert auf den „Guidelines for Presentation of Methodological Choices in the Publication of Computational Results. B. Semiempirical Electronic Structure Calculations“ des Subcommittee on Theoretical Chemistry der Commission on Molecular Structure and Spectroscopy der Physical Chemistry Division der International Union of Pure and Applied Chemistry, veröffentlicht in Pure Appl. Chem. 2000 , 72, 1149–1452. Das Original wurde von James J. P. Stewart (Stewart Computational Chemistry, Colorado Springs, USA) für die Veröffentlichung vorbereitet.     

A Stable Saddle‐Shaped Polycyclic Hydrocarbon with an Open‐Shell Singlet Ground State

Diindeno‐fused bischrysene, a new diindeno‐based polycyclic hydrocarbon (PH), was synthesized and characterized. It was elucidated in detailed experimental and theoretical studies that this cyclopenta‐fused PH possesses an open‐shell singlet biradical structure in the ground state and exhibits high stability under ambient conditions (t _1/2=39 days). The crystal structure unambiguously shows a novel saddle‐shaped π‐conjugated carbon skeleton due to the steric hindrance of the central cove‐edged bischrysene unit. UV/Vis spectral measurements revealed that the title molecule has a very narrow optical energy gap of 0.92 eV, which is consistent with the electrochemical analysis and further supported by density functional theory (DFT) calculations.