The Structure of Hexabenzotriphenylene and the Problem of Overcrowded “<i>D</i><sub>3</sub><i><sub>h</sub></i>” Polycyclic Aromatic Compounds Lisa Barnett Douglas M. Ho Kim K. Baldridge Robert A. Pascal 10.1021/ja983471i.s001 https://acs.figshare.com/articles/dataset/The_Structure_of_Hexabenzotriphenylene_and_the_Problem_of_Overcrowded_i_D_i_sub_3_sub_i_sub_h_sub_i_Polycyclic_Aromatic_Compounds/3673008 Hexabenzotriphenylene (<b>1</b>, dibenzo[<i>f,j</i>]phenanthro[9,10-<i>s</i>]picene) has been prepared in 5% yield by vacuum pyrolysis of phenanthrene-9,10-dicarboxylic anhydride, and its X-ray structure has been determined. Compound <b>1</b> is a strongly twisted, <i>D</i><sub>3</sub>-symmetric molecular propeller, in contrast to other highly substituted triphenylenes (perfluoro- and perchlorotriphenylene) which adopt <i>C</i><sub>2</sub>-symmetric conformations. Computational studies of these and other overcrowded, nominally <i>D</i><sub>3</sub><i><sub>h</sub></i>-symmetric, polycyclic aromatic compounds are reported, and the origins of their conformational preferences and the adequacy of various computational methods for treating these compounds are discussed. 1999-01-14 00:00:00 origin Compound 1 C 2 compound Aromatic phenanthro triphenylene D 3 h Hexabenzotriphenylene picene Polycyclic Overcrowded perfluoro Computational studies vacuum pyrolysis anhydride phenanthrene conformation polycyclic adequacy dibenzo propeller Problem method D 3 contrast perchlorotriphenylene preference