title: Synthesis of polyphenylene dendrimers related to "cubic graphite".
abstract: Four large, 6-fold symmetric, polyphenylene hydrocarbons have been prepared by short syntheses that chiefly employed alkyne trimerization, palladium-catalyzed coupling, and Diels-Alder reactions. The two largest of these molecules, hexakis[4'-(pentaphenylphenyl)biphenyl-4-yl]benzene (4, C(294)H(198)) and hexakis[4'-(2,3,4,5-tetraphenylphenyl)biphenyl-4-yl]benzene (5, C(258)H(174)) are substructures of "phenylogous cubic graphite", and the other two, hexakis(2',3',4',5',6'-pentaphenylbiphenyl-4-yl)benzene (26, C(258)H(174)) and hexakis(2',3',4',5'-tetraphenylbiphenyl-4-yl)benzene (25, C(222)H(150)) are strongly pitched, six-bladed molecular propellers. The X-ray crystal structure of compound 26 has also been determined; dendrimer 26 is at present the largest crystallographically characterized hydrocarbon.
authors.affiliation: Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Shen
authors.forename: Douglas M
authors.initials: DM
authors.lastname: Ho
authors.forename: Robert A
authors.initials: RA
authors.lastname: Pascal