Crystal structure and rotational barrier of octakis(bromomethyl)naphthalene.
Octakis(bromomethyl)naphthalene (4) adopts in the crystal a chiral conformation with a helical central naphthalene core and the bromomethyl groups disposed in an alternate up-down "in" arrangement. According to MM3 calculations, this conformation is less stable than the corresponding all alternated "out" form, while B3LYP/LANL2DZ calculations suggest the opposite stability order. The topomerization barrier (16.0 kcal mol(-1)) is ascribed to an enantiomerization process requiring 180 degrees rotation of all the bromomethyl groups and reversal of the helical sense of the naphthalene core.
Simaan
Samah
S
Department of Organic Chemistry, The Hebrew University of Jerusalem, Israel.
Marks
Vered
V
Gottlieb
Hugo E
HE
Stanger
Amnon
A
Biali
Silvio E
SE