Relative substituent position on the strength of pi-pi stacking interactions.
It was observed that the relative position of the arene substituents have a profound influence on the strength of pi-pi stacking in the 9-benzyl substituted triptycene system. A new series of model compounds (3a-i) capable of revealing quantitatively pi-pi stacking interactions was studied. This series of compounds (3a-i) has an ortho substituted methyl group in one of the two interacting arenes and the syn/anti ratios were determined and compared to a series previously studied compounds (4a-i) that have a para methyl group on the corresponding arene. A greater than 50% increase in the strength of pi-pi stacking interactions was observed with the methyl group in the ortho position comparing to that in the para position. No difference in pi-pi stacking interactions was observed when the other aromatic ring was a pentafluorobenzoate group.
Gung
Benjamin W
BW
Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056.
Emenike
Bright U
BU
Alverez
Celeste N
CN
Rakovan
John
J
Kirschbaum
Kristin
K
Jain
Nirbhay
N