Chemistry Reference
In-Depth Information
Twisted Arenes
Kung K. Wang
Abstract
The nonbonded steric interactions of substituents at the crowded C4 and
C5 positions of phenanthrene cause the aromatic system to twist out of planarity.
Similarly, the presence of substituents at the C1 and C12 positions of benzo[
c
]
phenanthrene and at the C1 and C14 positions of dibenzo[
c
,
g
]phenanthrene are
responsible for the helical twists of the aromatic frameworks. Highly substituted
acenes, such as octamethylnaphthalene and decaphenylanthracene, also exhibit
substantial end-to-end twists. The X-ray structures of these compounds allow direct
measurements of the extent of the structural distortions. The configurational
stabilities of many twisted arenes have also been determined.
Keywords
1,12-Dimethylbenzo[
c
]phenanthrene 1,14-Disubstituted dibenzo[
c
,
g
]
phenanthrenes 4,5-Dimethylphenanthrene Helical aromatics
Contents
1 Introduction ................................................................................... 32
2 Twisted Phenanthrenes and Related Compounds ........................................... 34
2.1 4,5-Dialkylphenanthrenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
2.2 4,5-Diarylphenanthrenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.3 4,5-Dihalophenanthrenes ............................................................... 43
2.4 1,10-Disubstituted 4,7-Phenanthrolines ................................................ 44
2.5 1,10-Phenanthroline 1,10-Dioxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3 Twisted Benzo[
c
]phenanthrenes and Related Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
3.1 1,12-Dialkylbenzo[
c
]phenanthrenes . . . . . . . . . . . . . . . . ................................... 47
3.2 1,12-Diarylbenzo[
c
]phenanthrenes .................................................... 50
4 Twisted Dibenzo[
c
,
g
]phenanthrenes and Related Compounds . . ........................... 52
4.1
1,14-Dialkyldibenzo[
c
,
g
]phenanthrenes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
4.2
1,14-Diaryldibenzo[
c
,
g
]phenanthrenes . ............................................... 54
