The transfer of electronic energy from the triplet states of coronene and anthraquinone to that of anthracene may be observed in bromobenzene, but does not occur in solutions of Lucite plastic; this finding supports the proposal that collision is necessary to efficient triplet—triplet energy transfer. Using these systems, the photoreactive state of anthracene with carbon tetrachloride was studied. Comparison was made of the reaction rates in carbon tetrachloride; (a) when anthracene was excited in such a way as to populate both the excited singlet and triplet states, and (b) when anthracene was excited by energy transfer so that it was populated only in its triplet state. The results show within experimental error that it is possible for the entire photoreaction of anthracene and CCl4 to take place via the triplet state of anthracene.

1.
F.
Wilkinson
,
J. Phys. Chem.
66
,
2569
(
1962
).
2.
E. J.
Bowen
and
K. K.
Rohatgi
,
Discussions Faraday Soc.
14
,
146
(
1953
).
3.
E. J.
Bowen
and
B.
Brocklehurst
,
Trans. Faraday Soc.
51
,
774
(
1955
);
R.
Hardwick
,
J. Chem. Phys.
26
,
323
(
1957
).
4.
G.
Porter
and
F.
Wilkinson
,
Proc. Roy. Soc. (London)
A264
,
1
(
1961
);
A.
Terenin
and
V.
Ermolaev
,
Trans. Faraday Soc.
52
,
1042
(
1956
).
5.
S. Kusuhara and E. R. Hardwick (to be published).
6.
This requires that the anthracene singlet not be depleted by reaction with CCl4, thus reducing the argument from necessity to sufficiency. It is well known that CCl4quenches the anthracene singlet, but whether this quenching occurs partly via reaction is not known.
This content is only available via PDF.
You do not currently have access to this content.