J . A m . Chem. SOC.1986, 108, 1716-1718
1716
Table 1. 1R Vibrations of Triplet 1,3-Perinaphthadiyl and Their
Polarizations exptl
calcd"
compd
t , cm-'
Kb)
K(z)
sym
t , cm-'
1A
2742 2761 3056
0.36 0.33' 0.28 0.35
0.44 0.22
x
2824
z
0.39 0.19
J'
2885 3011
z
3016
3066
sym
K,(y) = 0.26 K J y ) = K , b ) = 0.37' K z ( z ) = 0.23 K , ( z ) = K , ( z ) = 0.39' 1c
2046 2061
0.38 0.35
2237
0.22
2253
0.39
0.41
x
2081
0.26 0.36 0.23
z J'
2088 2208
z
2212
stretches and do not reproduce the large shift of the CH, as stretch in 1 although they presumably take full account of the special stability of phenalenyl. A crude comparison also can be made with published a b initio calculations" on the parent edge-to-edge .CH2CH2CH2.triplet. The calculated s and as stretches of the central CH, group are now in the opposite order than found in 1. With a multiplicative correction factor of 0.892. fitted to the as CH, stretch of cyclopropane, the C H 2 as stretch is predicted at 2824 cm-I, so that the striking shift we observe in 1 is again not reproduced. Thus, the observed very low frequency of the (3 C-H stretch in 1 does not currently have a satisfactory quantitative interpretation. Acknowledgment. This project was supported by the National Science Foundation, Grant CHE-84-21117, and by the awards of an N I H fellowship to J.H.P. and of a NATO fellowship to D.D.
K , b ) = 0.24 K , b ) = KJy) = 0.4Ic K,(z) =
0.22 K , ( z ) = K , ( z ) = 0.38'
MNDO, corrected by a multiplicative factor of 0.885, obtained by fitting the CH2 as stretch in propane. bSubject to a large experimental uncertainty.
