8587 Table I. Proton Nmr Parameters for Methylcyclopentadienes
1 1.978
H4E .,EH, W,,,
n,
A,
2 5.996 I
Jiz
Jz 3
Jz 4
+1.9
+1.4
J2 5
2,
2 1.911 Jiz
-1.5
H4
s
fl.4 7
2.788 5 7
Jz 6
-
+2.0
J14
Jl 5
J3 4
J3 5
J4 5
+1.4
$1.8
+1.8
+5.4
-1.4
+1.4
Chemical shiftsa5 3.03 Coupling constantsb J C H a , H a 2: 7 . 8
r
H1
A1
H*zHH
-Chemical shiftsa3 6.43 Coupling constantsb
7
1 6.21
d
H,
J4
-1.5
J13
3; Ji
+5.4
---. J3 6
3 4 6.230 6.230 Methyl proton coupling constantsb J2 3 Jz 4 -0.4 +0.4 Other coupling constantsb
Olefinic protons -6.35
H,
Ji 5
-0.2
-Chemical shiftsa-
r
Aa
J3 4
-1.3
1
5.834
CH,
HJ
7
$0.4 -0.4 -Other coupling constantsb-
7
r
5 2.695
J14
J13
-1.6
---
Chemical shifts. 3 4 6.246 6.066 -Methyl proton coupling constantsb
2 6.43
z
5.05
Jl 3
1.09
a Chemical shifts in ppm downfield from TMS. from ref 9.
b
J2 3
J14
1.98
1.93
Coupling constants in Hz.
c
7
(CH315 1.08
-5
4 6.27
---
2.80
J2 5
J15
1.33
-1.51
Data from ref 5 for nonequilibrated conditions.
Data
completely responsible for the spin coupling in such The results of the complete analysis are given in conjugated systems as cis-dienes.'O Table I. In accordance with the previously reported data no AI isomer has been detected. The ratio of (10) (a) R. A. Hoffman, Mol. Phys., 1,326(1958); (b) P. Albriktson, vinylic isomers is equal to almost 1 : 1 (accuracy f 1 A. V. Cunliffe, and R. I
