TABLE 1.

Computed ¹³C hyperfine tensors for different conformations of isolated 2,3-dimethoxy-5,6-dimethyl-1,4-benzoquinone radical anion

Relative stabilitya	Dihedral angle τ2b (Group 2)	Dihedral angle τ3b (Group 3)	Isotropic hfic constant and three principal values of hfi tensor
			13C-O-CH3		C-O-13CH3
			Group 2	Group 3	Group 2	Group 3
cm−1	degrees	degrees	MHz
0a	−123	124	−2.2	−2.2	1.2	1.2
			9.5, −7.8, −8.3	9.5, −7.8, −8.3	2.0, 1.2, 0.6	1.9, 1.1, 0.6
727	−78	142	−1.4	−3.0	6.4	0.8
			10.9, −7.3, −7.7	8.7, −8.7, −9.2	7.4, 5.9, 5.9	1.4, 0.6, 0.2
830	−49	−119	−0.3	−3.5	5.2	0.7
			14.6, −7.4, −8.0	5.4, −7.8, −8.2	6.2, 4.7, 4.6	1.3, 0.7, 0.1
975	−121	−120	−2.4	−2.4	1.6	1.6
			9.5, −8.1, −8.6	9.5, −8.1, −8.6	2.3, 1.5, 0.9	2.4, 1.6, 1.0
1451	−67	−74	−0.7	−1.1	8.9	8.5
			13.6, −7.6, −8.1	12.6, −7.7, −8.2	9.9, 8.4, 8.3	9.5, 8.0, 8.0
1498	−120	143	−3.0	−2.4	1.2	0.8
			6.7, −7.6, −8.1	9.7, −8.2, −8.8	1.9, 1.2, 0.6	1.5, 0.7, 0.2
1505	180	180	−4.8	−4.8	−0.9	−0.9
			2.4, −8.1, −8.7	2.6, −8.1, −8.9	−0.4, −1.1, −1.2	−0.4, −1.1, −1.2
3824d	180	0	−5.8	−2.2	−0.7	−1.0
			0.5, −8.7, −9.2	8.6, −7.3, −7.9	−0.2, −0.9, −1.1	−0.6, −1.1, −1.3

^a Corresponds to the most stable conformation.

^b Dihedral angles are defined in the same manner, D(X_b-X_a-C_ortho-C_ortho), as in Ref. 49.

^c hfi, hyperfine interaction.

^d Saddle point.