Abstract: In the present paper the calculation method of proton chemical shifts in the rings of fused benzenoid hydrocarbons and its berivatives and in its alkyl chains has been proposed.
The fused benzenoid compounds must be presented by Kckul'e formulas, and the proton chemical shifts of its rings can be calculated by following formula:
δ=σ_j.c-c+σ_mi.ci
σ_j.c-c are the effects of various ethenyls σ_mi.ci are the net ring-current effe-cts of six electrons orbitals of various benzene rings, and its calculation formula is:
σ_m.e=(1/2) ^m×1,52 m=n-u
The m are sim the order numbers of the net ring-current effects,and equal to the bond number n from the proton to the benzene ring minus the cis-form bond number u.
As concerns protons in 4. 5 positions or 9,10 positions, of phenanthrene ring and analogous phenanthrene rings,the phenanthrene ring effect must be used. As concerns protons in coronene ring, the coronene ring effect be used. And as concerns protons in the compounds ring with displaced groups, the group effects be used.
The calculation formula for the protons in the ring's alkyl chain is:
δ=σ_p.CH3+ασ_2.CH3+βσ_t.CH3+σ_i.G
This formula has been reported in the former article of this author.σ_i,G is a certain order effect of fused benzenoid radical.