Quantitative empirical treatment of 13 C NMR chemical shifts of aliphatic halides

The 13 C NMR chemical shifts of the α, β, γ and δ carbons of aliphatic fluorides, chlorides, bromides and iodides can be reproduced by a four‐parameter equation; the charge Q on the carbon atom, the number of hydrogen atoms three bonds away, N 3H , the interactions of the polarizabilities of the halogen atoms one bond away with the hydrogens present in the first sphere, as represented by P X N 1H , and the polarizabilities of halogens in the second sphere, P X (2). A regression coefficient of 0.9714 and a standard deviation of 4.85 ppm are obtained for all aliphatic halides in which the R skeleton includes alkyl, acyclic and bicyclic rings. For alkyl compounds only the correlation is of the order of R = 0.997 and the standard deviation is less than 2 ppm. Here the influence of C, H, F, Cl, Br and I are reproduced quantitatively.