The 13C NMR chemical shifts of the a , b , g and d carbons of 17 sets of aliphatic halides (F, Cl, Br and I ), including mono, bi and tricyclic componds, can be reproduced by a linear equation composed with two constants and two variables: d R-X = A * d R-X1 + B* d R-X2, where A and B are constants derived from multilinear regression of 13C chemical shifts observed; d R-X, the chemical shifts of aliphatic halide (R-X) and d R-X1, d R-X2 the chemical shifts of other halides. Were observed better correlation for aliphatic bromides (R-X) by using data of aliphatic fluorides (R-X1) and aliphatic iodides (R-X2), resulting R2 of 0.9989 and average absolute deviation (AVG) of 0.39 ppm. For the clorides (R-X), the better correlation were observed by using data of bromides (R-X1) and iodides (R-X2), R2 of 0.9960 and AVG of 0.76ppm. For the fluorides (R-X) were observed better correlation with data of bromides (R-X1) and iodides (R-X2), R2 of 0.9977 and AVG of 1.10 ppm. For the iodides (R-X) were observed better correlation with data of fluorides (R-X1) and bromides (R-X2), R2 of 0.9972 and AVG of 0.60.
Empiric equation; aliphatic halide; 13C NMR; chemical shifts
