SIMULATION OF C-13 NMR CHEMICAL-SHIFTS FOR POLYCHLORINATED AND POLYBROMINATED OXYBENZENES WITH 2-PARTICLE INCREMENT SCHEME

A two-particle system of OY-Cl and OY-Br mixed increments for predicti ng C-13 NMR chemical shifts of polyhalogenated polyoxybenzenes has bee n developed. It has been found that only the ortho- and pore-interacti ons of the OY and Hal substituents contribute significantly to the C-1 3 chemical shifts and that the ortho-effects of the OY located between Hal and H and those of the OY located between two Hal atoms are diffe rent. Additional effects are due to solvating solvents. The increment scheme is predictive over the whole class of compounds under considera tion and may be realized on personal computers.