Ab initio 13C and 19F NMR chemical shifts calculations for halogenated propanes

Ab initio GIAO calculations were carried out on halogenated propanes, CClF2-CF2-CXYZ (X, Y, Z; H, Cl or Fl and CF3-CXY-CHCl2 (X, Y; ii, Cl or Fl, to estimate their F-19 and C-13 NMR chemical shifts values, considering all their rotamers. Although, the calculated values tend to be larger for the F-19 NMR chemical shifts and smaller for the C-13 NMR chemical shifts than the observed values, the calculated values show fairly good linear relationships with the observed values. The Hartree-Fock 6-31G(d) level of theory is of sufficient accuracy for application of assignment and prediction of C-13 and F-19 NMR chemical shifts of halogenated propanes. (C) 2000 Elsevier Science S.A. All rights reserved.