Full multinuclear magnetic resonance analysis of 2,4-dinitrofluorobenzene

The complete assignment of the high-resolution NMR spectra 2,4-dinitrofluorobenzene was made, including the H-1, C-13, N-15, O-17 and F-19 nuclei. The C-13, F-19, 13 C,H-1, N-15,F-19 and N-15,H-1 one-bond and long-range coupling constants were determinated and the signs were obtained by means of two-dimensional correlation spectroscopy: H-1-H-1-COSY, C-13-H-1-COSY, C-13-H-1-COLOC and H-1-N-15, F-19-N-15 and F-19-C-13 HMQC. The spin-lattice relaxation times of 13C revealed their anisotropy components and it was evident that the dipole-dipole contribution of fluorine was an efficient mechanism for C-1 relaxation. The T(1)s of H-1 agreed with the classical description: at low temperature the main contribution is dipole-dipole relaxation and at high temperature the relaxation is dominated by the spin-rotation mechanism. A linear relationship between delta(13)C((exp)) and sigma(C) using GIAO (hybrid functional B3LYP) was found. (3)J(C-13, H-1) and the (1)J(C-13, C-13) have a relationship with the delocalization energies estimated by the NBO approach. Copyright (C) 2002 John Wiley Sons, Ltd.