Complete prediction of the H-1 NMR spectrum of organic molecules by DFT calculations of chemical shifts and spin-spin coupling constants

H-1 NMR chemical shifts and coupling constants for several aromatic and ali phatic organic molecules have been calculated with DFT methods In some test cases (furan, o-dichlorobenzene and n-butyl chloride) the performance: of several functionals and basis sets has been analyzed, and the various contr ibutions to spin-spin coupling (Fermi-contact. diamagnetic and para-magneti c spin-orbit) have been evaluated. The latter two components cancel each ot her, so that the calculation of the contact term only is sufficient for an accurate evaluation of proton-proton couplings. Such calculated values are used to simulate the H-1 NMR spectra of organic molecules with complicated spin systems (e.g. naphthalene, o-bromochlorobenzene), obtaining a generall y very good agreement with experimental spectra with no prior knowledge of the involved parameters.