Ab initio calculations of spin-spin coupling constants in anhydrodeoxythymidines

For relatively large organic molecules (containing 16 non-hydrogen atoms ea ch), anhydrodeoxythymidines, three- ((3)J(HH)) and two-bond ((2)J(HH)) H-1- H-1 and one-bond H-1-C-13 ((1)J(CH)) spin-spin coupling constants (J-coupli ngs) were determined both experimentally and theoretically using NMR spectr oscopy and density functional theory (DFT). A very good agreement between D FT-predicted and measured values was obtained for (3)J(HH) (rmsd = 0.4 Hz). (2)J(HH) and 1JCH were underestimated relative to the experiment. For all J-couplings investigated, noncontact contributions were negligible or cance led each other out. In general, the level of agreement between DFT and expe riment is very promising.