NMR and DFT studies of bis-quinolizidine complexes with LiClO4 and LiCl

Complexes made by 17-oxosparteine, α-isosparteine, and N16-oxides of sparteine and 2-methylsparteine with LiClO4 and LiCl have been synthesized and studied by NMR and DFT methods. All complexes have the 1:1 stoichiometry. The structure of 17-oxosparteine and α-isosparteine remains unchanged on complexation. The complexation with N16-oxides involves the inversion of the configuration at the N16 atom, converting ring C from a boat into a chair form with the oxygen atom engaged in the coordination process.