Molecular and crystal structure of 6-methylsparteine diperchlorate

Abstract

The crystal structure determined by X-rays and the¹³C-NMR spectra of 6-methylsparteine diperchlorate, [C₁₆H₃₀N₂]²⁺*2C1O ⁻₄ , are presented. The title compound was obtained by chemical transformations of sparteine. The crystals are monoclinic,P2₁, the finalR being 0.075 for 1441 independent reflections. The quinolizidine moieties (piperidine-rings systemsA/B andC/D) are both preset in thetrans configuration; the piperidine ringsA, B, C andD have a chair, chair, boat, and chair conformation, respectively.¹³C-NMR spectra revealed the same conformation in DMSO-²H₆-solution as in the crystal. The two protonated nitrogen atoms are each hydrogenbonded to a different perchlorate anion: N(1)⋯O(2) is 3.003(11) and N(16)⋯O(8) is 2.940(14) Å. The two perchlorate anions show a strong orientational disorder; similarly large vibrational parameters are observed for the terminal atoms of the cation and for the atoms in flexible quinolizidine moietyC/D.