Synthesis and crystal and molecular structure of 1,2-Di(N-piperidyl)ethane-bis-N-oxide tetrahydrate

Authors:

• Mariusz Jaskólski,
• Z. Kosturkiewicz,
• D. Mickiewicz-Wichłacz,
• M. Wiewiórowski

Abstract

1,2-Di(N-piperidyl)ethane-bis-N-oxide (VIII) has been synthesized and obtained in crystalline form as VIII · 4H₂O. IR spectra of these crystals and IR and ¹H NMR spectra of the solutions of VIII are presented and discussed. The pK′_MCS and pK′_H2O values for VIII and for similar systems as well as for sparteine and its derivatives are reported and analysed, and structural conclusions are drawn. In a MCS/H₂O (8:2, v/v) system the "cisoidal" rotamers (with intramolecular H bond) seem to prevail for both VIII · H⁺ and VIII · 2H⁺ cations, while in H₂O solutions the "transoidal" forms are predominant. Solid state IR spectra indicate that in VIII · HClO₄ the VIII · H⁺ cation exists in "cisoidal" form and in VIII · 2HClO₄ the appropriate cation is in "transoidal" conformation and involved in H-bond association with perchlorate anions. Full X-ray structure determination for VIII · 4H₂O is reported. The VIII molecules are located on centres of symmetry. The results are discussed and compared with predictions. The fine network of H bonds in the crystals of VIII · 4H₂O is discussed in detail and explanation of the behavior of H₂O molecules in VIII · 4H₂O on heating is given. © 1979.