Synthesis and crystal structure of a spiro amine: 3,9,12-triaza-6-azoniaspiro[5,8]tetradecane chloride trihydrochloride dihydrates

A spiro amine, 3,9,12-triaza-6-azoniaspiro[5.8]tetradecane chloride trihydrochloride dihydrate, was synthesized from 1-(toluenesulfonyl)-1,3,7-triazacyclononane and N,O,O'-tris(p-toluenesulfonyl)bis(2-hydroxyethyl)amine. The structure of 3,9,12-triaza-6-azoniaspiro[5.8]tetradecane chloride trihydrochloride dihydrate has been solved by the X-ray diffraction technique at T = 120 K; Mr = 380.2, orthorhombic, Pbca, a = 18.922(4), b = 21.706(4), c = 8.512(4) .ANG., Z = 8, Dx = 1.44 g cm-3, MoKa = 0.71073 .ANG., m = 6.9 cm-1, F(000) = 1624, R = 0.056 for 1921 unique reflections. The nine-membered ring adopts a triangular [333] conformation with the nitrogen atoms occupying the corner positions. The six-membered ring has a chair conformation. The 3,9,12-triaza-6-azoniaspiro[5.8]tetradecane cations are connected through hydrogen bonds to the chloride ions and the water mols. The concn. acid dissocn. consts. have been detd. potentiometrically, and the following values were obtained: pKa1 = 0.55(6), pKa2 = 5.23(3), pKa3 = 7.11(5) (1 M NaCl, 25 DegC). The 13C NMR spectrum is in agreement with a time-averaged C2v symmetry in soln.