Crystal structure of (S)-N-(1,3-dimethylimidazolidin-2-ylidene)- N-(1-phenylethyl)ammonium chloride, [C13H20N3]Cl

Abstract

Experimental detailsHatoms were located on difference fourier map, but refined with fixed individual displacement parameters using ar iding model with d(C-H) ranging from 0.93 to 0.98 Å,except for H3 of the ammonium ion which is refined free because of its relevance for the intermolecular hydrogen bond. In addition, the methyl groups were allowed to rotate but not to tip. DiscussionThe absolute configuration of the title compound, as known from the starting material (S)-1-phenyl-ethylamine, was confirmed by the absolute structure determination by X-ray data indicated by the Flack parameter of x=0 .01(11). The imidazolidine ring is showing af lat conformation forced by the guanidinium system C1, N1, N2 and N3 and is characterized by ar.m.s. d =0.0344 Å of the best plane formed by the atoms N1, C1, N2, C2 and C3. N1 and N2 are showing aslight pyramidalization, where the methyl group C4 lies 0.43 Å above and the methyl group C5 −0.34 Å below this plane. Astrong intermolecular hydrogen bond between the ammonium ion N3−H3 as donor and the chlorine ion Cl1 as acceptor is evident. The H3···Cl1 distance is 2.32(3) Å and the angle N3−H3···Cl1 is 174(3)°.