Crystal structure of di-(N-methylmorpholine betaine)-L(+)-tartrate

The crystal structure of di-(N-methylmorpholine betaine)-L(+)-tartrate has been determined by X-ray diffraction method. Crystals are orthorhombic, space group P2(1)2(1)2(1), a = 9.580(1), b = 12.208(1), c = 18.677(1) Angstrom, Z = 4, R = 0.037. The molecule of L(+)-tartaric acid appears in the extended form with the hydroxyl groups as well as carboxyl groups in anti positions. The molecule is involved in a number of the intra- and intermolecular hydrogen bonds. The COOH groups of the tartaric acid link two non-equivalent N-methylmorpholine betaine molecules by a short, intermolecular O-H...O bonds of the lengths 2.456(1) and 2.510(1) Angstrom. The OH groups form two different bifurcated hydrogen bonds, the intramolecular with the C=O oxygen atoms (2.641(2) and 2.638(2) Angstrom) and the intermolecular (2.919(2) and 3.084(2) Angstrom) with neighbouring tartaric acid molecules, and link complexes in the zigzag ribbon parallel to the x-axis. The morpholine rings of both betaine molecules are in chair conformation with methyl groups in an axial position and CH2COO- substituents in an equatorial one. lit the crystals and the PM3-optimized structures there is no symmetry, both in the tartrate and N-methylmorpholine betaine moieties. FTIR spectrum confirms the complex structure of the investigated molecule. (C) 2002 Elsevier Science B.V. All rights reserved.