Crystal structure and spectroscopic properties of N-methylmorpholine betaine phosphate

The crystal and molecular structure of N-methylmorpholine betaine phosphate was solved by X-ray diffraction and four O .H .O hydrogen bonds were found . Two hydrogen atoms of phosphoric acid link both oxygen atoms of the N-met hylmorpholine betaine by one short (O . . .O = 2.466(3) Angstrom) and one l onger (O . . .O = 2.557(3) Angstrom) hydrogen bonds. The third hydrogen ato m of phosphoric acid occupies the special position in the inversion centers of the unit cell and links PO4 groups by two short and symmetrical hydroge n bonds (2.464(3) and 2.444(3) Angstrom) into infinite chains parallel to t he x-axis. The FTIR spectrum of the complex shows a broad and intense absor ption in the 3000-400 cm(-1) region. Two different isotope effects (nu OH/n u OD) suggest that the absorption of the longer hydrogen bond is located in the 3000-1600 cm(-1) region, but that attributed to the shorter hydrogen b onds is in the 1600-400 cm(-1) region. (C) 2000 Elsevier Science B.V. All r ights reserved.