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Indexed by: Journal Article

Date of Publication: 2009-02-17

Journal: JOURNAL OF MOLECULAR STRUCTURE

Included Journals: EI、SCIE

Volume: 919

Issue: 1-3

Page Number: 21-25

ISSN: 0022-2860

Key Words: Morpholine; Molecular complex; Hydrogen bond; Electron transfer; Single crystal

Abstract: Morpholine absorbs CO2 and H2O in air to form a molecular complex: morpholinium-1-morpholinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction H-1 NMR, and FT-IR. The crystal structure was determined to be triclinic space group P (1) over bar with a = 6.494(2) angstrom, b = 8.098(4) angstrom, c = 13.533(4) angstrom, alpha = 96.99(3)degrees, beta = 102.57(2)degrees, gamma = 104.15(3)degrees, Z = 2. The complex is stabilized via three hydrogen bonds between the three components, N center dot center dot center dot O electrostatic attraction and O center dot center dot center dot O interaction (electron transfer). Due to electron transfer of the carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of free water molecules. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein. (c) 2008 Elsevier B.V. All rights reserved.