Molecular structure of hydrated complex of trigonelline with L(+)-tartaric acid

作者：Dega Szafran Z^*; Dutkiewicz G; Kosturkiewicz Z; Szafran M; Barczynski P

来源：Journal of Molecular Structure, 2011, 991(1-3): 178-185.

DOI：10.1016/j.molstruc.2011.02.022

• Trigonelline
• L(+)-Tartaric acid
• Hydrogen bonds
• X-ray diffraction
• DFT calculations
• FTIR and NMR spectra

Crystal structure of the 1:1:1 complex of trigonelline with L(+)-tartaric acid and water has been determined by X-ray diffraction. The crystals are monoclinic, space group P2(1). Trigonelline is protonated and it is linked with the semi-tartrate anion by the COOH center dot center dot center dot OOC hydrogen bond of 2.475(2) angstrom. The semi-tartrate anions form infinite chains through the COOH center dot center dot center dot OOC hydrogen bonds of 2.599(2) angstrom. Water molecules play a role of double donors and double acceptors of hydrogen bonds with the semi-tartrate anions and link them into a three-dimensional net. In the optimized structure of the title complex at the B3LYP/6-31G(d,p) level of theory trigonelline is linked with L(+)-tartaric acid by the COO center dot center dot center dot HOOC hydrogen bond of 2.473 angstrom. The solid-state FUR spectrum is consistent with the X-ray results. The H-1 and C-13 NMR spectra elucidate the structure of the complex investigated in aqueous solutions. The value of pK(a) of trigonelline has been determined by the potentiometric titration of its hydrochloride.

• 出版日期2011-4-5