L-Tryptophan L-tryptophanium bromide: Anhydrous and monohydrate

L-Tryptophan L-tryptophanium bromide (I) and L-tryptophan L-tryptophanium bromide monohydrate (II) are new salts with (A center dot center dot center dot A(+)) type dimeric cation. The salt (I) crystallizes in the monoclinic system (space group P2(1), Z = 2) and is isostructural with respective chloride (V.V. Ghazaryan et al., Spectrochim. Acta A 136(2015) 743-750), while the salt (II) was obtained previously (T. Takigawa et al., Bull. Chem. Soc. Jap. 39(1966) 2369-2378) and described as hemyhydrate without structure determination. The salt (II) crystallizes in orthorhombic system (space group P2(1)2(1)2(1), Z = 4). The dimeric cations in (I) and (II) are formed by O-H center dot center dot center dot 0 hydrogen bonds with the O center dot center dot center dot O distances equal to 2.538(3) angstrom and 2.481(3) angstrom respectively. The infrared and Raman spectra of the crystals are studied and compared with the spectra of L-tryptophan L-tryptophanium chloride and L-tryptophanium bromide. (c) 2015 Elsevier B.V. All rights reserved.