Structure and vibrational spectra of l-alanine l-alaninium picrate monohydrate

Preparation, crystal and molecular structure as well as vibrational spectra of the crystal l-alanine l-alaninium picrate monohydrate are described. The title crystal is monoclinic, space group P21. The asymmetric unit contains one dimeric (l-Ala⋯l-Ala+) cation, one picrate anion and a water molecule. The O⋯O distance in the dimeric cation is equal to 2.553(2) Å. The IR and Raman spectra are interpreted based on the structure.

► A new member of the family of salts of amino acids with dimeric cation is presented.
► The O⋯O distance in the dimeric cation is longest among salts with l-alanine l-alaninium cation.
► The presence of dimeric cation is reflected in the Infrared spectrum.