Infrared spectra and X-ray structure of (tetrazol-5-yl)acetic acid

The (tetrazol-5-yl)acetic acid crystal was characterized by the X-ray diffraction and FTIR spectroscopic methods. The analysis of the crystal structure reveals that the compound exists in the solid state as 1H-tautomer. The molecules are linked by two types of the intermolecular hydrogen bonds forming an infinite two-dimensional network in the (1 0 1) plane. Intramolecular NH⋯O hydrogen bonds are also formed in the crystal. The analysis of the FTIR spectra of the crystalline sample and its deuterated analogue, based on the B3LYP/6-311++G(2d,2p) frequency calculations of two model tetramers, has been performed in relation to the obtained crystal structure data.

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► (Tetrazol-5-yl)acetic acid (TA) as an example of heterocycles with many applications.
► TA – a compound with NH group and CH2COOH moiety attached to the tetrazole C atom.
► IR results discussed in relation to the X-ray structure and DFT calculations.
► Complicated spectroscopic pattern of strongly coupled internal modes of TA.