Experimental and theoretical FT-IR, Raman and XRD study of 2-acetyl-5-chlorothiophene

•FT-IR, Raman, single-crystal XRD and DFT analyses of 2-acetyl-5-chlorothiophene.•According to conformational energy barrier, the O,S-cis isomer is preferred.•Compound crystallizes in monoclinic space group C2/c.

The structure of 2-acetyl-5-chlorothiophene (ACT) has been characterized by FT-IR, Raman and single-crystal X-ray diffraction techniques. The isomers, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of ACT (C6H5ClOS) have been examined by the density functional theory, with the Becke-3–Lee–Yang–Parr functional and the 6-311+G(3df,p) basis set. Reliable vibrational assignments have been investigated by the potential energy distribution analysis. ACT crystallizes in monoclinic space group C2/c with the O,S-cis isomer. There is a good agreement between the theoretically predicted structural parameters and vibrational frequencies and those obtained experimentally.

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