The structure and vibrational spectra of the 2,5-dimethylpyrazine (2,5-DMP) 1:1 adduct with 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (CLA)

► A novel complex of 2,5-dimethylpyrazine with 2,5-dichloro-3,6-dihydroxy-p-benzoquinone. ► The crystal structure at 100 K is presented. ► The infrared, Raman and inelastic neutron scattering spectra are shown. ► They are compared with calculated by using the DFT methods applied to the crystalline state. ► The calculated structure and the frequencies are well consistent, except of the CH3 torsional mode.