Conformation analysis of 1″,4″-Dispirocyclohexane-6,6′-bis(benzothiazoline): Combined IR, Raman, XRD and DFT approach

• The combined IR, Raman, and Single crystal XRD data confirmed that in DCB central cyclohexyl ring is in chair conformation and sulfur and nitrogen atoms f both the rings are in trans configuration.
• Theoretical calculations at the B3LYP/6-311 ++G** level strongly supports the experiment.
• N-H…S, C-H…S and C-H…π interactions stabilize the molecule in the solid state.
• DCB has center of symmetry and therefore IR and Raman peaks are complimentary to each other.

The subject of the study is the structure and conformation of 1″,4″-Dispiro-cyclohexane-6,6′-bis(benzothiazoline), a dispiro compound that has a cyclohexyl ring flanked by two benzothiazoline rings on either side. Using single crystal X-ray diffraction measurements, Infra-red absorption, and Raman spectroscopy techniques, it is found that the central cyclohexyl ring assumes the chair conformation and the sulfur, nitrogen atoms in both the benzothiazole rings are in the trans configurations. The experimental findings are further corroborated by geometry optimization and frequency calculations at B3LYP/6-311 ++G** level of theory using Gaussian 09 suite of program.

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