Investigation of the UV–Vis absorption of bis(N-methylthiosemicarbazonato) zinc Zn[ATSM]

The electronic structure and absorption spectra of Zn[ATSM] 2 has been modelled using ZINDO and TD-DFT methods. The calculations reproduce both the physical and electronic structure of the complex, and provided good agreement with the X-ray crystal structure and UV–Vis absorption spectrum. The calculated electronic structure was used to generate a qualitative picture of the changes in electron distribution that occur during the absorption of light. The calculated shifts in electron density after absorption of a photon suggest a new synthetic direction for this project.

Graphical abstractThe UV–Vis spectra for Zn[ATSM] have been calculated using DFT methods and compared to the observed spectra in DMSO and water. The effect of bound solvent molecules on the predicted spectrum was considered. Electron density maps were produced for the orbitals of Zn[ATSM] relevant to the electronic transitions involved in the absorption spectra and the implications for further synthetic work examined.Figure optionsDownload full-size imageDownload as PowerPoint slide