Complexation of Zn(II), Cd(II) and Hg(II) with thiourea and selenourea: A 1H, 13C, 15N, 77Se and 113Cd solution and solid-state NMR study

Abstract Zinc(II), cadmium(II) and mercury(II) complexes of thiourea (TU) and selenourea (SeU) of general formula M(TU)2Cl2 or M(SeU)2Cl2 have been prepared. The complexes were characterized by elemental analysis and NMR (1H, 13C, 15N, 77Se and 113Cd) spectroscopy. A low-frequency shift of the C=S resonance of thiones in 13C NMR and high-frequency shifts of N–H resonances in 1H and 15N NMR are consistent with sulfur or selenium coordination to the metal ions. The Se nucleus in Cd(SeU)2Cl2 in 77Se NMR is deshielded by 87 ppm on coordination, relative to the free ligand. In comparison, the analogous Zn(II) and Hg(II) complexes show deshielding by 33 and 50 ppm, respectively, indicating that the orbital overlap of Se with Cd is better. Principal components of 77Se and 113Cd shielding tensors were determined from solid-state NMR data. Keywords: ThioureaSelenoureaZn(II), Cd(II), Hg(II) complexesNMRCP MAS NMR Acknowledgements This work was supported by the KFUPM Research Committee (Project CY/NMR STUDY/277) and the Chemistry Department of the King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia. Notes Corresponding author. Email: miwazeer@kfupm.edu.sa Additional informationNotes on contributorsMohammed I. M. Wazeer Footnote* Corresponding author. Email: miwazeer@kfupm.edu.sa