Unprecedented Pt(II) complex of an asymmetric 2,6-diacetylpyridine bis(4N-substituted thiosemicarbazone) ligand

Reaction of 2,6-diacetylpyridine bis(4N-o-tolylthiosemicarbazone), H2L1, with K2PtCl4 and further recrystallization in DMSO/MeOH of the [PtL1] complex obtained, led to the isolation of the novel platinum complex, [PtL2], which was structurally characterized by single crystal X-ray diffraction. The molecular structure shows that the ligand has undergone an unexpected chemical transformation viz. reduction of one of the terminal phenyl rings into cyclohexyl. The resulted asymmetrical ligand acts a dianionic tetradentate donor, coordinating to the platinum(II) center in a square planar geometry through the Npyridinic atom and the Niminic and the S atoms from one thiosemicarbazone arm, the fourth coordination position is occupied by the Nhydrazinic atom of the other arm.

Graphical abstractA new neutral platinum(II) complex derived of 2,6-diacetylpyridine bis(thiosemicarbazone) ligand has been synthesized and structurally characterized by single crystal X-ray diffraction. The molecular structure shows that the ligand has undergone an unexpected chemical transformation via hydrogen transfer.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Evolution from α-N-heterocyclic bis(thiosemicarbazone) to a new asymmetric ligand. ► The Pt(II) complexes synthesized present uncommon thiosemicarbazone coordination. ► Molecular structure of the complex was confirmed by X-ray crystallography.