First example of bridge mono-coordination mode for the ligand 1,8-bis-(2-pyridyl)-3,6-dithiaoctane (pdto) in a Co(II) tetrahedral complex

The reaction between CoCl2·6H2O and the ligand 1,8-bis(2-pyridyl)-3,6-dithiaoctane (pdto) in acetonitrile leads to the formation of the tetrahedral Co(II) complex, [Co(κ-1N-pdto)Cl2]. This compound presents an unusual bridge mono-coordination mode of the tetradentate N2S2 ligand, pdto, not observed with other transition metals before. It was found that the complex presents a similar coordination environment around the Co(II) ion, either in solid sate or in solution, with an important role of chloride ions. Single crystal X-ray diffraction analysis of the compound shows a polymeric structure, where pdto acts as a bimetallic bridge with supramolecular array via intermolecular contacts C–H⋯X, with X = Cl, N and S.

This work presents the first Co(II)–pdto complex with tetrahedral geometry in which this versatile ligand (pdto = 1,8-bis(2-pyridyl)-3,6-dithiaoctane) presents an unusual bridge monodentate mode. It was found that in solid sate and in solution the complex presents similar coordination environment around Co(II) metal center.Figure optionsDownload as PowerPoint slide