Platinum(II) Complexes with Tetradentate Dianionic (O∧C*∧C*∧O)-Ligands

New tetradentate O∧C*∧C*∧O-ligands and the corresponding biscarbene platinum(II) complexes are reported. They were fully characterized by 1H NMR and 13C NMR spectroscopy as well as elemental analysis. Additionally, solid-state structures of bis[3,3′-(2-hydroxyethyl)-1H-imidazolium-2,2′-diylidene]methane-1,1′-diylplatinum(II) dibromide and of bis[3,3′-(2-ethoxide)-1H-imidazolium-2,2′-diylidene]methane-1,1′-diylplatinum(II) potassium bromide are reported. The latter can be characterized as a one-dimensional chain structure formed by coordination of potassium bromide.