Tridentate Complexes of Group 10 Bearing Bis-Aryloxide N-Heterocyclic Carbene Ligands: Synthesis, Structural, Spectroscopic, and Computational Characterization

A series of group 10 complexes featuring chelating tridentate bis-aryloxide N-heterocyclic carbenes were synthesized and characterized by using different techniques. Ni(II), Pd(II), and Pt(II) complexes were isolated in good yields by straightforward direct metalation of the corresponding benzimidazolium or imidazolium precursors in a one-pot procedure. All of the compounds were fully characterized, including single-crystal X-ray diffractometric determination for three of the derivatives. In the solid state, the complexes adopt a typical square-planar coordination geometry around the platinum atom, sizably distorted in order to comply with the geometrical constraints imposed by the bis-aryloxide N-heterocyclic carbene ligand. For platinum and palladium derivatives, a joint experimental and theoretical characterization was performed in order to study the optical properties of the newly prepared complexes by means of electronic absorption and steady-state and time-resolved photophysical techniques as well a...