Inorganic Chemistry, Vol.59, No.17, 12005-12016, 2020
Bent 1,10-Phenanthroline Ligands within Octahedral Complexes Constructed around a TiO4N2 Core
The synthesis of monomeric octahedral complexes constructed around a TiO4N2 core bearing neocuproine derivatives is detailed. These architectures follow the [Ti(1)(2)(N-N)] general formulas, where 1 is the 6,6'-diphenyl-2,2'-biphenolato ligand and N-N is a 1,10-phenanthroline derivative. Single-crystal analysis revealed that the neocuproine-based ligands within these architectures adopt a nonplanar geometry. The distortion of these aromatic diimine systems has been quantified through measurement of a torsion angle (alpha) and a dihedral angle (beta) defined by two planes within the aromatic diimine molecule (pi(1) and pi(2)), permitting one to evaluate the twisting and bending of a coordinated nitrogen ligand, respectively. Next, the scope of this investigation was extended to the synthesis of a dimeric architecture, [Ti-2(1)(4)(3)], where 3 is the 5,5'-bis(neocuproine) ligand. Again, a strong distortion of the neocuproine fragments was characterized in the crystalline state for such a complex. The UV-visible properties of these complexes were interpreted with the help of time-dependent density functional theory calculations. The solution behavior as well as good hydrolytic stability of these species has been established.