Ruthenium(II) bipyridine complexes incorporating (NN'S) azoimine ancillary ligands. Synthesis, spectroscopy, solid state structure and DFT calculations

Four ruthenium complexes of N'NS donor thiomethyl-azoimine ligands (L) of the general type trans[Ru-II(biPy)(L)(Cl)(2)](C1-C4) (L = xC(6)H(4)N = NC(COMe)= NC6H4(2-SMe), X = H (L1), Cl; CH3 (L2), C2; Br (L3), C3; NO2 (L4), C4) have been synthesized by the reaction of ruthenium trichloride trihydrate with the corresponding L ligands and bipyridine (bipy) in refluxing ethanol. The molecular structure of trans-[Ru(bpy)(L3)(Cl)(2)](C3) in the solid state is reported. The thiomethyl-azoimine ligands (L) bind as NN' bidentate ligands with no direct Ru-S interaction. Furthermore, the complexes have been characterized by spectroscopic data (IR, Willis and H-1 NMR) and cyclic voltammetry. The electrochemical parameters (E-L(L)) of the azoimine ligands (L1-L4) are reported. The electronic excitations of a representative complex (C3) are interpreted by DFT and TDDFT calculations. (C) 2016 Elsevier Ltd. All rights reserved.