INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
Four chromophores in one building block: synthesis, structure and characterization of trans-[Ru(MQ)4Cl2]4+ and trans-[Ru(4,4'-bpy)4Cl2] (MQ+ = N-methyl-4,4'-bipyridinium, bpy = bipyridine)
CADRANEL, ALEJANDRO; HODAK, JOSÉ H.
JOURNAL OF COORDINATION CHEMISTRY
TAYLOR & FRANCIS LTD
Lugar: Londres; Año: 2015 vol. 68 p. 1452 - 1452
We report the synthesis, crystallographic structure, electrochemical and spectroscopic properties of the complex trans-[Ru(MQ)4Cl2]4+ (14+), where MQ+ = N-methyl-4,4?-bipyridinium. The crystal structure of 14+ shows the pyridinic rings bound in a trans fashion to the Ru ion. In 14+ and in its analogue trans-[Ru(4,4?-bpy)4Cl2] (2, bpy = bipyridine), the electrochemical reduction waves of the four iminic ligands occur at very closely spaced potentials. 14+ and 2 present high molar extinction coefficients in acetonitrile (ε = 20000-50000 M-1cm-1) and absorptions that are red-shifted (up to 800 nm for 14+ and up to 600 nm for 2) relative to previously reported analogues. Upon protonation of the four exposed nitrogen atoms of 2 and electrochemical reduction of the ligands in 14+ and 2, spectral changes occur with retention of isosbestic points, revealing the presence of four independent chromophores. Together these results suggest poor electronic communication between the aromatic ligands within each compound, in clear contrast to what happens with related complexes such as cis-[Ru(2,2?-bpy)2Cl2] (3).