Energy Transfer Pathways in Dinuclear Heteroleptic Polypyridyl Complexes:  Through-Space vs Through-Bond Interaction Mechanisms

Abstract

A series of homo- and heteronuclear ruthenium and osmium polypyridyl complexes with the bridging ligands 1,3-bis(5-(2-pyridyl)-1H-1,2,4-triazol-3-yl)benzene (H(2)mL) and 1,4-bis(5-(2-pyridyl)-1H-1,2,4-triazol-3-yl)benzene (H(2)pL) are reported. The photophysical properties of these compounds are investigated, and particular attention is paid to the heteronuclear (RuOs) compounds, which exhibit dual emission. This is in contrast to phenyl-bridged polypyridine Ru-Os complexes with a similar metal-metal distance, in which the Ru emission is strongly quenched because the nature of the bridging ligand allows for an efficient through-bond coupling. The results obtained for the compounds reported here suggest that energy transfer is predominantly taking place via a dipole-dipole, Förster type, mechanism, that may dominate when through-bond coupling is weak. This is in stark contrast to ground state interaction, which is found to be critically dependent on the nature of the bridging unit employed.

Dinuclear metal complexes: multifunctional properties and applications

“…12). 123 The homo-dinuclear complexes 17, 19, 20 and 22 showed a similar redox potential corresponding to their mononuclear species. However, the hetro-dinuclear complexes 18 and 21 presented Fig.…”

“…Photoinduced electron and energy transfer processes commonly occur in dinuclear metal systems, such as Ru(II)−Rh(III), 120,121 Ru(II)−Os(II), [122][123][124][125][126][127][128] Ru(II)−Ni(II), 129 Ru(II)−Zn(II), 130 Ru(II)−Cu(II), 131 Ru(II)−Ru(II), 64,67 Ir(III)−Ru(II), 125,132,133 Ir(III)−Pt(II), 129 Ir(III)−Eu(III), 134 Ir(III)−Ir(III) 56 . Therefore, bimetallic complexes are popular choices as donor-bridge-acceptor (D-B-A) systems for investigations of photoinduced electron and energy transfer process.…”

Self‐Assembly Synthesis of a [2]Catenane CoII Single‐Molecule Magnet

“…The 1,2‐bis(5‐(2‐pyridyl)‐4 H ‐1,2,4‐triazol‐3‐yl)‐benzene ligand, H 2 L , (Figure 1) was synthesized following literature procedures [20] (see the Supporting Information) and is relatively insoluble in all common laboratory solvents. However, a solution could be obtained in the presence of a metal salt.…”

Heterodinuclear ruthenium(ii)–cobalt(iii) complexes as models for a new approach to selective cancer treatment

“…Pyridine-2-carbohydrazonamide, 37 pyrazine-2-carbohydrazonamide, 37 3-(pyridin-2-yl)- [1,2,4]triazino [5,6- [Ru(bpy) 2 ( pytp)](PF 6 ) 2 . [Ru(bpy) 2 ( pytp)](PF 6 ) 2 was synthesised by a modification of the literature method of Zou.…”