Effect of electronic structure of energy transfer in bimetallic Ru(ii)/Os(ii) complexes

Abstract

Novel monometallic (µ-LL’)Ru, Ru(µ-LL’), homobimetallic Ru(µ-LL’)Ru, and heterodimetallic Ru(µ-LL’)Os and Os(µ-LL’)Ru complexes based on two asymmetrical ligands LL’ (where LL’= L1L1’, L2L2’) have been synthesized and characterized. Spectroscopic analysis indicates...

Ru(II)–Ru(II) and Ru(II)–Os(II) Homo-/Heterodinuclear Complexes and Ru3(II)–Ru(II) Homotetranuclear Complexes Based on Heteroditopic Bridging Ligands: Synthesis, Photophysics, and Effective Energy Transfer

“…The spectrum information allows for a more direct observation of the energy transfer processes of 6 and 12 in comparison to that of the previous Ru/Os complexes without dihedral angles. 38,49,53 As shown in Figure 5c, the excited-state energy of Ru → phen (L 1 ) in the tetranuclear complexes was transferred to Ru-bpy at the far end, thus quenching the central Ru II -phen (L 1 )-based luminescence in the tetramers. The energy transmission possibly occurred through Coulombic interactions (Forster) and electron exchange (Dexter).…”

“…The planar phen unit in the ligand L x was a better π* electron acceptor, making the oxidation of metal more difficult. 49 Homodinuclear complex 3 revealed two Ru II -based quasireversible waves at +1.29 and +1.36 V, which were attributed to the (bpy) 2 Ru(bpy-L 1 )-based subunit and (bpy) 2 Ru(phen-L 1 )-based subunit, respectively. Two Ru II -based quasi-reversible oxidation peaks (+0.9 and +1.32 V, respectively) were also observed in dinuclear complex 9.…”

“…38 In addition, Baitalik group found that intercomponent energy transfer in the RuOsRu/OsRuOs triads 10,60,61 became thermodynamically more facile and kinetically much faster upon deprotonation of the imidazole protons situated at their second coordination sphere. In heterodinuclear complexes RuLOs (4 and 10), energy transfer was accompanied by electron transfer (eq 3) after the light excitation of the photosensitizer Ru II center (eq 2) 49 because the lower oxidation potential of the Os II /Os III (∼0.85 V) can participate in the reduction of the 3 MLCT centered at the Ru-based chromophore as follows. The electron transfer was followed by a thermal back-electron-transfer process (eq 4).…”

“…As shown in Figure , the mononuclear complexes ( 2 and 8 ) displayed a small difference for the Ru III/II redox couple compared with that of 1 and 7 due to the asymmetric coordination environment of the ligands L x ( x = 1, 2). The planar phen unit in the ligand L x was a better π* electron acceptor, making the oxidation of metal more difficult . Homodinuclear complex 3 revealed two Ru II -based quasi-reversible waves at +1.29 and +1.36 V, which were attributed to the (bpy) 2 Ru(bpy- L 1 )-based subunit and (bpy) 2 Ru(phen- L 1 )-based subunit, respectively.…”

Conjugated Cu-Ni bimetallic complex supported on Fe 3 O 4 @SiO 2 : An efficient nanocatalyst with synergistic performance for the solvent-free Sonogashira, and C-N cross-couplings

“…In this work, we employed 4-ABPT as a ligand with a large conjugated system and synthesized Fe3O4@SiO2@4-ABPT as a suitable support for stabilizing bimetallic Cu-Ni nanoparticles. To the best of our knowledge, there are some bimetallic π-conjugated complexes that were unsupported on reusable magnetic materials [42][43][44][45] , but Fe3O4@SiO2@4-ABPT/Cu-Ni is the first example of a π-conjugated system between two metals that supported on magnetic materials. The resultant Fe3O4@SiO2@4-ABPT/Cu-Ni as nanocatalyst had excellent catalytic activity for Sonogashira and C-N cross-coupling reactions under solvent-free conditions.…”