Syntheses and electrochemical properties of ruthenium(II) complexes with 4,4′-bipyrimidine and 4,4′-bipyrimidinium ligands

Fujihara, Tetsuaki; Wada, Tohru; Tanaka, Koji

doi:10.1016/j.ica.2003.10.015

Cited by 12 publications

(7 citation statements)

References 46 publications

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“…The individual differences in each spectrum showed higher number of signals in the case of the first compound rather than the second one. Some authors have pointed out such behaviour with the presence of geometric isomers . This information together with the NMR characterization confirmed complex 1 as the trans isomer (See supporting information).…”

Section: Resultsmentioning

confidence: 60%

ZnO Nanoparticles Photosensitization Using Ruthenium(II)‐polypyridyl Isomeric Complexes

et al. 2020

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The coordination of photosensitizing dyes to zinc oxide nanoparticles (ZnO NPs) has attracted extensive attention as promising candidates for applications in solar cells. Here, we report the synthesis of ZnO NPs functionalized with geometric isomers of ruthenium(II)‐polypyridyl complexes and a preliminary study of their photophysical properties by fluorescence spectroscopy. ZnO NPs synthesis was carried out by direct precipitation. IR, UV‐Vis spectroscopy, XRD and TG‐DTA techniques were used for ZnO NPs characterization. Trans and cis complexes of Ru(II) using 2,2′‐bipyridine and 2,2’‐bipyridine‐4,4’‐dicarboxylic acid as ligands were assembled to ZnO NPs. The presence not only of a band of around 355 nm, but also at 465 nm, in the electronic spectrum indicates the modification of the ZnO surface with the synthesized complexes. The fluorescence behaviour of Ru(II) complexes modified ZnO NPs suggested an electron transfer process through the system. Remarkably, the trans isomer modified system showed better response during the electron transfer. This information could be considered during the design of photoanodes in Dye‐Sensitized Solar Cells.

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Section: Resultsmentioning

confidence: 60%

ZnO Nanoparticles Photosensitization Using Ruthenium(II)‐polypyridyl Isomeric Complexes

et al. 2020

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“…Furthermore, these were done quantitatively by using the well-known ferrocene/ferrocenium system as internal reference. Regarding its reduction potential ( V vs. Fc/Fc + ), 1 2+ ( E 1/2 = –0.54 V) is an intermediate but strong electron-acceptor between the prototype 3,3′-diazamethylviologen (DAMV˙ + ) ( E 1/2 = –0.35 V) 19 , 20 , 36 and the methylviologen ( E 1/2 = –0.89 V). 7 Thus, in two experiments, either the dication [ 1 2+ ](BF 4 ) 2 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

A fascinating multifaceted redox-active chelating ligand: introducing the N,N′-dimethyl-3,3′-biquinoxalinium “methylbiquinoxen” platform

et al. 2016

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“…Mass spectra were collected via electrospray ionization mass spectrometry using a Waters Synapt G2-Si ESI mass spectrometer. Ru-bpm was synthesized according to the previously published procedure . MS-ESI: m / z (CH 3 CN) 528 ([M–PF 6 ] + ), 1 H NMR (500 MHz, CD 3 CN) δ (ppm): 10.81 (s, 1H), 9.26 (d, 1H), 8.64 (m, 2H), 8.52 (m, 2H), 8.39 (m, 2H), 8.35 (m, 1H), 8.15 (m, 2H), 7.92 (m, 2H), 7.68 (d, 2H), 7.27 (t, 2H).…”

Section: Methodsmentioning

confidence: 99%

Proton-Coupled Electron Transfer in a Ruthenium(II) Bipyrimidine Complex in Its Ground and Excited Electronic States

et al. 2022

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Proton-coupled electron transfer (PCET) was studied for the ground and excited electronic states of a [Ru(terpy)(bpm)(OH 2 )(PF 6 ) 2 ] complex, Ru-bpm. Cyclic voltammetry measurements show that the Ru(II)-aqua moiety undergoes PCET to form a Ru(IV)-oxo moiety in the anodic region, while the bpm ligand undergoes PCET to form bpmH 2 in the cathodic region. The photophysical behavior of Ru-bpm was studied using steady-state and femtosecond transient UV−vis absorption spectroscopy, coupled with density functional theory (DFT) calculations. The lowest-lying excited state of Ru-bpm is described as a (Ru → bpm) metal-toligand charge-transfer (MLCT) state, while the metal-centered (MC) excited state was found computationally to be close in energy to the lowest-energy bright MLCT state (MC state was 0.16 eV above the MLCT state). The excited-state kinetics of Ru-bpm were found via transient absorption spectroscopy to be short-lived and were fit well to a biexponential function with lifetimes τ 1 = 4 ps and τ 2 = 65 ps in aqueous solution. Kinetic isotope effects of 1.75 (τ 1 ) and 1.61 (τ 2 ) were observed for both decay components, indicating that the solvent plays an important role in the excited-state dynamics of Ru-bpm. Based on the pH-dependent studies and the results from prior studies of similar Rucomplexes, we hypothesize that the 3 MLCT state forms an excited-state hydrogen-bond adduct with the solvent molecules and that this process occurs with a 4 ps lifetime. The formation of such a hydrogen-bond complex is consistent with the electronic density accumulation at the peripheral N atoms of the bpm moiety in the 3 MLCT state. The hydrogen-bonded state 3 MLCT decays to the ground state with a 65 ps lifetime. Such a short lifetime is likely associated with the efficient vibrational energy transfer from the 3 MLCT state to the solvent.

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Syntheses and electrochemical properties of ruthenium(II) complexes with 4,4′-bipyrimidine and 4,4′-bipyrimidinium ligands

Cited by 12 publications

References 46 publications

ZnO Nanoparticles Photosensitization Using Ruthenium(II)‐polypyridyl Isomeric Complexes

ZnO Nanoparticles Photosensitization Using Ruthenium(II)‐polypyridyl Isomeric Complexes

A fascinating multifaceted redox-active chelating ligand: introducing the N,N′-dimethyl-3,3′-biquinoxalinium “methylbiquinoxen” platform

Proton-Coupled Electron Transfer in a Ruthenium(II) Bipyrimidine Complex in Its Ground and Excited Electronic States

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