Poly(pyrrole-2,2'-bipyridyl rhodium(III) complexes) modified electrodes: molecular materials for hydrogen evolution and electrocatalytic hydrogenation

Oliveira, Ione Maria Ferreira de; Moutet, Jean‐Claude; Vlachopoulos, Nikolaos

doi:10.1016/0022-0728(90)87191-l

Cited by 37 publications

(6 citation statements)

References 15 publications

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“…The dmebpy analogue adsorbs onto the electrode surface, therefore the dmebpy 0/– reduction cannot be accurately measured. Regardless, the identity of the π-accepting bidentate ligand modulates the Rh- and NN-based redox potentials, , which will affect the rate of electron transfer from the Cu PS to the Rh WRC.…”

Section: Resultsmentioning

confidence: 99%

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

et al. 2018

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The synthesis of two new heteroleptic Cu(I) photosensitizers (PS), [Cu(Xantphos)(NN)]PF (NN = biq = 2,2'-biquinoline, dmebiq = 2,2'-biquinoline-4,4'-dimethyl ester; Xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), along with the associated structural, photophysical, and electrochemical properties, are described. The biquinoline diimine ligand extends the PS light absorbing properties into the visible with a maximum absorption at 455 and 505 nm for NN = biq and dmebiq, respectively, in CHCl solvent. Following photoexcitation, both Cu(I) PS are emissive at low energy, albeit displaying stark differences in their excited state lifetimes (τ = 410 ± 5 (biq) and 44 ± 4 ns (dmebiq)). Cyclic voltammetry indicates a Cu-based HOMO and NN-based LUMO for both complexes, whereby the methyl ester substituents stabilize the LUMO within [Cu(Xantphos)(dmebiq)] by ∼0.37 V compared to the unsubstituted analogue. When combined with HO, N,N-dimethylaniline (DMA) electron donor, and cis-[Rh(NN)Cl]PF (NN = Mebpy = 4,4'-dimethyl-2,2'-bipyridine, bpy = 2,2'-bipyridine, dmebpy = 2,2'-bipyridine-4,4'-dimethyl ester) water reduction catalysts (WRC), photocatalytic H evolution is only observed using the [Cu(Xantphos)(biq)] PS. Furthermore, the choice of cis-[Rh(NN)Cl] WRC strongly affects the catalytic activity with turnover numbers (TON = mol H per mol Rh catalyst) of 25 ± 3, 22 ± 1, and 43 ± 3 for NN = Mebpy, bpy, and dmebpy, respectively. This work illustrates how ligand modification to carefully tune the PS light absorbing, excited state, and redox-active properties, along with the WRC redox potentials, can have a profound impact on the photoinduced intermolecular electron transfer between components and the subsequent catalytic activity.

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Section: Resultsmentioning

confidence: 99%

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

et al. 2018

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“…The higher activity of Rh9 versus Rh8, can be attributed to the higher reactivity under acidic conditions of the Rh III hydride intermediate for Rh9 compared with that of Rh8 [127][128][129][130][131]. In this study, the cyclometallated iridium complex, [Ir(ppy) 2 (bpy)] + (Ir2) was also tested with Rh9 and HA − /H 2 A in substitution to the Ru1 photosensitizer.…”

Section: Rhodium(iii) Bis(bipyridine) Bis(chloro) As Catalystmentioning

confidence: 99%

Photo-induced redox catalysis for proton reduction to hydrogen with homogeneous molecular systems using rhodium-based catalysts

Stoll

Castillo

Kayanuma

et al. 2015

Coordination Chemistry Reviews

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“…Nevertheless, the electrochemical behavior of such Rh(III) hydrides species, and hence their reduction potential, has never been reported even in organic solvent, which is a more appropriate medium than water to obtain reliable electrochemical data. Our group has previously reported the elaboration of modified electrodes with polypyrrole films functionalized by such Rh(III) complexes for electrocatalytic hydrogen evolution and hydrogenation of organic compounds, but the corresponding hydrides were never electrochemically characterized. The determination of the redox properties of the hydride species should provide valuable information about the mechanism involved in the catalytic hydrogen evolution.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

et al. 2018

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We previously reported that the [Rh(dmbpy)Cl] (dmbpy = 4,4'-dimethyl-2,2'-bipyridine) complex is an efficient H-evolving catalyst in water when used in a molecular homogeneous photocatalytic system for hydrogen production with [Ru(bpy)] (bpy = 2,2'-bipyridine) as photosensitizer and ascorbic acid as sacrificial electron donor. The catalysis is believed to proceed via a two-electron reduction of the Rh(III) catalyst into the square-planar [Rh(dmbpy)], which reacts with protons to form a Rh(III) hydride intermediate that can, in turn, release H following different pathways. To improve the current knowledge of these key intermediate species for H production, we performed herein a detailed electrochemical investigation of the [Rh(dmbpy)Cl] and [Rh(dtBubpy)Cl] (dtBubpy = 4,4'-di- tert-butyl-2,2'-bipyridine) complexes in CHCN, which is a more appropriate medium than water to obtain reliable electrochemical data. The low-valent [Rh(Rbpy)] and, more importantly, the hydride [Rh(Rbpy)(H)Cl] species (R = dm or dtBu) were successfully electrogenerated by bulk electrolysis and unambiguously spectroscopically characterized. The quantitative formation of the hydrides was achieved in the presence of weak proton sources (HCOOH or CFCOH), owing to the fast reaction of the electrogenerated [Rh(Rbpy)] species with protons. Interestingly, the hydrides are more difficult to reduce than the initial Rh(III) bis-chloro complexes by ∼310-340 mV. Besides, 0.5 equiv of H is generated through their electrochemical reduction, showing that Rh(III) hydrides are the initial catalytic molecular species for hydrogen evolution. Density functional theory calculations were also performed for the dmbpy derivative. The optimized structures and the theoretical absorption spectra were calculated for the initial bis-chloro complex and for the various rhodium intermediates involved in the H evolution process.

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Poly(pyrrole-2,2'-bipyridyl rhodium(III) complexes) modified electrodes: molecular materials for hydrogen evolution and electrocatalytic hydrogenation

Cited by 37 publications

References 15 publications

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

Photo-induced redox catalysis for proton reduction to hydrogen with homogeneous molecular systems using rhodium-based catalysts

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts

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Poly(pyrrole-2,2'-bipyridyl rhodium(III) complexes) modified electrodes: molecular materials for hydrogen evolution and electrocatalytic hydrogenation

Cited by 37 publications

References 15 publications

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H2

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H2

Photo-induced redox catalysis for proton reduction to hydrogen with homogeneous molecular systems using rhodium-based catalysts

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H2-Evolving Catalysts

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Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

Visible-Light-Driven Photosystems Using Heteroleptic Cu(I) Photosensitizers and Rh(III) Catalysts To Produce H₂

Electrochemical Generation and Spectroscopic Characterization of the Key Rhodium(III) Hydride Intermediates of Rhodium Poly(bipyridyl) H₂-Evolving Catalysts