Investigation of Cyclam Based Re‐Complexes as Potential Electrocatalysts for the CO2Reduction Reaction

Gerschel, Philipp; Cordes, Anna; Bimmermann, Sarah; Siegmund, Daniel; Metzler‐Nolte, Nils; Apfel, Ulf‐Peter

doi:10.1002/zaac.202000450

Cited by 8 publications

(12 citation statements)

References 55 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the mononuclear [Re(CO) 3 Cl(adcpip)], a further band at 1704 cm −1 represents the uncoordinated adcpip CO group. Generally, the IR spectra of the Re(CO) 3 Cl complexes agree with those of previously reported fac -[Re(CO) 3 X] (X = any ligand) complexes showing three CO stretching resonances [ 47 , 49 , 50 , 51 , 52 , 53 , 59 , 60 , 61 , 62 , 63 ], the two at lower energy are sometimes merged into one broad band ( Table 1 ).…”

Section: Resultssupporting

confidence: 89%

“…The essential metrics of the [Re(CO) 3 Cl(N^O)] entities around the Re centres ( Table S3A ) were very similar to reported [Re(CO) 3 X(N^N)] structures with the exception that the N^O chelate bite with about 72° is markedly smaller than N^N chelate bites with values ranging from 80 to 83° [ 43 , 44 , 47 , 49 , 61 , 62 , 63 , 64 , 65 ].…”

Section: Resultssupporting

confidence: 74%

“…The reactions were monitored by IR spectroscopy, showing the typical pattern ( Supplementary Figure S1 ) for [Re(CO) 3 ] fragments in their facial configuration [ 47 , 49 , 50 , 51 , 53 , 59 , 60 , 61 , 62 , 63 ]. IR also allowed the discrimination between mono- and dinuclear reaction products.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

et al. 2022

View full text Add to dashboard Cite

The excellent π-accepting azodicarboxylic esters adcOR (R = Et, iPr, tBu, Bn (CH2-C6H5) and Ph) and the piperidinyl amide derivative adcpip were used as bridging chelate ligands in dinuclear Re(CO)3 complexes [{Re(CO)3Cl}2(µ-adcOR)] and [{Re(CO)3Cl}2(µ-adcpip)]. From the adcpip ligand the mononuclear derivatives [Re(CO)3Cl(adcpip)] and [Re(CO)3(PPh3)(µ-adcpip)]Cl were also obtained. Optimised geometries from density functional theory (DFT) calculations show syn and anti isomers for the dinuclear fac-Re(CO)3 complexes at slightly different energies but they were not distinguishable from experimental IR or UV–Vis absorption spectroscopy. The electrochemistry of the adc complexes showed reduction potentials slightly below 0.0 V vs. the ferrocene/ferrocenium couple. Attempts to generate the radicals [{Re(CO)3Cl}2(µ-adcOR)]•− failed as they are inherently unstable, losing very probably first the Cl‒ coligand and then rapidly cleaving one [Re(CO)3] fragment. Consequently, we found signals in EPR very probably due to mononuclear radical complexes [Re(CO)3(solv)(adc)]•. The underlying Cl−®solvent exchange was modelled for the mononuclear [Re(CO)3Cl(adcpip)] using DFT calculations and showed a markedly enhanced Re-Cl labilisation for the reduced compared with the neutral complex. Both the easy reduction with potentials ranging roughly from −0.2 to −0.1 V for the adc ligands and the low-energy NIR absorptions in the 700 to 850 nm range place the adc ligands with their lowest-lying π* orbital being localised on the azo function, amongst comparable bridging chelate N^N coordinating ligands with low-lying π* orbitals of central azo, tetrazine or pyrazine functions. Comparative (TD)DFT-calculations on the Re(CO)3Cl complexes of the adcpip ligand using the quite established basis set and functionals M06-2X/def2TZVP/LANL2DZ/CPCM(THF) and the more advanced TPSSh/def2-TZVP(+def2-ECP for Re)/CPCMC(THF) for single-point calculations with BP86/def2-TZVP(+def2-ECP for Re)/CPCMC(THF) optimised geometries showed a markedly better agreement of the latter with the experimental XRD, IR and UV–Vis absorption data.

show abstract

Section: Resultssupporting

confidence: 89%

Section: Resultssupporting

confidence: 74%

See 1 more Smart Citation

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Homogeneous electrocatalysts are preferred for investigations over heterogeneous electrocatalysts because of their simple structures and properties. , Therefore, homogeneous electrocatalysts serve as a key to understand crucial features for an efficient electrocatalytic CO 2 reduction reaction. The electrochemical properties of homogeneous complexes ( d 6 metal centers such as Re(I), Ru(II), etc.)…”

Section: Introductionmentioning

confidence: 99%

Electrocatalytic CO₂ Reduction by [Re(CO)₃Cl(3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole)] and [Re(CO)₃Cl(3-(2-pyridyl)-1,2,4-triazole)]

et al. 2022

View full text Add to dashboard Cite

The exploration of novel electrocatalysts for CO 2 reduction is necessary to overcome global warming and the depletion of fossil fuels. In the current study, the electrocatalytic CO 2 reduction of [Re(CO) 3 Cl( N - N )], where N - N represents 3-(2-pyridyl)-1,2,4-triazole (Hpy), 3-(pyridin-2-yl)-5-phenyl-l,2,4-triazole (Hph), and 2,2′-bipyridine-4,4′ dicarboxylic acidic (bpy-COOH) ligands, was investigated. In CO 2 -saturated electrolytes, cyclic voltammograms showed an enhancement of the current at the second reduction wave for all complexes. In the presence of triethanolamine (TEOA), the currents of Re(Hpy), Re(Hph), and Re(bpy-COOH) enhanced significantly by approximately 4-, 2-, and 5-fold at peak potentials of −1.60, −150, and −1.69 V Ag/Ag+ , respectively (in comparison to without TEOA). The reduction potential of Re(Hph) was less negative than those of Re(Hpy) and Re(COOH), which was suggested to cause its least efficiency for CO 2 reduction. Chronoamperometry measurements showed the stability of the cathodic current at the second reduction wave for at least 300 s, and Re(COOH) was the most stable in the CO 2 -catalyzed reduction. The appearance and disappearance of the absorption band in the UV/vis spectra indicated the reaction of the catalyst with molecular CO 2 and its conversion to new species, which were proposed to be Re- DMF + and Re- TEOA and were supposed to react with CO 2 molecules. The CO 2 molecules were claimed to be captured and inserted into the oxygen bond of Re- TEOA , resulting in the enhancement of the CO 2 reduction efficiency. The results indicate a new way of using these complexes in electrocatalytic CO 2 reduction.

show abstract

“…Excessive electrochemical reduction steps have been shown to facilitate this process, but they typically occur at more negative standard potentials, thus leading to high overpotentials. [4][5][6][7][8][9][10] In nature, carbon monoxide dehydrogenase enzymes (CODH) can efficiently and reversibly convert CO to CO2. 11 In the active site of CODH from the anaerobic bacterium C. hydrogenoformans, there is a [Ni-4Fe-5S] cluster, called the C-cluster, which consists of a [Ni-3Fe-4S] cubane linked to a unique Fe site through a sulfide.…”

Section: Introductionmentioning

confidence: 99%

Alternating substrate/ligand-metal coordination enables a low-energy pathway for C-O bond cleavage in the electrocatalytic reduction of carbon dioxide

Agarwala

Chen²,

Lyonnet³

et al. 2021

Preprint

View full text Add to dashboard Cite

Molecular electrocatalysts for CO2-to-CO conversion often operate at large overpotentials, the cleavage of C-O bond in the intermediate largely contributing to this phenomenon. Additional Lewis acids have been shown to aid in weakening the C-O bond. We herein present computational and experimental evidence, with ruthenium polypyridyl based CO2 reduction electrocatalysts, for a mechanistic route that involves one metal center acting as both Lewis base and Lewis acid at different stages of the catalytic cycle. The Lewis basic character of Ru is seen in the initial nucleophilic attack at CO2 to form [Ru-CO2]0, while its Lewis acid character allows the formation of a 5-membered metallacyclic intermediate, [Ru-CO2CO2]0,c, by intramolecular cyclization of a linear [Ru-CO2CO2]0 species that is formed from [Ru-CO2]0 and a second equivalent of CO2. [Ru-CO2CO2]0,c is crucial for energy-conserving turnover, as it allows for a third reduction at a more positive potential than that of the starting complex Ru2+. The calculated activation barrier for C-O bond cleavage in [Ru-CO2CO2]-1,c is dramatically decreased to 10.5 kcal mol-1 from 60 kcal mol-1, the latter required for C-O bond cleavage in the linear intermediate [Ru-CO2CO2]0. The intermediates are characterized experimentally by FT-IR and 13C NMR spectroscopy during electrocatalytic turnover and are corroborated by density functional theory (DFT).

show abstract

Investigation of Cyclam Based Re‐Complexes as Potential Electrocatalysts for the CO₂Reduction Reaction

Cited by 8 publications

References 55 publications

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

Electrocatalytic CO₂ Reduction by [Re(CO)₃Cl(3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole)] and [Re(CO)₃Cl(3-(2-pyridyl)-1,2,4-triazole)]

Alternating substrate/ligand-metal coordination enables a low-energy pathway for C-O bond cleavage in the electrocatalytic reduction of carbon dioxide

Contact Info

Product

Resources

About

Investigation of Cyclam Based Re‐Complexes as Potential Electrocatalysts for the CO2Reduction Reaction

Cited by 8 publications

References 55 publications

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

Rhenium Tricarbonyl Complexes of Azodicarboxylate Ligands

Electrocatalytic CO2 Reduction by [Re(CO)3Cl(3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole)] and [Re(CO)3Cl(3-(2-pyridyl)-1,2,4-triazole)]

Alternating substrate/ligand-metal coordination enables a low-energy pathway for C-O bond cleavage in the electrocatalytic reduction of carbon dioxide

Contact Info

Product

Resources

About

Investigation of Cyclam Based Re‐Complexes as Potential Electrocatalysts for the CO₂Reduction Reaction

Electrocatalytic CO₂ Reduction by [Re(CO)₃Cl(3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole)] and [Re(CO)₃Cl(3-(2-pyridyl)-1,2,4-triazole)]