Impact of Mn(I) photoCORM ligand set on photochemical intermediate formation during visible light-activated CO release

Pordel, Shabnam; White, Jessica K.

doi:10.1016/j.ica.2019.119206

Cited by 17 publications

(20 citation statements)

References 55 publications

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“…The three CO stretches showed up at 2027, 1936, and 1923 cm –1 for Mn-bpy-H-BDP and 2027, 1934 and 1924 cm –1 for Mn-bpy-I-BDP. These values are in good agreement with the previously reported values for the model complex Mn(Me 2 bpy)(CO) 3 Br . The similar CO stretches in both Mn-bpy-R-BDP (R = H or I) complexes are consistent with the observed redox potentials discussed above.…”

Section: Resultssupporting

confidence: 92%

“…Two additional reduction peaks were also observed for Mn-bpy-I-BDP, the first of which overlapped with the BDP peak at around −1.28 V, and the second new reduction peak appeared at −1.59 V in DCM. After comparing the potentials with free ligands and the model complex Mn(Me 2 bpy)(CO) 3 Br potentials, we attributed the first irreversible oxidation peak in both complexes to the Mn I/II oxidation and the second oxidation peak to the oxidation of the BDP unit. The first reduction peak was attributed to BDP 0/– , and the next two reduction peaks were assigned as Mn I/0 , followed by the rapid dissociation of Br – to form a five-coordinate radical species .…”

Section: Resultsmentioning

confidence: 99%

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Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

2021

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Carbon monoxide (CO) is shown to enhance the sensitivity of cancer cells to generate reactive oxygen species such as singlet oxygen ( 1 O 2 ) from chemotherapeutics and reduce the drug resistance. Herein, we introduced two Mn-based photoactivated CO releasing molecules conjugated with an emissive BODIPY (BDP) moiety with a general formula of Mn(CO) 3 (bpy-R-BDP)Br (R = H or I), labeled as Mn-bpy-H-BDP and Mn-bpy-I-BDP. While both complexes release CO with visible light, Mn-bpy-I-BDP releases CO and produces 1 O 2 from a single molecule. In addition to 1 O 2 generation, iodination of BDP red shifts the absorption of Mn-bpy-I-BDP further into the visible region and significantly increases the dark stability of the complex. Cyclic voltammetry and density functional theory (DFT) calculations suggest a Mn-based highest occupied molecular orbital (HOMO) and a BDP-based lowest unoccupied molecular orbital (LUMO) in these complexes. However, time-dependent DFT calculations suggest that the HOMO − 2(π BDP ) → LUMO(π BDP * ) is the main optical transition upon excitation with visible light in both complexes. The presence of a phosphorescence peak from the triplet excited state of bpy-I-BDP in both the free ligand and its Mn complex at 77 K was used as additional evidence for 1 O 2 production. We also probed formation of photo-intermediates and products during photolysis with Fourier-transform infrared, 1 H NMR, emission, and absorption experiments and DFT calculations.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

2021

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“…The redox properties of the reference Mn-bpy are also similar to those of the Mn-phen species described above [ 4 , 13 , 39 ]. Unclear redox waves were observed in Mn-qpy owing to its poor solubility in almost all organic solvents ( Table 3 and Figure S2 ).…”

Section: Resultsmentioning

confidence: 69%

Effects of Chemically-Modified Polypyridyl Ligands on the Structural and Redox Properties of Tricarbonylmanganese(I) Complexes

2020

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Carbonyl complexes with manganese(I) as the central metal are very attractive catalysts. The introduction of redox-active ligands, such as quinones and methyl viologen analogs into these catalysts, would be expected to lead to superior catalyst performances, since they can function as excellent electron carriers. In this study, we synthesized four tricarbonylmanganese(I) complexes containing typical bidentate polypyridyl ligands, including 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy) frameworks bound to redox-active ortho-quinone/catechol or methyl viologen-like units. The molecular structures of the resulting complexes were determined by X-ray crystallography to clarify their steric features. As expected from the infrared (IR) data, three CO ligands for each complex were coordinated in the facial configuration around the central manganese(I) atom. Additionally, the structural parameters were found to differ significantly between the quinone/catechol units. Electrochemical analysis revealed some differences between them and their reference complexes, namely [MnBr(CO)3(phen)] and [MnBr(CO)3(bpy)]. Notably, interconversions induced by two-electron/two-proton transfers between the quinone and catechol units were observed in the phenanthroline-based complexes. This work indicated that the structural and redox properties in tricarbonylmanganese(I) complexes were significantly affected by chemically modified polypyridyl ligands. A better understanding of structures and redox behaviors of the present compounds would facilitate the design of new manganese complexes with enhanced properties.

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“…Ultrahigh purity Ar (99.995%), Ar (for synthesis), CO, CO 2 , and H 2 were purchased from Airgas. Re(bpy-H)(CO) 3 Cl, 28 Re(bpy-CH 3 )-(CO) 3 Cl, 29 Re(bpy-t Bu) (CO) 3 Cl, 29 4,4′-di-phenyl-2,2′-dipyridyl, 42 4,4′-di-mesityl-2,2′-dipyridyl, 43 4,4′-di-methyl ester-2,2′-dipyridyl, 44 and [Zn(cyclam)](BF 4 ) 2 28 were prepared according to previously reported procedures.…”

Section: Methodsmentioning

confidence: 99%

Substituents and Cocatalyst Effect on the Catalytic Response and Overpotential of Re(I) Catalysts for CO₂ Reduction

Boraghi

White

Pordel

et al. 2021

ACS Appl. Energy Mater.

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To design an efficient electrocatalyst for CO 2 reduction, a comprehensive understanding of the catalytic architecture and the reaction mechanism is required. Herein, we synthesized and analyzed a series of fac-[Re(bpy-X) (CO) 3 Cl] (abbreviated as Re I (bpy-X); bpy-X = 4,4′-disubstituted-2,2′bipyridine; X = t Bu, CH 3 , mesityl, H, phenyl, and methyl ester) catalysts for electrocatalytic CO 2 reduction with and without adding the cocatalyst [Zn(cyclam)] 2+ (cyclam = 1,4,6,11tetraazacyclotetradecane). Both computational and experimental results show that in the experiments bearing the [Zn(cyclam)] 2+ cocatalyst, the Re(I) catalysts require less energy input to reduce the CO 2 , indicating that the CO 2 -to-CO conversion occurs at a lower overpotential. Interestingly, in the Re(I) electrocatalyst bearing a strong electron-withdrawing group (methyl ester), [Zn(cyclam)] 2+ does not improve the CO 2 reduction activity. These results emphasize the importance of how the electronic distribution throughout the molecular architecture can enhance or suppress the nucleophilicity of Re I (bpy-X) electrocatalysts, even in the presence of a cocatalyst.

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Impact of Mn(I) photoCORM ligand set on photochemical intermediate formation during visible light-activated CO release

Cited by 17 publications

References 55 publications

Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Effects of Chemically-Modified Polypyridyl Ligands on the Structural and Redox Properties of Tricarbonylmanganese(I) Complexes

Substituents and Cocatalyst Effect on the Catalytic Response and Overpotential of Re(I) Catalysts for CO₂ Reduction

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Impact of Mn(I) photoCORM ligand set on photochemical intermediate formation during visible light-activated CO release

Cited by 17 publications

References 55 publications

Release of CO and Production of 1O2 from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Release of CO and Production of 1O2 from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Effects of Chemically-Modified Polypyridyl Ligands on the Structural and Redox Properties of Tricarbonylmanganese(I) Complexes

Substituents and Cocatalyst Effect on the Catalytic Response and Overpotential of Re(I) Catalysts for CO2 Reduction

Contact Info

Product

Resources

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Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Release of CO and Production of ¹O₂ from a Mn-BODIPY Photoactivated CO Releasing Molecule with Visible Light

Substituents and Cocatalyst Effect on the Catalytic Response and Overpotential of Re(I) Catalysts for CO₂ Reduction