Light-Assisted Molecular and Hybrid Systems for Artificial Photosynthesis

Editorial

07 April 2022

Editorial: Light-Assisted Molecular and Hybrid Systems for Artificial Photosynthesis

Mirco Natali

Xavier Sala

Souvik Roy

Andrea Pannwitz

and

Albert Ruggi

1,819 views

0 citations

Editors

Albert Ruggi

Département de Chimie, Faculté des Sciences et de Médecine, Université de Fribourg

Mirco Natali

University of Ferrara

Andrea Pannwitz

University of Ulm

Souvik Roy

University of Lincoln

Xavier Sala

Autonomous University of Barcelona

Impact

The complexes studied in this paper and the previously reported (Põldme et al., 2019) RuPd complex.

Original Research

24 December 2021

Ruthenium Assemblies for CO2 Reduction and H2 Generation: Time Resolved Infrared Spectroscopy, Spectroelectrochemistry and a Photocatalysis Study in Solution and on NiO

Florian J. R. Cerpentier

, 6 more and

Mary T. Pryce

Two novel supramolecular complexes RuRe ([Ru(dceb)₂(bpt)Re(CO)₃Cl](PF₆)) and RuPt ([Ru(dceb)₂(bpt)PtI(H₂O)](PF₆)₂) [dceb = diethyl(2,2′-bipyridine)-4,4′-dicarboxylate, bpt = 3,5-di(pyridine-2-yl)-1,2,4-triazolate] were synthesized as new catalysts for photocatalytic CO₂ reduction and H₂ evolution, respectively. The influence of the catalytic metal for successful catalysis in solution and on a NiO semiconductor was examined. IR-active handles in the form of carbonyl groups on the peripheral ligand on the photosensitiser were used to study the excited states populated, as well as the one-electron reduced intermediate species using infrared and UV-Vis spectroelectrochemistry, and time resolved infrared spectroscopy. Inclusion of ethyl-ester moieties led to a reduction in the LUMO energies on the peripheral bipyridine ligand, resulting in localization of the ³MLCT excited state on these peripheral ligands following excitation. RuPt generated hydrogen in solution and when immobilized on NiO in a photoelectrochemical (PEC) cell. RuRe was inactive as a CO₂ reduction catalyst in solution, and produced only trace amounts of CO when the photocatalyst was immobilized on NiO in a PEC cell saturated with CO₂.

5,946 views

9 citations

Original Research

30 September 2021

Sensitized Photocatalytic CO2 Reduction With Earth Abundant 3d Metal Complexes Possessing Dipicolyl-Triazacyclononane Derivatives

Martin Obermeier

, 3 more and

Matthias Schwalbe

Comparison of catalytic activity of the Fe and Co based catalysts (5 × 10−5 M), in DMF applying a λ > 400 nm longpass filter, with 5% TEA as SR, Ir(dFppy)3 and a 200 W Hg-lamp. Dotted line: H2 formation and solid line: CO formation.

Complexes based on nitrogen and sulfur containing ligands involving 3d metal centers are known for the electrocatalytic reduction of CO_2. However, photocatalytical activation has rarely been investigated. We herein present results on the light-driven CO₂ reduction using either Ir(dFppy)₃ [Ir, dFppy = 2-(4,6-difluorophenyl)pyridine] or [Cu(xant)(bcp)]⁺, (Cu, xant = xantphos, bcp = bathocuproine) as photosensitizer in combination with TEA (triethylamine) as sacrificial electron donor. The 3d metal catalysts have either dptacn (dipicolyl-triazacyclononane, L^N3) or dpdatcn (dipicolyl-diazathiocyclononane, L^N2S) as ligand framework and Fe³⁺, Co³⁺ or Ni²⁺ as central metal ion. It turned out that the choice of ligand, metal center and solvent composition influences the selectivity for product formation, which means that the gaseous reduction products can be solely CO or H₂ or a mixture of both. The ratio between these two products can be controlled by the right choice of reaction conditions. With using Cu as photosensitizer, we could introduce an intermolecular system that is based solely on 3d metal compounds being able to reduce CO₂.

4,842 views

8 citations

Original Research

24 November 2021

Basicity as a Thermodynamic Descriptor of Carbanions Reactivity with Carbon Dioxide: Application to the Carboxylation of α,β-Unsaturated Ketones

Pietro Franceschi

, 5 more and

Andrea Sartorel

3,873 views

3 citations

Mini Review

24 June 2021

Photocatalytic Oxidation Reactions Mediated by Covalent Organic Frameworks and Related Extended Organic Materials

José Alemán

and

Rubén Mas-Ballesté

Covalent Organic Frameworks (COFs) and related extended organic materials have been widely used as photocatalysts in the last few years. Such interest arises from the wide range of covalent linkages employed in their construction, which offer many possibilities to design extended frameworks and to link photoactive building blocks. Thus, the potential utility of predesigned organic photoactive fragments can be synergistically added to the inherent advantages of heterogeneous catalysis, such as recyclability and easy separation of catalyst. In this overview, the current state of the art on the design of organic materials for photocatalytic oxidation reactions will be presented. The designing process of these materials is usually conditioned by the generally accepted concept that crystallinity and porosity defines the quality of the heterogeneous catalysts obtained. The care for the structural integrity of materials obtained is understandable because many properties and applications are intimately related to these features. However, the catalytic activity does not always directly depends on these characteristics. A critical compilation of the available literature is performed in order to offer a general perspective of the use of COFs and Covalent Triazine Frameworks (CTFs) in photocatalytic oxidation processes, including water oxidation, which constitute an important outcome relevant to artificial photosynthesis.

5,086 views

10 citations