Metalen en licht: sleutels naar een gezondere wereld

Oratie uitgesproken door Prof.dr. S. Bonnet bij de aanvaarding van het ambt van hoogleraar in de PhotoBioAnorganische Chemie aan de Universiteit Leiden op 8 September 2023Oratie uitgesproken door Prof.dr. S. Bonnet bij de aanvaarding van het ambt van hoogleraar in de PhotoBioAnorganische Chemie aan de Universiteit Leiden op 8 September 2023Metals in Catalysis, Biomimetics & Inorganic Material

Catalytic photoinduced electron transport across a lipid bilayer mediated by a membrane-soluble electron relay

Unidirectional photocatalytic electron transfer from a hydrophilic electron donor encapsulated in the interior of a liposome, to a hydrophilic electron acceptor on the other side of the membrane, has been achieved using the simple membrane-soluble electron relay 1-methoxy-N-methylphenazinium (MMP+). The total amount of photoproduct (>140 nmol) exceeds the number of moles of MMP+ present (125 nmol), thus showing that the transport of electrons is catalytic.Metals in Catalysis, Biomimetics & Inorganic Material

Simple and efficient method for mono‐ and di‐amination of polypyridine N‐oxides

Metals in Catalysis, Biomimetics & Inorganic Material

Photoinduced ligand exchange dynamics of a polypyridyl ruthenium complex in aqueous solution

The understanding of photoinduced ligand exchange mechanisms in polypyridyl ruthenium(II) complexes operating in aqueous solution is of crucial importance to rationalize their photoreactivity. Herein, we demonstrate that a synergetic use of ab initio molecular dynamics simulations and static calculations, both conducted at the DFT level, can provide a full understanding of photosubstitution mechanisms of a monodentate ligand by a solvent water molecule in archetypal ruthenium complexes in explicit water. The simulations show that the photoinduced loss of a monodentate ligand generates an unreactive 16-electron species in a hitherto undescribed pentacoordinated triplet excited state that converts, via an easily accessible crossing point, to a reactive 16-electron singlet ground state, which combines with a solvent water molecule to yield the experimentally observed aqua complex in less than 10 ps. This work paves the way for the rational design of novel photoactive metal complexes relevant for biological applications.Metals in Catalysis, Biomimetics & Inorganic Material

A stable alkylated cobalt catalyst for photocatalytic H2 generation in liposomes

Photocatalytic proton reduction is a promising way to produce dihydrogen (H-2) in a clean and sustainable manner, and mimicking nature by immobilising proton reduction catalysts and photosensitisers on liposomes is an attractive approach for biomimetic solar fuel production in aqueous solvents. Current photocatalytic proton reduction systems on liposomes are, however, limited by the stability of the catalyst. To overcome this problem, a new alkylated cobalt(II) polypyridyl complex (CoC12) was synthesised and immobilised on the lipid bilayer of liposomes, and its performance was studied in a photocatalytic system containing an alkylated ruthenium photosensitiser (RuC12) and a 1 : 1 mixture of sodium ascorbate and tris-2-carboxyethylphosphine hydrochloride as sacrificial electron donors. Several parameters (concentration of CoC12 and RuC12, pH, membrane composition) were changed to optimise the turnover number for H-2 production. Overall, CoC12 was found to be photostable and the optimised turnover number (161) was limited only by the decomposition of the ruthenium-based photosensitiser.Metals in Catalysis, Biomimetics & Inorganic MaterialsBiological and Soft Matter Physic

A note on divergent selection for total fleece weight in adult Angora rabbits: direct response to selection on total fleece weight at first and second harvest

[EN] In order to explore the genetic variability of wool production and other quantitative traits, an 8-cohort divergent selection experiment for total fleece weight (TFW) was carried out in French Angora rabbits. Studies were made on the wool production of a total of 669 female rabbits born between 1994 and 2001 and having produced wool from first to 12th harvests. The aim of the selection experiment was to obtain two divergent lines (low and high) on TFW. From preliminary analysis, the dataset was separated into three subsets according to the harvest number: one for each of the first two harvests and one for the third to the 12th harvests. In this paper, wool production data of the first and second harvests was analysed separately. Response to selection for total fleece weight at 3-12 harvest (TFW3-12) on this trait at first and second harvest was the aim of this paper. The second objective was to study the possibility of utilising values of the first or second harvest to estimate breeding values and as selection criteria for total fleece weight in the French Angora rabbit. Preliminary analysis of the data for non-genetic factors was done by the GLM procedure of SAS. Genetic parameters and breeding value estimates were carried out using a BLUP animal model using ASReml. A linear mixed model for a bivariate analysis of total fleece weight at first or second harvest and TFW3-12 was used. Heritability estimates of total fleece weight at first and second harvests were 0.36 and 0.38, respectively, and were similar to that observed at later harvests (0.35). The genetic correlation between TFW3-12 and fleece weight at first harvest was close to zero indicating that wool production at first harvest is a different trait from that of subsequent harvests. Genetic correlation estimates observed at second harvest were high (0.76) and response to selection at second harvest was similar to that observed for TFW3-12. These observations confirm that total fleece weight at first harvest is a different trait from TFW3-12. In French Angora rabbits, the high genetic correlation between TFW3-12 and total fleece weight at second harvest suggests the possibility of selection at this time for TFW3-12.The authors thank Gérard Auvinet, Jean Claude Musseau and Patricia Bayle of the Institut National de la Recherche Agronomique (INRA), Génétique Expérimentale en Productions Animales, Le Magneraud Poitou-Charentes Research Centre for the collection of data and the supply and care of Angora rabbits.Rafat, S.; Thébault, R.; Bonnet, M.; Deretz, S.; Pena-Arnaud, B.; De Rochambeau, H.; Allain, D. (2009). A note on divergent selection for total fleece weight in adult Angora rabbits: direct response to selection on total fleece weight at first and second harvest. World Rabbit Science. 17(1):39-44. doi:10.4995/wrs.2009.669394417

Causality in real-time dynamic substructure testing

Causality, in the bond graph sense, is shown to provide a conceptual framework for the design of real-time dynamic substructure testing experiments. In particular, known stability problems with split-inertia substructured systems are reinterpreted as causality issues within the new conceptual framework. As an example, causality analysis is used to provide a practical solution to a split-inertia substructuring problem and the solution is experimentally verified

Imaging the lipid bilayer of giant unilamellar vesicles using red-to-blue light upconversion

Red-to-blue triplet–triplet annihilation upconversion was obtained in giant unilamellar vesicles. The upconverted light was homogeneously distributed across the membrane and could be utilized for the imaging of individual giant vesicles in three dimensions. These results show the great potential of TTA-UC for imaging applications under anoxic conditions

d- Versus l-Glucose Conjugation: Mitochondrial Targeting of a Light-Activated Dual-Mode-of-Action Ruthenium-Based Anticancer Prodrug

Metals in Catalysis, Biomimetics & Inorganic Material

Red light activation of Ru(II) polypyridyl prodrugs via triplet-triplet annihilation upconversion: feasibility in air and through meat

Metals in Catalysis, Biomimetics & Inorganic Material