Ru(II)-diimine complexes and cytochrome P450 working hand-in-hand

With a growing interest in utilizing visible light to drive biocatalytic processes, several light-harvesting units and approaches have been employed to harness the synthetic potential of heme monooxygenases and carry out selective oxyfunctionalization of a wide range of substrates. While the fields of cytochrome P450 and Ru(II) photochemistry have separately been prolific, it is not until the turn of the 21st century that they converged. Non-covalent and subsequently covalently attached Ru(II) complexes were used to promote rapid intramolecular electron transfer in bacterial P450 enzymes. Photocatalytic activity with Ru(II)-modified P450 enzymes was achieved under reductive conditions with a judicious choice of a sacrificial electron donor. The initial concept of Ru(II)-modified P450 enzymes was further improved using protein engineering, photosensitizer functionalization and was successfully applied to other P450 enzymes. In this review, we wish to present the recent contributions from our group and others in utilizing Ru(II) complexes coupled with P450 enzymes in the broad context of photobiocatalysis, protein assemblies and chemoenzymatic reactions. The merging of chemical catalysts with the synthetic potential of P450 enzymes has led to the development of several chemoenzymatic approaches. Moreover, strained Ru(II) compounds have been shown to selectively inhibit P450 enzymes by releasing aromatic heterocycle containing molecules upon visible light excitation taking advantage of the rapid ligand loss feature in those complexes

Utilisation des simulations informatiques et de la réalité virtuelle pour comprendre, concevoir et optimiser les canaux d'eau artificiels

International audienceIn biology, metabolite transport across cell membranes occurs through natural channels and pores. Artificial ion-channel architectures represent potential mimics of natural ionic conduction. Many such systems were produced leading to a remarkable set of alternative artificial ion-channels. Far less advances were achieved in the area of synthetic biomimetic water channels, even though they could improve our understanding of the natural function of protein channels and may provide new strategies to generate highly selective, advanced water purification systems. Most realizations have used the selectivity components of natural protein channels embedded in artificial systems. Such biomolecules provide building blocks to constitute highly selective membrane-spanning water transport architec-tures. The simplification of such compounds, while preserving the high conduction activity of natural macromolecules, lead to fully synthetic artificial biomimet-ic channels. These simplified systems offer a particular chance to understand mechanistic and structural behaviors, providing rationales to engineer better artificial water-channels. Here we focus on computer simulations as a tool to complement experiment in understanding the properties of such systems with the aim to rationalize important concepts, design and optimize better compounds. Molecular dynamics simulations combined with advanced visual scrutiny thereof are central to such an approach. Novel technologies such as virtual reality headsets and stere-oscopic large-scale display walls offer immersive collaborative insight into the complex mechanisms underlying artificial water channel function.En biologie, le transport des métabolites à travers les membranes cellulaires se fait par les canaux naturels et les pores. Les architectures artificielles à canaux ioniques représentent des imitations potentielles de la conduction ionique naturelle. Beaucoup de ces systèmes ont été produits, ce qui a conduit à un ensemble remarquable de canaux ioniques artificiels alternatifs. Beaucoup moins d'avancées ont été réalisées dans le domaine des canaux d'eau biomimétiques synthétiques, même si elles pourraient améliorer notre compréhension de la fonction naturelle des canaux protéiques et peuvent fournir de nouvelles stratégies pour générer des systèmes de purification d'eau avancés et hautement sélectifs. La plupart des réalisations ont utilisé les composants de sélectivité des canaux protéiques naturels intégrés dans des systèmes artificiels. Ces biomolécules fournissent des éléments constitutifs pour constituer des architec-tures de transport d'eau à membrane hautement sélective. La simplification de ces composés, tout en préservant l'activité de conduction élevée des macromolécules naturelles, conduit à des canaux biomimétiques artificiels entièrement synthétiques. Ces systèmes simplifiés offrent une chance particulière de comprendre les comportements mécanistiques et structurels, offrant des justifications pour concevoir de meilleurs canaux d'eau artificiels. Ici, nous nous concentrons sur les simulations informatiques en tant qu'outil pour compléter l'expérience dans la compréhension des propriétés de ces systèmes dans le but de rationaliser les concepts importants, de concevoir et d'optimiser de meilleurs composés. Les simulations de dynamique moléculaire combinées à un examen visuel avancé de celles-ci sont au cœur d'une telle approche. De nouvelles technologies telles que des casques de réalité virtuelle et des murs d'affichage à grande échelle stéréoscopiques offrent un aperçu collaboratif immersif des mécanismes complexes qui sous-tendent la fonction de canal d'eau artificiel

Synthesis, structural determination and antimicrobial evaluation of two novel CoII and ZnII halogenometallates as efficient catalysts for the acetalization reaction of aldehydes

Background: Complexes of imidazole derivatives with transition metal ions have attracted much attention because of their biological and pharmacological activities, such as antimicrobial, antifungal, antiallergic, antitumoural and antimetastatic properties. In addition, imidazoles occupy an important place owing to their meaningful catalytic activity in several processes, such as in hydroamination, hydrosilylation, Heck reaction and Henry reaction. In this work, we describe the crystallization of two halogenometallate based on 2-methylimidazole. Their IR, thermal analysis, catalytic properties and antibacterial activities have also been investigated. Results: Two new isostructural organic-inorganic hybrid materials, based on 2-methyl-1H-imidazole, 1 and 2, were synthesized and fully structurally characterized. The analysis of their crystal packing reveals non-covalent interactions, including C/N–HCl hydrogen bonds and stacking interactions, to be the main factor governing the supramolecular assembly of the crystalline complexes. The thermal decomposition of the complexes is a mono-stage process, confirmed by the three-dimensional representation of the powder diffraction patterns (TDXD). The catalytic structure exhibited promising activity using MeOH as solvent and as the unique source of acetalization. Moreover, the antimicrobial results suggested that metal-complexes exhibit significant antimicrobial activity. Conclusion: This study highlights again the structural and the biological diversities within the field of inorganic–organic hybrids. [Figure not available: see fulltext.]