Semiartificial Photosynthetic Nanoreactors for H Generation.

A relatively unexplored energy source in synthetic cells is transmembrane electron transport, which like proton and ion transport can be light driven. Here, synthetic cells, called nanoreactors, are engineered for compartmentalized, semiartificial photosynthetic H production by a [FeFe]-hydrogenase (Hase). Transmembrane electron transfer into the nanoreactor was enabled by MtrCAB, a multiheme transmembrane protein from MR-1.

Challenges and Future Perspectives in Photocatalysis: Conclusions from an Interdisciplinary Workshop.

Photocatalysis is a versatile and rapidly developing field with applications spanning artificial photosynthesis, photo-biocatalysis, photoredox catalysis in solution or supramolecular structures, utilization of abundant metals and organocatalysts, sustainable synthesis, and plastic degradation. In this Perspective, we summarize conclusions from an interdisciplinary workshop of young principal investigators held at the Lorentz Center in Leiden in March 2023. We explore how diverse fields within photocatalysis can benefit from one another.

Relationship between Respiratory Microbiome and Systemic Inflammatory Markers in COPD: A Pilot Study.

The respiratory microbiome may influence the development and progression of COPD by modulating local immune and inflammatory events. We aimed to investigate whether relative changes in respiratory bacterial abundance are also associated with systemic inflammation, and explore their relationship with the main clinical COPD phenotypes. Multiplex analysis of inflammatory markers and transcript eosinophil-related markers were analyzed on peripheral blood in a cohort of stable COPD patients (n = 72).

Proteomic Blood Profiles Obtained by Totally Blind Biological Clustering in Stable and Exacerbated COPD Patients.

Although Chronic Obstructive Pulmonary Disease (COPD) is highly prevalent, it is often underdiagnosed. One of the main characteristics of this heterogeneous disease is the presence of periods of acute clinical impairment (exacerbations). Obtaining blood biomarkers for either COPD as a chronic entity or its exacerbations (AECOPD) will be particularly useful for the clinical management of patients.

Photocatalytic CO Reduction Using Homogeneous Carbon Dots with a Molecular Cobalt Catalyst.

A simple and precious-metal free photosystem for the reduction of aqueous CO to syngas (CO and H) is reported consisting of carbon dots (CDs) as the sole light harvester together with a molecular cobalt bis(terpyridine) CO reduction co-catalyst. This homogeneous photocatalytic system operates in the presence of a sacrificial electron donor (triethanolamine) in DMSO/HO solution at ambient temperature. The photocatalytic system exhibits an activity of 7.

Bioinspired photocatalytic systems towards compartmentalized artificial photosynthesis.

Artificial photosynthesis aims to produce fuels and chemicals from simple building blocks (i.e. water and carbon dioxide) using sunlight as energy source.

Size-dependent activity of carbon dots for photocatalytic H generation in combination with a molecular Ni cocatalyst.

Carbon dots (CDs) are low-cost light-absorbers in photocatalytic multicomponent systems, but their wide size distribution has hampered rational design and the identification of the factors that lead to their best performance. To address this challenge, we report herein the use of gel filtration size exclusion chromatography to separate amorphous, graphitic, and graphitic N-doped CDs depending on their lateral size to study the effect of their size on photocatalytic H evolution with a DuBois-type Ni cocatalyst. Transmission electron microscopy and dynamic light scattering confirm the size-dependent separation of the CDs, whereas UV-vis and fluorescence spectroscopy of the more monodisperse fractions show a distinct response which computational modelling attributes to a complex interplay between CD size and optical properties.

Low-Volume Reaction Monitoring of Carbon Dot Light Absorbers in Optofluidic Microreactors.

Optical monitoring and screening of photocatalytic batch reactions using cuvettes is time-consuming, requires substantial amounts of samples, and does not allow the analysis of species with low extinction coefficients. Hollow-core photonic crystal fibers (HC-PCFs) provide an innovative approach for reaction detection using ultraviolet-visible absorption spectroscopy, with the potential for high-throughput automation using extremely low sample volumes with high sensitivity for monitoring of the analyte. HC-PCFs use interference effects to guide light at the center of a microfluidic channel and use this to enhance detection sensitivity.

Synthesis and characterization of highly diluted polyanionic iron(II) spin crossover systems.

Spin crossover (SCO) complexes, through their reversible spin transition under external stimuli, can work as switchable memory materials. Here, we present a protocol for the synthesis and characterization of a specific polyanionic iron SCO complex and its diluted systems. We describe steps for its synthesis and the determination of crystallographic structure of the SCO complex in diluted systems.

Hybrid photocathode based on a Ni molecular catalyst and SbSe for solar H production.

We report a H evolving hybrid photocathode based on SbSe and a precious metal free molecular catalyst. Through the use of a high surface area TiO scaffold, we successfully increased the Ni molecular catalyst loading from 7.08 ± 0.

Influence of COPD systemic environment on the myogenic function of muscle precursor cells in vitro.

Background: Loss of muscle mass and function are well-recognized systemic manifestations of chronic obstructive pulmonary disease (COPD). Acute exacerbations, in turn, significantly contribute to upgrade these systemic comorbidities. Involvement of myogenic precursors in muscle mass maintenance and recovery is poorly understood.

Photocatalytic Removal of the Greenhouse Gas Nitrous Oxide by Liposomal Microreactors.

Nitrous oxide (NO) is a potent greenhouse and ozone-reactive gas for which emissions are growing rapidly due to increasingly intensive agriculture. Synthetic catalysts for NO decomposition typically contain precious metals and/or operate at elevated temperatures driving a desire for more sustainable alternatives. Here we demonstrate self-assembly of liposomal microreactors enabling catalytic reduction of NO to the climate neutral product N.

Photocatalytic Removal of the Greenhouse Gas Nitrous Oxide by Liposomal Microreactors.

Nitrous oxide (N O) is a potent greenhouse and ozone-reactive gas for which emissions are growing rapidly due to increasingly intensive agriculture. Synthetic catalysts for N O decomposition typically contain precious metals and/or operate at elevated temperatures driving a desire for more sustainable alternatives. Here we demonstrate self-assembly of liposomal microreactors enabling catalytic reduction of N O to the climate neutral product N .

Engineering Electro- and Photocatalytic Carbon Materials for CO Reduction by Formate Dehydrogenase.

Semiartificial approaches to renewable fuel synthesis exploit the integration of enzymes with synthetic materials for kinetically efficient fuel production. Here, a CO reductase, formate dehydrogenase (FDH) from Hildenborough, is interfaced with carbon nanotubes (CNTs) and amorphous carbon dots (-CDs). Each carbon substrate, tailored for electro- and photocatalysis, is functionalized with positive (-NHMe) and negative (-COO) chemical surface groups to understand and optimize the electrostatic effect of protein association and orientation on CO reduction.

Bridging Plastic Recycling and Organic Catalysis: Photocatalytic Deconstruction of Polystyrene via a C-H Oxidation Pathway.

Chemical recycling of synthetic polymers represents a promising strategy to deconstruct plastic waste and make valuable products. Inspired by small-molecule C-H bond activation, a visible-light-driven reaction is developed to deconstruct polystyrene (PS) into ∼40% benzoic acid as well as ∼20% other monomeric aromatic products at 50 °C and ambient pressure. The practicality of this strategy is demonstrated by deconstruction of real-world PS foam on a gram scale.

XAS and EPR in Situ Observation of Ru(V) Oxo Intermediate in a Ru Water Oxidation Complex.

In this study, we combine in situ spectroelectrochemistry coupled with electron paramagnetic resonance (EPR) and X-ray absorption spectroscopies (XAS) to investigate a molecular Ru-based water oxidation catalyst bearing a polypyridinic backbone . Although high valent key intermediate species arising in catalytic cycles of this family of compounds have remain elusive due to the lack of additional anionic ligands that could potentially stabilize them, mechanistic studies performed on this system proposed a water nucleophilic attack (WNA) mechanism for the O-O bond formation. Employing experimental conditions and complementary spectroscopic techniques allowed to observe intermediates that provide support for a WNA mechanism, including for the first time a Ru(V) oxo intermediate based on the ligand, in agreement with the previously proposed mechanism.

Light-driven reduction of aromatic olefins in aqueous media catalysed by aminopyridine cobalt complexes.

A catalytic system based on earth-abundant elements that efficiently hydrogenates aryl olefins using visible light as the driving-force and HO as the sole hydrogen atom source is reported. The catalytic system involves a robust and well-defined aminopyridine cobalt complex and a heteroleptic Cu photoredox catalyst. The system shows the reduction of styrene in aqueous media with a remarkable selectivity (>20 000) water reduction (WR).

An Integrated Carbon Nitride-Nickel Photocatalyst for the Amination of Aryl Halides Using Sodium Azide.

The synthesis of primary anilines via sustainable methods remains a challenge in organic synthesis. We report a photocatalytic protocol for the selective synthesis of primary anilines via cross-coupling of a wide range of aryl/heteroaryl halides with sodium azide using a photocatalyst powder consisting of nickel(II) deposited on mesoporous carbon nitride (Ni-mpg-CN ). This heterogeneous photocatalyst contains a high surface area with a visible light-absorbing and adaptive "built-in" solid-state ligand for the integrated catalytic Ni site.

Photocatalytic C-H Azolation of Arenes Using Heterogeneous Carbon Nitride in Batch and Flow.

The functionalization of aryl C(sp )-H bonds is a useful strategy for the late-stage modification of biologically active molecules, especially for the regioselective introduction of azole heterocycles to prepare medicinally-relevant compounds. Herein, we describe a practical photocatalytic transformation using a mesoporous carbon nitride (mpg-CN ) photocatalyst, which enables the efficient azolation of various arenes through direct oxidation. The method exhibits a broad substrate scope and is amenable to the late-stage functionalization of several pharmaceuticals.

Bespoke Biomolecular Wires for Transmembrane Electron Transfer: Spontaneous Assembly of a Functionalized Multiheme Electron Conduit.

exchanges electrons between cellular metabolism and external redox partners in a process that attracts much attention for production of green electricity (microbial fuel cells) and chemicals (microbial electrosynthesis). A critical component of this pathway is the outer membrane spanning MTR complex, a biomolecular wire formed of the MtrA, MtrB, and MtrC proteins. MtrA and MtrC are decaheme cytochromes that form a chain of close-packed hemes to define an electron transfer pathway of 185 Å.

Isolation of a Ru(IV) side-on peroxo intermediate in the water oxidation reaction.

The electrons that nature uses to reduce CO during photosynthesis come from water oxidation at the oxygen-evolving complex of photosystem II. Molecular catalysts have served as models to understand its mechanism, in particular the O-O bond-forming reaction, which is still not fully understood. Here we report a Ru(IV) side-on peroxo complex that serves as a 'missing link' for the species that form after the rate-determining O-O bond-forming step.

Visible-Light Promoted C-O Bond Formation with an Integrated Carbon Nitride-Nickel Heterogeneous Photocatalyst.

Ni-deposited mesoporous graphitic carbon nitride (Ni-mpg-CN) is introduced as an inexpensive, robust, easily synthesizable and recyclable material that functions as an integrated dual photocatalytic system. This material overcomes the need of expensive photosensitizers, organic ligands and additives as well as limitations of catalyst deactivation in the existing photo/Ni dual catalytic cross-coupling reactions. The dual catalytic Ni-mpg-CN is demonstrated for C-O coupling between aryl halides and aliphatic alcohols under mild condition.

Electrocatalytic Water Oxidation with α-[Fe(mcp)(OTf)] and Analogues.

The complex α-[Fe(mcp)(OTf)] (mcp = ,'-dimethyl-,'-bis(pyridin-2-ylmethyl)-cyclohexane-1,2-diamine and OTf = trifluoromethanesulfonate anion) was reported in 2011 by some of us as an active water oxidation (WO) catalyst in the presence of sacrificial oxidants. However, because chemical oxidants are likely to take part in the reaction mechanism, mechanistic electrochemical studies are critical in establishing to what extent previous studies with sacrificial reagents have actually been meaningful. In this study, the complex α-[Fe(mcp)(OTf)] and its analogues were investigated electrochemically under both acidic and neutral conditions.