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The photocatalytic generation of an NADH synthetic analogue, i.e. 1-benzyl-1,4-dihydronicotinamide (1,4-BNAH), has been studied using the cobalt diimino–dioxime complexes and the BF2-bridged derivative as catalysts. 1,4-BNAH was produced in both aqueous and organic media at unprecedented turnover numbers with metal and organic photosensitizers, respectively.

The iron(II) complex bearing the 2,2′:6′,2′′:6′′,2′′′:6′′′,2′′′′-quinquepyridine (qnpy) ligand, [Fe(qnpy)(H2O)2]2+, is a highly efficient and robust catalyst for photocatalytic reduction of CO2 to CO in aqueous acetonitrile solution. A turnover number (TON) for CO of up to 14 095 with 98% selectivity can be achieved using Ru(phen)3Cl2 (phen = 1,10-phenanthroline) as the photosensitizer and BIH (1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole) as the sacrificial reductant in a CO2-saturated MeCN/H2O (1 : 1, v/v) solution under visible light irradiation. This Fe complex is state-of-the-art for CO2 visible-light-driven catalysis.

The development of efficient and cost-effective electrocatalysts for the hydrogen evolution reaction (HER) is of intense interest because H2 is one of the most promising renewable energy sources. Herein, we report a highly efficient and stable HER electrocatalyst composed of ruthenium nanoparticles embedded in nitrogen-doped carbon (NC), which is synthesized via a simple thermolysis process using a ruthenium complex as metal precusor and using ethylenediaminetetraacetic acid tetrasodium (Na4EDTA) salt as ligand and carbon source. It is found that the amount of Na4EDTA employed plays an important role in achieving sutiable and uniform Ru nanoparticles. The resulting Ru@NC(1 : 5) was found to exhibit excellent HER activity and robust stability in alkaline media (1.0 M KOH) with a low overpotential at 10 mA cm−2 (29 mV), small Tafel slope (27 mV per decade) and a high turnover frequency (TOF) of 0.96 s−1 at an overpotential of 50 mV, which are comparable to the state-of-the-art commercial Pt/C catalyst. Based on the characterization of the samples and the electrochemical measurements, this high performance of Ru@NC(1 : 5) is ascribed to its smallest particle size (ca. 2.1 nm diameter), large active site density and the high electrochemical conductivity by the N-doped carbon support. In addition, Ru@NC(1 : 5) also works well in acidic media (0.5 M H2SO4) indicating it is a pH-universal catalyst.

Artificial photosynthesis is considered as one of the most promising strategies for solar-to-fuel conversion through sunlight-driven water splitting and CO2 reduction. This tutorial describes recent developments in the use of metal quaterpyridine complexes as electrocatalyts and photocatalysts for artificial photosynthesis.

In this work we provide direct experimental evidence on the correlation of remote interactions between a newly synthesized MnI-complex (1) and different alkali cations with redox potential tuning. Furthermore we report the electrochemical behavior of 1 towards carbon dioxide, including the effects of added alkali salts using cyclic voltammetry.

Novel energy and atom efficiency processes will be keys to develop the sustainable chemical industry of the future. Electrification could play an important role, by allowing to fine-tune energy input and using the ideal redox agent: the electron. Here we demonstrate that a commercially available Milstein ruthenium cata-lyst (1) can be used to promote the electrochemical oxidation of ethanol to ethyl acetate and acetate, thus demonstrating the four electron oxidation under preparative conditions. Cyclic voltammetry and DFT-calculations are used to devise a possible catalytic cycle based on a thermal chemical step generating the key hydride intermediate. Successful electrification of Milstein-type catalysts opens pathway to use alcohols as renewable feedstock for the generation of esters and other key building blocks in organic chemistry, thus contributing to increase energy efficiency in organic redox chemistry.

The aircraft seat has been shown to impact passenger comfort experience in the cabin interior. A previous study defined passenger comfort experience in the cabin in terms of eight experiential themes. This study first investigated the possibility of differentiating passenger comfort and discomfort experience in economy class based on participants’ rating of those themes. No significant differences were found between the two concepts. Second, themes that were found to be most connected to the seat and participants’ respective concerns were highlighted. The theme ‘physical wellbeing’ was mentioned most frequently, followed by ‘peace of mind’, and ‘proxemics’. These three accounted for more than 70% of passengers’ seat experience. Among those, only the physical experience correlated with participants’ height, suggesting that to improve the passengers’ comfort experience, design efforts should go beyond the physical fit of the seat to the occupant’s body and explore passenger’s concerns for ‘peace of mind’ and ‘proxemics’.

Efficient and selective photocatalytic CO

A pyrazole–based ligand substituted with terpyridine groups at the 3 and 5positions has been synthesized to form the dinuclear cobalt complex 1, that electrocatalytically reduces carbon dioxide (CO2) to carbon monoxide (CO) in the presence of Brønsted acids in DMF. Chemical, electrochemical and UV–vis spectro–electrochemical studies under inert atmosphere indicate a single 2 electron reduction process of complex 1 at first, followed by a 1 electron reduction at the ligand. Infrared spectro–electrochemical studies under CO2 and CO atmosphere allowed us to identify a reduced CO–containing dicobalt complex which results from the electroreduction of CO2. In the presence of trifluoroethanol (TFE), electrocatalytic studies revealed single–site mechanism with up to 94 % selectivity towards CO formation when 1.47 M TFE were present, at –1.35 V vs Saturated Calomel Electrode in DMF (0.39 V overpotential). The low faradaic efficiencies obtained (

Nitrogen reduction in mild conditions (i.e. room temperature and atmospheric pressure) and using a non-fossil source of hydrogen remains a high chemistry challenge. Molecular metal complexes, notably Mo based, have recently shown to be active for such nitrogen fixation. In this work, we report about the electrochemical N2 splitting with MoIII triphosphino com-plex ((PPP)MoI3), at room temperature and a moderately negative potential. A MoIV nitride species was generated, which was confirmed by electrochemistry and NMR studies. The reaction goes through the bi-electronic reduction of the starting Mo species, coordination of an N2 molecule, and further splitting to a MoIV nitride complex. Preliminary DFT investigation supports the intermediacy of a bridging MoIN2MoI dinitrogen dimer evolving to the Mo nitride via a low energy transition state. This example joins a short list of molecular electrochemical complexes for N2 reductive cleavage. It opens a door to molecular electrochemical PCET conversion studies of N2 to NH3.

Reduction of carbon dioxide has as main objective the production of useful organic compounds and fuels - renewable fuels - in which solar energy would be stored. Molecular catalysts can be employed to reach this goal, either in photochemical or electrochemical (or combined) contexts. They may in particular provide excellent selectivity thanks to easy tuning of the electronic properties at the metal and of the ligand second and third coordination sphere. Recently it has been shown that such molecular catalysts may also be tuned for generating highly reduced products such as methanol and methane, leading to new exciting advancements. Hybridization of these catalysts with conductive or semi-conductive materials may lead to enhance stability and new catalytic properties, as well as inclusion of molecular catalysts in devices for applications. This approach bridges between homogeneous and heterogeneous, and it raises new fundamental questions that may further lead to breakthrough in CO2 reduction chemistry. Our recent results in these various areas will be discussed, using earth abundant metal (Fe, Co) porphyrins and phthalocyanines as well as related complexes as catalysts. References P. B. Pati, E. Boutin, R. Wang, S. Diring, S. Jobic, N. Barreau, F. Odobel, M. Robert, Nat. Commun. 2020, 11:3499. S. Ren, D. Joulie, D. Salvatore, K. Torbensen, M. Wang, M. Robert, C. Berlinguette, Science 2019, 365, 367-369. E. Boutin, M. Wang, J. C. Lin, M. Mesnage, D. Mendoza, B. Lassalle-Kaiser, C. Hahn, T. F. Jaramillo, M. Robert, Angew. Chem. Int. Ed. 2019, 58, 16172-16176. Z. Guo, C. Cometto, G. Chen, L. Chen, B. Ma, H. Fan, T. Groizard, W-L. Man,S-M. Yiu, K-C. Lau, T-C. Lau, M. Robert, Nat. Catal. 2019, 2, 801-808. H. Rao, L. Schmidt, J. Bonin, M. Robert, Nature 2017, 548, 74-77. C. Costentin, S. Drouet, M. Robert, J-M. Savéant, Science 2012, 338, 90-94.

Carbon dioxide (CO2) is the iconic greenhouse gas and the major factor driving present global climate change, incentivizing its capture and recycling into valuable products and fuels. The 6H+/6e− reduction of CO2 affords CH3OH, a key compound that is a fuel and a platform molecule. In this Review, we compare different routes for CO2 reduction to CH3OH, namely, heterogeneous and homogeneous catalytic hydrogenation, as well as enzymatic catalysis, photocatalysis and electrocatalysis. We describe the leading catalysts and the conditions under which they operate, and then consider their advantages and drawbacks in terms of selectivity, productivity, stability, operating conditions, cost and technical readiness. At present, heterogeneous hydrogenation catalysis and electrocatalysis have the greatest promise for large-scale CO2 reduction to CH3OH. The availability and price of sustainable electricity appear to be essential prerequisites for efficient CH3OH synthesis. This Review identifies competitive advantages and drawbacks of heterogeneous and homogeneous catalytic hydrogenation, as well as enzymatic catalysis, photocatalysis and electrocatalysis, for CO2 reduction to methanol.

In the quest for designing efficient and stable photocatalytic materials for CO

International audience

A Fe quaterpyridine complex was used as a molecular precursor for the electrochemical reduction of CO2 to CH4 in acetonitrile in the presence of triethanolamine. CH4 was produced with a faradaic yield of approximately 2.1 % at 25 °C and 1 atm pressure of CO2 as reactant. Controlled potential electrolysis coupled to ex situ X-ray photoelectron spectroscopy and X-ray absorption spectroscopy of the electrode surface revealed the formation of metallic iron covered by iron oxides as species responsible for catalysis.

It is highly desirable to discover molecular catalysts with controlled selectivity for visible-light-driven CO2 reduction to fuels. In the design of catalysts employing earth-abundant metals, progress has been made for CO production, but formate generation has been observed more rarely. Here, we report a binuclear Co complex bearing a bi-quaterpyridine ligand that can selectively reduce CO2 to HCOO− or CO under visible light irradiation. Selective formate production (maximum of 97%) was obtained with a turnover number of up to 821 in basic acetonitrile solution. Conversely, in the presence of a weak acid, CO2 reduction affords CO with high selectivity (maximum of 99%) and a maximum turnover number of 829. The catalytic process is controlled by the two Co atoms acting synergistically, and the selectivity can be steered towards the desired product by simply changing the acid co-substrate. Performing photocatalytic CO2 reduction in a selective fashion with molecular catalysts represents a considerable challenge. Here, a binuclear cobalt complex featuring a bi-quaterpyridine ligand is developed that can selectively afford either carbon monoxide or formate by selection of the reaction medium acidity.

Molecular catalysts that combine high product selectivity and high current density for CO2 electrochemical reduction to CO or other chemical feedstocks are urgently needed. While earth-abundant metal-based molecular electrocatalysts with high selectivity for CO2 to CO conversion are known, they are characterized by current densities that are significantly lower than those obtained with solid-state metal materials. Here, we report that a cobalt phthalocyanine bearing a trimethyl ammonium group appended to the phthalocyanine macrocycle is capable of reducing CO2 to CO in water with high activity over a broad pH range from 4 to 14. In a flow cell configuration operating in basic conditions, CO production occurs with excellent selectivity (ca. 95%), and good stability with a maximum partial current density of 165 mA cm−2 (at −0.92 V vs. RHE), matching the most active noble metal-based nanocatalysts. These results represent state-of-the-art performance for electrolytic carbon dioxide reduction by a molecular catalyst., Molecular electrocatalysts reducing CO2 to CO with high selectivity and high rate are urgently needed. A cobalt phthalocyanine complex is capable of reducing CO2 to CO in water with a maximum partial current density up to 165 mA cm−2, matching the most active noble metal-based nanocatalysts.

We develop management innovation theory, providing insights into the role of time in the implementation phase. The management innovation literature has sought to empirically identify factor...

The novel rhenium complexes fac-Re(pdbpy)(CO)3Cl (pdbpy = 4-phenyl-6-(phenyl-2,6-diol)-2,2′-bipyridine), 1, and fac-Re(ptbpy)(CO)3Cl (ptbpy = 4-phenyl-6-(phenyl-3,4,5-triol)-2,2′-bipyridine), 2, have been synthesized, and the single crystal X-ray diffraction (SC-XRD) structure of 1 was solved. The electrochemical behaviors of the complexes in acetonitrile under Ar and their catalytic performances for CO2 reduction with added water and MeOH are discussed. A detailed IR spectroelectrochemical study under Ar and CO2 atmospheres coupled with DFT calculations allows the identification of reduced species and the interpretation of the reduction mechanisms. Comparison between the rhenium complexes and the corresponding Mn derivatives Mn(pdbpy)(CO)3Br, 3, and Mn(ptbpy)(CO)3Br, 4, has been also considered. Finally, photostimulated conversion of the CO2 was investigated with catalysts (1, 3, and 4) under visible light irradiation (λ > 420 nm) in acetonitrile as solvent. Remarkably, 1 and 3 catalysts were active towa...

A new pentadentate quinoline-pyridine ligand and its iron (1), cobalt (2) and nickel (3) complexes have been synthesized and characterized. The iron complex exhibits excellent photocatalytic activity towards CO2-to-CO conversion with a TON(CO) of 544 and a selectivity of 99.3% using the commercially available organic dye purpurin as the photosensitiser and BIH as the electron donor. In contrast, the cobalt and nickel complexes result in very low activity for CO production with a TON of only 8 and 15, respectively. On the other hand, all the three complexes show good electrocatalytic activity for CO2 reduction when using 2,2,2-trifluoroethanol as the proton source with the active intermediate of M0 species. The lack of activity in photocatalytic CO2 reduction by 2 and 3 can be attributed to the redox potential of MI/M0 which is significantly more negative than that of PP-/PP2- while in the case of 1 the FeI/Fe0 redox potential becomes more positive than that of the PP-/PP2- couple.

4089 Background: Immune checkpoint inhibitors (ICI) alone or in combination with tyrosine kinase (TKI) or VEGF pathway inhibitors (VEGFi) are therapeutic options in unresectable HCC (uHCC). Whether exposure to antibiotics (ATB), a consolidated adverse prognostic factor in ICI recipients, affects outcome in HCC remains unclear. Methods: FDA analysed patient-level data of 4098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or combinations (n = 584), TKI (N = 1968), VEGFi (n = 480) or placebo (n = 808) as part of 9 international clinical trials submitted to the US Food and Drug Administration in support of marketing applications. Associations for ATB exposure within 30 days before or after initiation of anti-cancer treatment (ATB) with overall (OS) and progression-free survival (PFS) were examined across therapeutic modality. Estimates were weighted by propensity score (PSW) using clinically relevant covariates. Results: Out of 4098 patients with uHCC mostly secondary to Hepatitis B (39%) or C (21%) infection, the majority were males (83%) with a median age of 64 (range 18-88), ECOG performance status of 0 (60%) and Child-Pugh A class (98%). Most patients had metastases (68%) but did not have macrovascular invasion (71%). Overall, 620 patients (15%) were ATB+, with comparable rates across placebo (12%), TKI (16%), VEGFi (15%), and ICI (16%). In the overall population, ATB was associated with shorter PFS (2.8 vs 3.9 months [m], HR 1.29, 95%CI 1.22-1.36) and OS (6.4 vs. 8.8 m; HR 1.36, 95%CI 1.29-1.43). In PSW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52, 95%CI 1.34-1.73), TKI (HR 1.29, 95%CI 1.19-1.39) and placebo (HR 1.23, 95%CI 1.11-1.37). Similar results were observed in PSW analyses of OS in patients treated with ICI (HR 1.22, 95%CI 1.08-1.38), TKI HR 1.40, 95%CI 1.30-1.52), and placebo (HR 1.40, 95%CI 1.25-1.57). Consistent outcomes were observed for ATB+ patients within ICI treatment subgroups, including patients treated with anti-PD-1 monotherapy (PFS HR 1.49, 95%CI 1.22-1.80; OS HR 1.31 1.02-1.68) and ICI combinations (PFS HR 1.50, 95%CI 1.26-1.77; OS HR 1.14 0.99-1.32). Conclusions: Unlike other oncological indications where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with inferior outcomes across a broad range of anti-cancer therapies for HCC and placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut liver axis remains to be demonstrated in translational studies.

The correlates of natural protective immunity to SARS-CoV-2 in the majority who experience asymptomatic infection or non-severe disease are not fully characterised, and remain important as new variants emerge. We addressed this question using blood transcriptomics, multiparameter flow cytometry and T cell receptor (TCR) sequencing spanning the time of incident infection. We identified a type 1 interferon (IFN) response common to other acute respiratory viruses, and a cell proliferation response that discriminated SARS-CoV-2 from other viruses. These responses peaked by the time the virus was first detected, and in some preceded virus detection. Cell proliferation was most evident in CD8 T cells and associated with rapid expansion of SARS-CoV-2 reactive TCRs. We found an equally rapid increase in immunoglobulin transcripts, but circulating virus-specific antibodies lagged by 1-2 weeks. Our data support a protective role for rapid induction of type 1 IFN and CD8 T cell responses to SARS-CoV-2.

SummaryAntigen recognition and T-cell mediated cytotoxicity in clear-cell renal cell carcinoma (ccRCC) remains incompletely understood. To address this knowledge gap, we analysed 115 multiregion tumour samples collected from 15 treatment-naïve patients pre- and post-nivolumab therapy, and at autopsy in three patients. We performed whole-exome sequencing, RNAseq, TCRseq, multiplex immunofluorescence and flow cytometry analyses and correlated with clinical response. We observed pre-treatment intratumoural TCR clonal expansions suggesting pre-existing immunity. Nivolumab maintained pre-treatment expanded, clustered TCR clones in responders, suggesting ongoing antigen-driven stimulation of T-cells. T-cells in responders were enriched for expanded TCF7+CD8+T-cells and upregulated GZMK/B upon nivolumab-binding. By contrast, nivolumab promoted accumulation of new TCR clones in non-responders, replacing pre-treatment expanded clonotypes. In this dataset, mutational features did not correlate with response to nivolumab and human endogenous retrovirus expression correlated indirectly. Our data suggests that nivolumab potentiates clinical responses in ccRCC by binding pre-existing expanded CD8+T-cells to enhance cytotoxicity.

International audience; Prof. Jean-Michel Savéant sadly passed on August 16 2020. We would like to honor his memory, his tremendous contribution to electrochemistry and its use for a general understanding of the laws of physical chemistry. In this review, we highlight his decisive role in the foundation of molecular electrochemistry. We also present his major achievements in the field of molecular and biomolecular catalysis. Finally, we review his unique contribution to dissociative electron transfers and to the electrochemical approach of proton-coupled electron transfers. This shows how various concepts rigorously established and experimentally validated assemble to each other to enlighten complex systems.