Linear N-alkenyl or alkynyl N-sulfonyl 1-aminobut-3-yn-2-ones are converted into bicyclic indolizines and pyrrolo1,2-aazepine-type alkaloids upon gold(I) catalysis (17 examples, 10–85%). The ...reaction cascade allowed formation of C–N, O–S, and C–C bonds via a cycloisomerization/sulfonyl migration/cyclization process using 10 mol % of (2-biphenyl)di-tert-butylphosphinegold(I) triflimide complex in dichloromethane.
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IJS, KILJ, NUK, PNG, UL, UM
Two types of porphyrin copolymer thin films were obtained by electropolymerization of zinc-5,15-bis(p-tolyl)porphyrin. Electrogenerated porphyrin radical cation and dication are powerful ...electrophiles which can rapidly react with 1,1″-(1,3-propanediyl)bis-4,4′-bipyridinium hexafluorophosphate salt (bpy+–(CH2)3–+bpy·2PF6−) as nucleophiles to form copolymers containing stable isoporphyrin radicals or porphyrins, depending of the applied upper potential limit (1.0 V versus 1.6 V). Electrochemical routes leading to these electroactive copolymers are discussed and the unusual redox properties of copolymers containing stable isoporphyrin radicals are studied. The electropolymerization of the two copolymers was monitored by electrochemical quartz crystal microbalance (EQCM). The copolymers were characterized by UV–Vis–NIR spectroscopy, X-ray photoelectron spectroscopy (XPS), electrochemistry, electron spin resonance (ESR) and atomic force microscopy (AFM). Their electrical properties have been studied by electrochemical impedance spectroscopy and their photovoltaic performances have been investigated by photocurrent transient measurements under visible-NIR light irradiation. The isoporphyrin radical copolymer exhibited considerably better photocurrent generation when compared to the porphyrin copolymer.
Electro-oxidation of zinc-5,15-bis(p-tolyl)porphyrin in the presence of dipyridyl ligand led to the formation of copolymers containing stable isoporphyrin radicals or porphyrins depending on the applied upper potential limit (1.0 V versus 1.6 V). The electrochemical properties as well as the photovoltaic performances have been investigated. The photocurrent generation was significantly improved in the case of the isoporphyrin radical copolymer. Display omitted
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Porphyrins and Polyoxometalate Scaffolds Lamare, Raphaël; Ruppert, Romain; Boudon, Corinne ...
Chemistry : a European journal,
November 22, 2021, 2021-11-22, 20211122, Volume:
27, Issue:
65
Journal Article
Peer reviewed
Open access
Polyoxometalates (POMs) can act as unique reservoirs for multiple electron transfers. As POMs display only weak absorption in the visible spectrum, they can be associated with chromophores such as ...porphyrins and porphyrin antennae. In this Minireview, the research dedicated to the combination of porphyrins and polyoxometalates is put in context and the state of the art identifying the challenges addressed in the optimization of hybrid materials for applications is detailed.
Winning combo: Porphyrins and polyoxometalates can be combined into useful architectures for energy conversion, this minireview highlights the most successful strategies developed to date.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A series of porphyrin dimers have been prepared and characterized in order to form inclusion complexes with Lindqvist-type polyoxometallates. The synthesis of the porphyrin dimer has been optimized ...and can serve general purposes. The formation of inclusion complexes has been monitored using spectroscopic methods and moderate affinities with $\log \, K_{\mathrm{assoc}}$ varying from 2.6 to 4.2 have been determined and the parameters governing the formation of the complexes have been examined.
Porphyrins and polyoxometalates can be combined into useful architectures for energy conversion, this Minireview highlights the most successful strategies developed to date. For more information, see ...the Minireview by Ruhlmann, Weiss et al. on page 16071
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
For the last fifteen years, on-surface synthesis became an extremely popular and powerful method to fabricate nanostructures which otherwise would not have been accessible by conventional wet organic ...syntheses. The syntheses, realized in the chamber of high vacuum scanning tunneling microscope (STM), permitted the fabrication and the characterization of atomically defined nanostructures such as polycyclic aromatic hydrocarbons (PAH), graphene nanoribbons or 2D covalent networks.
1
Among the organic molecules studied by STM, porphyrins are of particular importance because of their electronic and optical properties. Initial studies were mainly devoted to the supramolecular organization of porphyrins and porphyrin derivatives on surface and it is only in 2004 that noble metal surfaces were used as catalytic surface to perform reactions on the porphyrin cores.
2
Since then, examples of open-shell porphyrin derivatives
3
and conjugated oligomers
4
were reported.
While the synthesis of fused bis- and tetra-4,5-bis-(2,4,6-trimethylphenoxy)anthracen-9-yl porphyrins containing Ni(II) was reported by Anderson about 10 years ago,
5
the formation π-extended porphyrin bearing unsubstituted anthracenyl moieties were never achieved. The formation of such compounds became possible by on-surface synthesis. Herein, we report on the synthesis of fused bis- and tetra-anthracenylporphyrin derivatives via the cyclodehydrogenation the parent meso-substituted molecules on a catalytic Au(111) surface.
6
Depending on the annealing temperature, anthracenylporphyrins with the four anthracene fully linked to the porphyrin core or over-oxidized porphyrin in which the anthracene are connected two by two in 2-2’ position were observed by STM (Figure 1).
Figure 1. STM images of the fused tetra-anthracenylporphyrins and related porphyrin structures
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Figure 1
We conducted 2 independent population-based SARS-CoV-2 serosurveys in Yaoundé, Cameroon, during January 27-February 6 and April 24-May 19, 2021. Overall age-standardized SARS-CoV-2 IgG seroprevalence ...increased from 18.6% in the first survey to 51.3% in the second (p<0.001). This finding illustrates high community transmission during the second wave of COVID-19.
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DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A prospective study was extended to the new antiretroviral and monitoring strategies in HIV-infected adults in low-income countries (NAMSAL-ANRS)-12313 trial, a 96-week open-label, multicenter, ...randomized phase 3 trial comparing dolutegravir (DTG) 50 mg with efavirenz 400 mg (EFV400), both administered with tenofovir disoproxil fumarate and lamivudine (TDF/3TC) as first-line treatment for antiretroviral therapy (ART)-naive people living with human immunodeficiency virus type 1 (HIV). Noninferiority of DTG to EFV400 was demonstrated at 48-week and sustained at 96 weeks. Here, we present results at 192-week.
Previous trial participants were reconsented and followed up on their initial randomization arm (1:1 DTG/TDF/3TC:EFV400/TDF/3TC). Assessments included changes in viral suppression, biological parameters, and new serious adverse events (SAEs).
Among the participants enrolled in the trial, 81% (499/613) were analyzed at week 192: 84% (261/310) on DTG/TDF/3TC and 78% (238/303) on EFV400/TDF/3TC. HIV RNA suppression was maintained in 69% (214/310) on DTG/TDF/3TC-based and 62% (187/303) on EFV400/TDF/3TC-based regimens (difference, 7.3% 95% confidence interval, -.20 to 14.83;
= .057). Five (DTG/TDF/3TC = 2; EFV400/TDF/3TC = 3) new viral failures (World Health Organization definition) without related resistance DTG mutations and 24 new SAEs were observed (DTG/TDF/3TC = 13; EFV400/TDF/3TC = 11). Mean weight gain was +9.4 kg on DTG/TDF/3TC and +5.9 kg on EFV400/TDF/3TC. The percentage of participants with obesity increased from 6.9% to 27.7% on DTG/TDF/3TC (
< .0001) and from 8.3% to 16.7% on EFV400/TDF/3TC (
= .0033).
Four-year follow-up of people with HIV on DTG- and EFV400-based regimens showed long-term efficacy and safety of both ARTs, markedly among participants on DTG/TDF/3TC with high baseline viral load. However, unexpected substantial weight gain over time was prominent among participants on DTG/TDF/3TC, which should be closely monitored.
NCT02777229.
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