Perhalophenyl Three-Coordinate Gold(I) Complexes as TADF Emitters : A Photophysical Study from Experimental and Computational Viewpoints

We report the synthesis of novel perhalophenyl three- coordinated gold( I) complexes using 1,2- bis-(diphenylphosphino)benzene (dppBz) as the chelating ligand and [AuR(tht)] (R = C6F5, C6Cl2F3, C6Cl5) as the perhalophenyl-gold(I) source, leading to [AuR(dppBz)] (R = C6F5 (1), C6Cl2F3 (2), C6Cl5 (3)) complexes. The solid-state structures of compounds 2 and 3 consist of discrete three-coordinated Au(I) complexes, which show a distorted trigonal planar geometry for the gold center with dissimilar Au-P distances. The distorted structural arrangement is closely related to its photophysical properties. The studied complexes display very intense emissions at room temperature (RT) and at 77 K in the solid state. Studies of the emissive properties of the complexes at different temperatures suggest that the emissions are phosphorescent at 77 K and exhibit thermally activated delayed fluorescence (TADF) at RT. First-principle calculations of the photophysical processes yielded rate constants for intersystem crossing and reverse intersystem crossing that are in excellent agreement with experimental data.Peer reviewe

Mini AuAg Wavy Nanorods Displaying Plasmon-Induced Photothermal and Photocatalytic Properties

Alloyed AuAg wavy nanorods (wNRs) of approximate to 24.0 nm length and 3.5 nm width are formed by the mild decomposition of the organometallic complex [Au2Ag2(C6F5)(4)(OEt2)(2)](n) in tetrahydrofuran (THF) in the presence of oleic acid. Ligand exchange with l-glutathione (GSH) or poly(ethylene glycol) methyl ether thiol (PEG-SH) leads to water-soluble nanostructures. These AuAg wNRs display tunable size-dependent longitudinal localized surface plasmon resonance (l-LSPR) broad absorptions beyond 750 nm in the near-infrared (NIR) I and II regions. These intense plasmonic absorptions lead to interesting photothermal, catalytic, and photocatalytic properties, including the catalytic reduction of 4-nitrophenol, the photocatalytic reduction of 4-nitrostyrene, or the photocatalytic dehydrogenation of ammonia borane for H-2 release

Influence of perhalophenyl groups in the TADF mechanism of diphosphino gold(I) complexes

New perhalophenyl three-coordinated gold(i) complexes using the chelate ligand 1,2-bis(diphenyl-phosphino)benzene (dppBz) and [AuR(tht)] (R = C6F5 (1), o-C6BrF4 (2), p-C6BrF4 (3), o-C6F4I (4), p-C6F4I (5); tht = tetrahydrothiophene) have been prepared. The crystal structures of compounds 1 and 2 consist of distorted three-coordinated Au(i) complexes displaying different Au-P distances at the same gold atom. The complexes show intense photoluminescent emission in the solid state at room temperature (RT) and at 77 K. The study of the dependence of the emission lifetime with temperature suggests the existence of thermally activated delayed fluorescence (TADF) processes at RT. We have computed the rate constants for intersystem crossing and reverse intersystem crossing of the photophysical processes through first-principle calculations, supporting the experimental observations with very good agreement.Peer reviewe

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

On the Use of Mixed Thia/Aza Macrocycles in the Development of Fluorescent Chemosensors for Toxic Heavy Metals and Fluorescent Materials

The main results from the work of the authors, concerning the use of mixed thia/aza medium sized macrocycles for the development of optically selective fluorescent chemosensors for toxic heavy metals, and luminescent gold(I) complexes will be discussed. Particular attention will be paid to underline both the role played by these macrocyclic ligands in determining the properties of the systems developed and the structure/function relationships observed

Predictors of faster virological suppression in early treated infants with perinatal HIV from Europe and Thailand The European Pregnancy and Paediatric HIV Cohort Collaboration (EPPICC) and Early-treated Perinatally HIV-infected Individuals: Improving Children's Actual Life with Novel Immunotherapeutic Strategies (EPIICAL) study groups

Objective: To identify predictors of faster time to virological suppression among infants starting combination antiretroviral therapy (cART) early in infancy. Design: Cohort study of infants from Europe and Thailand included in studies participating in the European Pregnancy and Paediatric HIV Cohort Collaboration. Methods: Infants with perinatal HIV starting cART aged less than 6 months with at least 1 viral load measurement within 15 months of cART initiation were included. Multi-variable interval-censored flexible parametric proportional hazards models were used to assess predictors of faster virological suppression, with timing of suppression assumed to lie in the interval between last viral load at least 400 and first viral load less than 400 copies/ml. Results: Of 420 infants, 59% were female and 56% from Central/Western Europe, 26% United Kingdom/Ireland, 15% Eastern Europe and 3% Thailand; 46 and 54% started a boosted protease inhibitor-based or nonnucleoside reverse transcriptase inhibitor-based regimen, respectively. At cART initiation, the median age, CD4(+) % and viral load were 2.9 [interquartile range (IQR): 1.4-4.1] months, 34 (IQR: 24-45)% and 5.5 (IQR: 4.5-6.0) log(10) copies/ml, respectively. Overall, an estimated 89% (95% confidence interval: 86-92%) achieved virological suppression within 12 months of cART start. In multivariable analysis, younger age [adjusted hazard ratio (aHR): 0.84 per month older; P < 0.001], higher CD4(+) % (aHR: 1.11 per 10% higher; P=0.010) and lower log(10) viral load (aHR: 0.85 per log(10) higher; P < 0.001) at cART initiation independently predicted faster virological suppression. Conclusion: We observed a significant independent effect of age at cART initiation, even within a narrow 6 months window from birth. These findings support the earliest feasible cART initiation in infants and suggest that early therapy influences key virological and immunological parameters that could have important consequences for long-term health. Copyright (C) 2019 The Author(s). Published by Wolters Kluwer Health, Inc