Reactive AgAuS and Ag₃AuS₂ Synthons Enable the Sequential Transformation of Spherical Nanocrystals into Asymmetric Multicomponent Hybrid Nanoparticles

Nanoscale heterostructures that interface with multiple distinct materials provide opportunities to engineer functional complexity into single-particle constructs. However, existing synthetic pathways to such hybrid nanoparticles emphasize surface-seeded growth, which limits the scope of accessible systems. Here, we introduce an alternative approach that transforms isotropic nanocrystals into asymmetric, multicomponent Janus particles through sequential deposition, reactive phase segregation, and cation exchange processes that are mediated by an unusual class of reactive synthons. After Ag–Au seed particles had formed and had reacted with sulfur, a series of segregated Au_1–<i>x</i>Ag_<i>x</i>–AgAuS and Au_1–<i>x</i>Ag_<i>x</i>–Ag₃AuS₂ hybrid nanoparticles form. The AgAuS and Ag₃AuS₂ domains provide a synthetic entryway into solution-mediated cation exchange reactions, with the compositions of the Ag–Au–S synthons defining the components, morphologies, and interfaces of the hybrid nanoparticle products. Upon cation exchange with Pb²⁺, Au_1–<i>x</i>Ag_<i>x</i>–AgAuS forms Ag_1–<i>x</i>Au_<i>x</i>–PbS heterodimers while Au_1–<i>x</i>Ag_<i>x</i>–Ag₃AuS₂ forms Ag_1–<i>x</i>Au_<i>x</i>–Ag₂S–PbS heterotrimers. The process by which isotropic metal nanoparticles transform into asymmetric hybrid nanoparticles through reactive Ag–Au–S synthons provides important insights that will be applicable to the retrosynthetic design of complex nanoscale heterostructures having expanded multifunctionality and synergistic properties

biomass data

These are observations on biomass, which form the core of the study. See Supplemental Figure S1 for a graphical representation. COLUMN HEADINGS: 'spcode' the number of the species (names available in 'species data' file). 'house': Which shadehouse did the seedling grow in? 'indiv' Which individual was the observation made on?, 'light' the light (in %) in the shadehouse. 'day' how many days since the start of the study did the observation occur? 'biomass': the estimated biomass on this day in grams (see Methods for details on how biomass was estimated)

Variation in the importance of each growth component to RGR over a light-availability gradient.

<p>A) results from age-standardized analysis, B) results from size-standardized analyses. NAR makes the largest contribution to RGR, regardless of light availability or analysis.</p

gas exchange data

This file provides details on rates of gas exchange made at the time of the second harvest. The first six columns are just as in the biomass data file. 'Area' represents the leaf area measured for photosynthetic rate in the cuvette, in cm^2. 'N' leaf nitrogen concetration, on a mass basis, in percent. 'thickness': leaf blade thickness, in micrometers. 'LMR' leaf mass ratio. 'Lcp' Light compensation point - the amount of light (in µmol m-2·s-1) at which photosynthesis is zero. 'Amax': the predicted maximal rate of photosynthesis per unit area in CO2·m-2·s-1. SLA_photo: specific leaf area, 'Amass': predicted maximal photosynthetic rate per unit leaf biomass in nmol CO2·g-1·s-1

harvest data

This file contains data from the two destructive harvests. The first six columns are just like in the biomass data file. 'Harvest' indicates which of the two harvests the observation was made. 'date' gives the number of days since the start of the study of the harvest. 'height' is the height of teh measured individual. girth_1 and girth_2 are two perpendicular basal diameters of the stem. BiomassR, BiomassS, BiomassL, and BiomassA give, respectively, the individual's biomass of roots, stem, leaves and all (the sum of the three prior). THickness gives leaf thickness in micrometers (measured only at harvest 3). Leaf area is leaf area of the individual, in cm^2

Nickel-Catalyzed Reductive Cross-Coupling of (Hetero)Aryl Iodides with Fluorinated Secondary Alkyl Bromides

A mild and efficient nickel-catalyzed reductive cross-coupling between fluorinated secondary alkyl bromides and (hetero)­aryl iodides is described. The use of FeBr₂ as an additive successfully overcomes the hydrodebromination and β-fluorine elimination of fluorinated substrates and allows the efficient synthesis of a wide range of trifluoromethyl and difluoroalkyl containing aliphatic compounds with a fluoroalkyl substituted tertiary carbon center. The notable features of this protocol are the synthetic and operational simplicity without preparation of moisture sensitive organometallic reagents and excellent functional group compatibility, even toward active proton containing substrates

Species descriptions

THis is basically Table 1. It summarises chaarcteristics of each species used in the study, linking the species codes (spcode) to the famil, genus and species of each taxon. column 'deciduous' indicates whether the species is deciduous or evergreen. Max height is in meters. Successional stage gives the rough shade tolerance of the taxon

Associations between SGR and its components (SLA, LMR and NAR).

<p>A-C) present the age-standardized analysis of data from the first harvest (August 2008), whereas D-F) present the size-standardized analysis, at a standard biomass of 10 g. Statistically significant relationships are shown with solid lines, derived from standardized major axis regression. Numbers show the Pearson correlation coefficient for each light level (*:<i>P</i> <0.05, ***: <i>P</i> <0.0001, ns: not significant).</p

Biomass trajectory for one of 14 studied species, <i>Choerospondias axillaris</i> (Anacardiaceae).

<p>Until November 2008, growth was modeled as a logistic function of time, whereas afterwards, it was modeled as an exponential function. Vertical arrows indicate dates on which destructive harvests were made and functional traits assessed. Biomass trajectory plots for all species are provided in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150644#pone.0150644.s001" target="_blank">S1 Fig</a>. Note that the Y-axis is log transformed.</p

Correlations between SGR and NAR and functional traits, evaluated over a gradient of light availability at the time of the first harvest, when gas-exchange rates were measured.

<p>Panels A, B, E and F show functional traits calculated on a biomass basis, whereas C, D, G and H show traits calculated on an area basis. Statistically significant relationships are shown with solid lines, derived from standardized major axis regression. Thick lines indicate relationships over the entire dataset (i.e., disregarding light availability).</p