DJL

Two imaging modalities based on molecular and elemental spectroscopy were used to characterize a painting by Cosimo Tura. Visible-to-near-infrared (400–1680 nm) reflectance imaging spectroscopy (RIS) and X-ray fluorescence (XRF) imaging spectroscopy were employed to identify pigments and determine their spatial distribution with higher confidence than from either technique alone. For example, Mary’s red robe was modeled through the distribution of an insect-derived red lake (RIS map) and lead white (XRF lead map), rather than a layer of red lake on vermilion. The RIS image cube was also used to isolate the preparatory design by mapping the reflectance spectra associated with it. In conjunction with results from an earlier RIS study (1650–2500 nm) to map and identify the binding media, a more thorough understanding was gained of the materials and techniques used in the painting.

Technical art history: Visible-to-near-infrared reflectance imaging spectroscopy (RIS) and X-ray fluorescence (XRF) imaging spectroscopy were used as complementary chemical imaging methods to provide a robust spatial distribution of pigments. Hyperspectral RIS analysis allowed the isolation of the preparatory drawing from both the overlying original paint of the artist and the inpaint of the conservator.

Radical functionalization of reduced graphene oxide has been achieved by reaction with a xanthate in the presence of peroxide as a radical initiator. X-ray photoelectron spectroscopy, bulk elemental analyses, and thermogravimetric analyses showed that the xanthate grafting is covalent and efficient. The synthesis and use of seven xanthates and three peroxides showed that the highest grafting yield is obtained when xanthate and peroxide are introduced in stoichiometric amounts. It also revealed that the peroxide used as radical initiator is grafted at the graphenic surface during the functionalization. The method presented in this contribution therefore allows bifunctionalized reduced graphene oxide samples to be easily obtained in one single step. This method leads to undamaged graphene sheets with higher dispersibility than the pristine sample.

Two birds with one stone! Xanthates and peroxides are used as radical precursors to graft various functions at the reduced graphene oxide surface. The developed method allows a double functionalization by both xanthate and peroxide radicals to be performed in one single step. The versatility of the method is highlighted by the grafting of seven xanthates and four peroxides. The resulting material shows no visible structural damage and long-lasting dispersibility.

A top-down approach, i.e., creating small particles by mechanical force starting from bulk materials, probably presents the most logical approach to particle size reduction and, therefore, top-down techniques are among the first to achieve small particles. A new solvent-free, amazingly simple approach is reported, suitable to achieve nanoparticles and sub-micro particles.

The reaction of [Cp^BnFe(η⁵-P₅)] (1) (Cp^Bn=η⁵-C₅(CH₂Ph)₅) with CuI selectively yields a novel spherical supramolecule (CH₂Cl₂)_3.4@[(Cp^BnFeP₅)₁₂{CuI}₅₄(MeCN)_1.46] (2) showing a linkage of the scaffold atoms which is beyond the Fullerene topology. Its extended CuI framework reveals an outer diameter of 3.7 nm—a size that has not been reached before using five-fold symmetric building blocks. Furthermore, 2 shows a remarkable solubility in CH₂Cl₂, and NMR spectroscopy reveals that the scaffold of the supramolecule remains intact in solution. In addition, a novel 2D polymer [{Cp^BnFe(η⁵-P₅)}₂{Cu₆(μ-I)₂(μ₃-I)₄}]_n (3) with an uncommon structural motif was isolated. Its formation can be avoided by using a large excess of CuI in the reaction with 1.

The four Ss: Novel scaffold, large size, remarkable solubility and high stability are the unique features of the supramolecule based on [Cp^BnFe(η⁵-P₅)] (Cp^Bn=C₅(CH₂Ph)₅) and CuI. A scaffold beyond the fullerene topology is formed by an extended CuI framework. Its solubility is provided by the Cp^Bn ligands, and the nano-sized sphere remains intact in solution demonstrating its stability.

Nanotechnology has become ubiquitous in our everyday lives, from medicine and information storage to sunscreens and cosmetics. With so many applications, its risks also need to be considered. This issue, which starts with an Editorial by Y. Xia on page 12268, gives an overview of the most recent developments and challenges of nanotechnology. It contains five Reviews on current topics including nanosafety research, nanoparticles in the environment, inorganic nanoparticles, soot nanoparticles, and nanoparticles for drug delivery, as well as Communications that cover the whole spectrum of nanotechnology, from fundamental studies to catalysis, energy, and materials research.

The ability to engineer the surface properties of magnetic nanoparticles is important for their various applications, as numerous physical and chemical properties of nanoscale materials are seriously affected by the chemical constitution of their surfaces. For some specific applications, nanoparticles need to be transferred from a polar to a nonpolar environment (or vice versa) after synthesis. In this work we have developed a universal method for the phase transfer of magnetic nanoparticles that preserves their shape and size. Octadecyltrimethoxysilane was used to cap the surfaces of the aqueous magnetic nanoparticles, thereby allowing their transfer into nonpolar solution. The resulting hydrophobic magnetic nanoparticles were transferred back into aqueous solution by subsequently covering them with an egg-PC lipid monolayer. The superparamagnetic properties of the particles were retained after the phase transfer. The maximum transfer yields are dependent on their particle size with a maximum value of 93.16±4.75 % for magnetic nanoparticles with a diameter of 100 nm. The lipid-modified magnetic particles were stable over 1 week, and thus they have potential applications in the field of biomedicine. This work also provides a facile strategy for the controllable engineering of the surface properties of nanoparticles.

Reversible phase transfer: Octadecyltrimethoxysilane (ODTS) has been used to cap the surfaces of hydrophilic magnetic nanoparticles (NPs), thereby allowing their transfer into nonpolar solution. The resulting hydrophobic magnetic nanoparticles were transferred back into aqueous solution by covering them with a lipid monolayer (see figure; Egg-PC=egg yolk phosphatidylcholine).