Chemical Science Blog

Star-shaped bimetallic nanobundles are better catalysts for fuel cells than conventional platinum nanoparticles, say US and Chinese scientists. The team made the branched platinum–nickel nanostructures by diffusing Ni species into the crystal lattice of Pt seeds; a method they claim opens a new avenue for the morphology control of bimetallic alloys. The steps and kinks on the nanostructures’ surfaces make them better at oxidising methanol.

Link to journal article
Highly Branched Pt-Ni Nanocrystals Enclosed by Stepped Surface
Z Niu et al
Chem. Sci., 2012, DOI: 10.1039/c2sc00004k

Aromaticity and antiaromaticity is one of the most fundamental concepts of chemistry but the nature of antiaromaticity remains elusive because of the lack of stable species.

A research team from Japan has provided an explanation for why heteroarene-fused boroles are higher in antiaromaticity and benzene-fused boroles are lower in antiaromaticity than the parent borole, providing a crucial design principle for more fascinating antiaromatic π-conjugated molecular systems.

Link to journal article
Heteroarene-fused Boroles: What Governs the Antiaromaticity and Lewis Acidity of the Borole Skeleton?
A Iida, A Sekioka and S Yamaguchi
Chem. Sci., 2012, DOI: 10.1039/c2sc20100c

A low temperature route to making diverse carbon nanoforms, including nanoonions and multiwalled nanotubes, has been developed by researchers in Spain. The route is cheaper and more environmentally friendly than other routes and is scalable.

The method involves a thermal decomposition of a sebacate-intercalated NiFe layered double hydroxide at 400^oC and benefits from the catalytic activity of the FeNi₃ nanoparticles generated in situ.

Applications of these nanocarbons include photovoltaic materials, lubricants, drug delivery, magnetic storage materials and electrochemical devices.

Link to journal article
Layered double hydroxide (LDH) – organic hybrids as precursors for the low-temperature chemical synthesis of carbon nanoforms
G Abellán et al
Chem. Sci., 2012, DOI: 10.1039/c2sc01064j

US scientists have designed a scaffold that can covalently attach to substrates and induce directed functionalisation at remote C–H bonds. This should help to overcome the limited substrate scope seen with current methods for functionalising unreactive C–H bonds, in which the directing groups are generally embedded in the structure of the substrate, effectively limiting the reactions to highly specific substrate classes.

Link to journal article
Molecular Scaffolds with Remote Directing Groups for Selective Palladium-Catalyzed C-H Bond Functionalizations
E E Stache et al
Chem. Sci., 2012, DOI: 10.1039/c2sc20176c

The growth mechanism of organic nanomaterials is unclear – understanding more about it would help in the design of optoelectronic devices. Scientists in China have come up with a mechanism for polymeric nanowire growth. Dynamic light scattering studies revealed that after nucleation growth, a mesoscale assembly existed as an intermediate, which then formed the nanowires.

Link to journal article
How does a Supramolecular Polymeric Nanowire Form in Solution?
T Lei et al
Chem. Sci., 2012, DOI: 10.1039/c2sc01123a

Nitrite impurities in a commercially available palladium catalyst – palladium acetate – can have a serious effect on synthesis, say scientists in the UK and US.

The team found that the impurities affect the synthesis of pure palladium complexes derived from palladium acetate. A previous proposal that the nitrite anion can be formed by oxidation of acetonitrile by metallic palladium and air resulting in cyclo(ortho)palladated complexes containing the nitrite anion, for example Pd(NO₂)(C^N)L, can be explained by Pd₃(OAc)₅NO₂ acting as the nitrite source, say the researchers. Finally, photocrystallographic metastable linkage isomerisation and complete conversion to an oxygen-bound nitrito complex Pd(η¹-ONO)(C^N)PPh₃ has been seen, they add.

Link to journal article
NO₂ anion contamination in Pd(OAc)₂. On the synthesis of pure Pd(OAc)₂L₂ and palladacycles containing NO₂ anion: the photocrystallographic identification of a metastable Pd(η¹-ONO)(C^N)PPh₃ complex
S E Bajwa et al, Chem. Sci., 2012, DOI: 10.1039/c2sc01050j