Chemical Science Blog

I am delighted to announce that Professors Melanie Sanford (University of Michigan) and Tom Muir (Princeton University) have joined the Chemical Science Editorial Board as the Associate Editors for physical organic chemistry and chemical biology respectively.

	Professor Melanie Sanford’s research focuses on the development and mechanistic study of new transition metal-catalysed reactions which she applies to organic synthesis. Her Editorial Office is now open and welcoming submissions in the area of physical organic chemistry.
	Professor Tom Muir is an expert in protein engineering and its application to studying cellular signalling networks.His Editorial Office opens on 1st August 2012 and will welcome submissions in the area of chemical biology.

Chemical Science publishes findings of exceptional significance from across all area of the chemical sciences. To submit your research to Melanie, Tom or any of our other outstanding Associate Editors, please use our online submission site.

Having synthesised the first example of a rigid acetylene-linked perylene bismuth macrocycle, scientists in Germany and Korea have made a series of these compounds with varying ring sizes and looked at their light-harvesting capabilities with regards to ring size, to establish a structure-property relationship.

They found that the larger the ring size, the slower the energy hopping. They add that the compounds have fast energy transfer capabilities compared to other artificial light-harvesting complexes such as porphyrin-based ones.

Enormous efforts have been invested into mimicking natural light-harvesting bacteria over the past two decades; investigations have focused on efficient energy transfer in particular.

Link to journal article
Excitation energy migration in covalently linked perylene bisimide macrocycles
F Schlosser et al
Chem. Sci., 2012, DOI: 10.1039/c2sc20589k

The well-known semiconductor CdS can be transformed into an efficient, visible light photocatalyst that can selectively oxidise C-H bonds using molecular oxygen as the oxidant under ambient conditions, say scientists from China.

The team attributes the high performance to the catalyst’s cubic phase, high surface area and efficient separation of photogenerated charge carriers upon visible light irradiation. It is easy to make and could be used to activate C-H selectively to make fine chemicals, they say.

Link to journal article
Transform CdS to an efficient visible light photocatalyst for selective oxidation of saturated primary C–H bonds under ambient conditions
Y Zhang et al
Chem. Sci., 2012, DOI: 10.1039/c2sc20603j

A small autonomous boat powered by a volatile surfactant has been developed by scientists in Finland and Israel. The surfactant modifies the surface tension of the liquid it floats on to create a surface tension gradient that propels the boat forward.

Propulsion induced by a surface tension gradient is known as Marangoni propulsion. It’s used in nature by small creatures such as Microvelia (small aquatic insects) to give a burst of speed to escape predators. In man-made devices, the Marangoni effect has been used to power small ‘camphor boats’ and ‘soap boats’; however, these systems normally offer only short term propulsion or require the boat to be confined to specific channels.

To develop a longer-term propulsion system, the team led by Robin Ras at Aalto University, Finland, created a boat from a lightweight membrane made from a nanocellulose aerogel. The membrane is impermeable to water (and oil) but it allows the gaseous surfactants to pass through it. The team used ethanol as the fuel to power a boat floating on water.

Read the full article in Chemistry World

Link to journal article
Vapour-driven Marangoni propulsion: continuous, prolonged and tunable motion
Hua Jin, Abraham Marmur, Olli Ikkala and Robin H. A. Ras
Chem. Sci., 2012, Advance Article, DOI: 10.1039/C2SC20355C, Edge Article

Scientists in the US and Saudi Arabia have made a new family of conjugated polymers that change colour in response to changes in their redox state. The stimuli-responsive polymers are the first example where an azulene building block is incorporated into the polymer backbone through linkages in the 7-membered ring, rather than the more synthetically accessible 5-membered ring.

The polymers’ properties may be of great importance for developing new organic field-effect transistors, organic light-emitting diodes, and dye-sensitised organic solar cells.

Link to journal article
Azulene-Based Conjugated Polymers: Unique Seven-Membered Ring Connectivity Leading to Stimuli-Responsiveness
Masahito Murai , Elizabeth Amir , Roey J. Amir and Craig J. Hawker
Chem. Sci., 2012, DOI: 10.1039/c2sc20615c

While most people over a certain age are trying to slow down the ageing process, scientists from the UK and Canada are trying to speed it up to help them make new materials more cleanly.

‘Accelerated ageing’ could become a new paradigm for the clean, low energy and solvent-free synthesis of metal-organic materials, claim the researchers. They were inspired by the slow geological processes of mineral weathering, which convert metal oxides and sulfides to metal-organic materials by exposing them to small organic molecules. By accelerating this process, they claim materials can be made without the continuous input of mechanical energy, high temperatures or organic solvents. Their simple process involves exposing a mixture of a metal oxide and an organic ligand to catalytic amounts of an ammonium salt at mild temperature and high humidity.

Link to journal article
Accelerated aging: a low energy, solvent-free alternative to solvothermal and mechanochemical synthesis of metal-organic materials
Tomislav Friscic, Matthew J Cliffe, Cristina Mottillo, Robin S Stein and Dejan-Kresimir Bucar
Chem. Sci., 2012, DOI: 10.1039/c2sc20344h

UK scientists have isolated and identified the biosynthesis genes of the metabolite coelimycin P1 (a yellow pigment, unprecedented in nature to the team’s knowledge) by Streptomyces coelicolor M145, using a combination of genetic experiments, bioinformatic analyses and structural analyses.

Analysing the genome sequences of plants, bacteria and filamentous fungi, together with the screening of extracts of novel organisms isolated from underexplored habitats, revealed that many (perhaps most) structurally novel bioactive natural products remain to be discovered. Sequencing the complete or partial genomes of several Streptomyces species and related actinomycetes has shown that they invariably contain numerous cryptic gene clusters with the potential to direct the production of hitherto undiscovered bioactive natural products, say the researchers.

Link to journal article
Structure and biosynthesis of the unusual polyketide alkaloid coelimycin P1, a metabolic product of the cpk gene cluster of Streptomyces coelicolor M145
Juan-Pablo Gomez-Escribano, Lijang Song, David Fox, Valerie Yeo, Mervyn Bibb and Gregory L Challis
Chem. Sci., 2012, DOI: 10.1039/c2sc20410j