Journal of Materials Chemistry Blog

In addition to making the study of chemistry more complicated than it needs to be, three-centre-two-electron bonds also provide carboranes with many useful properties. The inclusion of carborane clusters allows the thermal and chemical stability of polymers to be improved, glass transition temperatures to be increased and the propensity for unwanted aggregation to be reduced.

Recent work by Marshall et al. has focused on the incorporation of ortho­-carborane into conjugated polymers for use in organic electronics. Carboranes are of particular interest in this area due to the possibility that their electron deficiency will allow them to fulfil the role of the electron acceptor in a donor-acceptor polymer. By preparing a novel monomer based on benzocarborane, it was possible to carry out a Stille polymerisation with an electron donating monomer and prepare polymers with molecular weights of the order of 10 kDa.

In comparison to analogous materials that contained no carborane, both novel polymers showed a decrease in band gap. One polymer was found to behave as a p-type semiconductor in a field effect transistor (FET) – the first time that a carborane-containing polymer has been used in such a device.

Incorporation of benzocarborane into conjugated polymer systems: synthesis, characterisation and optoelectronic properties
Jonathan Marshall, Zhuping Fei, Chin Pang Yau, Nir Yaacobi-Gross, Stephan Rossbauer, Thomas D. Anthopoulos, Scott E. Watkins, Peter Beavis and Martin Heeney
J. Mater. Chem. C, 2014, 2, 232.  DOI:10.1039/C3TC31663g

James Serginson is a guest web writer for the Journal of Materials Chemistry blog. He currently works at Imperial College London carrying out research into nanocomposites.

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Although the chemistry of life is usually considered to be organic, living organisms also need to carry out inorganic synthesis. The formation of bones, teeth and shells all depend on the ability of cellular machinery to efficiently prepare inorganic materials with the correct morphology. This machinery is complex and involves the concerted action of small molecules, enzymes and high concentrations of macromolecules.

It is the role of the macromolecules that is the focus of a recent paper by David N. Carace and Christine D. Keating. They aimed to mimic the formation of CaCO₃ by conducting a mineralization reaction in an aqueous two-phase system (ATPS). This system consisted of two immiscible polymer solutions: a poly(ethylene glycol) (PEG) solution floating on a solution of dextran. The mineralisation reaction involved the urease–mediated conversion of urea to carbonate ions and their subsequent reaction with calcium. It was found that biomineralization occurred predominantly in the dextran layer due to the localization of urease. It was also found that decreasing the relative volume of the dextran phase increased the rate of CaCO₃ formation.

This work has demonstrated a fascinating method of biological reaction compartmentalization that does not rely on membranes.

Biocatalysed mineralization in an aqueous two-phase system: effect of background polymers and enzyme partitioning
David N. Cacace and Christine D. Keating
J. Mater. Chem. B, 2013, 1, 1794.  DOI:10.1039/C3TB00550j

James Serginson is a guest web writer for the Journal of Materials Chemistry blog. He currently works at Imperial College London carrying out research into nanocomposites.

To keep up-to-date with all the latest research, sign-up to our RSS feed or Table of contents alert.