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Melanins are a class of conjugated biopolymers with varying compositions and functions, which have a variety of potential medical and technical applications. Here, this work examines the conjugated polymers derived from a variety of phenolic monomers (catechol (CAT), levodopa (DOPA), and homogentisic acid (HGA)), using a selection of different analytical chemistry techniques to compare their properties with a view to understanding structure–function relations. The polymers display measurable conductivity, with electronic properties tuned by the functional groups pendant on the polymer backbones (which served as dopants) suggesting their potential for application in electronic devices.

The catalytic formation of hydroxyl radicals in oxidative hair colourant systems in the presence of added copper ions was measured and quantified using a colorimetric probe N,N'-(5-nitro-1,3-phenylene)bisglutaramide. Also monitored in the same experiments was the decomposition of hydrogen peroxide. The first set of experiments was performed using aqueous model solutions containing the key oxidant actives in a hair colourant, ammonium hydroxide and hydrogen peroxide at pH 10, with added copper and calcium ions. The second set of experiments was performed in the presence of hair containing different levels of copper in conditions very close to those found during hair colouring. Both sets of experiments demonstrate the ability of copper ions to trigger the formation of hydroxyl radicals and catalyse the decomposition of hydrogen peroxide. The ability of chelants ethylenediamine tetraacetic acid (EDTA) and N,N'-ethylenediamine disuccinic acid (EDDS) to moderate the flux of hydroxyl radicals formed in solution systems was demonstrated in the presence of copper ions alone. However, only EDDS was successful in the presence of both calcium and copper ions. This was confirmed in the hair experiments where again only EDDS was successful at preventing hydroxyl radical formation where hair is added as the source of copper and calcium ions. These results are explained using metal speciation modelling and demonstrate the importance of the chelant to be able to specifically bind and prevent the one-electron redox chemistry of copper in the presence of high levels of calcium ions as found in hair. The formation of hydroxyl radicals during the colouring process was shown to lead to hair structure damage as measured by protein loss. EDDS was demonstrated to significantly reduce cuticle damage by suppressing the formation of the hydroxyl radicals in systems with realistic concentrations of calcium and copper.

The results of three experimental studies, i.e. GC-MS of peroxide-crosslinked alkene/alkane mixtures, 13 C NMR of peroxide-cured, 13 C-labeled 2 -ethylidene- 5 norbornene - ethylene-propylene-diene-monomer (EPDM) and EPR of peroxide curing of EPDM, are combined, yielding a more accurate description of the mechanism of peroxide cure of EPDM. Both alkyl and allyl macro-radicals are formed via H-abstraction from the EPM main chain and the residual diene unsaturation, respectively. Combination of these macro-radicals yields alkyl/alkyl, alkyl/allyl and allyl/allyl cross-links and addition of these macro-radicals to the residual diene unsaturation yields alkyl/alkene and allyl/alkene cross-links.

Self-assembled monolayers (SAMs) are excellent models for studying interfacial reactions. Here monolayer chemistry is reviewed, focusing on the features that have no analogues in solution chemistry. The growth of surface-attached polymers, intrafilm reactions, chemistry, photochemistry and reactivity issues are all discussed.

This Account reports the synthesis and characterization of dendrimer-encapsulated metal nanoparticles and their applications to catalysis. These materials are prepared by sequestering metal ions within dendrimers followed by chemical reduction to yield the corresponding zerovalent metal nanoparticle. The size of such particles depends on the number of metal ions initially loaded into the dendrimer. Intradendrimer hydrogenation and carbon−carbon coupling reactions in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO2 are also described.

Ligand exchange reaction is a very important and useful tool for preparing functionalised metal nanoparticles. Understanding the mechanism of this process is essential for rational design of nanoparticle-based devices. However the underlying chemistry was found to be very rich. In this article, we summarise the research efforts of several groups to unravel the mechanisms of ligand exchange reaction, and discuss implications for future developments.