Lipophilicity organometallic compounds

Mercury, tin, lead, arsenic, and antimony form toxic lipophilic organometallic compounds, which have a potential for bioaccumulation/bioconcentration in food chains. Apart from anthropogenic organometallic compounds, methyl derivatives of mercury and arsenic are biosynthesized from inorganic precursors in the natural environment. 

A preparation and characterization of new PtRu alloy colloids that are suitable as precursors for fuel-cell catalysts have been reported [43cj. This new method uses an organometallic compound both for reduction and as colloid stabilizer leading to a Pt/Ru colloid with lipophilic surfactant stabilizers that can easily be modified to demonstrate hydrophilic properties. The surfactant shell is removed prior to electrochemical measurements by reactive annealing in O2 and H2. This colloid was found to have nearly identical electrocatalytic activity to several other recently developed Pt/Ru colloids as well as commercially available Pt/Ru catalysts. This demonstrates the potential for the development of colloid precursors for bimetallic catalysts especially when considering the ease of manipulating the alloy composition when using these methods. 

It can be seen that, as in many other supramolecular structures of organometallic compounds, the lipophilic organic groups wrap the inorganic chain, which is embedded in the interior of the helix. 

A great variety of organic and organometallic compounds, such as organic ligands and catalysts as well as organometallic catalysts, but also organic polymers and amphiphilic/lipophilic compounds, has been incorporated into carbon paste electrodes for sensor applications. They are briefly presented hereafter. 

The majority of the devices mentioned thus far rely on the Hofmeister series for anion selectivity. However, for anions that deviate from this series, organometallic receptors can be utilised. The type of ligand or metal centre will influence the sensor selectivity due to the characteristics of the electron acceptance of the complex. An interesting development that is being explored here is the use of calixarenes. These have previously found use as cation-selective species, but with suitable substitution are now being incorporated within anion-selective devices. Compounds suitable as receptors for halides [61],benzoate [61] and acetate [62] have been developed. Reinhoudt and his co-workers have reported the production of a POj-selective CHEMFET based on a uranyl cation immobilised within a salophene ligand (Fig. 5), which shows selectivity over more lipophilic anions such as Br" and NOj [63]. 

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