Receptors organometallic

8 Lenthall, J. T. and Steed, J. W., Organometallic cavitands Cation-Jt interactions and anion binding via Jt-metallation , Coord. Chem. Rev. 2007, 251, 1747-1760. 

As with cation binding hosts, it is also possible to use calixarene frameworks (Section 3.14) to organise anion binding moieties. Addition of a cobaltocinium bis(amide) moiety to the upper rim of a calix[4]arene with p-toluenesulfonate functionalities to enhance solubility results m a rigi ost 

Kaifer, A. E. Electrochemical techniques , in Comprehensive Supramolecular Chemistry, J. L. Atwood, J. E. D. Davies, D. D. MacNicol and F. Vdgtle (eds), Pergamon Oxford, 1996, 499-535. 

The cyclic voltammetric experiment is an interfacial electrochemical technique (i.e. monitoring of processes occurring near the electrode surface) that involves measurement of current flow as a function of applied potential. The potential is swept from a resting potential, (measured against a reference such as the saturated calomel electrode or the potential of the Fe(II)/Fe(III) couple in ferrocene), at a constant rate (usually 

The cyclic voltammetric experiment can give a great deal of information about the redox activity of a compound and the stability and accessibility of its reduced or oxidised forms. For a fully chemically reversible process, i must equal i, i.e. all of the material oxidised at the electrode surface on the forward scan must be re-reduced on the reverse scan (or vice versa). If this condition does not hold true, then the process may be partially reversible (Ip i f) or irreversible = 0). Observation of processes that are not fully reversible implies decomposition or chemical reaction of the reduced or oxidised species and the ratio of ip to i will show a strong dependence on scan rate since the reverse current is related to the lifetime of the redox-generated material. Note that processes that are chemically reversible (in the sense that the reduced and oxidised species are both stable) may not be electrochemically reversible (a term that relates to the relative rates of forward and back electron transfer). Electrochemically reversible processes are characterised by a separation between the forward and reverse potential peaks of exactly 59 mV. 

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Sen A (1999) Catalytic Activation of Methane and Ethane by Metal Compounds. 3 81-95 Severin K (2006) Organometallic Receptors for Biologically Interesting Molecules. 17 123— 142... 

Severin K (2006) Organometallic Receptors for Biologically Interesting Molecules. 17 123-142... 

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]. 

Keywords Anion recognition Organometallic receptors Transition metal receptors Electrochemical sensors Optical sensors... 

Organometallic Receptors for Charged and Neutral Guest Species ... 

Section 12.09.6 details recent advances toward the application of organometallic receptors as sensing devices, including their use in dendrimer, polymer, functionalized nanoparticle, and self-assembled monolayer systems. 

A unique mixed organometallic receptor has been prepared by Jurkschat and co-workers. Macrocycle 85... 

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