Devices, anion-sensing

Large differences in composition are, in principle, possible by changing the metal center in metallocenes combined with macrocyclic ethers or cryptands, but these were mostly limited to air- and water-stable compounds, which could be considered for further cation and anion sensing devices. So far ruthenocene, titanocene, mo-lybdocene, and tungstocene moieties associated with crown ether-type macrocycles have been described. 

In the near future, it must be hoped that anion coordination chemists can provide further devices, be they catalytic, sensing, or medicinal and that biological anions will be able to be fully addressed, both efficiently and selectively in their natural environment. Hopefully, the field of anion recognition will reach a similar stage to cation recognition where, when a particular cation is to be bound, the coordination chemist reaches out for a well established and specific receptor. 

The use of zirconia as a sohd electrolyte (and especially for oxygen-sensing devices) is facUitated by the fact that stabilized zirconia has a defect structure with a finite concentration of octahedral interstitial voids. The void space in the lattice is larger for the anions than for the Zr + cations, and the 0 anions are therefore the rate-... 

Miura N, Yan Y, Sato M, Yao S, Nonaka S, Shimizu Y, Yamazoe N (1995) Solid state potentiometric CO sensors using anion conductor and metal carbonate. Sens Actuators B 24-25 260-265 Miura N, Lu G, Yamazoe N (2000) Progress in mixed-potential type devices based on solid electrolyte for sensing redox gases. Solid State Ionics 136-137 533-542... 

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