Transferred election devices

In making rotaxanes usable as parts of molecular devices and with the purpose of studying long range election transfer processes within large molecular systems of well controlled geometries, the introduction of photoactive and electroactive compounds has been a valuable development. Photoinduced electron transfer between porphyrin species has a particular relevance to the primary events occurring in bacterial photosynthetic reaction center complexes, and so is a well studied phenomenon. 

Self-assembled and spontaneously adsorbed monolayers offer a facile means of controlling the chemical composition and physical structure of a surface. As discussed later in Chapter 5, applications of these monolayers include modeling election transfer reactions, biomimetic membranes, nano-scale photonic devices, solar energy conversion, catalysis, chemical sensing and nano-scale lithography. 

R.A.Chapman, S.R.Borrello, A.Simmons, J.D.Beck, A.L.Lewis, M.A.Kinch, Jollynecek, C.G. Roberts Monolithic HgCdTe Charge Transfer Device Infrared Imaging Arrays , to be published IEEE Trans. Elect. Dev. 

The energy released in a spontaneous redox reaction can be used to perform electrical work. This task is accomplished through a voltaic (or galvanic) cell, a device in which flie transfer of elections takes place through an external patiiway rather than directly between reactants. 

There are a considerable number of reactions in which the products contain two electrons, more than the starting compounds, and the consecutive two-stqr one-electron electron transfer process proves to be energetically unfavorable. In such cases, it is presumed that the two-electron process occurs in one elementary two-electron step. An example of a two-electron process is the hydride transfer, when two elections are transported together with a proton. BH4", hydroquinones and reduced nicotinamides are typical hydrid donors. A specific feature of quinones is the capacity to accept and then to reversibly release electrons one by one or two electrons as a hydride. Therefore, quinones can serve as a molecular device, which can switch consecutive one-electron process to single two-electron process. 

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