Dendrimer molecular batteries

Because of all the described properties, these dendrimers behave as molecular batteries that might find applications in molecular-electronic devices. 

Some researchers see a bright future for dendrimers in many different industrial, medical, research, and consumer applications. One company that produces dendrimers lists applications in drug delivery systems, gene transfection, biotechnology, sensors for diagnostics and detection systems, carbon fiber coatings, microcontact printing, adhesion, molecular batteries, catalysis, separation systems, lasers, composites, and ultrathin films used in optics. 

I have reviewed, in Chapter No. 12, the activation of arenes by the strongly electron-withdrawing 12-electron fragment CpFe+, isolobal to Cr(CO)3 and Mn(CO)3+, and its application to the synthesis of dendritic cores, dendrons, dendrimers, and metallodendrimers, including molecular batteries. 

Chart 1. Third-generation polyallyl dendrimer with was hydrosilylated using dimethylferrocenylsilane a theoretical number of 243 allyl branches syn- Fc(Me)2SiH to 243-Fc , a molecular battery thesized according to Scheme 20. This 243-allyl dendrimer with a theoretical number of 243 dendrimer (like the 9-allyl, 27-allyl, and 81 -allyl peripheral ferrocenyl units,... 

Large Dendrimers Functionalized on their Branches by the Electron-Reservoir [FeCp(i/6-C6Me6)]+ Groups A Molecular Battery in Action... 

S. Nlate, J. Ruiz, V. Sartor, R. Navarro, J.-C. Blais, and D. Astruc, Molecular Batteries Ferrocenylsilylation of Dendrons, Dendritic Cores, and Dendrimers New Convergent and Divergent Routes to Ferrocenyl Dendrimers with Stable Redox Activity, Chem. Eur. J. 6, 2544-2553 (2000). 

A dendrimer consisting of multiple identical and non-interacting redox units, able to reversibly exchange electrons with another molecular substrate or an electrode, can perform as a molecular battery [64, 65]. The redox-active units should exhibit chemically reversible and fast electron transfer processes at easily accessible potential difference and chemical robustness under the working conditions. 

We briefly mention here the use of the ferrocene/ferrocenium redox couple to mediate electron transfer on the oxidation (anodic) side, especially in derivatized electrode. This broad area has been reviewed [349]. For instance, polymers and dendrimers containing ferrocene units have been used to derivatize electrodes and mediate electron transfer between a substrate and the anode. Recently, ferrocene dendrimers up to a theoretical number of 243 ferrocene units were synthesized, reversibly oxidized, and shown to make stable derivatized electrodes. Thus, these polyferrocene dendrimers behave as molecular batteries (Scheme 42). These modified electrodes are characterized by the identical potential for the anodic and cathodic peak in cyclic voltammetry and by a linear relationship between the sweep rate and the intensity [134, 135]. Electrodes modified with ferrocene dendrimers were shown to be efficient mediators [357-359]. For the sake of convenience, the redox process of a smaller ferrocene dendrimer is represented below. 

Dendrimers and star polymers containing redox active sites have been utilized in the design of new types of catalysts, sensors, bioelectronic devices, and molecular batteries. Highly branched polymers containing arenes coordinated to oiganometallic moieties have been prepared witii chromium tricarbonyl, cyclopenta-dienyliron, " and pentamethylcyclopentadienylrutheniiun moieties. Astruc and... 

Dendrimers have attracted considerable attention since their discovery three decades ago [1 3], Potential applications involve supramolecular properties [11] in the fields of nanomedicine [29], materials science [4-13] and catalysis [16, 30, 38 3], Since the late 1980s, we have focused our attention on metallodendrimers [14, 44] with the aim to develop knowledge concerning redox properties that are useful for redox sensing and catalysis as well as for the design of molecular batteries. In this microreview article, we will illustrate the design of our recent smes of metallodendrimers and some of their properties and applications. 

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