Switches three-pole switching

Figure 11. Schematic representation of the concept of a Figure 10 A, B, and C are suitably chosen chromophoric three-pole supramolecular switching of energy transfer. The groups. For more details, see the text, cartoons correspond to the molecular components shown in...

Scheme 15.2 Cartoon displaying the electrochemically reversible three-pole supramolecular switch based on the three-component mixture CBPQT4 + -1/5DN38C10-TTF. (See the color version of this figure in Color Plates section.)...

The next incremental step up the ladder of complexity of switching was the development [38] of a three-pole supramolecular switch. Such a switch is one that can be adjusted to any one of three different settings. Bolstered by the success and rich electrochemistry of the dual mode switch, a three-pole switch was designed without delay and investigated. 

Fig. 21. The three-pole switch can exist in any one of three states, a When the three components TTF, CBPQT4+, and 1/5DN38C10 are mixed in solution, TTF resides within the cavity of the cyclophane. b Oxidation of the TTF to its radical cation leads to its expulsion from the tetracationic cyclophane. c Further oxidation to the TTF dication leads to its encirclement by 1/5DN38C10...

TTF c CBPQT Figure 13 A three-pole supramolecular switch. 

Tetrathiafulvalene (TTF) is an excellent candidate for redox-driven molecular switch because it can be easily oxidized into TTF" and TTF + ions. In 1999, Stoddart et al. reported a three-pole supramolecular switch (Figure 38), in which the mechanical action was mediated by the electrochemical adjustment of the TTF oxidation... 

Bolted pressure switch of the quick-make, quick-break type. It should be a three-pole 240-V 480-V unit with a continuous current rating of ... 

Figure 12. Schematic representation of a three-pole supramolecular switching of energy transfer.

Another example of a photoredox molecular switch is based on a ferrocene-ruthenium trisbipyridyl conjugate, in which the luminescent form 4 switches to the non-luminescent form 5 upon electrochemical oxidation (Figure 2/bottom)171. Biological systems exploit the interplay of redox and molecular recognition to regulate a wide variety of processes and transformations. In an attempt to mimic such redox systems, Deans et al. have reported a three-component, two-pole molecular switch, in which noncovalent molecular recognition can be controlled electrochemically. x Willner et al. have reported on their research activities in developing novel means to achieve reversible photostimulation of the activities of biomaterials (see Chapter 6).[91 Recently, we have shown that it is possible to switch the luminescence in benzodi-furan quinone 6 electrochemically. 101 The reduction in THF of the quinone moiety... 

Fig. 14 Schematic representation of two-pole, three-component switching based on redox-modulated recognition.

Isolation at the consumer s service position can be achieved by a double-pole switch which opens or closes all conductors simultaneously. On three-phase supplies the switch need only break the live conductors with a solid link in the neutral, provided that the neutral link cannot be removed before opening the switch. 

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