Reduction potentials fluorine

The cathode reaction comes directly from a table of standard reduction potentials, while the anode reaction is the reverse reaction from such a table. However, how did we know that it was the fluorine reaction requiring reversal ... 

What happens if we replace our reactant, KF(1), with KF(aq) This apparently minor change makes a big difference in the results. The potassium ions and the fluoride ions are still present, so they are still under consideration, but we also need to consider water. Water appears in many places in a table of reduction potentials. We must examine every place it appears alone on a side or with one of the ions we know to be present, K+ and I. The potassium and fluorine halfreactions, with their reduction potentials are ... 

Thinking about the position of elements in the periodic table and their valence electron structure should help in understanding the relative order of the reduction potentials. Fluorine gas is very electronegative and readily accepts electrons to obtain a stable configuration. Conversely, alkalines and... 

Table 1. Peak Reduction Potentials of Selected Electrophilic Fluorinating Reagents13...

Table 1. Half-wave reduction potentials of fluorinated alkenes (-E1/2, V vs SCE) [24]...

Rozhkov IN, Stepanoff A A, Borisov YA (1985) The fourth regular meeting of soviet-japanese fluorine chemists. Electronic structure and polarographic reduction potentials of fluoroolefins, Kiev, p 125... 

Table 5. Electrophilic fluorinating agents and their electrochemical reduction potentials (Ep).

The most dramatic example of the use of functionalization to tune the properties of an organic semiconductor is found in perfluoropentacene 41 (Scheme 3.9) [53]. Perfluoropentacene has a strongly shifted LUMO, evidenced by lowering of the reduction potential by more than 700 mV. The fluorinated compound adopts a herringbone packing in the crystal that is very similar to that of the parent acene. Top-contact FET devices made from evaporated 41 had an electron mobility of 0.11 cm2 V-1 s 1, demonstrating the change from p-type to n-type behavior. 

An attractive feature of fullerenes is the interaction of their n electrons with fluorine, which has given a very broad array of fullerene fluorides as is described in the previous section. Electronic properties of these new fluorides based on the third allotrope of carbon are of great interest and importance from the view points of materials science and potential use. In fact, as will be described in the next section, electrochemical properties such as electromotive force and reduction potential strongly reflect the changes in the C6o electronic structure through fluorination. 

Zhou et al. reported the first cyclic voltammetric (CV) study of C60F48 in solution and showed that the reduction potential of C60F48 is more positive than that of the first reduction wave of C6o by 1.38 V [65]. This shift reflects exactly the change of the LUMO level of C6o upon fluorination as is shown in Fig. 19. Based on the CV behavior and electrospray mass spectroscopy, they proposed the following EECEEC mechanism for the first four reduction waves of C60F48. 

I. N. Rozhkov, A. A. Stepanov and Y.A. Borisov, Fourth Regular meeting of Soviet—Japanese Fluorine Chemists. Electronic Stucture and Polarographic Reduction Potentials of Olefines, Kiev, 1985, p. 125. 

This reaction has been assigned a potential of 0.000 volts under standard conditions. The standard reduction potential for fluorine gas is 2.890 volts while that for sodium metal is -2.714 volts. 

Influence in extension of chromophore conjugation on TPA was studied for the fluorinated polyenes 1-3. Pentafluorosubstitution reduces re-electron density at the left aromatic benzene ring. This results in an electron-deficient substituted benzene with a re-electron density comparable with that of cyanobenzene [341]. This was concluded from the reduction potentials of 1,2,4,5-tetrafluorobenzene (El = -2.4 V vs. SCE [342]) and cyanobenzene = -2.3 V vs. SCE [341]). The larger re-conjugation in 3 causes an increase of e compared to 1 but the change of A/i()] was rather modest compared to the increased size of the chromophore [224]. TPA data and representative photophysical parameters are summarized in Table 3.1. 

What must be the pressure of fluorine gas to produce a reduction potential of 2.75 V in a solution that contains 0.38 MF- ... 

E17.2 Since chlorine and fluorine have strongly positive reduction potentials, the oxidation of the chloride and fluoride anions require very strong oxidizing agents. As a result only electrolytic oxidation of Cl" and F" is commercially reasonable. 

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