Such behavior would be expected for the complexes in which the alkyl chloride must intercalate itself between the cyclopentadienyl rings to facilitate complexation.
However, iron would prefer to exist as iron (II) or (III); thus, the iron could transfer the newly acquired electron back to the cyclopentadienyl ring or to the neighboring chlorine of the alkyl chloride, which, in either case, would return the iron to a stable electron configuration as iron (II).
The extinction coefficient of each CTC was determined by using Beer's Law, where the extinction coefficient can be calculated from the slope and plotting the absorbance versus the concentration of the desired ferrocene derivative in either dichloromethane or benzyl chloride as the solvent, assuming that the low concentration of the ferrocene derivative and the high concentration of the alkyl chloride will cause only the CTC to be present in solution.
With literature references indicating that ferrocene derivatives complex with alkyl chlorides, the mixture of ferrocene and benzyl chloride forms a charge transfer complex ([K.sub.assoc, 310 nm] = 1.04 L [mol.sup.-1]).
FICs such as C|F.sub.3~I C|F.sub.3~ C|F.sub.2~I and C|F.sub.3~ C|F.sub.2~ C|F.sub.2~I, in their study, were mixed with hydrocarbons, ethers, HFCs or alkyl chlorides
to produce nonflammable blends, and at least one of the blends was actually tested in a small refrigerator.