Lucigenin, structure

Figure 5 Chemical structure of lucigenin (10,10 - dimethyl-9,9 -biscridinium (nitrate)).

The second system to be described is the CL obtained in the transformation of lucigenin and related derivatives here, too, the mechanisms which lead to chemiexcitation are still discussed in the literature. Finally, we will concentrate our discussion on one of the most efficient CL systems known, the peroxyoxalate reaction. After a brief discussion of kinetic results obtained with the different peroxyoxalate substrates, we will focus mainly on studies which attempt to elucidate the structure of the high-energy intermediate in these reactions and describe the experimental evidence obtained with respect to the mechanism of the excitation step. 

Maeda K, Kashiwabara T, Tokuyama M, Mechanism of the chemiluminescence of lucigenin. 2. The charge-transfer structure of lucigenin and reduction of by electron transfer from nucleophiles. Bull Chem Soc Jpn 1977 50 473-81. 

While luminol and isoluminol require an oxidant plus a catalyst for initiation of the chemiluminescent reaction, esters derived from A -methyl acridinium carboxylic acid require only alkaline hydrogen peroxide (W4). Acridinium esters were first introduced by McCapra s group (M23, M25, S32), based on earlier work on the bioluminescence of the lucigenin/luciferase system (G18), and reviewed in McCapra and Beheshti (M21). From Fig. 19, one can see the structural similarity between lucigenin and a typical acridinium ester. 

Acridinium Ester Fig. 19. Structural similarity between lucigenin and an acridinium ester. 

Similar classical countercations for the detection of anion antiport in U-tubes do not exist. However, most standard probes including lucigenin (see below) will work for this purpose (unpublished results). Many alternative methods for the detection of U-tube activity are conceivable (ion-selective electrodes, probes, etc). For the transport of charged molecules, standard probes such as 8-hydroxy-l,3,6-pyrenetrisulfonate (HPTS) and 5(6)-carboxyfluorescein (CF) have been used directly to detect anion transport, and p-xylene bis(pyridinium) bromide (DPX), or safranin O has been used to detect cation transport (see below for structures). ... 

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