| Research Abstract |
Although the chemistry of quinodimethanes has been studied to a great extent, and the physical and chemical properties for numerous these compounds have been well documented, nothing has so far been established for preparation of 7,7,8,8-tetrakisazulenyl-p-quinodimethanes. As a series of basic studies on the creation of novel functional materials with delocalized π-electron systems and on their potential utility, we have been particularly interested in the chemistry of p-quinodimethanes possessing azulenyl groups (as a representative example of nonbenzenoid aromatics) at C-7 and C-8 positions. We have accomplished for a facile preparation and electrochemical behavior of novel quinodimethane compounds, [e.g., 7,7,8,8-tetrakis(3-methoxycarbonyl-azulen-1-yl)-p-quinodimethane (3) from methyl 1-azulenecarboxylate (1) via 1,4-bis[di(3-methoxycarbonyl-azulen-1-yl)methyl]benzene (2)] and their related compounds. Compound 3 is the first example of 7,7,8,8-tetrakisazulenyl-p-quinodimethane deriv
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The electrochemical behavior (Potential/V vs. SCE) of compound 3 was measured by means of CV and DPV in 0.1 M (TBA)ClOィイD24ィエD2, CHィイD22ィエD2ClィイD22ィエD2. Two redox potentials observed by DPV were positioned at the Ep values of +0.25 and -1.27 V, while the corresponding one reversible electrooxidation (presumed to be two-electrons electrooxidation) and one irreversible electroreduction potentials determined by CV were located at the values of +0.22 (EィイD21/2ィエD2 and -1.33 V (Epc). The redox potentials thus obtained for 3 indicated that the four 3-methoxycarbonylazulen-1-yl groups were susceptible to reduction compared with methyl 1-azulenecarboxylate (1)(Ep : -1.38 V, EィイD21/2ィエD2 : -1.40 V). A plausible electron transfer mechanism for 3 is considered as follows : Namely, compound 3 gives relatively stable di-cation 3b derived from cation-radical 3a, rapidly, and unstable anion-radical 3c which do not undergo further reduction to di-anion but decompose. Thus, the CV for 3 showed one reversible electrooxidation and one irreversible electroreduction potentials. As a conclusion, the electrochemical behavior of 3 has revealed that the compound played as an electron donor. Studies on the crystal structure and other characteristic properties of compound 3 are currently in progress. Less
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