Synthetic and Mechanistic Studies on Zinc Tetrabenzporphyrins.
Final rept. May 91-Aug 91,
ARMY NATICK RESEARCH DEVELOPMENT AND ENGINEERING CENTER MA
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Tetrabenzporphyrins have been reported to possess very high values for third-order nonlinear optical susceptibility Chi-3. The preparation of meso substituted zinc tetrabenzporphyrins TBPs from isoindole, zinc acetate and aldehydes is described. The scope of the reaction is discussed with regard to several aromatic aldehydes used for the synthesis. Benzaldehydes with electron withdrawing gave little or no product, and sterically hindered aldehydes gave low yields of TBPs that were only partially substituted in the positions. Poor yields in these cases are discussed in terms of charge transfer interactions or steric factors in the reactions. A mechanism for the formation of TBPs under these conditions is presented and discussed. The mechanism involved initial condensation of isoindole and the aldehyde to form an isoindolidene which then oligimerizes and cyclizes. Then oxidation to form the fully conjugated TBP. In the oxidation, the aldehyde is proposed to function as a hydride acceptor. Plans for future research in this area are discussed. Tetrabenzporphyrins, Porphyrins, Metalloporphyrins, Nonlinear Optical Materials, Oxidation, Eye Protection.
- Organic Chemistry
- Laminates and Composite Materials