SYNTHESIS OF NOVEL UNSYMMETRICALLY SUBSTITUTED PUSH-PULL PHTHALOCYANINES

The synthesis and characterization of novel non-centrosymmetrically pu sh-pull substituted metal-free phthalocyanines 3-9 are described. The compounds have different donor (dialkoxy, tert-butyl, methyl, p-tolylt hio) and/or attractor (p-tolylsulfinyl, p-tolylsulfonyl, nitro) functi onal groups, are soluble in organic solvents, and are especially desig ned to study their second- and third-order nonlinear optical propertie s. Compounds 7-9 are mixtures of the four corresponding regioisomers. For preparing the unsymmetrical phthalocyanines 7-9, the effectiveness of the subphthalocyanine route, using different substituted diiminois oindolines as reagents, has been tested. Furthermore, a comparison bet ween this method versus the statistical one has been done. The results obtained show that the ring enlargement reaction of subphthalocyanine s to obtain unsymmetrically substituted phthalocyanines is not a selec tive reaction but a multistep process, which depends dramatically on t he nature of the substituents on the subphthalocyanines, the reactivit y of the iminoisoindoline, the solvent, and other factors that limit i ts general synthetic utility. Preliminary data of the experimental sec ond-order hyperpolarizabilities of compounds 3-9 are also given.