Reactions of phthalonitriles with carbohydrates and alkali: phthalocyanine and oligomer formation

Abstract

Reducing sugars and sodium hydroxide react with phthalonitrile and 4-methoxyphthalonitrile to form mixtures of the phthalocyanine and oligomers. The oligomers, obtained in yields up to 54%, were deduced to have a structure that is predominantly polyazine with the o-cyanophenyl group as a substituent from elemental analysis and spectral data. Since carbohydrate related compounds lacking the reducing linkage gave no products, it is suggested that the observed reactions require the a-hydroxycarbonyl grouping.

Use of Unmodified Carbohydrate Reagents for the Polymerization of Dicyanoalkenes and Dicyanoarenes

“…The evidence for reaction at one cyano group follows from observation of cyano infrared absorption near 2200 cm -1 and the 13 C NMR resonance for a cyano group at a chemical shift of about 115 ppm in each of these polymers, as we have reported 14,15 for products from 2b,e. The infrared and 13 C NMR spectra of the polymer from 4 are exhibited in Figure 1.…”

“…This is also indicated in reactions of 2b and 4-methoxyphthalonitrile (2e). 14,15 The difference in the kind of polymer structure obtained from 1 and 2a and 2c,d, 3, and 4 (see Supporting Information) suggest that the electronreleasing effect of R 2 N would enhance electron density at the -CN group para to the R 2 N group. Even if initial nucleophilic addition occurred at the -CN group meta to the R 2 N group, an anion on the substituent meta to the R 2 N group would encounter the excess electron density at the cyano group para to R 2 N. In contrast to the electron-releasing amino groups in 2c,d, the 1,3-dithiole ring in 1 and the nitro group in 2a would tend to decrease electron density at the cyano groups in their molecular structures, possibly facilitating cycloaddition leading to cyclopolymerization.…”

New model phthalonitrile resin system based on self‐promoted curing reaction for exploring the mechanism of radical promoted‐polymerization effect

“…Therefore, it can be understood the metal‐free phthalocyanine can be easily found in the PN model system studied in this work from proposed curing mechanism of Scheme . On the other hand, the formation of polyisoindoline has been reported to be carried out usually by an ionic mechanism (anionic solution polymerization initiated by sodium alkoxide), but does not exhibit selectivity (yield <15%). As is reported, the thermal polymerization of the PN resin by an ionic mechanism usually tends to form triazine segment.…”

“…Among them, the polymerization reaction product that is dominated by the chain growth mechanism of triazine formation has probably a local conjugated characteristic due to the steric hindrance effect of the residual nitrile group (about one‐third or so) . In contrast, both linear and cyclized polyisoindoline have large conjugated features . Among them, phthalocyanine has a unique electronic structure (maximum ultraviolet–visible absorption at 600–700 nm), which has great application potentials in the field of optoelectronics, luminescence, and catalysis .…”

“…In addition, isoindoline derivatives are also widely used in luminescent materials, biomedicine, and chemical catalysis . Thus, poly‐isoindoline with linear conjugated features is also expected to have some interesting functionalities of conductive polymers in the aforementioned fields . Therefore, the functionality and application range of PN will be further expanded with the controllable reaction product.…”