Tetra-substituted zinc(II) and copper(II) phthalocyanines bearing peripheral alkoxy-monoterpene groups were prepared by conventional vs. non-conventional synthetic approaches (ultrasound and microwave irradiation). The synthesis of (1[Formula: see text]-(–)-myrtenol (a) and (1[Formula: see text],2[Formula: see text],5[Formula: see text]-([Formula: see text]-menthol (b) derived phthalonitrile precursors was performed through ipso-nitro aromatic substitution reactions, with optimal conditions being obtained using ultrasound irradiation, which allowed us to achieve full conversions in 4.5 h, with isolated yields up to 74%. The subsequent cyclotetramerization of monoterpene-based phthalonitriles was carried out using Zn(II) or Cu(II) salts as metal templates, and also using conventional and non-conventional heating methods. Microwave-assisted synthesis was shown to be the most efficient approach, providing complete conversions in 1 h, yielding the target monoterpene-based metallophthalocyanines in up to 70% isolated yields. Furthermore, photophysical and photochemical studies revealed that Zn(II) phthalocyanines possess fluorescence quantum yields in the range of [Formula: see text] 0.27–0.29, while Cu(II) phthalocyanines exhibited room temperature phosphorescence. In addition, the monoterpene-based Zn(II) phthalocyanines led to high singlet oxygen quantum yields ([Formula: see text] 0.55–0.69).
The development of efficient chemical processes capable of transforming carbon dioxide (CO2) into value-added products constitutes one of the greatest challenges for the scientific community. In this context, the use of carbon dioxide as a C1 source is a relevant topic and, over the last decade, there has been remarkable scientific and technological advances regarding the development of chemical processes for converting CO2 into added value products. We highlight the reaction of CO2 addition to epoxides, from which it is possible to selectively obtain two types of products: cyclic carbonates and polycarbonates, both with relevant applications as fine chemicals and polymeric materials, respectively.
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