Monoterpene-based metallophthalocyanines: sustainable synthetic approaches and photophysical studies.
GONZALEZ, Andreia C. S.; DAMAS, Liliana; AROSO, Rafael T.; TOMÉ, Vanessa A.; DIAS, Lucas Danilo; PINA, João; CARRILHO, Rui M. B.; PEREIRA, Mariette M.
GONZALEZ, Andreia C. S.; DAMAS, Liliana; AROSO, Rafael T.; TOMÉ, Vanessa A.; DIAS, Lucas Danilo; PINA, João; CARRILHO, Rui M. B.; PEREIRA, Mariette M.
Abstract: Tetra-substituted zinc(II) and copper(II) phthalocyanines bearing peripheral alkoxymonoterpene groups were prepared by conventional vs. non-conventional synthetic approaches (ultrasound and microwave irradiation). The synthesis of (1R)-(-)-myrtenol (a) and (1R,2S,5R)-(-)- 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 FF = 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 (FD = 0.55-0.69).
@article={002997031,author = {GONZALEZ, Andreia C. S.; DAMAS, Liliana; AROSO, Rafael T.; TOMÉ, Vanessa A.; DIAS, Lucas Danilo; PINA, João; CARRILHO, Rui M. B.; PEREIRA, Mariette M.},title={Monoterpene-based metallophthalocyanines: sustainable synthetic approaches and photophysical studies},journal={Journal of Porphyrins and Phthalocyanines},note={v. 24, n. 05n07, p. 947-958},year={2020}}