3.1. General Synthesis of Unsubstituted Phthalocyanines

In a two-necked 50 mL round bottom flask equipped with a reflux condenser and a magnetic stirrer, 1.0 g (1 eq) of phthalonitrile, 0.30 eq of hydrated salt and two Pasteur-drops (approx. 32 mg, 0.21 mmol, 0.027 eq) of DBU (or 0.21 eq of KOH) were added and stirred in 5 mL of solvent (or in a 5.5 g of anisole/glycerol mixture) under reflux for 3 h. The mixture was then cooled, treated with 15 mL of HCl 1N, filtered and washed with water (2 × 20 mL) and methanol (2 × 15 mL). It was then purified in a Soxhlet extractor with glacial acetic acid until the extracts were colorless.

CoPc: purple microcrystalline powder; UV (THF) λ_abs 324, 593, 656 nm.

CuPc: purple microcrystalline powder; UV (THF) λ_abs 342, 601, 666 nm. *scarcely soluble

ZnPc: purple microcrystalline powder; UV (THF) λ_abs 342, 601, 666 nm [46]; ¹H NMR (DMSO-d₆, 600 MHz) δ 9.44 (8H, m), 8.28 (8H, m).