Aliphatic amines

Unsubstituted ZnPc was synthesized according to the slightly modified procedure¹⁵ from phthalonitrile and zinc acetate in the presence of a small amount of N,N-dimethylacetamide. To obtain a dye sample for dissolution experiments, the synthesized ZnPc crystals were converted into the dry sulfate salt followed by regeneration with ammonia in absolute methanol. Organic solvents supplied by various manufactures are listed in Table S1.† They were used as received except for cyclopentanone that was doubly distilled to collect a narrow fraction boiling at (130.5–131.0) °C. All aliphatic amines were obtained from Sigma-Aldrich and thoroughly distilled just before using.

1,4,5,8‐Naphthalenetetracarboxylic dianhydride, aliphatic amines, and ethylenediamine were purchased from Sigma Aldrich (Bengaluru, Karnataka, India); 4‐amino benzonitrile and 4‐cyano benzoic acid were purchased from Spectrochem (Hyderabad, Telangana, India) and were used without further purification. Furthermore, all other solvents and chemicals were distilled and dried before use such as DMF, DCM, and triethylamine. Spectroscopic‐grade solvents were used for all optical measurements.