New Unsymmetrical Zinc-Phthalocyanine Conjugated with One Azo-Dye Moiety: Synthesis via Opening the Fused Triazole Ring and Spectral Properties

A new method for the preparation of compounds containing an azo‐dye moiety via opening the activated triazole ring upon coupling with nucleophiles was successfully applied to a mono‐triazole‐fused phthalocyaninato zinc complex 1. The prepared unsymmetrical zinc‐phthalocyanine 3 conjugated with a 2‐hydroxy‐1‐naphthylazo moiety in the periphery was characterized by means of UV/Vis‐, FTIR‐, 1H and 13C NMR spectroscopy, MALDI‐TOF spectrometry, and elemental analysis, and the data support its structure. The assignment of signals in the 1H and 13C NMR spectra of compound 3 was based on the data from 2‐D CH‐COSY and HC‐HMBC measurements (C–H coupling across one bond and long‐range H–C coupling). The compound exhibits interesting spectroscopic properties, indicating high acidity of the hydroxy group. This phthalocyanine behaves as a strongly solvatochromic compound and can exist in different forms depending on the concentration and nature of solvent. Additionally, photodecomposition of 3 in chloroform and tetrahydrofuran was found to proceed via different pathways. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)