Solubility Properties of Unsubstituted Metal Phthalocyanines in Different Types of Solvents

We investigated quantitatively the solubility properties of a number of unsubstituted metal phthalocyanines with various metal atoms such as Co, Cu, Fe, Mg, Mn, Ni, Sn, and Zn. We studied three categories of solvents: conventional solvents, ionic liquids, and acids. The conventional liquids comprised 20 typical representatives from acetone to toluene. We tested two ionic liquids and five acids. For each solution we measured the molar absorption coefficient and the saturation concentration (or estimated these values if the solubility was too low). The absorption coefficients and saturation concentrations were derived from UV–vis absorption measurements of the Q-band. The solution spectra are presented and discussed as well as the chemical properties (stability) of the solutions.