Synthesis and solution studies on azaphthalocyanines with quaternary aminoethyl substituents

Abstract

A pyrazinedinitrile derivative carrying dimethylaminoethylsulphanyl groups at positions 5 and 6 was synthesised from 2‐dimethylaminoethanethiol hydrochloride and 2,3‐dicarbonitrile‐5,6‐dichloropyrazine. The dicarbonitrile gave magnesium azaphthalocyanine (MgAzaPc) when reacted with magnesium propoxide in propanol. The conversion of the MgAzaPc to a metal‐free derivative was achieved by treatment with trifluoroacetic acid. Incorporation of transition metal ions into the inner core of azaphthalocyanine was accomplished by treatment of the metal‐free derivative with metal acetates, i.e. Zn(OAc)2, Co(OAc)2. These azaphthalocyanines were converted into water‐soluble quaternised products by reaction with methyl iodide. Aggregation phenomena were followed for magnesium azaphthalocyanine with quaternisable dimethylamino substituents within a specific range of pH. The compounds were characterised by Fourier transform–infrared, proton nuclear magnetic resonance, mass and ultraviolet–visible spectral data.