Convenient and Efficient Method for the Synthesis of Phthalocyanines and Metallophthalocyanines in Task-Specific 2-Hydroxyethyl Ionic Liquids

Abstract

Tetramerization of substituted phthalonitriles in task-specific 2-hydroxylethyl-based imidazolium and ammonium ionic liquids at 100 °C gave corresponding phthalocyanines in moderate yield. Further the reaction of substituted phthalonitriles in the presence of transition-metal salts in ionic liquids gave the corresponding metallophthalocyanines. The 2-hydroxylethyl ammonium ionic liquids gave better yields of phthalocyanines than 2-hydroxylethyl imidazolium and nonhydroxyl functionalized ionic liquids. The isolation and separations of different phthalocyanines were accomplished by silica-gel column chromatography, and products were characterized by various spectroscopic techniques.

GRAPHICAL ABSTRACT

Keywords:

• 2-Hydroxyethyl ionic liquids
• metal salts
• phthalocyanines
• phthalonitriles
• tetramerization

Notes

^a Reaction condition ratio, phthalonitrile (4a)–ionic liquid–metal salt = 1:1:0.25 in 2 h.

^b Isolated yields.

^c The same ionic liquid was reused for each consecutive run.

^a Reaction condition ratio, phthalonitrile (4a–4i)–ionic liquid (2c)–metal salt = 1:1:0.25 in 2 h.

^b Isolated yields.

^a Reaction condition ratio, phthalonitrile–ionic liquid (2c)–metal salt = 1:1:0.25 in 2 h.

^b Isolated yields.

^a Reaction condition ratio, phthalonitrile–ionic liquid (2c) = 1:1.

^b Isolated yields.