Synthesis, characterization and electrochemical investigation of phthalocyanines carrying 96 boron atoms

• Phthalocyanines carrying eight dodecaborate substituents were synthesized.
• Electrochemical and in-situ spectroelectrochemical measurements were carried out.
• ZnPc gives ring-based, CoPc gives both metal and ring-based redox processes.
• Electrocolorimetry showed the color of the reduced and oxidized species.

Metal-free and Co(II)-phthalocyanines carrying eight dodecaborate substituents (96 boron atoms) on the peripheral positions were synthesized in a multistep reaction sequence. The first step of the preparation of metal-free and Co(II) target phthalocyanines was cyclotetramerization of 4-(3,5-dimethoxyphenoxy)phthalonitrile in pentanol in the presence of lithium pentanolate and Co(II) salt, respectively. After cleavage of methyl groups the reaction of (Bu4N)[B12H11O(CH2CH2)2O] with hydroxyphenoxy substituted phthalocyanines gives the novel phthalocyanines 7, 8 with eight dodecaborate units. The new phthalocyanine compounds were characterized by NMR, FT-IR and UV–VIS spectral data. The electrochemical investigations of cobalt(II) phthalocyanine together with Zn(II) derivative having identical substituents were studied.

Novel phthalocyanines carrying eight dodecaborate substituents on the periphery were prepared by multistep reaction sequence. The electrochemical and in-situ spectroelectro-chemical measurements showed that while zinc phthalocyanine (9) gives only ring-based redox process, cobalt phthalocyanine (8) gives both metal-based and ring-based redox processes.Figure optionsDownload as PowerPoint slide