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

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(CH ₂CH₂)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.