Preparation and Optical and Electrochemical Properties of Phthalocyanine with Four Bis(carbomethoxy)tetrathiafulvalene Units

α-Octaoctylphthalocyaninato Ni(II) with four bis(carbomethoxy)tetrathiafulvalene units was prepared from β-tetrakis(o-xylylenedithio)-α-octaoctylphthalocyaninato Ni(II) via C-S bond cleavage, carbonylation, and condensation with 4,5-bis(carbomethoxy)-1,3-dithiol-2-one.The structure of the product was determined by NMR and MALDI-TOF-MS and the electrochemical and optical properties were examined by cyclic voltammetry, UV-vis spectra, and ESR spectrum.Research on phthalocyanines (Pcs) has been done to develop new functional materials or photocatalysts for electrochromic displays, field-effect transistors, solar cells, photodynamic therapy of cancer and so on. 1,2Pcs and related compounds can be prepared through the tetramerization reaction of phthalonitrile derivatives modified in electrochemical and/or optical properties. 1,2Functional group transformation on the Pc core is one of the methods to prepare π-expanded macrocycles. 3In a related study, we reported that the removal of the benzyl and o-xylylene groups can be performed on the Pc core via the C-S bond cleavage, which can be applied to the construction of the tetrathiafulvalene (TTF) unit and the dithiaphosphole ring. 4,5It is important that the Q band absorption of α-alkylated Pcs is observed at the lower energy field than that of β-alkylated ones. 6Recently, we prepared α-octaoctylPcs fused with four TTF units [PcTTF4(SMe)8] and [PcTTF4(EDT)4] bearing eight methylthio and four ethylenedithio (EDT) groups as electron donating substituents on the TTF edges, respectively. 4While porphyrins and Pcs fused with the TTF units were reported by several research groups, 7,8 tetraazaporphyrins with four TTF units which have eight carboalkoxy groups as electron acceptors, were reported by Yin et al. 9 To prepare α-substituted Pcs fused with the TTF units substituted with carbomethoxy groups, we tried a