Structure–Function Relationship of Novel Tetrakis (Mercapto-Terphenyl)Benzene Cobalt (II) Phthalocyanines: Synthesis and Computational Evaluation

This study introduces a newly synthesized Co(II) phthalocyanine complex (Co-Pc, <b>4</b>) incorporating two (mercapto-terphenyl)thio-dione substituents, along with a detailed exploration of its structural, spectroscopic, and binding characteristics. The key precursor, 4-[(4''-mercapto-[1,1':4',1''-terphenyl]-4-yl)thio]phthalonitrile (compound <b>3</b>), was first obtained and subsequently used to construct the phthalocyanine macrocycle through cyclotetramerization in the presence of cobalt and zinc salts under heat and vacuum in dimethylformamide. The resulting compounds (<b>3</b> and <b>4</b>) were characterized using a comprehensive array of analytical techniques, including elemental analysis, UV-Vis spectroscopy, FT-IR, ¹H-NMR, and Q-TOF mass spectrometry. Additionally, density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were employed to elucidate the electronic structure and geometrical features of Co-Pc <b>4</b>, providing theoretical support for the experimental findings. The integration of theoretical and experimental findings provides in-depth insight into the electronic behavior and reactivity of compound <b>4</b>, highlighting its promise as a candidate for photovoltaic applications. Further studies may investigate how structural modifications influence these properties, potentially leading to improved device performance.