The current study describes the synthesis, electrochemical, computational, and photochemical properties of octa (3-hydroxypropylthio) substituted cobalt (II) (4), copper (II) (5), nickel (II) (6) and zinc(II) (7) phthalocyanine derivatives. These novel compounds were characterized by elemental analysis, 1H, 13C NMR, FT-IR, UV-Vis, and MS. The redox behaviors of these metallophthalocyanines were investigated by the cyclic voltammetric method. The optimized molecular structure and gauge-including atomic orbital (GIAO) 1H and 13C NMR chemical shift values of these phthalocyanines in the ground state had been calculated by using B3LYP/6–31G(d,p) basis set. | Turkish Journal of Chemistry Turk J Chem 2021 45 143-156 http chem TÜBİTAK Research Article doi kim-2008-48 Novel nonperipheral octa-3-hydroxypropylthio substituted metallo-phthalocyanines synthesis characterization and investigation of their electrochemical photochemical and computational properties 1 2 3 4 5 5 6 Nilgün KABAY Yasemin BAYGU Metin AK İzzet KARA EsraNur KAYA Mahmut DURMUŞ Yaşar GÖK 1 Department of Biomedical Engineering Pamukkale University Denizli Turkey 2 Tavas Vocational School of Higher Education Pamukkale University Denizli Turkey 3 Department of Chemistry Pamukkale University Denizli Turkey 4 Department of Physical Education Pamukkale University Denizli Turkey 5 Department of Chemistry Gebze Technical University Kocaeli Turkey 6 Department of Chemical Engineering Uşak University Uşak Turkey Received Accepted Published Online Final Version Abstract The current study describes the synthesis electrochemical computational and photochemical properties of octa 3-hydroxypropylthio substituted cobalt II 4 copper II 5 nickel II 6 and zinc II 7 phthalocyanine derivatives. These novel compounds were characterized by elemental analysis 1H 13C NMR FT-IR UV-Vis and MS. The redox behaviors of these metallo- phthalocyanines were investigated by the cyclic voltammetric method. The optimized molecular structure and gauge-including atomic orbital GIAO 1H and 13C NMR chemical shift values of these phthalocyanines in the ground state had been calculated by using B3LYP 6 31G d p basis set. The outcomes of the optimized molecular structure were given and compared with the experimental NMR values. The photochemical properties including photodegradation and singlet oxygen generation of zinc II phthalocyanine were studied in DMSO solution for the determination of its photosensitizer behaviors. Key words Metallo-phthalocyanines cyclic voltammetry computational chemistry photodynamic therapy photochemical .