Non-peripheral tetra methoxylated pyrazoline bearing CoII, CuII and MnIIICl phthalocyanines: Syntheses, electrochemistry and spectroelectrochemistry

Abstract

• Synthesis of pyrazoline containing methoxy groups. • Electrochemical properties of metallated phthalocyanines. • Spectroelectrochemical properties of metallated phthalocyanines. The novel and highly soluble cobalt(II), copper(II) and manganese(III) phthalocyanines (( Pc -Co, Pc -Cu , and Pc -Mn ) bearing 3-(5-(3,5-dimethoxyphenyl)-1-phenyl-4,5-dihydro-1 H -pyrazol-3-yl)phenol have been synthesized and characterized by FT-IR, NMR, UV-Vis and mass spectroscopic methods. Additionally, electrochemical and spectroelectrochemical properties of these phthalocyanine compounds were investigated. Due to the redox inactivity of the Cu 2+ central cation of ( Pc -Cu ), Pc based reductions and oxidation processes are recorded. [Co II Pc 2− ]/[Co I Pc 2− ] 1− and [Co II Pc 2− ]/[Co III Pc 2− ] 1+ couples for the central metal redox reactions, and [Co I Pc 2− ] 1− /[Co I Pc 3− ] 2− , [Co I Pc 3− ] 2− /[Co I Pc 4− ] 3− and [Co III Pc 2− ] 1+ /[Co III Pc 1− ] 2+ couples for the Pc based reduction and oxidation are observed respectively with ( Pc -Co ). Like ( Pc -Co ), ( Pc -Mn ) also illustrated metal-based reduction processes, [Cl 1− -Mn III Pc 2− ]/[Cl 1− -Mn II Pc 2− ] 1− and [Cl 1− -Mn II Pc 2− ] 1− /[Cl 1− -Mn I Pc 2− ] 2− in addition to the Pc based [Cl 1− -Mn I Pc 2− ] 2− /[Cl 1− -Mn I Pc 3− ] 3− , [Cl 1− -Mn I Pc 3− ] 3− /[Cl 1− -Mn I Pc 4− ] 4− and [Cl 1− -Mn III Pc 2− ]/[Cl 1− -Mn III Pc 1− ] 1+ redox couples were also recorded. These redox mechanisms were supported with the characteristic spectral changes observed during the in-situ spectroelectrochemical measurements. Especially metal-based electron transfer changes caused distinct spectral and color changes, which are the desired properties of the complexes for the possible opto-electrochemical applications.