Abstract
•New pentacoordinated Zn(II) porphyrinates (1-2) were synthesized.•X-ray molecular structures of (1-2) showed high ruffling deformation.•Optical properties were modulated via tuning the axial ligand.•Methylene blue degradation followed: [Zn(TEBOP)] + H2O2 (47%) > 2 (38.5.9%) > 1 (26.9%).
In the present work, we report synthesis, structural elucidation and photophysical properties of new pentacoordinated Zn(II) porphyrinates (1-2). Complexes with formula [Zn(TEBOP)(DABCO)](DABCO) (1) [TEBOP = meso-tetrakis(ethyl-4(4-butyryl)oxyphenyl) porphyrinato), DABCO = 1,4-diazabicyclo [2.2.2] octane], and (2) [Zn(TEBOP)(pyz)] [pyz = pyrazine] have been studied to explore the effects of axial ligand on the structural and photophysical properties of [Zn(TEBOP)]. Both the solution and solid-state characterization unambiguously confirmed the pentacordinated nature of the complexes 1 and 2. The X-ray molecular structures showed that these complexes exhibited high ruffling deformation. We showed here that some of the optical properties (absorption features and quantum yield) could be modulated by varying the axial ligand whereas emission wavelength (λem) and lifetime (τf) values were found to remain unchanged. Electrochemical studies suggested that the characteristic reduction and oxidation potentials of the porphyrin ring varied with the axial ligand. Finally, [Zn(TEBOP)] and complexes 1 and 2 were checked for the oxidative degradation of methylene blue (C0 = 30 mg/L, T = 22°C, pH = 6, H2O2 = 4 mL/L). The degradation yields followed the order: [Zn(TEBOP)] + H2O2 (47%) > 2 (38.5.9%) > 1 (26.9%).
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