Photophysical and photochemical properties and TD-DFT calculations of novel zinc and platinum phthalocyanines

• Synthesis of novel dimethyl 2-(3-methylbut-2-enyl)malonate substituted zinc and platinum phthalocyanines by green chemistry is reported.
• The bulky ester substituents enhance the solubility of the Pt(II)Pc complexes and minimize the extent of aggregation.
• The Pt(II) has a higher singlet oxygen quantum yield due to the heavy atom effect.
• TD-DFT calculations were carried out to compare the electronic structures of the Pt(II) and Zn(II) complexes.

The synthesis and characterization, and spectral, photophysical and photochemical properties of dimethyl 2-(3-methylbut-2-enyl)malonate substituted zinc and platinum phthalocyanines are reported. The phthalocyanines were characterized by electronic absorption, infrared, and nuclear magnetic resonance spectroscopy, mass spectrometry and elemental analysis. Trends observed in the singlet oxygen, photodegradation, fluorescence and triplet state quantum yields and the fluorescence and triplet state lifetimes are described. DFT and TD-DFT calculations were carried out so that the electronic structure and optical spectroscopy of the Pt(II) complex could be compared to that of the Zn(II) complex. As would normally be anticipated, the bulky peripheral substituents were found to enhance the solubility of the complexes in organic solvents.

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