Photophysical and Photochemical Properties and Aggregation Behavior of Phthalocyanine and Naphthalocyanine Derivatives

Thalita de Souza, Felipe Antonio, Mateus Zanotto, Paula Homem-de-Mello, Anderson Ribeiro
2017 Journal of the Brazilian Chemical Society  
The photophysical and photochemical properties of phthalocyanine and naphthalocyanine with similar structures were studied in solution and with density-functional theory (DFT) computational method. The extended π-conjugated system in naphthalocyanines causes a bathochromic shift in UV-Vis, emission and excitation bands, and promotes lesser generation of singlet oxygen in solution when compared to phthalocyanines. Time dependent DFT (TD-DFT) calculations point out the molecular orbitals involved
more » ... r orbitals involved in Q-band transition, corresponding to highest occupied molecular orbital (HOMO) to lowest unoccupied molecular orbital (LUMO) transition with a concentration of charge along x-axis, while the transition to LUMO+1 is in y-axis direction. The presence of tert-butyl substituents does not affect the molecular orbitals shape, but affect their energies. Aggregation studies in dimethyl sulfoxide (DMSO):water solutions showed that naphthalocyanines studied have more aggregation tendency than the phthalocyanines. DFT studies indicated that stacked-dimers are preferred to rotated-stacked conformation due the interaction between Zn II and nitrogen atom from different monomers.
doi:10.21577/0103-5053.20170215 fatcat:siq67hvlyfhjvcegwo2nfxzgla