Synthesis, Photophysical Properties and Computational Studies of beta‐Substituted Porphyrin Dyads
Praseetha E. Kesavan, Vijayalakshmi Pandey, Masatoshi Ishida, Hiroyuki Furuta, Shigeki Mori, Iti Gupta
Abstract
Abstract Beta ‐ pyrrole‐substituted porphyrin dyads connected by ethynyl linkage to N ‐butylcarbazole or triphenylamine donors are reported. Donor‐π‐acceptor type beta ‐ substituted porphyrin dyads and their Zn(II) and Pd(II) complexes were characterized by MALDI‐MS, NMR, UV‐vis absorption, fluorescence and cyclic voltammetry techniques. The S 1 emission dynamics were analyzed by time‐resolved spectroscopy (TCSPC); dyads exhibited efficient energy transfer up to 93% from beta‐donors ( N ‐butylcarbazole or triphenylamine group) to the porphyrin core. The efficiency of energy transfer for the beta‐substituted porphyrin dyads were much higher than those of the corresponding meso‐substituted porphyrin dyads, reflecting enhanced communications between the beta‐donors and the porphyrin core. The Pd(II) dyads, showed characteristic phosphorescence in the near IR region and very efficient singlet oxygen quantum yields (53–60%); these dyads are promising candidates for photocatalytic oxidations of organic compounds. The donor‐acceptor interaction between the porphyrin core and the beta‐donors was supported by the DFT studies in the porphyrin dyads.