Spectroscopic and computational characterization of new promising donors - Manganese(III) porphyrins bearing carbazole groups

UV-vis, IR, MALDI-TOF, and femtosecond transient absorption spectroscopic techniques together with DFT and TDDFT computations have been employed to explore new manganese(III) porphyrins bearing [3,6-di-tert-butyl- carbazol-9-yl-benzoyloxy]- (MnP1) and [3,6-bis(3",6"-di(tert-butyl)-9"H-carbazol)-9H-carbazolbenzoyloxy] phenyl (MnP2) groups. MnP1 and MnP2 demonstrate the significant deviation of the macrocycle from planarity, which can be due to the high spin (S = 2) state of the manganese(III). By studying MnP1 and MnP2 excited states, the formation of the trip-quintet ones decaying in 13.7 ps and 17.3 ps, respectively, was established. The comparisons of MnP1 and MnP2 with the Co and Zn analogs have shown that both the number of generations and metal ion influence excited-state dynamics and electronic/structural properties.