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The studies were conducted to investigate the triplet excited-state deactivation of a gold porphyrin (AuP) in porphyrin-based donar-bridge-acceptor (D-B-A) systems. The results show that quenching of (super 3) AuP occurs with high efficiency in the dimers that were connected by fully conjugated budging chromophores, whereas no quenching was observed when the conjugation of the bridge was broken.

A series of donor-bridge-acceptor (D-B-A) systems with varying donor-acceptor distances was analyzed with respect to their energy transfer properties. The study was performed in 2-MTHF at 150K and it was found that triplet excitation energy transfer occurs with high efficiency in all D-B-A systems with the distance dependence being exponential and the donor and acceptor chromophores were separated by oligo-p-phenyleneethynylene (OPE) bridge units.

The electron transfer process in the ZnP-nB-AuP(super +) systems is verified by detection of formation and decay of the zinc porphyrin radical cation with femtosecond transient absorption spectroscopy. The efficiency of electron transfer, based on time-resolved fluorescence measurements, is 0.98, 0.77, 0.31, and 0.14 in C3H7CN for ZnP-nB-AuP(super +) with the edge to edge distance 12.7, 19.6, 26.5, an d33.4 Angstrom, respectively.

An investigation of the photophysics of gold(III) porphyrins with steady state and time-resolved spectroscopic methods as well as DFT calculations is presented. The result suggests a short-lived state, with a lifetime of about 20-50 ns in rigid media that is an intermediate between the first excited singlet state and the triplet manifold and acts as a gatekeeper state for formation of the triplets.