Synthesis and excited-state photodynamics of perylene–porphyrin dyads Part 3. Effects of perylene, linker, and connectivity on ultrafast energy transfer

Abstract

New perylene-porphyrin dyads have been designed that exhibit superior light-harvesting and energy-utilization activity compared with earlier generations of structurally related dyads. The new dyads consist of a perylene mono(imide) dye (PMI) connected to a porphyrin (Por) via an ethynylphenyl (ep) linker. The PMI-ep-Por arrays were prepared with the porphyrin as either a zinc or magnesium complex (Por ~Zn or Mg) or a freebase form (Por ~Fb). The absorption properties of the perylene complement those of the porphyrin. Following excitation of the perylene (forming PMI*) in toluene, each array exhibits ultrafast (k ENT ¢ (0.5 ps) 21 ) and essentially quantitative energy transfer from PMI* to the ground-state porphyrin (forming Por*). In each of the arrays, the properties of the excited porphyrin (lifetime, fluorescence yield, etc.) are basically unperturbed from those of the isolated pigment. Thus, following energy transfer, the excited porphyrin is not quenched by deleterious reactions involving the perylene accessory unit that would otherwise limit the ability of Por* to emit light or transfer energy to another stage in a molecular photonic device. Collectively, the PMI-ep-Por dyads represent the successful result of a molecular design strategy to produce arrays with excellent properties for use as light-input and energy-transduction elements for applications in molecular optoelectronics.{For Parts 1 and 2, see refs. 14 and 15 respectively.

Synchrotron ultrafast techniques for photoactive transition metal complexes

“…Metalloporphyrins have been widely studied, both experimentally [255][256][257][258][259][260] and theoretically [261][262][263], due to their application as versatile substrates in various technologically relevant light-driven processes, e.g. in the fields of light harvesting and photocatalysis [264][265][266][267].…”

Long-Range Electron Transfer in Zinc-Phthalocyanine-Oligo(Phenylene-ethynylene)-Based Donor-Bridge-Acceptor Dyads

“…This type of bridging unit has been shown to mediate electron transfer over long distances 14f−h,20 and when connected through an ethynylene group to the donor and acceptor units this occurs with surprisingly high rates. 13c,d, 21 These two new dyads are compared with our earlier investigation, where the acceptor was a tin(IV) dichloride porphyrin (SnP). 13a Our data strongly suggest that the reduction of a gold porphyrin first occurs on the macrocycle (Au III P • ) but that the system then relaxes, resulting in a metal based reduction (Au II P).…”

The Synthesis and Characterisation of a Free‐Base Porphyrin–Perylene Dyad that Exhibits Electronic Coupling in Both the Ground and Excited States

“…[5,6] Comprehensive studies have also been performed on porphyrin-perylene dyads formed through alkynyl linkages between the two chromophores. [7][8][9] These particular modes of connections between chromophores in previously reported dyads caused the arrays to behave as a supposition of the individual dye molecules, as observed through absorption spectroscopy. Recently, we have synthesised and characterised a dyad composed of a free-base porphyrin and a perylene diimide, in which the two components are connected covalently through a methylene amide spacer, pictured in Figure 1.…”