In:
European Journal of Inorganic Chemistry, Wiley, Vol. 2019, No. 39-40 ( 2019-10-31), p. 4256-4262
Abstract:
A molecular triad comprising a [Ru(bpy) 3 ] 2+ (bpy = 2,2′‐bipyridine) photosensitizer, a primary phenothiazine (PTZ) donor and a secondary (extended) tetrathiafulvalene (exTTF) donor was synthesized and explored by UV/Vis transient absorption spectroscopy. Initial photoinduced electron transfer from PTZ to the 3 MLCT‐excited [Ru(bpy) 3 ] 2+ occurs within less than 60 ps, and subsequently PTZ is regenerated by electron transfer from exTTF with a time constant of 300 ps. The resulting photoproduct comprising exTTF · + and [Ru(bpy) 3 ] + has a lifetime of 6100 ps in de‐aerated CH 3 CN at room temperature. Additional one‐ and two‐pulse laser flash photolysis studies of the triad were performed in the presence of excess methyl viologen (MV 2+ ), to explore the possibility of light‐driven charge accumulation on exTTF. MV 2+ clearly oxidized [Ru(bpy) 3 ] + and thereby re‐instated ground‐state [Ru(bpy) 3 ] 2+ in triads in which exTTF had been oxidized to exTTF · + , but further excitation of the solution containing the exTTF · + ‐PTZ‐[Ru(bpy) 3 ] 2+ photoproduct did not provide evidence for exTTF 2+ . Nevertheless, it seems that the design principle of a covalent donor‐donor‐sensitizer triad (as opposed to simpler donor‐sensitizer dyads) is beneficial for light‐driven accumulation of oxidation equivalents. These investigations are relevant in the greater context of multi‐electron photoredox chemistry and artificial photosynthesis.
Type of Medium:
Online Resource
ISSN:
1434-1948
,
1099-0682
DOI:
10.1002/ejic.v2019.39-40
DOI:
10.1002/ejic.201900453
Language:
English
Publisher:
Wiley
Publication Date:
2019
detail.hit.zdb_id:
1475009-0
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