scholarly journals 3d-d Excited States of Ni(II) Complexes Relevant to Photoredox Catalysis: Spectroscopic Identification and Mechanistic Implications

2020 ◽  
Vol 142 (12) ◽  
pp. 5800-5810 ◽  
Author(s):  
Stephen I. Ting ◽  
Sofia Garakyaraghi ◽  
Chelsea M. Taliaferro ◽  
Benjamin J. Shields ◽  
Gregory D. Scholes ◽  
...  
2020 ◽  
Author(s):  
Shangze Wu ◽  
Jonas Zurauskas ◽  
Michal Domanski ◽  
Patrick Hitzfeld ◽  
Valeria Butera ◽  
...  

<p>Electrochemically-mediated Photoredox Catalysis emerged as a powerful synthetic technique in recent years, overcoming fundamental limitations of electrochemistry and photoredox catalysis in the single electron transfer activation of small organic molecules. However, the mechanism of how photoexcited radical ion species with ultrashort (picosecond-order) lifetimes could ever undergo productive photochemistry has eluded synthetic chemists. We report tri(<i>para</i>-substituted)biarylamines as a tunable class of electroactivated photocatalysts that become superoxidants in their photoexcited states, even able to oxidize molecules (such as dichlorobenzene and trifluorotoluene) beyond the solvent window limits of cyclic voltammetry. Furthermore, we demonstrate that precomplexation not only permits the excited state photochemistry of tris(<i>para</i>-substituted)biarylaminium cations, but enables and rationalizes the surprising photochemistry of their <i>higher-order</i> doublet (D<i><sub>n</sub></i>) excited states.</p>


SynOpen ◽  
2021 ◽  
Author(s):  
Samuel Oger ◽  
Hajar Baguia ◽  
Tuan-Anh Phan ◽  
Titouan Teunens ◽  
Jérôme Beaudelot ◽  
...  

The development of photoredox catalysis has recently enabled the design of remarkably powerful synthetic tools now commonly used in a wide array of chemical transformations, and notably for the generation of radical species under mild, safe and environmentally friendly conditions. This field is largely dominated by ruthenium and iridium complexes, the main alternative to the use of these photocatalysts mostly relying on the use of organic dyes, which poses problems not only in terms of cost - therefore strongly limiting synthetic applications of photocatalysis - but also, more importantly, for the design of new light-mediated transformations. Much less attention has been devoted to the use of copper complexes in photoredox catalysis, despite their strong potential not only as cheaper catalysts but also for the activation of a broader range of substrates. Most copper complexes are indeed known to be poor photocatalysts, mostly due to their short-lived excited states and low redox potentials. Over the last decade, one copper-based copper complex has however emerged as a remarkably efficient and general photoredox catalyst, which is at the core of this Spotlight that highlights its applications as a photosensitizer and its potential.


2020 ◽  
Author(s):  
Shangze Wu ◽  
Jonas Zurauskas ◽  
Michal Domanski ◽  
Patrick Hitzfeld ◽  
Valeria Butera ◽  
...  

<p>Electrochemically-mediated Photoredox Catalysis emerged as a powerful synthetic technique in recent years, overcoming fundamental limitations of electrochemistry and photoredox catalysis in the single electron transfer activation of small organic molecules. However, the mechanism of how photoexcited radical ion species with ultrashort (picosecond-order) lifetimes could ever undergo productive photochemistry has eluded synthetic chemists. We report tri(<i>para</i>-substituted)biarylamines as a tunable class of electroactivated photocatalysts that become superoxidants in their photoexcited states, even able to oxidize molecules (such as dichlorobenzene and trifluorotoluene) beyond the solvent window limits of cyclic voltammetry. Furthermore, we demonstrate that precomplexation not only permits the excited state photochemistry of tris(<i>para</i>-substituted)biarylaminium cations, but enables and rationalizes the surprising photochemistry of their <i>higher-order</i> doublet (D<i><sub>n</sub></i>) excited states.</p>


1988 ◽  
Vol 102 ◽  
pp. 239
Author(s):  
M.S.Z. Chaghtai

Using R.D. Cowan’s computations (1979) and parametric calculations of Meinders et al (1982), old analyses are thoroughly revised and extended at Aligarh, of Zr III by Khan et al (1981), of Nb IV by Shujauddin et Chaghtai (1985), of Mo V by Tauheed at al (1985). Cabeza et al (1986) confirmed the last one largely.Extensive studies have been reported of the 1–e spectra, Zr IV (Rahimullah et al 1980; Acquista and Reader 1980), Nb V (Shujauddin et al 1982; Kagan et al 1981) and Mo VI (Edlén et al 1985). Some interacting 4p54d2levels of these spectra have been reported from our laboratory, also.Detailed spectral analyses of transitions between excited states have furnished complete energy values for J ≠ 1 levels of these spectra during 1970s and 80s. Shujauddin et al (1982) have worked out Nb VI and Tauheed et al (1984) Mo VII from our lab, while Khan et al (1981) share the work on Zr V with Reader and Acquista (1979).


Physica ◽  
1952 ◽  
Vol 18 (2) ◽  
pp. 1101-1104
Author(s):  
B FLOWERS
Keyword(s):  

1985 ◽  
Vol 46 (C7) ◽  
pp. C7-409-C7-412 ◽  
Author(s):  
C. K. Jørgensen
Keyword(s):  

1984 ◽  
Vol 45 (C4) ◽  
pp. C4-337-C4-350 ◽  
Author(s):  
K. A. Snover

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