Making Copper Photocatalysis Even More Robust and Economic: Photoredox Catalysis with [Cu^II(dmp)₂Cl]Cl

Abstract

The CuII complex [CuII(dmp)2Cl]Cl (dmp = 2,9‐dimethyl‐1,10‐phenanthroline) is evaluated as an oxidation stable precursor for visible‐light‐mediated CuI‐photoredox catalysis, being efficient and considerable more cost‐effective compared to previously established copper(I) photocatalysts. Its performance and efficiency are demonstrated within a broad scope of atom transfer radical addition (ATRA) reactions, allowing the 1,2‐difunctionalization of alkenes, as well as for decarboxylative coupling and an Appel reaction. Moreover, the utility of the complex is shown by various gram‐scale functionalizations of styrene, thus suggesting [CuII(dmp)2Cl]Cl to be a low‐priced alternative precatalyst for processes run on scale. Furthermore, this study provides UV/Vis evidence on the mechanism for the visible light activation of CuII complexes.

Evaluating heteroleptic copper(I)-based complexes bearing π-extended diimines in different photocatalytic processes

“…However, the homoleptic complex Cu(dmp) 2 BF 4 was essentially inactive, increasing the -extension provided homoleptic complexes that afforded good yields of product. 37 The results would have been difficult to rationalize when examining the excited state reduction potentials and excited state lifetimes (Cu(dmp) 2 BF 4 , E = -1.12 V; Cu(ddpq) 2 BF 4 , E = -1.36 V; Cu(ddppz) 2 BF 4 , E = -0.90 V; Cu(dbdppz) 2 BF 4 , E = -1.34 V). All of the above catalysts possess excited state reduction potentials that should promote SET to CBr 4 (E ½ = 0.30 V vs. SCE).…”

Methyl Radical Initiated Kharasch and Related Reactions

“…The unstable heat and light sensitive 2-iodoacetophenone 2k did not afford cleanly the iodide 3k (entry 11). On the other hand, the corresponding bromoketone 2l [51,52] did provide 3l in 50% yield (entry 12). Again, the xanthate 2m added to 1a in a quantitative manner (entry 13).…”

Durch sichtbares Licht induzierte Homolyse unedler, gut verfügbarer Metallsubstratkomplexe: Eine komplementäre Aktivierungsstrategie in der Photoredoxkatalyse

“…a-v]). [18] Direkte spektroskopische Beweise aus einer Folgestudie in Zusammenarbeit mit der Castellano-Gruppe [8] haben gezeigt, dass die Spaltung der L n Cu-Cl-Bindung in < 100 fs erfolgt und eine blaue Anregung in den Cl! Cu-LMCT-Übergang fürd ie photochemische Umwandlung von Cu II zu Cu I und die Erzeugung eines reaktiven Chloratomradikals erforderlich ist.…”