Enhanced p-Terphenyl-Catalyzed Photoreduction of CO2 to CO through the Mediation of Co(III)–Cyclam Complex

Abstract

Efficient p-terphenyl-catalyzed photoreduction of CO2 to carbon monoxide can be achieved by combination with Cobalt3+–cyclam (cyclam = 1,4,8,11-tetra-azacyclotetradecane) as an electron mediator in organic solvent.

Electro- and Solar-Driven Fuel Synthesis with First Row Transition Metal Complexes

“…(QY CO = 15% and QY HCO2H = 10% at λ = 313 nm). 445 Conversely, when irradiated (λ > 290 nm) with PS26 instead of PS23 in MeCN:MeOH:TEA (2:1:1), Co55 yields almost exclusively HCO 2 H, showing TON HCO2H = 4.4, TON CO = 0.3, and TON H2 < 0.1 (QY HCO2H of 7% at λ = 313 nm). 431 In contrast to photoreduced [ PS23 ] •– , [ PS26 ] •– has insufficient driving force to reduce Co55 to the Co + state.…”

“…Unmodified cyclam Co55 reduces CO 2 when paired with organic PSs. 444,445 After 1 h irradiation (λ > 290 nm) of PS23 in MeCN:MeOH:TEA (4:1:1), Co55 yielded a TON CO = 4.7, TON HCO2H = 2.4, and TON H2 = 0.7. Replacing MeOH with H 2 O lowers activity, whereas exchanging TEA for TEOA yields TON CO = 10.2, TON HCO2H = 6.7, and TON H2 = 0.7.…”

CoIICryptates Convert CO2into CO and CH4under Visible Light

“…Even though human society is slowly movingt oa lternative ways of generating energy,8 5% of the total energyc onsumed still hasits origins in fossil fuels, resulting in an uncontrolled increase of CO 2 in the atmosphere.T his has not only been connected to climate change and its dramatic irreversiblee ffects, but has also been seen by scientists as an opportunity to develop new materials and alternative methods to capturea nd/ or convert CO 2 into other chemicals with economic value. [1,2] One of the mosta ppealing of these new methods is the use of visible light to convert or recycle this greenhouse gas, which has been chosen by many groups who have reported the applicationo fs everalt ypes of metal complexes as catalystst o photoreduceC O 2 .C yclams and their derivatives, [3][4][5][6][7][8][9][10][11] porphyrins [12][13][14][15][16][17] and polypyridyl [18][19][20][21][22][23][24][25] are among the moste xplored ligands.…”

“…One of the most appealing of these new methods is the use of visible light to convert or recycle this greenhouse gas, which has been chosen by many groups who have reported the application of several types of metal complexes as catalysts to photoreduce CO 2 . Cyclams and their derivatives, porphyrins and polypyridyl are among the most explored ligands.…”

Artificial Photosynthetic Systems for CO2 Reduction: Progress on Higher Efficiency with Cobalt Complexes as Catalysts

“…[13] Thereafter,av arietyo fm olecular cobalt catalysts were investigated for photocatalytic CO 2 reduction in homogeneous solutions. [14][15][16][17][18][19][20][21][22][23][24] These systems realized CO 2 -to-CO and/or CO 2 -to-formate conversion successfully under light irradiation. Recently,awidev ariety of novel cobaltc omplexes have been reported for photocatalytic CO 2 reduction, [25][26][27][28][29][30][31] exhibitingi mpressive activitiesa nd selectivities.…”