Table 2.

Catalytic systems, major products, maximum FEs, and mechanisms of Mn complexes in electrochemical CO₂ reduction (n.a.=not available, prop.=proposal, comp.=computational investigation, exp.=experimental evidence).

Entry	Cat. system	Substitution	Major product	Max. FE (%)	Mechanism	Basis	Method	Ref.
1a		n=0, 1 X=CN, CO, MeCN Y=CH, N	CO/H2O	98 [89]	ETM	exp. comp.	IR‐SEC, [89] VSFG, [90] UV/Vis, XRD [86] DFT[ 88 , 91 ]	[86, 88–91]
1b		n=0, 1 R=H, Me, Et, tBu, Ph, Bn, CN, CO2H, CO2C3H6C4H5N, CF3, NMe2, OH, OMe, SMe X=MeCN, Br	CO/H2O H2	100±15 [80] 45 [92]	ETM	exp. comp.	EPR [93] , IR‐SEC [80] DFT [93]	[79–80, 92–94]
1c		R1=H, OMe, Br R2=C2H4OH	n.a.	n.a.	ETM	exp. comp.	IR, NMR DFT	[95]
1d		–	CO/H2O HCO2H H2	34±4 8±2 59±8	low c cat: ETH high c cat: ETM	exp.	IR‐, UV/Vis‐SEC	[96]
1e		R=C6H4NH2, SMe	CO/H2O	100±5 [94a]	ETM	prop. [97]	n.a.	[94a, 97, 98]
1f		R1=H, Ph R2=H, CH2NEt2, OH, OMe R3=H, OH, F	CO HCO2H	90 [99] 63 [100]	no H+: ETM H+: ETH ETM	exp.[ 62a , 99 , 101 ] comp.[ 99 , 102 ]	NMR, IR‐SEC DFT	[62a, 99–102]
1g		n=0, 1 R1=H, Me, Et, CH2NHEt, CH2NEt2, CH2‐morpholine, CH2OH, CHO, CO2H, NH2, OH,OMe, F R2=H, Me, CH2NEt2, OH X=MeCN, OTf, Br	CO/CO3 2−[64, 103] CO/H2O [103] HCO2H	98±3 [64] n.a. 90 [100]	ETM ETH	exp. comp.[ 103 , 104 ] exp. [100] comp. [100]	IR‐SEC, [64] (PR‐) TRIR [104] DFT IR‐SEC, NMR DFT	[64, 81, 100, 103, 104]
1h		R1=H, Me R2=Me, tBu	CO/H2O	78	ETM	comp.	DFT	[105]
1i		–	CO/H2O	98	ETM	comp.	DFT	[91]
2a		–	CO/CO3 2−	96	n.a.	n.a.	n.a.	[83a]
2b		–	CO/CO3 2− H2	96 (CO+H2)	n.a.	n.a.	n.a.	[83a]
3		R1=Me, Et R2=H, C6H4OH X=CN, SCN, Br, I Y=CH, N	CO/H2O H2	73 [106] 53 [107]	ETM	comp.[ 106 , 108 ]	DFT	[106–108, 109]
4		R1=H, Me R2=H, iPr, tBu R3=H, iPr	CO/CO3 2−	60	ETM	exp. comp.	IR‐, UV/Vis‐SEC DFT	[83b]
5		–	CO/H2O	n.a.	ETM	exp.	IR‐, UV/Vis‐SEC	[110]
6		Ar=CN(2,6‐(2,6‐(iPr)2C6H3)2C6H3) n=0, 1 X=THF, Cl, Br, I	CO/CO3 2−	n.a.	ETM	exp.	IR‐SEC	[111]
7		–	CO/H2O	129[a]	n.a.	n.a.	n.a.	[112]
8a		n=0, 1 X=MeCN, Br	CO/H2O	100	ETM	exp.	EPR, IR‐, UV/Vis‐SEC	[113]
8b		n=0, 1 R=H, Me, C6H4CH2NEt2 X=MeCN, Br	CO/H2O HCO2H	62 [91] 70 [100]	ETM (CO) ETH (HCO2H)	exp. comp.[ 91 , 100 ]	NMR, IR‐SEC [100] DFT	[91, 94c, 100]
9		R=Me, Mes	CO/CO3 2− CO/H2O	95 [114] 98 [109b]	ETM	exp. [109b] comp. [109b]	IR‐, [114] UV/Vis‐SEC DFT	[ 109b , 114 ]
10		–	CO/H2O	88	ETM	exp. comp.	EPR‐, IR‐SEC, PR‐TRIR DFT	[115]
11		R=Me, Bn	CO/CO3 2− CO/H2O	93 [116] 87±3 [117]	ETM	comp.[ 116 , 118 ]	DFT	[ 116 , 117 , 118 ]
12		R=C6F4‐S‐(PEG7)‐OMe	CH3OH CH3CO2 −	23 63	ETM	exp. comp.	EAS,[b] GC‐MS, IL, IR‐, UV/Vis‐SEC, NMR DFT	[119]
13		–	HCO2 − H2	26 77	n.a.	n.a.	n.a.	[120]

[a] Likely caused by loss of carbonyl ligand. [b] Electronic absorption spectroscopy.