Enzymatic Methane Hydroxylation: sMMO and pMMO
49
Table 1
Key factors in catalytic activity of models of active sites of MMOH
Q for the cleavage of a methane C–H bond used in literatures
References
Method
Cluster model a
Spin states
CN of Fe b
Active site c
C–H bond cleavage
Energy barrier d
Fashion e
Yoshizawa group
[46]
DFT (B3LYP)
(a, b)
1
A
4, 5
Fe
4.3
Nonradical
[52]
DFT (B3LYP)
(c)
1
A (IS-AF)
5, 6
Fe
30.4
Nonradical
[56]
DFT (B3LYP*)
(d)
HS-AF/HS-FM f
6, 6
B–O
25.2
Radical
(e)
HS-AF/HS-FM f
6, 6
B–O
23.5
(f)
HS-AF/HS-FM f
4, 6
B–O
17.4 g
(g)
HS-AF/HS-FM f
5, 6
B–O
19.4 g
(h)
HS-AF/HS-FM f
6, 6
B–O
22.6 g
(i)
HS-AF/HS-FM f
6, 6
T–O
21.9 g
(j)
HS-AF/HS-FM f
4, 6
B–O
14.3 g
Siegbahn group
[57]
DFT (B3LYP)
(k)
9
A
4, 5
B–O
4.5
Radical
[59]
(l)
9
A
6, 6
B–O
7.1
Radical
[63]
(m)
9
A
6, 6
B–O
13.8
Radical
Morokuma group
[66]
DFT (B3LYP)
(n)
9
A/ 11
A h
6, 6
B–O
19.5
Radical
[68]
DFT (B3LYP)
(n)
9
A/ 11
A h
6, 6
B–O
23.2 (O-side)
19.5 (N-side)
Radical
[74]
DFT (B3LYP)
(o)
9
A/ 11
A h
6, 6
B–O
21.8
Radical
(continued)