186
4 Toward More Sophisticated Problems
HOMO
LUMO
SOMO A
SOMO B
-3.212 eV
-4.840 eV
-3.950 eV
-5.841 eV
Easily electron-injectable
Ground state of (a-1)
Excited state of (a-1): 3 MLCT
Fig. 4.42 Schematic energy diagrams of N3 working as the reductive catalyst taking advantage of
3 MLCT state. MLCT signifies metal to ligand charge transfer
+
(a-3)
(a-4)
+CO 2
+H +
+H +
+e −
+e −
−HCOO −
−OH −
−CO
a-10
a-20
a-30
a-50
a-40
a-60
a-70
+
+
+
(a)
(b)
Fig. 4.43 Two kinds of CO 2 reduction pathways via a OCO and b COO additions to (a–3) state
with various intermediates
+CO 2
+H +
−HCOO −
+
Energy (eV)
+
+e −
a-3
+CO 2
+H +
+e −
a-10
+H +
+e −
a-20
+e −
a-4
+HCOO −
a-4
+CO 2
+H +
+e −
a-30
(-0.202)
(+0.047)
(-11.415)
(-17.239)
(-11.263)
(+5.006)
Fig. 4.44 A series of relative energy changes in the Ru–OCO cycle. See Fig. 4.41(a–1) as to setting
of the zero energy
4 Toward More Sophisticated Problems
HOMO
LUMO
SOMO A
SOMO B
-3.212 eV
-4.840 eV
-3.950 eV
-5.841 eV
Easily electron-injectable
Ground state of (a-1)
Excited state of (a-1): 3 MLCT
Fig. 4.42 Schematic energy diagrams of N3 working as the reductive catalyst taking advantage of
3 MLCT state. MLCT signifies metal to ligand charge transfer
+
(a-3)
(a-4)
+CO 2
+H +
+H +
+e −
+e −
−HCOO −
−OH −
−CO
a-10
a-20
a-30
a-50
a-40
a-60
a-70
+
+
+
(a)
(b)
Fig. 4.43 Two kinds of CO 2 reduction pathways via a OCO and b COO additions to (a–3) state
with various intermediates
+CO 2
+H +
−HCOO −
+
Energy (eV)
+
+e −
a-3
+CO 2
+H +
+e −
a-10
+H +
+e −
a-20
+e −
a-4
+HCOO −
a-4
+CO 2
+H +
+e −
a-30
(-0.202)
(+0.047)
(-11.415)
(-17.239)
(-11.263)
(+5.006)
Fig. 4.44 A series of relative energy changes in the Ru–OCO cycle. See Fig. 4.41(a–1) as to setting
of the zero energy