TPEN
Zn(OAc)
2
2H
2
O
TPEN
N
0,004
74 75
74.2H
+
0,002
0,000
g lum
–0,002
–0,004
350 400 450 500 550 600 650 700 750
P Helices
M Helices
800
l / nm
N
N
N
N +
+
N
Zn
Zn
L
L: ligand
AcO OAc
N
N
N
N
H
H
H
+
OH
–
N
N
O
O
N
N
N
N
N
N
O
O
(P,P)-73
(P,P)-72
(P,P)-75
a
a
b
(P,P)-74.2H
+
(P,P)-74
Zn
"
"
Fig. 4.29
(a) Reversible Zn(II) complexation-decomplexation process of (P,P)-72 to (P,P)-73 using Zn(OAc)
2 and TPEN as the chemical stimuli [69]. (b)
Reversible Zn(II) complexation-decomplexation process of (P,P)-74 to (P,P)-75 using Zn(OAc)
2 and TPEN as the chemical stimuli and acid-base triggered
switch between (P,P)-74 and (P,P)-74.2H
+
. Emission colors and CPL activity of 72
(black), 75
(red) and 74.2H
+
(blue). Plain lines are for the (P) helicenes and
dotted lines for the (M ) ones. Adapted with permission [70]. Copyright 2019, American Chemical Society
4 Circularly Polarized Luminescence in Helicene and Helicenoid Derivatives
89