スライド 1

Blue-Colored Donor-Acceptor
[2]Rotaxane
Taichi Ikeda, Ivan Aprahamian, and J. Fraser Stoddart,
Org. Lett. 2007, 9, 1481-1484.
Kazuhiro IKUTA
Tobe Lab.
Contents
□Introduction
・Structure of Rotaxane
・Color of the CT complex
・Idea of RGB dye
・Purpose of this Work
□Results and Discussion
・Synthesis of Rotaxane
・UV-vis Spectra
・Electrochemical Properties
□Summary
Structure of Rotaxane
Rotaxane
Dumbbell component
Stopper unit
Ring component
☆ A rotaxane is a mechanically interlocked molecular
architecture consisting of a dumbbell-shaped
component that is threaded through a ring component.
☆ The ring component can not be pulled out because
the bulky substituents called ‘Stoppers’ exist at both
edges of axle, then this component is called ‘Dumbbell’.
Shuttling
(moving in parallel)
Color of CT Complex
Stabilization by
Coulombic interaction
Idea of RGB dye
Color change scheme of the RGB dye
・The color of this three-station catenane changes as a function of the
CBPQT4+ ring location which, in principle, can be controlled by
the oxidation of each station in turn.
Stoddart, J. F. et al. J. Am. Chem. Soc. 2005, 127, 15994.
Purpose of this Work
Green
≡
Stoddart, J. F. et al. Org. Lett, 2007, 9, 1287.
Red
Purpose of this Work
・Synthesis of blue-colored rotaxane
・investigation of its optical and
electrochemical properties
New guest compound
Synthesis of the Blue-colored [2]Rotaxane
(Orange wax)
(White powder)
(Blue solid)
UV-vis Absorption Spectra
UV-vis absorption spectra (rt, MeCN, 1 mM) of
(a) a 1:1 mixture of DFBZ and CBPQT·4PF6,
(b) a 1:1 mixture of DFBZ-TEG and CBPQT·4PF6,
and
(c) the blue-colored [2]rotaxane 1·4PF6.
A photograph of the blue-colored [2]rotaxane
solution is shown in the inset.
The introduction of tetraethyleneglycol chains
⇒a change of the maximum absorption wavelength (λmax) from 570 to 610 nm.
⇒the HOMO energy level of DFBZ changes as a direct result of the alkylation
Cyclic Voltammetry
+0.95
+0.76
The redox potentials of (a) are higher
than those of (b).
⇒consistent with UV-vis results.
+0.83
+0.65
+1.02
+0.85
distorting
⇒assuming that the flexible linker
enables the ring to move freely
around the station.
⇒the broadening of the redox CV peak
Cyclic Voltammetry
+0.83
+0.65
Shifting in the same magnitude
+1.02
+0.85
⇒ring translocated slightly from
the DFBZ station to TEG spacer
⇒influence of the CBPQT4+ ring to
second redox potential
Cyclic Voltammetry
binding
constant
first E1/2 vs
SCE (V)
λmax of CT
band (nm)
TTF-TEG
416,000
+0.36
835
DFBZ-TEG
300
+0.65
610
DNPC5DEG
100
+1.16
525
Stoddart, J. F. et al. Org. Lett. 2006, 8, 2205
(ⅰ) (ⅱ) (ⅲ)
Summary
• We have designed, synthesized, and characterized DFBZ-TEG
and the [2]rotaxane consisting of DFBZ-TEG and CBPQT4+.
• We confirmed the blue color of the CT absorption band
between DFBZ-TEG and CBPQT・4PF6.
• The acquired data on model compounds –absorption spectra,
and electrochemical properties – indicates that the design of
an RGB dye using the discussed donor –acceptor motif is
attainable.
740 nm
610 nm
500 nm
補色
Introduction
・The color of the complex with CBPQT4+ as
the host is determined
by the wavelength of the CT absorption band.
・The absorption wavelength depends on
the energy gap
between the LUMO of CBPQT4+ and the HOMO
of the guest molecule.
Guest
We can generate a range of different colors by altering
the HOMO energy level of the guest molecules.