Rapidly Color-Switching
Photochromic compounds

Featurespseudogem-BisDPI[2.2]paracyclophane derivatives
have excellent photochromic characteristics.
1. Rapid Color-Switching
2. High Fatigue Resistance
3. Photochromism at a Wide Rangeof Temperature

Product Introduction
Photochromic materials change their colors upon irradiation with light. The main
possible application of photochromic materials has been thought as use in optical
data storages, hologram materials and light modulators. There have been considerably researches and studies about photochromic compounds.
There are 2 types of photochromic compounds, P-type and T-type. The photogenerated P-type compound can be converted back to its initial structure by irradiation witha specific wavelength of light. Meanwhile, the photogenerated T-type compound canbe converted back to its initial structure thermally. However, the thermal bleach reaction of photogenerated T-type compounds requires several minutes at room temperature, and for practical use in certain applications, it demands a much faster speed
in the return to the initial state.
Hxaarylbisimidazole (HABI) was discovered in the early 1960s by Hayashi andMaeda, and it has subsequently attracted significant interest because of its unusualphysical properties. The solution of HABI changes from colorless to purple under UVirradiation. The thermal transformation of TPIRs to HABI requires several minutes atroom temperature.

HABI

TPIRs

Kanto Chemical has commercialized pseudogem-Bis(diphenylimidazole) [2.2]paracyclophane (1) and pseudogem-Bis(3,3’, 4,4’ - tetramethoxydiphenylimidazole)[2.2]paracyclophane (2) novel hexaarylbisimidazole (HABI) derivatives whichhave a [2.2]paracyclophane structure. This novel compounds are originally designedand synthesized by professor Abe from Aoyama Gakuin University. These compounds have an excellent color switching character. They are colorless when dissolved in benzene, and change to blue or green upon UV irradiation. After the irradiation ceases, these color bleaches immediately.

◆ Molecular structure
１２◆Photochromic reaction of 1 and 2◆ Photochromic reaction of 1.

11R◆ Photocromic reaction of 222R

◆1 and 2 dissolved in benzene change there color upon UV irradiation
１２Solv.：Benzene
Concentration：0.1〜0.5mMTemperature：20℃,
Quartz Cell： 1mm × 10mm × 40mm,

UV irradiator：Keyence UV-400
UV-LED(UV-50H) / UV-L6,
Exciting light：(Wavelength) 355nm, (Intensity) 300mW/cm2

◆ Transient vis-NIR absoraption spectra and Decay profile of 1

Figure 1
Transient vis-NIR absorption spectra of 1 in degassed benzene after excitation with a nanosecond
laser pulse.(Conc. 2.1 x 10-4M, 298K, recorded
at 20ms intervals).

Figure 2
Decay profiles of the colored species generated
from 1, monitored at 400 nm in degassed benzene(Conc 1.5×10-4M).

11R◆ The photochromic properties of a polymer film doped with

1.

A transparent amorphous polymer film of 1 also shows fast thermal bleaching of the photochromic
reaction at room temperature. Moreover, the photochromic properties of a poly(methyl methacrylate)(PMMA) film doped with 20 wt %-1 have an excellent fatigue resistance. The practical application of 1
has been highly expected.

Figure 3
Time profiles of the transient absorbanceat 400nm of the PMMA film doped with
Conc. 20 wt %-1, measured at 298K (○,freshly pre-pared sample; ▲ , after
irradiation with 10,000 laser pulses).

◆ Transient vis-NIR absoraption spectra and Decay profile of 2

Figure 4
Transient vis-NIR absorption spectra of 2 in degassed benzene after excitation with a nanosecond
laser pulse. (2.1 x 10-4M, 298K, recorded at 20msintervals).

2

Figure 5
Decay profiles of the colored species generated
from 2, monitored at 400 nm in degassed benzene(1.5×10-4M).

2R◆ Decay profiles of 1 and 2
The half-life of 1R is 33 ms at 25 ℃
The half-life of 2R is 173 ms at 25 ℃Figure 6
Decay profiles of the colored species generated
from 1 and 2, in degassed benzene.

◆UV-Vis absorption spectrum of 1 and 2
2 shows relatively strong absorption band in the UVA radiation region.

１Solv. ：benzene
Conc. 2.1 x 10-4M
Temp ：25℃

２

Solv ：benzene
Conc. 2.1 x 10-5M
Temp ：25℃

Product List
ProductCat. No.

Package04425-96

100mg

04425-95

500mg

04426-68

100mg

04426-95

500mg

pseudogem-Bis(diphenylimidazole)[2.2]paracyclophane (1)FW 672.79･46.07 / C46H34N4･C2H5OH
Purity: >98%１

pseudogem-Bis(3,3’,4,4’-tetramethoxydiphenylimidazole)[2.2]paracyclophane (2)FW 883.00 / C54H50N4O8
Purity: >98%

２Reference1)
2)

Y. Kishimoto, J. Abe, “A Fast Photochromic Molecule That Colors Only under UV Light”,
J. Am. Chem. Soc., 131, 4227 (2009)
K. Mutoh, S. Hatano, J. Abe, ”An Efficient Strategy for Enhancing the Photosensitivity of
Photochromic [2.2]Paracyclophane-Bridged Imidazole Dimers” J. Photopolym. Sci. Technol.,23, 301 (2010)

Relative Products －Diarylethene－Kanto Chemical has commercialized a typical P-type photochromic compound, diarylethene, which
was developed by professor Irie from Rikkyo University.
ProductCat. No.

Package

1,2-Bis(2-methylbenzo[b]thiophene-3-yl)perfluorocyclopentene (3a)05058-63100mg05058-96

500mg

FW 468.48 / C23H14F6S2
Purity: >96%

F

F

F
FF

FF

F

F

F
CH3CH3S

H 3CS

3a Colorless

June. 2021

FF

S

H3 C

3b RedS