scholarly journals Structurally and electronically modulated spin interaction of transient biradicals in two photon-gated stepwise photochromism

2018 ◽  
Vol 17 (3) ◽  
pp. 290-301 ◽  
Author(s):  
Izumi Yonekawa ◽  
Katsuya Mutoh ◽  
Yoichi Kobayashi ◽  
Jiro Abe
Keyword(s):  
Spin Interaction ◽  
Photochromic Properties ◽  
Photochromic Compounds ◽  
Two Photon ◽  
Radical Complex

Bi-photochromic compounds composed of two photochromic phenoxyl-imidazolyl radical complex units are developed. The stepwise photochromic properties can be regulated by control of the central bridging part.

Research on Photochromic Compounds with Efficient Synthesis and Photochromic Properties of 1-(2-methyl-5-phenyl-3-thienyl)-2-[2-methyl-5-(4-pentylphenyl)-3-thienyl] perfluorocyclopentene

2014 ◽  
Vol 1003 ◽  
pp. 39-42
Author(s):  
Jun Jie Song ◽  
Gang Liu
Keyword(s):  
Fluorescence Intensity ◽  
Uv Light ◽  
Pmma Film ◽  
Efficient Synthesis ◽  
Photochromic Properties ◽  
Photochromic Compounds

A novel isomeric photochromic diarylethene, 1-(2-methyl-5-phenyl-3-thienyl)-2-[2-methyl-5-(4-pentylphenyl)-3-thienyl] perfluorocyclopentene, was designed and synthesized. Its fluorescent and photochromic properties were also studied in detail. The compound exhibited excellent photochromism, changing from colorless to bule after irradiation with UV light both in solution and in PMMA film. In addition, the fluorescence intensity of the photochromic diarylethene 1a declined remarkably, when irradiation with UV light.

Enhancement of Negative Photochromic Properties of Naphthalene‐Bridged Phenoxyl‐Imidazolyl Radical Complex

ChemPhysChem ◽  
2020 ◽  
Vol 21 (14) ◽  
pp. 1578-1586
Author(s):  
Hiroki Ito ◽  
Katsuya Mutoh ◽  
Jiro Abe
Keyword(s):  
Photochromic Properties ◽  
Radical Complex

Crystalline state photochromism of 3-furylfulgides: impact of size and bond flexibility of the non-aromatic alkylidene group

2015 ◽  
Vol 71 (5) ◽  
pp. 535-542 ◽  
Author(s):  
Champika V. Hettiarachchi ◽  
Roshan K. Weerasekara ◽  
Hidehiro Uekusa
Keyword(s):  
Thermal Stability ◽  
Solid State ◽  
Spectroscopic Data ◽  
Crystalline State ◽  
High Thermal Stability ◽  
Molecular Devices ◽  
Isopropyl Group ◽  
Photochromic Properties ◽  
Photochromic Compounds ◽  
Cyclohexyl Group

3-Furylfulgides are photochromic compounds showing high thermal stability in their closed forms. However, their photochromic properties in the solid state should be improved further to fabricate molecular devices. Understanding how the size and the flexibility of the non-aromatic alkylidene moiety alter the crystalline state photochromic properties is also important here, as the alkylidene group is directly involved in the photochromic ring closing and opening reactions. The synthesis of four 3-furylfulgides composed of different alkylidene groups (rigid isopropyl, flexible 2-butyl, rigid cyclopentyl and flexible cyclohexyl), their crystal structures and structure–photochromic property correlation in the crystalline state are reported here. Crystallographic data along with reaction cavity volumes calculated using the programCAVITY[Ohashiet al.(1981),J. Am. Chem. Soc.103, 5805–5812] disclosed that fulgides with flexible groups at the ring closing site have more free volume around the reactive area in the crystal lattice, which can provide more space for the atomic movements in the reaction and flexibility can reduce the strain built up in the closedC-isomers by making conformations. According to UV–vis spectroscopic data, a higher yield ofC-isomers and a better fatigue resistance were obtained for the 3-furylfulgide with the largest and flexible cyclohexyl group showing greater photochromic properties in the crystalline state than the fulgide containing the smallest and rigid isopropyl group.

Research on Photochromic Compounds with Efficient Synthesis and Photochromic Properties of 1-(2-methyl-5-chlorine-3-thienyl)-2-[2-methyl -5-(4-chlorophenyl)-3-thienyl] Perfluorocyclopentene

2014 ◽  
Vol 1003 ◽  
pp. 43-46
Author(s):  
Feng Xia Sun ◽  
Shi Qiang Cui ◽  
Shou Zhi Pu
Keyword(s):  
Solid State ◽  
Phenyl Ring ◽  
Uv Light ◽  
Amorphous Film ◽  
Fluorescence Properties ◽  
Efficient Synthesis ◽  
Photochromic Properties ◽  
Photochromic Compounds ◽  
Fluorescence Switching

A novel unsymmetrical diarylethene derivative bearing both phenyl and thiophene moieties, in which two chlorine groups were separately substituted at thiophene and the para-positions of the terminal phenyl ring, were synthesized. Its photochemical , fluorescence properties were investigated systematically both in solution and PMMA amorphous film. The results showed that this compound exhibited reversible photochromism, changing from colorless to purple after irradiation with 313 UV light both in solution and in PMMA amorphous film. Also, it exhibited remarkable fluorescence switching in the solid state.

Research on Photochromic Compounds with Synthesis and Photochromism of 1-(2-methyl-3-benzofuryl)-2-{2-methyl-5-[4-formyloxyethyl (Rhodamine-B)] phenyl-3-thienyl} Perfluoroyclopentene

2014 ◽  
Vol 1003 ◽  
pp. 55-58
Author(s):  
Dan Dan Xue ◽  
Guan Ming Liao ◽  
Chun Hong Zheng ◽  
Shou Zhi Pu
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Uv Light ◽  
Amorphous Film ◽  
Order Reaction ◽  
First Order Reaction ◽  
Pmma Film ◽  
Photochromic Properties ◽  
Photochromic Compounds ◽  
First Order

A new photochromic diarylethene compound bearing a rhodamine B unit, 1-(2-methyl-3-benzofuryl)-2-{2-methyl-5-[4-formyloxyethyl (rhodamine-B)] phenyl-3-thienyl} perfluorocyclopentene (1o) was synthesized, and its photochromic properties such as photochromism in solution as well as in a polymethylmethacrylate (PMMA) amorphous film were investigated specfically. 1o exhibits good photochromism upon alternating irradiation with UV light and visible light (> 510 nm) in hexane and a PMMA film. The kinetic experiments showed that the cyclization and cycloreversion processes were zeroth and first order reaction, respectively.

scholarly journals Diarylethene-modified nucleotides for switching optical properties in DNA

2012 ◽  
Vol 8 ◽  
pp. 905-914 ◽  
Author(s):  
Sebastian Barrois ◽  
Hans-Achim Wagenknecht
Keyword(s):  
Optical Properties ◽  
Nucleic Acid ◽  
Modified Nucleotides ◽  
Photochromic Properties ◽  
Photochromic Compounds ◽  
Acid Absorption ◽  
Base Modification ◽  
Dna Base ◽  
Phosphoramidite Chemistry ◽  
The Way

Diarylethenes were attached to the 5-position of 2’-deoxyuridine in order to yield three different photochromic nucleosides. All nucleosides were characterized with respect to their absorption and photochromic properties. Based on these results, the most promising photochromic DNA base modification was incorporated into representative oligonucleotides by using automated phosphoramidite chemistry. The switching of optical properties in DNA can be achieved selectively at 310 nm (forward) and 450 nm (backward); both wavelengths are outside the normal nucleic acid absorption range. Moreover, this nucleoside was proven to be photochemically stable and allows switching back and forth several times. These results open the way for the use of diarylethenes as photochromic compounds in DNA-based architectures.

Synthesis and photophysical properties of a porphyrin-perinaphthothioindigo dye

2013 ◽  
Vol 17 (08n09) ◽  
pp. 821-830 ◽  
Author(s):  
Kazuya Ogawa ◽  
Joanne Dy ◽  
Rena Maeda ◽  
Yasunori Nagatsuka ◽  
Kenji Kamada ◽  
...  
Keyword(s):  
Cross Section ◽  
Trans Isomer ◽  
Triple Bond ◽  
Photophysical Properties ◽  
Reference Compound ◽  
Photochromic Compounds ◽  
Two Photon ◽  
Enhancement Factors ◽  
Homo Lumo ◽  
Cis Isomer

A new porphyrin-perinaphthothioindigo composite, where porphyrin and perinaphthothioindigo dye are connected though a triple bond, was synthesized. In UV-vis absorption spectra of the composite, absorption originating from the trans-isomer appeared at 655 nm. Upon photoirradiation at > 700 nm, the intensity of this absorption decreased with increase of absorption of the cis-isomer around at 530 nm. The HOMO–LUMO absorption of the cis-isomer is blue-shifted by 125 nm compared to that of trans-isomer due to the lack of π-conjugation. The 2PA cross-section values obtained for both isomers were 2,000 and 700 GM, respectively. The value of 2,000 GM is of the largest class among the values reported for photochromic compounds. The enhancement factors by the connection of porphyrin to perinaphthothioindigo were found to be 3.5–3.9 by measuring cross-section values of bis(TMS-ethynyl)perinaphthothioindigo as the reference compound. Two-photon isomerization of the trans-isomer to the cis-isomer was successfully conducted using femtosecond pulses.

Two-photon excitation microscopy in cellular biophysics

1995 ◽  
Vol 53 ◽  
pp. 62-63
Author(s):  
David W. Piston ◽  
Brian D. Bennett ◽  
Robert G. Summers
Keyword(s):  
Confocal Microscopy ◽  
Laser Beam ◽  
Duty Cycle ◽  
Excited Electronic State ◽  
Input Power ◽  
Two Photon ◽  
Simultaneous Absorption ◽  
Photon Excitation ◽  
Very High ◽  
Two Photon Excitation

Two-photon excitation microscopy (TPEM) provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging and photochemistry. Two-photon excitation arises from the simultaneous absorption of two photons in a single quantitized event whose probability is proportional to the square of the instantaneous intensity. For example, two red photons can cause the transition to an excited electronic state normally reached by absorption in the ultraviolet. In practice, two-photon excitation is made possible by the very high local instantaneous intensity provided by a combination of diffraction-limited focusing of a single laser beam in the microscope and the temporal concentration of 100 femtosecond pulses generated by a mode-locked laser. Resultant peak excitation intensities are 106 times greater than the CW intensities used in confocal microscopy, but the pulse duty cycle of 10-5 maintains the average input power on the order of 10 mW, only slightly greater than the power normally used in confocal microscopy.

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