JoVE Journal > Chemistry
Summary
Abstract
Introduction
Protocol
Resultados
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Acknowledgements
Materials
Referências
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Química

Nye teknikker til at observere strukturdynamik Photoresponsive flydende krystaller

Published: May 29, 2018
doi:
10.3791/57612
, , , , , ,
1Graduate School of Natural Science and Technology,Okayama University, 2Graduate School of Science,Kyoto University, 3Center for Computational Sciences,University of Tsukuba, 4Graduate School of Science,Kyushu University

Summary

Vi præsenterer her, protokoller af differential-påvisning analyser af tidsopløst infrarød vibrationelle spektroskopi og elektron diffraktion, som aktiverer observationer af deformationer af lokale strukturer omkring photoexcited molekyler i en søjleformede flydende krystal, giver en atomic perspektiv på forholdet mellem strukturen og dynamikken i dette photoactive materiale.

Abstract

Vi diskuterer i denne artikel de eksperimentelle målinger af molekylerne i flydende krystaller (LC) fase ved hjælp af tidsopløst infrarød (IR) vibrationelle spektroskopi og tidsopløst elektron diffraktion. Flydende krystal fase er en vigtig sag, der eksisterer mellem de faste og flydende faser og det er almindeligt i naturlige systemer såvel som i økologisk elektronik. Flydende krystaller er orientationally bestilt men løst pakket, og derfor, interne konformationer og tilpasninger af de molekylære komponenter af LCs kan ændres ved ekstern stimuli. Selv om avancerede tidsopløst diffraktion teknikker har afsløret Pico-skala molecular dynamics af enkelte krystaller og polycrystals, direkte observationer af pakning strukturer og ultrahurtig dynamikken i bløde materialer har været hæmmet af sløret diffraktion mønstre. Vi rapporterer her, tidsopløst vibrationelle IR-spektroskopi og elektron diffractometry at erhverve ultrahurtig snapshots af et kolonneformat LC materiale forsynet med en photoactive kerne gruppe. Differential-påvisning analyser af kombinationen af tidsopløst IR vibrationelle spektroskopi og elektron diffraktion er kraftfulde værktøjer til kendetegner strukturer og lysinducerede dynamikken i bløde materialer.

Introduction

Flydende krystaller (LCs) har en række funktioner og er meget udbredt i videnskabelige og teknologiske applikationer1,2,3,4,5,6. LCs adfærd kan tilskrives deres orientational bestilling samt at deres molekyler høj mobilitet. En molekylær struktur af LC materialer er typisk karakteriseret ved en mesogen kerne og lang, fleksibel kulstof kæder, der sikrer høj mobilitet af LC molekyler. Under eksterne stimuli7,8,9,10,11,12,13,14,15 , såsom lys, elektriske felter, ændringer i temperatur eller mekanisk pres, lille intra- og intermolekylære beslutningsforslag af LC molekyler årsag drastiske strukturel omorganisering i system, fører til dets funktionelle opførsel. For at forstå funktionerne af LC materialer, er det vigtigt at bestemme den molekylære skala struktur i LC fase og identificere vigtige beslutningsforslag af molekylære konformationer og pakning deformationer.

Røntgen diffraktion (XRD) er almindeligvis ansat som et effektivt redskab til bestemmelse af strukturer af LC materialer16,17,18. Dog er diffraktionsmønster med oprindelse fra en funktionel stimuli-responderende kerne ofte skjult af en bred halo mønster fra lange kulstof kæder. En effektiv løsning på dette problem er fastsat af tidsopløst diffraktion analyse, som giver mulighed for direkte observationer af Molekylær dynamik ved hjælp af photoexcitation. Denne teknik ekstrakter strukturelle oplysninger om den photoresponsive aromatiske gruppe ved hjælp af forskellene mellem de diffraktion mønstre fremstillet før og efter photoexcitation. Disse forskelle giver middel til at fjerne baggrundsstøjen og direkte observere de strukturelle ændringer af interesse. Analyser af differential diffraktion mønstre afsløre de modulerede signaler fra den photoactive gruppe alene og dermed udelukke den skadelige diffraktion fra ikke-photoresponsive kulstof kæder. En beskrivelse af denne analysemetode differential diffraktion er fastsat i Herskind, M. mfl19.

Tidsopløst diffraktion målinger kan give strukturelle oplysninger om de atomare rearrangementer, der opstår under fase overgangen i materialer20,21,22,23, 24 , 25 , 26 , 27 , 28 , 29 og kemiske reaktioner blandt molekyler30,31,32,33,34. Med disse programmer i tankerne, der er gjort bemærkelsesværdige fremskridt i udviklingen af funklende og ultrakorte pulserende X-ray35,36 og elektron37,38,39 , 40 kilder. Dog tidsopløst diffraktion er kun blevet anvendt til simple, isolerede molekyler eller til enkelt – eller poly-krystaller, i stærkt beordrede uorganiske gitter eller organiske molekyler producerer godt løst diffraktion mønstre giver struktur oplysninger. Derimod har ultrahurtig strukturelle analyser af mere komplekse bløde materialer været hæmmet på grund af deres mindre ordnede faser. I denne undersøgelse demonstrere vi brugen af tidsopløst elektron diffraktion samt forbigående absorption spektroskopi og tidsopløst infrarød (IR) vibrationelle spektroskopi til at karakterisere den strukturelle dynamik af photoactive LC materialer ved hjælp af dette diffraktion-udvundet metode19.

Protocol

1.time-løst infrarød vibrationelle spektroskopi Forberedelse af prøver Løsning: Opløses π-udvidet cyclooctatetraene (π-barneseng) molekyler i dichlormethan med ordentlig koncentration (1 mmol/L). LC fase: Smelt π-barneseng pulver på en calciumfluorid (CaF2) substrat ved hjælp af varmeplade ved temperatur på 100 ° C. Cool prøve ved en stuetemperatur.Bemærk: Vi har brug at vælge et materiale (CaF2 eller barium fluor (BaF2))…

Representative Results

Vi valgte en sadel-formet π-barneseng skelet43,44 som photoactive core enhed af LC-molekylet, fordi det danner en veldefineret stabling kolonnestruktur, og fordi den centrale otte-leddede COT ring forventes at vise en lysinducerede konformationelle ændre til en flad form på grund af de exciterede tilstand aromaticitet19,45. Syntetisk proces af dette materiale er fastsat…

Discussion

De afgørende trin i processen under tidsopløst elektron diffraktion målingerne er at bevare den høje spænding (75 keV) uden nuværende udsving siden afstanden mellem fotokatode og anode plade er kun ~ 10 mm. Hvis aktuelt svinger over vifte af 0,1 µA før eller under forsøgene, øge acceleration spændingen op til 90 keV decharge og angive det igen til 75 keV. Denne konditionering proces der skal gøres, indtil nuværende svinger i rækken af 0,1 µA. Den passende design af elektron kilde med nok dielektrisk styrke…

Declarações

The authors have nothing to disclose.

Acknowledgements

Vi takker Dr. S. Tanaka på Tokyo Institute of Technology for tidsopløst IR vibrationelle spektroskopi målinger og Prof. M. Hara og Dr. K. Matsuo på Nagoya University XRD målinger. Vi takker også Prof. S. Yamaguchi på Nagoya University, Prof. R. Herges ved Kiels Universitet og Prof. R. J. D. Miller på Max Planck Institute for struktur og dynamik af sagen for værdifuld diskussion.

Dette arbejde er støttet af japansk videnskab teknologi (JSO), PRESTO, til finansiering af projekter “molekylære teknologi og oprettelse af nye funktioner” (Grant antallet af JPMJPR13KD, JPMJPR12K5 og JPMJPR16P6) og “Kemisk omdannelse af lysenergi”. Dette arbejde er også delvist understøttet af JSP’ER Grant numre JP15H02103, JP17K17893, JP15H05482, JP17H05258, JP26107004 og JP17H06375.

Materials

Chirped pulse amplifier Spectra Physics Inc. Spitfire ACE For time-resolved IR vibration spectroscopy
Chirped pulse amplifier  Spectra Physics Inc. Spitfire XP For time-resolved electron diffractometry
Femtosecond laser Spectra Physics Inc. Tsunami For time-resolved IR vibration spectroscopy
Femtosecond laser Spectra Physics Inc. Tsunami For time-resolved electron diffractometry
Optical parametric amplifier Light Conversion Ltd. TOPAS prime
64-channel mercury cadmium tellurium IR detector array Infrared Systems Development Corporation FPAS-6416-D
FT-IR spectrometer Shimadzu Corporation IR Prestige-21
High voltage supply Matsusada precision HER-100N0.1
Rotary pump Edwards RV12
Molecular turbo pumps Agilent Technologies Japan, Ltd. Twis Torr 304FS
Vacuum gauges Pfeiffer vacuum systems gmbh PKR251 For ICF70 flange
Vacuum monitors Pfeiffer vacuum systems gmbh TPG261
Fiber coupled CCD camera Andor Technology Ltd. iKon-L HF
BaF2 and CaF2 substrates Pier optics Thickness 3 mm
AgGaS2 crystal Phototechnica Corporation Custom-order
BBO crystals Tokyo Instruments, Inc. SHG θ=29.2 deg
THG θ=44.3 deg
calcite crystals Tokyo Instruments, Inc. Thickness 1mm
Optical mirrors Thorlabs PF10-03-F01
PF10-03-M01
UM10-45A		 Al coat mirrors
Au coat mirrors
Ultrafast mirrors
Optical mirrors HIKARI,Inc. Broadband mirrors
Dichroic mirrors HIKARI,Inc. Custom-order
Reflection: 266 nm
Transmission: 400, 800 nm
Optical chopper Newport Corporation 3501 optical chopper
Optical shutters Thorlabs Inc. SH05/M
SC10
Optical shutters SURUGA SEIKI CO.,LTD. F116-1
Beam splitters Thorlabs Inc. BSS11R
Fused-silica lenses Thorlabs Inc. LA4663
LA4184
BaF2 lens Thorlabs Inc. LA0606-E
Polarized mirrors Sigmakoki Co.,Ltd Custom-order
Designed for 800 nm
Reflection: s-polarized light
Transmission : p-polarized light
Half waveplate Thorlabs Inc. WPH05M-808
Mirror mounts Thorlabs Inc. POLARIS-K1
KM100		 Kinematic mirror mounts
Mirror mounts Sigmakoki Co.,Ltd MHAN-30M
MHAN-30S		 Gimbal mirror mounts
Mirror mounts Newport Corporation ACG-3K-NL Gimbal mirror mounts
Variable ND filters Thorlabs Inc. NDC-25C-2M
Beam splitter mounts Thorlabs Inc. KM100S
Lens mounts Thorlabs Inc. LMR1/M
Rotational mounts Thorlabs Inc. RSP1/M
Retroreflector Edmund Optics 63.5MM X 30" EN-AL 
spectrometers ocean photonics USB-4000
Power meter Ophir 30A-SH Used for intensity monitor of CPA
Power meter Thorlabs Inc. S120VC
PM100USB		 Used for intensity measurements of pump pulse
Photodiodes Thorlabs Inc. DET36A/M
DET25K/M
DC power supply TEXIO PW18-1.8AQ Used for magnetic lens
Magnetic lens Nissei ETC Co.,Ltd Custom-order
Stages Newport Corporation M-MVN80V6
LTAHLPPV6		 Used for magnetic lens
Stage controller Newport Corporation SMC100
Stages  Sigmakoki Co.,Ltd SGSP20-35(X)
SGSP20-85(X)		 Used for sample position
Stages  Sigmakoki Co.,Ltd SGSP26-200(X)
OSMS26-300(X)		 Used for delay time generator
Stage controller Sigmakoki Co.,Ltd SHOT-304GS
Picoammeter Laboratory built
spin coater MIKASA Co.,Ltd 1H-D7
hot plate IKA®  C-MAG HP7
SiN wafer Silson Ltd Custom-order
KOH aqueous solution (50%) Hiroshima Wako Co.,Ltd. 168-20455
Chloroform Hiroshima Wako Co.,Ltd. 038-18495
Dichloromethane Hiroshima Wako Co.,Ltd. 132-02456
Personal computers for the controlling programs Epson Corporate Endeavor MR7300E-L 32-bit operation system
Program for the control the equipment National Instruments Corporation Labview2016
Program for the data analysis The MathWorks, Inc. Matlab2015b
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Referências

  1. Van Haaren, J., Broer, D. In search of the perfect image. Chem. Ind. 24, 1017-1021 (1998).
  2. Goodby, J. W., Collings, P. J., Kato, T., Tschierske, C., Gleeson, H. F., Raynes, P. . Handbook of Liquid Crystals. , (2014).
  3. Li, Q. . Liquid Crystal Beyond Displays. , (2012).
  4. Kato, T. Self-assembly of phase-segregated liquid crystal structures. Science. 295, 2414-2418 (2002).
  5. Fleismann, E. K., Zentel, R. Liquid-Crystalline Ordering as a Concept in Materials Science: From Semiconductors to Stimuli-Responsive Devices. Angew. Chem. Int. Ed. 52, 8810-8827 (2013).
  6. Sergeyev, S., Pisula, W., Geerts, Y. H. Discotic liquid crystals: a new generation of organic semiconductors. Chem. Soc. Rev. 36, 1902-1929 (2007).
  7. Goodby, J. W. Mesogenic molecular crystalline materials. Curr. Opin. Solid State Mater. Sci. 4, 361-368 (1999).
  8. Ichimura, K. Photoalignment of Liquid-Crystal Systems. Chemical Reviews. 100, 1847-1873 (2000).
  9. Ikeda, T. Photomodulation of liquid crystal orientations for photonic applications. J. Mater. Chem. 13, 2037-2057 (2003).
  10. Browne, W. R., Feringa, B. L. Making molecular machines work. Nat. Nanotech. 1, 25-35 (2006).
  11. Ikeda, T., Mamiya, J., Yu, Y. Photomechanics of liquid-crystalline elastomers and other polymers. Angew. Chem., Int. Ed. 46, 506-528 (2007).
  12. Sagara, Y., Kato, T. Brightly Tricolored Mechanochromic Luminescence from a Single-Luminophore Liquid Crystal: Reversible Writing and Erasing of Images. Angew. Chem. Int. Ed. 50, 9128-9132 (2011).
  13. Miyajima, D., et al. Ferroelectric columnar liquid crystal featuring confined polar groups within core-shell architecture. Science. 336, 209-213 (2012).
  14. White, T. J., Broer, D. J. Programmable and adaptive mechanics with liquid crystal polymer networks and elastomers. Nat. Mater. 14, 1087-1098 (2015).
  15. Saito, S., et al. Light-melt adhesive based on dynamic carbon frameworks in a columnar liquid-crystal phase. Nat. Commun. 7, 12094 (2016).
  16. Lagerwall, J. P. F., Giesselmann, F. Current Topics in Smectic Liquid Crystal Research. Chem. Phys. Chem. 7, 20-45 (2006).
  17. Yoon, H. G., Agra-Kooijman, D. M., Ayub, K., Lemieux, R. P., Kumar, S. Direct Observation of Diffuse Cone Behavior in de Vries Smectic-A and -C Phases of Organosiloxane Mesogens. Phys. Rev. Lett. 106, 087801 (2011).
  18. Takanishi, Y., Ohtsuka, Y., Takahashi, Y., Kang, S., Iida, A. Chiral doping effect in the B2 phase of a bent-core liquid crystal: The observation of resonant X-ray satellite peaks assigned to the 5/10 layer periodic structure. Euro. Phys. Lett. 109, 56003 (2015).
  19. Hada, M., et al. Structural Monitoring of the Onset of Excited-State Aromaticity in a Liquid Crystal Phase. J. Am. Chem. Soc. 139, 15792-15800 (2017).
  20. Cavalleri, A., et al. Femtosecond Structural Dynamics in VO2 during an Ultrafast Solid-Solid Phase Transition. Phys. Rev. Lett. 87, 237401 (2001).
  21. Hada, M., Okimura, K., Matsuo, J. Characterization of structural dynamics of VO2 thin film on c-Al2O3 using in-air time-resolved x-ray diffraction. Phys. Rev. B. 82, 153401 (2010).
  22. Eichberger, M., et al. Snapshots of cooperative atomic motions in the optical suppression of charge density waves. Nature. 468, 799-802 (2010).
  23. Ichikawa, H., et al. Transient photoinduced ‘hidden’ phase in a manganite. Nat. Mater. 10, 101-105 (2011).
  24. Hada, M., Okimura, K., Matsuo, J. Photo-induced lattice softening of excited-state VO2. Appl. Phys. Lett. 99, 051903 (2011).
  25. Zamponi, F., Rothhardt, P., Stingl, J., Woerner, M., Elsaesser, T. Ultrafast large-amplitude relocation of electronic charge in ionic crystals. P. Natl. Acad. Sci. USA. 109, 5207-5212 (2012).
  26. Beaud, P., et al. A time-dependent order parameter for ultrafast photoinduced phase transitions. Nat. Mater. 13, 923-927 (2014).
  27. Morrison, V. R., et al. A photoinduced metal-like phase of monoclinic VO revealed by ultrafast electron diffraction. Science. 346, 445-448 (2014).
  28. Han, T. -. R. T., et al. Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography. Sci. Adv. 5, 1400173 (2015).
  29. Waldecker, L., et al. Time-domain separation of optical properties from structural transitions in resonantly bonded materials. Nat. Mater. 14, 991-995 (2015).
  30. Minitti, M. P., et al. Imaging Molecular Motion: Femtosecond X-Ray Scattering of an Electrocyclic Chemical Reaction. Phys Rev. Lett. 114, 255501 (2015).
  31. Kim, K. H., et al. Direct observation of bond formation in solution with femtosecond X-ray scattering. Nature. 518, 385-389 (2015).
  32. Gao, M., et al. Mapping molecular motions leading to charge delocalization with ultrabright electrons. Nature. 496, 343-346 (2013).
  33. Ishikawa, T., et al. Direct observation of collective modes coupled to molecular orbital-driven charge transfer. Science. 350, 1501-1505 (2015).
  34. Xian, R., et al. Coherent ultrafast lattice-directed reaction dynamics of triiodide anion photodissociation. Nat. Chem. 9, 516-522 (2017).
  35. Chapman, H. N., et al. Femtosecond X-ray protein nanocrystallography. Nature. 470, 73-77 (2011).
  36. Ishikawa, T., et al. A compact X-ray free-electron laser emitting in the sub-ångström region. Nature Photonics. 6, 540-544 (2012).
  37. Zewail, A. H. Four-dimensional electron microscopy. Science. 328, 187-193 (2010).
  38. Sciaini, G., Miller, R. J. D. Femtosecond electron diffraction: heralding the era of atomically resolved dynamics. Rep. Prog. Phys. 74, 096101 (2011).
  39. Hada, M., Pichugin, K., Sciaini, G. Ultrafast structural dynamics with table top femtosecond hard X-ray and electron diffraction setups. Euro. Phys. J. Special Topic. 222, 1093-1123 (2013).
  40. Miller, R. J. D. Mapping atomic motions with ultrabright electrons: the chemists’ gedanken experiment enters the lab frame. Annu. Rev. Phys. Chem. 65, 583-604 (2014).
  41. Seki, T., Murase, T., Matsuo, J. Cluster size dependence of sputtering yield by cluster ion beam irradiation. Nucl. Instrum. Methods Phys. Res. B. 242, 179-181 (2006).
  42. Mueller, C., Harb, M., Dwyer, J. R., Miller, R. J. D. Nanofluidic Cells with Controlled Pathlength and Liquid Flow for Rapid, High-Resolution In Situ Imaging with Electrons. J. Phys. Chem. Lett. 4, 2339-2347 (2013).
  43. Mouri, K., Saito, S., Yamaguchi, S. Highly Flexible π-Expanded Cyclooctatetraenes: Cyclic Thiazole Tetramers with Head-to-Tail Connection. Angew. Chem. Int. Ed. 51, 5971-5975 (2012).
  44. Mouri, K., Saito, S., Hisaki, I., Yamaguchi, S. Thermal 8π electrocyclic reaction of heteroarene tetramers: new efficient access to π-extended cyclooctatetraenes. Chem. Sci. 4, 4465-4469 (2013).
  45. Rosenberg, M., Dahlstrand, C., Kilså, K., Ottosson, H. Excited State Aromaticity and Antiaromaticity: Opportunities for Photophysical and Photochemical Rationalizations. Chem. Rev. 114, 5379-5425 (2014).
  46. Kato, T., Mizoshita, N., Kishimoto, K. Functional Liquid-Crystalline Assemblies: Self-Organized Soft Materials. Angew. Chem. Int. Ed. 45, 38-68 (2006).
  47. Rosen, B. M., et al. Dendron-Mediated Self-Assembly, Disassembly, and Self-Organization of Complex Systems. Chem. Rev. 109, 6275-6540 (2009).
  48. Fukazawa, N., et al. Time-Resolved Infrared Vibrational Spectroscopy of the Photoinduced Phase Transition of Pd(dmit)2 Salts Having Different Orders of Phase Transition. J. Phys. Chem. C. 117, 13187 (2013).
  49. Mukuta, T., et al. Infrared Vibrational Spectroscopy of [Ru(bpy)2(bpm)]2+ and [Ru(bpy)3]2+ in the Excited Triplet State. Inorg. Chem. 53, 2481-2490 (2014).
  50. Tanaka, S., Takahashi, K., Hirahara, M., Yagi, M., Onda, K. Characterization of the excited states of distal-. and proximal-.[Ru(tpy)(pynp)OH2]2+ in aqueous solution using time-resolved infrared spectroscopy. J. Photochem. Photobio. A. 313, 87-98 (2015).
  51. Mukuta, T., Tanaka, S., Inagaki, A., Koshihara, S., Onda, K. Direct Observation of the Triplet Metal-Centered State in [Ru(bpy)3]2+ Using Time-Resolved Infrared Spectroscopy. ChemistrySelect. 1, 2802-2807 (2016).
  52. Epp, S. W., et al. Time zero determination for FEL pump-probe studies based on ultrafast melting of bismuth. Str. Dyn. 4, 054308 (2017).
  53. Hada, M., et al. Cold ablation driven by localized forces in alkali halides. Nat. Commun. 5, 3863 (2014).
  54. Hada, M., et al. Ultrafast time-resolved electron diffraction revealing the nonthermal dynamics of near-UV photoexcitation-induced amorphization in Ge2Sb2Te5. Sci. Rep. 5, 13530 (2015).
  55. Hada, M., et al. Evaluation of Damage Layer in an Organic Film with Irradiation of Energetic Ion Beams. Jpn. J. Appl. Phys. 49, 036503 (2010).
  56. Hada, M., et al. Bandgap modulation in photoexcited topological insulator Bi2Te3 via atomic displacements. J. Chem. Phys. 145, 024504 (2016).
  57. Manz, S., et al. Mapping atomic motions with ultrabright electrons: towards fundamental limits in space-time resolution. Faraday Discuss. 77, 467-491 (2015).

Tags

Photoresponsive Liquid CrystalsStructural DynamicsTime-resolved IR Vibrational SpectroscopyDifferential IR SpectrumDifferential Electron DiffractionPi-COTLiquid Crystal Phase SampleTitanium-sapphire LaserChirped Pulse AmplifierMercury-cadmium-tellurium IR DetectorTransient SignalFlow CellMotorized StageLaser-induced Damage

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Hada, M., Saito, S., Sato, R., Miyata, K., Hayashi, Y., Shigeta, Y., Onda, K. Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals. J. Vis. Exp. (135), e57612, doi:10.3791/57612 (2018).
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