Surface-Induced Changes in the Thermochromic Transformation of an Ionic Liquid Cobalt Thiocyanate Complex

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Details zur Publikation

Autor(en): May B, Hoenle M, Heller B, Greco F, Bhuin RG, Steinrück HP, Maier F
Zeitschrift: Journal of Physical Chemistry Letters
Verlag: AMER CHEMICAL SOC
Jahr der Veröffentlichung: 2017
Band: 8
Heftnummer: 6
Seitenbereich: 1137-1141
ISSN: 1948-7185


Abstract


We demonstrate that a thermodynamic. complex equilibrium within an ionic liquid film can be significantly influenced by the presence of the liquid-vacuum interface. Using surface sensitive X-ray photoelectron spectroscopy, we find that the temperature-driven transition from the blue-colored tetrahedral [Co(II) (NCS)(4)](2-) to the red-colored octahedral [Co(II) (NCS)(6)](4-) complex already occurs within the outermost nanometers at around +4 degrees C as compared with -25 degrees C in the bulk. This thermochromic transformation in the near-surface region goes along with a loss in preferential surface orientation of free [SCN](-) anions and with a pronounced decrease in the complex density; both effects are attributed to the formation of a weakly bound solvation shell around the [Co(II) (NCS)(6)](4-) anion, leading to an effective complex dilution. Our results are not only relevant for high-surface area thin film systems, such as in sensor and catalysis applications, but also shed light on the role of ionic liquid surfaces in particular and liquid surfaces in general.



FAU-Autoren / FAU-Herausgeber

Bhuin, Radha Gobinda
Lehrstuhl für Physikalische Chemie II
Greco, Francesco
Lehrstuhl für Physikalische Chemie II
Heller, Bettina
Lehrstuhl für Physikalische Chemie II
Maier, Florian Dr.
Lehrstuhl für Physikalische Chemie II
May, Benjamin
Lehrstuhl für Physikalische Chemie II
Steinrück, Hans-Peter Prof. Dr.
Lehrstuhl für Physikalische Chemie II


Zitierweisen

APA:
May, B., Hoenle, M., Heller, B., Greco, F., Bhuin, R.G., Steinrück, H.-P., & Maier, F. (2017). Surface-Induced Changes in the Thermochromic Transformation of an Ionic Liquid Cobalt Thiocyanate Complex. Journal of Physical Chemistry Letters, 8(6), 1137-1141. https://dx.doi.org/10.1021/acs.jpclett.7b00142

MLA:
May, Benjamin, et al. "Surface-Induced Changes in the Thermochromic Transformation of an Ionic Liquid Cobalt Thiocyanate Complex." Journal of Physical Chemistry Letters 8.6 (2017): 1137-1141.

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Zuletzt aktualisiert 2018-07-08 um 00:10