Anchoring of a Carboxyl-Functionlized Norbornadiene Derivative to an Atomically-Defined Cobalt Oxide Surface

Schwarz M, Mohr S, Xu T, Döpper T, Weiß C, Civale K, Hirsch A, Görling A, Libuda J (2017)


Publication Language: English

Publication Type: Journal article

Publication year: 2017

Journal

Book Volume: 121

Pages Range: 11508-11518

DOI: 10.1021/acs.jpcc.7b02620

Abstract

We have investigated the anchoring of the molecular energy carrier norbornadiene (NBD) to an atomically defined oxide surface. To this end, we synthesized a carboxyl-functionalized NBD derivative, namely 1-(2$\prime$-norbornadienyl)pentanoic acid (NBDA), and deposited it by physical vapor deposition (PVD) under ultrahigh vacuum (UHV) conditions onto a well-ordered Co3O4(111) film grown on Ir(100). In addition, we performed a comparative growth study with benzoic acid (BA) under identical conditions which was used as a reference. The interaction and orientation of NBDA and BA with the oxide surface were monitored in situ during film growth by isothermal time-resolved infrared reflection--absorption spectroscopy (TR-IRAS), both below and above the multilayer desorption temperature. The thermal behavior and stability of the films were investigated by temperature-programmed IRAS (TP-IRAS), with help of density functional (DF) calculations. BA binds to Co3O4(111) under formation of a symmetric chelating carboxylate with the molecular plane oriented nearly perpendicular to the surface. At low temperature (130 K), intact BA physisorbs in form of dimers on top of the saturated monolayer. Upon annealing to 155 K, a reordering transition is observed, in which BA in the multilayer adopts a more flat-lying orientation. The BA multilayer desorbs at 220 K, whereas the surface-anchored BA monolayer is stable up to 400 K. At higher temperature (400--550 K), desorption and decomposition are observed. Very similar to BA, NBDA binds to Co3O4(111) by formation of a symmetric chelating carboxylate. In the multilayer, which desorbs at 240 K, hydrogen-bonded NBDA dimers are formed. Upon PVD of NBDA at 300 K, only a surface anchored carboxylate is stable. The anchored NBDA film shows a characteristic restructuring behavior as a function of coverage. At low coverage the NBDA, adopts a flat-lying structure in which the norbornadiene unit interacts with the Co3O4 surface. With increasing coverage, the norbornadiene units detach from the oxide and the NBDA adopts an upright-standing orientation. Similar to BA, the anchored film is stable up to 400 K and decomposes in the temperature region between 400 and 550 K, leaving behind hydrocarbon residues on the oxide surface.

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APA:

Schwarz, M., Mohr, S., Xu, T., Döpper, T., Weiß, C., Civale, K.,... Libuda, J. (2017). Anchoring of a Carboxyl-Functionlized Norbornadiene Derivative to an Atomically-Defined Cobalt Oxide Surface. Journal of Chemical Physics, 121, 11508-11518. https://dx.doi.org/10.1021/acs.jpcc.7b02620

MLA:

Schwarz, Matthias, et al. "Anchoring of a Carboxyl-Functionlized Norbornadiene Derivative to an Atomically-Defined Cobalt Oxide Surface." Journal of Chemical Physics 121 (2017): 11508-11518.

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