Controlling the Self-Metalation Rate of Tetraphenylporphyrins on Cu(111) via Cyano Functionalization

Lepper M, Köbl J, Zhang L, Meusel M, Hölzel H, Lungerich D, Jux N, De Siervo A, Meyer B, Steinrück HP, Marbach H (2018)


Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Publisher: WILEY-V C H VERLAG GMBH

Book Volume: 57

Pages Range: 10074-10079

Journal Issue: 32

DOI: 10.1002/anie.201803601

Abstract

The reaction rate of the self-metalation of free-base tetraphenylporphyrins (TPPs) on Cu(111) increases with the number of cyano groups (n=0, 1, 2, 4) attached at the para positions of the phenyl rings. The findings are based on isothermal scanning tunneling microscopy (STM) measurements. At room temperature, all investigated free-base TPP derivatives adsorb as individual molecules and are aligned with respect to densely packed Cu substrate rows. Annealing at 400K leads to the formation of linear dimers and/or multimers via CN-Cu-CN bonds, accompanied by self-metalation of the free-base porphyrins following a first-order rate equation. When comparing the non-cyano-functionalized and the tetracyano-functionalized molecules, we find a decrease of the reaction rate by a factor of more than 20, corresponding to an increase of the activation energy from 1.48 to 1.59eV. Density functional theory (DFT) calculations give insights into the influence of the peripheral electron-withdrawing cyano groups and explain the experimentally observed effects.

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APA:

Lepper, M., Köbl, J., Zhang, L., Meusel, M., Hölzel, H., Lungerich, D.,... Marbach, H. (2018). Controlling the Self-Metalation Rate of Tetraphenylporphyrins on Cu(111) via Cyano Functionalization. Angewandte Chemie International Edition, 57(32), 10074-10079. https://dx.doi.org/10.1002/anie.201803601

MLA:

Lepper, Michael, et al. "Controlling the Self-Metalation Rate of Tetraphenylporphyrins on Cu(111) via Cyano Functionalization." Angewandte Chemie International Edition 57.32 (2018): 10074-10079.

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