Dery Shahar, Kim Suhong, Tomaschun Gabriele, Berg Iris, Feferman Daniel, Cossaro Albano, Verdini Alberto, Floreano Luca, Klüner Thorsten, Toste F Dean, Gross Elad
Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Department of Chemistry, University of California, Berkeley, California 94720, United States.
J Phys Chem Lett. 2019 Sep 5;10(17):5099-5104. doi: 10.1021/acs.jpclett.9b01808. Epub 2019 Aug 21.
The development of chemically addressable N-heterocyclic carbene (NHC) based self-assembled monolayers (SAMs) requires in-depth understanding of the influence of NHC's anchoring geometry on its chemical functionality. Herein, it is demonstrated that the chemical reactivity of surface-anchored NO-functionalized NHCs (NO-NHCs) can be tuned by modifying the distance between the functional group and the reactive surface, which is governed by the deposition technique. Liquid deposition of NO-NHCs on Pt(111) induced a SAM in which the NO-aryl groups were flat-lying on the surface. The high proximity between the NO groups and the Pt surface led to high reactivity, and 85% of the NO groups were reduced at room temperature. Lower reactivity was obtained with vapor-deposited NO-NHCs that assumed a preferred upright geometry. The separation between the NO groups in the vapor-deposited NO-NHCs and the reactive surface circumvented their surface-induced reduction, which was facilitated only after exposure to harsher reducing conditions.
基于化学可寻址氮杂环卡宾（NHC）的自组装单分子层（SAMs）的发展需要深入了解NHC的锚定几何结构对其化学功能的影响。在此，证明了通过改变官能团与反应性表面之间的距离（由沉积技术决定），可以调节表面锚定的NO官能化NHC（NO-NHCs）的化学反应性。NO-NHCs在Pt(111)上的液相沉积诱导形成了一种SAM，其中NO-芳基基团平躺于表面。NO基团与Pt表面之间的高接近度导致了高反应性，并且85%的NO基团在室温下被还原。气相沉积的NO-NHCs呈现出优选的直立几何结构，其反应性较低。气相沉积的NO-NHCs中NO基团与反应性表面之间的距离避免了它们的表面诱导还原，只有在暴露于更苛刻的还原条件下才会促进这种还原。
