Redox-Active On-Surface Assembly of Metal鈥揙rganic Chains with Single-Site Pt(II)

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• 作者：Daniel Skomski ; Christopher D. Tempas ; Kevin A. Smith ; Steven L. Tait
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：July 16, 2014
• 年：2014
• 卷：136
• 期：28
• 页码：9862-9865
• 全文大小：349K
• ISSN：1520-5126

文摘

The formation and stabilization of well-defined transition-metal single sites at surfaces may open new routes to achieve higher selectivity in heterogeneous catalysts. Organic ligand coordination to produce a well-defined oxidation state in weakly reducing metal sites at surfaces, desirable for selective catalysis, has not been achieved. Here, we address this using metallic platinum interacting with a dipyridyl tetrazine ligand on a single crystal gold surface. X-ray photoelectron spectroscopy measurements demonstrate the metal鈥搇igand redox activity and are paired with molecular-resolution scanning probe microscopy to elucidate the structure of the metal鈥搊rganic network. Comparison to the redox-inactive diphenyl tetrazine ligand as a control experiment illustrates that the redox activity and molecular-level ordering at the surface rely on two key elements of the metal complexes: (i) bidentate binding sites providing a suitable square-planar coordination geometry when paired around each Pt, and (ii) redox-active functional groups to enable charge transfer to a well-defined Pt(II) oxidation state. Ligand-mediated control over the oxidation state and structure of single-site metal centers that are in contact with a metal surface may enable advances in higher selectivity for next generation heterogeneous catalysts.