Ligands bind reversibly to metal porphyrins in processes such as molecular recognition, electron transport and catalysis. These chemically relevant processes are ubiquitous in biology and are important in technological applications. In this article, we focus on the current advances in ligand binding to metal porphyrin receptors noncovalently bound at the solution/solid interface. In particular, we restrict ourselves to studies at the single molecule level. Dynamics of the binding/dissociation process can be monitored by scanning tunneling microscopy (STM) and can yield both qualitative and quantitative information about ligand binding affinity and the energetics that define a particular ligation reaction. Molecular and time dependent imaging can establish whether the process under study is at equilibrium. Ligand-concentration-dependent studies have been used to determine adsorption isotherms and thermodynamic data for processes occurring at the solution/solid interface. In several binding reactions, the solid support acted as an electron-donating fifth coordination site, thereby significantly changing the metal porphyrin receptor’s affinity for exogenous ligands. Supporting calculations provide insight into the metalloporphyrin/support and ligand–metalloporphyrin/support interactions and their energetics.

中文翻译：

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可逆配体在溶液/固体界面与金属卟啉结合的单分子水平研究

配体在分子识别、电子传输和催化等过程中可逆地与金属卟啉结合。这些化学相关过程在生物学中无处不在，在技术应用中也很重要。在本文中，我们关注配体与在溶液/固体界面非共价结合的金属卟啉受体结合的当前进展。特别是，我们将自己限制在单分子水平上的研究。结合/解离过程的动力学可以通过扫描隧道显微镜 (STM) 进行监测，并且可以产生关于配体结合亲和力和定义特定连接反应的能量学的定性和定量信息。分子和时间依赖性成像可以确定所研究的过程是否处于平衡状态。与配体浓度相关的研究已用于确定在溶液/固体界面处发生的过程的吸附等温线和热力学数据。在几个结合反应中，固体支持物作为供电子的第五配位点，从而显着改变了金属卟啉受体对外源性配体的亲和力。支持计算提供了对金属卟啉/载体和配体-金属卟啉/载体相互作用及其能量学的深入了解。