Using SERS To Understand the Binding of N-Heterocyclic Carbenes to Gold Surfaces

Surface functionalization is an essential component of most applications of noble-metal surfaces. Thiols and amines are traditionally employed to attach molecules to noble-metal surfaces, but they have limitations. A growing body of research, however, suggests that N-heterocyclic carbenes (NHCs) can be readily employed for surface functionalization with superior chemical stability compared with thiols. We demonstrate the power of surface-enhanced Raman scattering combined with theory to present a comprehensive picture of NHC binding to gold surfaces. In particular, we synthesize a library of NHC isotopologues and use surface-enhanced Raman scattering to record the vibrational spectra of these NHCs while bound to gold surfaces. Our experimental data are compared with first-principles theory, yielding numerous new insights into the binding of NHCs to gold surfaces. In addition to these insights, we expect our approach to be a general method for probing the local surface properties of NHC-functionalized surfaces for their expanding use in sensing applications.

表面功能化是贵金属表面大多数应用的重要组成部分。传统上使用硫醇和胺将分子连接到贵金属表面，但它们存在局限性。然而，越来越多的研究表明，与硫醇相比，N - 杂环卡宾（NHCs）可方便地用于表面功能化，且具有优异的化学稳定性。我们展示了表面增强拉曼散射结合理论的强大作用，以全面呈现NHC与金表面结合的情况。特别是，我们合成了一个NHC同位素类似物库，并使用表面增强拉曼散射记录这些NHC在与金表面结合时的振动光谱。我们将实验数据与第一性原理理论进行了比较，对NHC与金表面的结合有了许多新的见解。除了这些见解之外，我们期望我们的方法成为一种通用方法，用于探究NHC功能化表面在传感应用中不断扩大使用时的局部表面性质。