The interactions between aromatic molecules and metal nanoparticles are ubiquitous in nanotechnology. Currently, π-metal interactions under ambient conditions are well appreciated for VIIIB but not for IB metals. Here, we demonstrate the direct probing of π-metal interactions under ambient conditions with molecular specificity using surface-enhanced Raman spectroscopy (SERS), which reveals that aromatic hydrocarbons adsorb strongly from solution onto the surfaces of Ag and Au nanoparticles, provided there is no surface oxidation. Theoretical modeling shows that this adsorption is driven by dispersive π-metal interactions and that the aromatic molecules co-adsorb alongside surface ligands that are present initially on the nanosurface. Finding direct evidence for this long-neglected interaction has significant implications for various applications. This is demonstrated with SERS sensing of an aromatic drug molecule whose structure would typically suggest it to be weakly adsorbing, and indeed it is not detected on conventional Ag colloids due to surface oxidation, but it is found to adsorb strongly onto Au particles.

芳香分子和金属纳米粒子之间的相互作用在纳米技术中无处不在。目前，环境条件下的 π-金属相互作用对于 VIIIB 金属很受欢迎，但对 IB 金属则不然。在这里，我们展示了使用表面增强拉曼光谱 (SERS) 在环境条件下直接探测具有分子特异性的 π-金属相互作用，这表明芳香烃从溶液中强烈吸附到 Ag 和 Au 纳米颗粒的表面上，前提是没有表面氧化。理论模型表明，这种吸附是由分散的 π-金属相互作用驱动的，并且芳香分子与最初存在于纳米表面上的表面配体一起共吸附。为这种长期被忽视的相互作用寻找直接证据对各种应用具有重要意义。