Solution-phase dynamics of DNA-stabilized metal quantum clusters: A Chiroptical spectroscopic approach

Abstract

DNA-stabilized metal quantum clusters are an emerging class of atomically precise chiral materials. Despite the inherent chirality and dynamic conformational landscape of DNA, chiroptical properties and structural dynamics of these clusters are poorly known. Here we present structural dynamics and dynamic chiral response of DNA-stabilized metal quantum clusters in solution probed using circular dichroism (CD) spectroscopy. CD spectroscopy reveals that stacking and helicity of orientation of nucleobases of the DNA ligands in these clusters are significantly different from that of the unbound DNA ligands. Our study reveals temperature-dependent, reversible, dynamic chiral response of these clusters in solution. No chirality inversion was observed for these clusters across a wide range of temperature, indicating that these clusters are structurally robust which is in contrary to what one would expect from dynamic nature of their DNA ligands. We hope that our work will stimulate further efforts to unravel the structural dynamics and its implications on the chiroptical properties of this new class of atomically precise matter.