Quantifying the Bonding Strength of Gold-Chalcogen Bonds in Block Copolymer Systems

Gold-chalcogen interactions are ubiquitous in gold biological and medicinal systems. Understanding the nature of these interactions can provide the basis for regulating their structures and functionalities, and a reasonable way to interpret the differences in various properties. However, the relative strength of gold-chalcogen bonds remains controversial, and the conclusions of many related works are inconsistent. Thus, in this work, we successfully quantified the relative strength of Au-X (X=S, Se, and Te from chalcogenide-containing A-B-A type block copolymers) interactions at the single-molecule level through single-molecule force spectroscopy (SMFS) from a kinetic point of view and quantum chemical studies from a thermodynamic point of view. Both sets of results suggested that the strength of the Au-X bonds decreases as Au-Te>Au-Se>Au-S. Our findings unveiled the relative strength and nature of gold-chalcogen interactions, which may help expand their application in electronics, catalysis, medicine and many other fields.