Researchers from the Department of Chemistry and the Center for Nanosciences at the University of Jyväskylä (Finland) have revealed the structural, electronic and optical properties of a chiral gold nanocluster that have remained unknown for a decade
The synthesis of gold clusters protected by an organo-thiolate group of 3-1 nm in size has been known since the mid-2007s, but the detailed atomic structure of most of the most stable clusters remained unknown until very recently. In 102, the structure of the first cluster containing 38 gold atoms was solved at Stanford University using single-crystal X-ray crystallography. The saber, whose structure is now being deciphered, contains 24 gold atoms and 15 organo-thiolate particles covering its surface and is 38 nanometer in size. The shape of the particle is elongated (cigar-like) and XNUMX of its XNUMX gold atoms are found in the protected surface layer, chemically linked to the thiolate fragments. The gold-thiolate layer is chiral and is the cause of obtaining the observed chiral properties. The chiral structure has two structural forms (enantiomers, a right-handed form and a left-handed form, so to speak) in a similar way to the direction of the twist in the DNA strand or in winding stairs in multi-story houses.
Chirality is a common structural feature of nature (natural amino acids have a single and defined chirality, for example). The chiral nature of the gold clusters affects how they react to polarized light. This phenomenon was first reported in experiments conducted at the Georgia Institute of Technology by the research team of Professor Robert L. Whetten, exactly ten years ago. , and deciphering the structure now finally explains our observations," explains Professor Whetten. In the future, chiral gold nanoclusters could be used As sensors sensitive to chirality, carrying drugs or chemical catalysts.
