Does gold cluster promote or scavenge radicals? A controversy at DFT. (25th October 2017)

• Record Type: Journal Article
• Authors: Ahmadi, Aliakbar; Kassaee, Mohammad Zaman; Fattahi, Alireza
• Is Part Of: Journal of physical organic chemistry. Volume 31:Number 3(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-10-25
• Subjects: DFT -- gold cluster -- NBO and AIM analyses -- scavenging radical; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.3776
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: Anticancer character of gold cluster has been indicated through its free radical scavenging properties. This is in contrast to its free radical promoting ability suggested by other workers. Here, we address this controversy by probing the stabilizing effects of Au3 cluster on RO vs its impacts on RO–H bond dissociation enthalpy, at B3LYP/ LACVP+* level (R═H, methyl, ethyl, n ‐propyl, i ‐propyl, n ‐butyl, t ‐butyl, and phenyl). In the presence of Au3 cluster, bond dissociation enthalpy of O–H bond and the spin density at the RO oxygen are reduced dramatically. These are clear evidences for both the Au3 facilitation of the RO–H bond breakage and its scavenging of RO radical. Since O–Au anchoring bond is responsible for the interaction of Au3 cluster and ROH (or RO ), its nature was interpreted by means of the quantum theory of atoms in molecules and the natural bond orbital. The results indicate that O–Au bond is stronger and has more covalent character in RO –Au3 than in ROH–Au3 . The interaction of Au3 cluster with RO is 1.5 to 3 times more than that with ROH. As a result, gold cluster scavenging property appears more prominent than its free radical initiation activity. Abstract : Anticancer character of gold cluster has been indicated through its free radical scavenging properties, which is in contrast to its free radical promoting abilities. Hence, the stabilizing effect of Au3 cluster on RO vs its impacts on RO–H bond dissociation enthalpy (BDE) is demonstrated at DFT.