Gold at crossroads of radical generation and scavenging at density functional theory level: Nitrogen and oxygen free radicals versus their precursors in the face of nanogold. (24th August 2020)

• Record Type: Journal Article
• Authors: Ahmadi, Aliakbar; Kassaee, Mohamad Z.; Ayoubi‐Chianeh, Mojgan; Fattahi, Alireza
• Is Part Of: Journal of physical organic chemistry. Volume 34:Number 1(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-24
• Subjects: DFT -- gold nanocluster -- radical scavenging -- RNS -- ROS; Chemistry, Physical organic -- Periodicals; 547.1
• DOI: 10.1002/poc.4126
• Languages: English
• ISSNs: 0894-3230

Abstract

Abstract: In our previous report ( J. Phys. Org. Chem., 2017), we discussed the dual behavior of gold nanocluster (Au3 NC), where it scavenged reactive oxygen species (ROS) while promoted their generation to a lesser extent. Continuing this quest, we investigate the effects of Au3 NC on common reactive nitrogen species (RNS: ON˙ and ON˙O) and their precursors (ONH and ONOH, respectively), at B3LYP/LACVP+* level of theory. We compare the results with those of prevalent ROS (HO˙ and HOO˙) and their precursors (HOH and HOOH, respectively). To this end, various parameters are probed such as binding energy ( E b ), bond dissociation energy (BDE), bond lengths, Mullikan spin density (MSD), critical point (CP) eigenvalues (atoms in molecules [AIM] analysis), and natural bond orbital (NBO) analysis including natural population analysis (NPA) and change of charge transfer energy (Δ E CT ). Our results show that in the presence of Au3 NC, BDEs of the NH and OH bonds increase in both ONHAu3 (1 ) and ONOHAu3 (2 ) compared with their free forms (ONH and ONOH, respectively). In other words, the tendency to dissociate these bonds and form their corresponding RNS (1′ and 2′ ) decreases in the presence of gold. This is exactly the opposite of what is observed for the OH bonds in HOHAu3 (3 ), HOOHAu3 (4 ), and their corresponding ROS (3′ and 4′ ). Therefore, we can conclude that gold shows a different behavior in the face of RNS compared with ROS where it is a better scavenger of ROS than RNS. Abstract : In our previous report ( J. Phys. Org. Chem., 2017), we discussed the dual behavior of gold nanocluster (Au3 NC), where it scavenged reactive oxygen species (ROS) while promoted their generation to a lesser extent. Continuing this quest, we investigate the effects of Au3 NC on common reactive nitrogen species (RNS: O=N˙ and O=N˙O) and their precursors (O=NH and O=NOH, respectively), at B3LYP/ LACVP+* level of theory.