The Bonding Situations in Ruthenium Chalcogenonitrosyl Compounds: A Physical Reasoning

This research presents, for the first time, a comprehensive and rigorous investigation of ruthenium(II) chalcogenonitrosyl bonding situations in two sets of coordination compounds: [Ru(NE)Cl₂(L_{OEt})] (1a-4a) and [Ru(NE)Cl₂(L_{OEt})]^- (1b-4b), where E = O, S, Se, Te. Prior to and following the monoelectronic reduction, the Ru-NE bonding situations were subjected to analysis. The calculated geometric parameters indicate that both the Ru-NE and N-E bond lengths are susceptible to variation depending on the nature of the chalcogen employed. Furthermore, the results demonstrate that the monoelectronic reduction process serves to diminish the N=E double bond character. The generalized Kohn-Sham energy decomposition analysis (GKS-EDA) was conducted to illustrate the Ru-NE bonding scenarios prior to and following the monoelectronic reduction. The results provide valuable insights into the nature of Ru(II)-NE (E = O, S, Se, Te) bonds, the influence of chalcogens on ruthenium compounds, as well as how the monoelectronic reduction affects the release of NE groups. The main findings indicate that the total interaction energy, prior to the monoelectronic reduction, is three to four times more stabilizing than in the reduced analogs, confirming that the reduction unequivocally enhances the lability of the Ru-NE bond even when heavier chalcogen analogues are employed.