Theoretical investigation into coordination and selectivity of uranyl‐unilateral benzotriazole salophens (X = O/S) for R/S‐triadimefons

The design of new uranyl‐ligands (uranyl‐Ls) is of great significance for the separation and utilization of uranium. In this paper, the triazole group was introduced into uranyl‐salophen (uranyl‐S) to form new asymmetric uranyl‐unilateral benzotriazole salophen (uranyl‐UBS); we further replaced two oxygen atoms of uranyl‐UBS with two sulfur atoms to generate uranyl‐unilateral benzotriazole thio‐salophen (uranyl‐UBTS) as a new receptor. Then, we comprehensively explored coordination models of uranyl‐UBS and uranyl‐UBTS with R/S‐triadimefons (R/S‐TDFs) enantiomers as the guests using density functional theory calculations at the B3LYP//RECP/6‐311G** level; we then investigated enantioselectivity recognition of the new receptors to the guests R/S‐TDFs. The results indicated that the uranium atoms of the receptors uranyl‐S, uranyl‐UBS and uranyl‐UBTS could coordinate with the carbonyl oxygens in guests R/S‐TDFs to form complexes of guest‐receptors R/S‐TDFs‐uranyl‐Ls that exhibited two stable V‐shaped structures with quite different properties. It was found that the coordination ability to the guests R/S‐TDFs is uranyl‐UBTS > uranyl‐UBS > uranyl‐S, while the enantioselectivity for the guests is uranyl‐UBTS > uranyl‐S > uranyl‐UBS and, when the receptor is the same, R‐TDF has stronger coordination ability than S‐TDF. These results provide information and theoretical supports for the experiments of asymmetric uranyl‐UBS with R/S‐TDFs, and produce a reference for further exploring the coordination characteristics of asymmetric uranyl‐salophen with the triazole derivatives. We designed an asymmetric unilateral benzotriazole salophen (UBS), further constructed a unilateral benzotriazole thiosalophen (UBTS) and uranyl‐UBTS by substituting two oxygens with sulfur atoms in UBS. Then, three receptors of uranyl‐S, uranyl‐UBS and uranyl‐UBTS were selectively coordinated with two chiral isomers of R/S‐types to produce different guest‐receptors of R/S‐TDFs‐uranyl‐Ls with various spatial structures and properties. This work will provide useful references for design of new uranyl‐salophens and for experimental study on molecular recognition of chiral isomers.