First Trifluoromethylated Phenanthrolinediamides: Synthesis, Structure, Stereodynamics and Complexation with Ln(III)

Abstract

The first examples of 1,10-phenanthroline-2,9-diamides bearing CF3-groups on the side amide substituents were synthesized. Due to stereoisomerism and amide rotation, such complexes have complicated behavior in solutions. Using advanced NMR techniques and X-ray analysis, their structures were completely elucidated. The possibility of the formation of complex compounds with lanthanoids nitrates was shown, and the constants of their stability are quantified. The results obtained are explained in terms of quantum-chemical calculations.

First Example of Fluorinated Phenanthroline Diamides: Synthesis, Structural Study, and Complexation with Lanthanoids

“…As an example, 1 H NMR spectra of 7c in benzene-d 6 at 25 °C and 60 °C are shown in Figure 3 . This phenomenon has already been studied by us earlier on the example of diamides of a similar structure [ 7 , 9 ]. The full assignment of the signals in the NMR spectra was done using 2D and 19 F NMR spectroscopy methods [ 9 ].…”

“…On the other hand, such structural diversity permits fine-tuning of the ligand properties. Recently, serious attention has been paid to such phenanthroline diamides which have various substituents in the aromatic core, such as chlorine atoms [ 6 , 7 , 8 , 9 ], alkoxy groups [ 3 , 10 ], and others.…”

2-Methylpyrrolidine derived 1,10-phenanthroline-2,9-diamides: promising extractants for Am(iii)/Ln(iii) separation

“…However, the formation of 2 : 1 complexes for all lanthanides was not observed under the same conditions. 32 Comparing the values log β of the binding constants for Nd(III) and Eu(III), determined in methanol 38,40 for L1, with the values log β from Table 4, we note that the latter are significantly higher. Besides, no 2 : 1 complexes were detected in methanol.…”

“…Recently we completely elucidated the structure of similar phenanthrolinediamides bearing CF 3 groups at pyrrolidine substituents using advanced NMR techniques and X-ray analysis. 32 Fig. 3 shows fragments of the aromatic part of the proton spectra of the L3 and L4 ligands in deuterated toluene at room temperature and under considerable heating.…”

“…To make ESP maps for ligand we used Gaussian 16 30 at B3LYP/6-31G(d,p) theoretical level. B3LYP is used as an universal, time-saving functional for making ESP maps, 32 6-31G(d,p) was chosen as a standard basis set.…”