In this work we report on new examples of phenanthrolindiamides containing asymmetric centers in amide substituents.

[Ru(phen)(bpy) ₂ ] ²⁺ -type complexes with a P(O)(OEt) ₂ -substituted phen ligand are efficient photocatalysts for photoreactions proceeding via the electron transfer and energy transfer pathways.

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.

Nitrile imine cycloaddition to hydantoins containing an exocyclic C=C double bond has been previously described in a very limited number of examples. In this work, regioselective synthesis of spiro-pyrazoline-imidazolidine-2,4-diones based on a 1,3-dipolar cycloaddition reaction of nitrile imines to 5-methylidene-3-phenyl-hydantoin have been proposed. It was found that, regardless of the nature of the aryl substituents at the terminal C and N atoms of the C-N-N fragment of nitrile imine (electron donor or electron acceptor), cycloaddition to the 5-methylidenhydantoin exocyclic C=C bond proceeds regioselectively, and the terminal nitrogen atom of the nitrile imine connects to the more sterically hindered carbon atom of the double bond, which leads to the formation of a 5-disubstituted pyrazoline ring. The observed cycloaddition regioselectivity was rationalized using DFT calculations of frontier molecular orbital interactions, global CDFT reactivity indices, and minimum energy paths.

An efficient approach to the synthesis of diamides of 4,7-difluoro-1,10-phenanthroline-2,9-dicarboxylic acid was elaborated. Direct nucleophilic substitution with 4,7-dichloro-1,10-phenanthroline precursors opened access to difluoro derivatives in high yield. As a result, four new fluorinated ligands were prepared in up to 88% yield. Their structure was proved by a combination of spectral methods and X-ray data. A set of lanthanoid complexes was prepared to demonstrate the utility of new ligands. The structure of the complexes was studied in solid state (IR-spectroscopy, X-ray diffraction) and in solution (NMR-spectroscopy).

Spontaneous diffusion of volatile reagent vapors into a solution, containing a stable precursor of an unstable reactive intermediate, may be the simplest method for carrying out some organic reactions, including 1,3-dipolar cycloaddition. In the present work, this technique was applied to generate nitrile imines and nitrile oxides for the subsequent reactions with dipolarophiles from hydrazonyl halogenides or N-hydroxyimidoyl halogenides by the action of volatile tertiary amines (Et₃N, as well as Me₃N or DIPEA). Generation of highly reactive intermediates as a result of tertiary amine vapor diffusion into the reaction mixture makes it possible to obtain the products of 1,3-dipolar cycloaddition reactions in high yields and without the side product formation due to the created conditions of “dipole starvation”. The proposed method of diffusion reagent mixing allows us to carry out 1,3-dipolar cycloaddition reactions with low-stability and easily dimerizing nitrile oxides and nitrile imines in high yields and is incredibly easy experimentally. In fact, 1,3-dipoles are obtained by this method “molecule-by-molecule”, which prevents their unwanted dimerization.