A set of tetradentate N,O-donor hybrid ligands based on a 1,8-naphthyridine core have been synthesized. The coordination chemistry of the synthesized diamides has been studied both in solution (NMR-titration) and in solid state (IR-spectroscopy and X-ray analysis). To investigate the impact of structural modifications of diamides L1-L6 on their photophysical properties, complexes with Eu(III), Gd(III), and Tb(III) nitrates have been synthesized. Single-crystal X-ray diffraction analysis of complexes L2 center dot Tb and L3 center dot Eu showed that this type of ligands is capable of forming the metallamacrocycles of L2M2 stoichiometric composition. Comprehensive comparative study of the photophysical behavior of six structurally related Eu3+ complexes, L1 center dot Eu - L6 center dot Eu, is provided focusing on the role of charge-transfer states in the sensitization process.

A set of 12 novel macrocyclic 1,10-phenanthroline-2,9-dicarboxamides (DAPhen's) with variable ring size were synthesized. A variety of ligands were prepared with different chain lengths between amide nitrogens; in addition, the corresponding 4,7-dichloro-substituted derivatives were prepared. Using a combination of quantum-chemical modeling, single-crystal X-ray diffraction, and nuclear magnetic resonance spectroscopy methods, the stereodynamics of such compounds was studied in detail. Solvent extraction tests of macrocyclic DAPhen's toward the Eu3+/Am3+ pair allowed to determine the most effective ligand in the series. It has been shown that 4,7-dichloro-substituted DAPhen's can exhibit much higher extraction efficiency for trivalent f-element cations under the same conditions compared to their unsubstituted analogs. These patterns were explained by using quantum-chemical modeling of the complexation of the synthesized macrocycles with lanthanide(III) nitrates.

We have shown for the first time that the visible-light-driven photocatalytic three-component reaction of ethyl acetoacetate, styrene, and CO2 affords two carboxylation products. The ratio of these products is determined by the CO2 pressure. Specifically, at 1.5 bar, the product ratio (4-aryl-2-acetylglutaric acid to 2-(2-aryl-3-oxobutyl)malonic acid) for unsubstituted styrene is 32:63. However, at 5.5 bar, this ratio shifts to 72:25. The impact of the substituents on the styrene ring is also noteworthy. Electron-withdrawing substituents favor the first carboxylation product, providing yields up to 95% (p-CF3, 5.5 bar CO2), while electron-donating substituents promote rearrangement, leading predominantly to the isomeric product in yields up to 71% (p-OMe, 1.5 bar CO2). The reaction proceeds at room temperature without transition metals, using an organic photocatalyst (4DPAIPN) and a base. The reaction pathway is dictated by both internal and external factors, namely the CO2 pressure and the electronic nature of the styrene substituent.

Three positional isomers of alkyl-aryl-substituted 1,10-phenanthroline-2,9-dicarboxamides (DAPhens) were synthesized and investigated. Using quantum chemical modeling, the difference in the conformational behavior of new DAPhens and their complexes characterized by the presence of alkyl substituents in the aryl fragment of the amide function was demonstrated. The coordination chemistry of the synthesized diamides has been studied in detail using spectroscopic methods and X-ray diffraction analysis. Complex compounds of DAPhens with trinitrates of selected rare-earth elements, including europium, gadolinium and terbium, were synthesized. The photophysical properties of these complex compounds were examined, revealing that the highest quantum yield is achieved for the complex containing symmetric 2,6-dimethylphenyl-DAPhen.

A series of 5-7-membered bis-lactam-derived phenanthroline ligands was synthesized. The structure of all of the obtained ligands was investigated by spectral methods, including 2D NMR spectroscopy and X-ray for all three ligands. The coordination chemistry of the synthesized ligands with d- and f-elements was studied. NMR titration of the ligands L1-L3 with lanthanides trinitrates and aluminum, zinc, and lead perchlorates was performed. It was shown that in the case of f-elements, the LM complex is often in equilibrium with the free ligand L. With d-elements, a clear formation of L2M complexes is observed. X-ray diffraction analysis of the single crystals obtained from solutions upon NMR titration showed that in the course of titration of L1 with Al(ClO4)3, no complexation occurred, but rather the asymmetrically protonated form of the ligand was formed with perchlorate as a counterion due to the higher Brønsted basicity of these ligands. The new ligands demonstrated moderate extraction ability toward Pb(II) and Pd(II), while the extraction of lanthanides and most other tested metal cations remained insignificant.

The phosphonylation of electron-deficient alpha-chloro-substituted nitrogen-containing heteroarenes with triethyl phosphite and triisopropyl phosphite using microwave-assisted SNAr-Arbuzov reaction was studied. The reaction proceeds at 200-270 degrees C in 30-75 min. The efficiency of the method depends on the relationship between substrate reactivity and the product stability against decomposition under the reaction conditions. It was shown that less reactive pyridine and pyrazine derivatives give low yields due to the insufficient stability of the substrates and products. In the case of 1,10-phenanthroline, quinoline, isoquinoline, quinoxaline, and pyrimidine derivatives, the phosphonylation products were obtained in 40-95% yields due to their higher stability under reaction conditions. An approach to assessing substrate reactivity using quantum chemical calculations is proposed. The reaction does not require transition metals or any other additives. Moreover, it does not affect halogen atoms at other positions of the heterocyclic system, which is beneficial for further modification of the reaction products.

The efficient synthesis of ditopic N-ligands via Pd-catalyzed N,N-diarylation of 5-amino-1,10-phenanthroline with various 2-halogenosubstituted heteroarenes is reported. A series of 1,10-phenanthroline ligands containing dipyridylamine (dpa) or its analog at position 5 as an additional chelating site was obtained. Photoactive mononuclear Ru(II) and Ir(III) complexes of these ligands were prepared and characterized. X-ray diffraction and NMR spectroscopy showed that the metal in these complexes is coordinated only to the phenanthroline moiety. The chelating substituent was found not to have any significant effect on the photophysical properties of the Ru(II) center. Three Ni(II) complexes with dpa ligands, including the binuclear complexes [(bpy)2Ru(L)NiCl2](PF6)2 (L = bis(pyridin-2-yl)amino-1,10-phenanthroline), were prepared and characterized. It has been shown that these bridging ligands allow to adjust the optical and electrochemical properties of Ni(II) and Ru(II) metal centers independently, which makes them perspective for systematic modulating the Ni-centred reduction potential, while the properties of the Ru-center remain largely unaffected.

The present study offers a new approach for designing inhibitors of protein tyrosine phosphatases. We have synthesized the cyclam derivatives with α,α-difluoro-β-ketophosphonate fragments covalently attached to tetraazamacrocyclic scaffold, which is known to be of medical interest. The obtained functionalized macrocycles were evaluated as inhibitors of PTP1B, TC-PTP, CD45, and other protein tyrosine phosphatases.

Three novel 1,10-phenanthroline-2,9-dicarboxamides (DAPhen) were prepared and investigated in detail. The presence of alkyl groups in the ortho-positions of the aryl substituent in the ligand amide functions results in completely inhibited rotation around the N-Ar bond and complicated conformational behavior. A very significant effect of ligand steric hindrance on the solvent extraction of lanthanides(III) and Am(III) from nitric acid solution was demonstrated. Extraction tests indicated that all three ligands L1-L3 extract Am better than all lanthanides. Very high separation factors of Am from early lanthanides (La and Ce) SFAm/La,Ce > 40 were observed. For all three ligands, the separation factors from all lanthanides are also high (SFAm/Ln > 10), which makes them suitable for practical applications in spent nuclear fuel (SNF) reprocessing. The extraction efficiency (distribution ratio) increases by almost two orders of magnitude for all tested f-elements while maintaining an overall extraction trend. Since the solvent extraction of Ln(III) and/or Am(III) involves the formation of corresponding complex compounds, a detailed investigation of the coordination chemistry of novel sterically hindered DAPhen ligands toward lanthanides and americium nitrates was performed. A combination of single-crystal X-ray analysis, spectral techniques and quantum-chemical calculations allowed us to explain the nearly hundredfold increase in Am(III) extraction efficiency when moving from ortho-methyl substituents toward more bulky ortho-isopropyl groups.

Two series of novel 4-nitro-5-styrylisoxazoles (11 compounds) containing various macrocyclic substituents at positions 3 and 5 of the isoxazole cycle were obtained. Isoxazoles with macrocyclic signal unit in the styryl moiety demonstrated sensor properties in organic solvents to a number of metal cations (Mg(II), Ca(II), Zn(II), La(III), Al(III), Pb(II)). Aggregation-induced emission for the obtained dyes was found in the mixture of DMSO/H2O. In the presence of serum albumin, aggregates of macrocyclic styrylisoxazoles in an aqueous medium dissociated into monomers and formed complex with macromolecule. The compounds demonstrated cytoplasmic distribution in cells in two different forms as aggregates with ‘red’ fluorescence and dyes complexes with cellular proteins with ‘green’ fluorescence, which is promising for studying metabolic processes in the cell.

A series of O-halobenzyl and O,O′-bis(halobenzyl) derivatives of (S)-1,1′-bi(2-naphthol) (BINOL) have been synthesized, and their amination in the presence of palladium and copper catalysts has been studied. As a result, a new family of macrocyclic and linear BINOL derivatives with various substituents at the oxygen atoms, including those possessing additional chiral centers, has been obtained. The synthesized compounds have been evaluated for their detecting properties toward metal cations by UV and fluorescence titration. Among the obtained open-chain derivatives, a potential fluorescent sensor for Al3+ cations has been found due to multiple emission enhancement. In addition, a fluorescent molecular probe for Hg2+ and Al3+ has been identified. Among the macrocyclic derivatives, the compound with the longest trioxadiamine linker can be used as a molecular probe for Mg2+ and Ca2+ ions due to fluorescence enhancement with a red shift, as well as for Al3+ and Hg2+ ions due to strong fluorescence enhancement without change of the position of the emission maximum.

A new series of polytopic ligands based on 1,10-phenanthroline and polyoxadiamines has been synthesized through SNAr amination between 2-chloro-1,10-phenanthroline and diamines of various structures. The obtained podands were investigated as polytopic ligands for potassium and zinc ions in the industrially important reaction of cyclic carbonates synthesis from CO2 and epoxides under mild conditions (p(CO2) = 1 atm., T = 60-80 degrees C). The advantage of 1,11-diamino-3,6,9-trioxaundecane functionalized by 1,10-phenanthroline units compared to the diamine itself is demonstrated. It is revealed that heteroarylated 1,11-diamino-3,6,9-trioxaundecane can be used as a catalyst in the presence of KI (2 mol.%) with a low loading of the ligand (0.2 mol.%) instead of the usually employed 5-10 mol.% for unfunctionalized podands. Under these reaction conditions mono-substituted cyclic carbonates of various structures have been synthesized in excellent preparative yields ranging from 87 to 99%. Coordination of two Zn(II) ions to both 1,10-phenanthroline moieties has been shown to provide additional enhancement of catalytic activity. The catalysts demonstrate excellent stability and can be reused at least in 6 cycles.

Molecular hybrid catalysts [(ppy)2Ir(BL)](PF6), [(dFCF3)Ir(BL)](PF6), and [(bpy)2Ru(BL)](PF6)2 (where BL = N,N-di(pyridin-2-yl)-1,10-phenanthrolin-4-amine), have been investigated in Ni-catalyzed C(sp2)-N coupling under visible light irradiation. The impact of the irradiation method-"in batch" or "in flow"-on the activity of hybrid and known dual catalytic systems was initially examined. The hybrid Ru(II) system demonstrated superior efficiency "in flow" compared to dual catalytic systems. The influence of the chelating moiety on the photophysical and electrochemical properties of the photocatalysts was analyzed to elucidate the observed catalytic activity. The hybrid photocatalysts could be utilized for the successful arylation of aromatic or aliphatic amines with moderate to excellent yields (21 examples), ranging from 33% to 91%. Hybrid photocatalysts facilitated the coupling of 4,7-dichloroquinoline and 5-iodopyridin-2-amine with piperazine in the synthesis of precursors for piperaquine and ribociclib.

Copper-based metal-organic frameworks (Cu-MOFs) were successfully used for the amination of aryl iodides for the first time. The conditions were selected using four different Cu-MOFs in a model reaction of n-octylamine with iodobenzene. Efficient reaction requires the use of O,O′-bidentate ligands (2-acetylcyclohexanone, 2-isobutyrylcyclo-hexanone, rac-1,1′-bi(2-naphthol), or rac-BINOL), and, in the best cases, the yields of N-octylaniline can exceed 80

The efficiencies of copper-containing metal–organic coordination polymers (Cu-MOFs) and com­mercially available unsupported copper nanoparticles (CuNPs) in the amination of 2-iodopyridine, 2-bromo­pyridine, 2-bromo-5-(trifluoromethyl)pyridine, and 2-bromo-6-(trifluoromethyl)pyridine with n-octylamine and adamantane-containing amines with different steric environments of the amino group have been compared. Under the optimized conditions, the yields of the amination products in the presence of both catalytic systems were generally similar. In the reactions with 2-bromopyridine, increased reactant concentration and the use of 2 equiv of the substrate were necessary to achieve good yields. The presence of a trifluoromethyl group at the 6-position of the pyridine ring improved the yield of the amination products. An increase in steric hindrances at the amino group resulted in an appreciable decrease in the yield under catalysis by Cu-MOFs; however, reactions with such amines were successfully performed in the presence of CuNPs, and CuNPs of the average size 25 nm proved to be superior to bifractional nanoparticles with average sizes of 10 and 80 nm. On the other hand, increased concentration of the reactants in the Cu-MOF-catalyzed amination provided good yields of the target compounds in the absence of a ligand.

Dinuclear complexes bearing Ru(II) photoactive center are of interest for the development of efficient dual catalysts for many photocatalyzed reactions. Ditopic polypyrine ligands – bis(pyridine-2-yl)amino-1,10-phenanthrolines – containing additional coordination site (bis(pyridine-2-yl)amine, dpa) at positions 3, 4 or 5 of 1,10-phenanthroline core (Phen-3NPy2, Phen-4NPy2 and Phen-5NPy2) were synthesized. They were used as bridging ligands to obtain dinuclear complexes of composition [(bpy)2Ru(Phen-NPy2)PdCl2](PF6)2 (Ru(Phen-NPy2)Pd) via stepvise comlexing in good yields. Ru(II) is coordinated to 1,10-phenanthroline in these complexes, while Pd(II) is bound to dpa chelating moiety, which was established by NMR spectroscopy and X-ray single crystal analysis. The influence of the position of dpa in phenanthroline ring on the structural, optical and electrochemical properties of Ru(Phen-NPy2)Pd complexes was studied. The complexes possess photoluminescence in argon-saturated MeCN solution with maxima in the range of 615–625 nm, emission quantum yields range from 0.11 to 0.15 for Ru(Phen-NPy2) complexes and from 0.018 to 0.026 for dinucear Ru(Phen-NPy2)Pd complexes. All the complexes have high extinction coefficients in the range of 370–470 nm, efficiently absorb visible light and can be used as photocatalysts. The Ru2+/3+ potential in Ru(Phen-NPy2)Pd complexes showed no significant dependence on dpa position, while Pd2+/0 reduction potential was quite lower for Ru(Phen-3NPy2)Pd and Ru(Phen-NPy2)Pd, than for Ru(Phen-NPy2)Pd (–0.57V and –0.72V vs Ag/AgCl, KCl(sat), respectively). The behaviour of the complexes was studied in Сu-free Sonogashira coupling under blue LED (12 W) irradiation. The reaction proceeds three times faster when Ru(Phen-4NPy2)Pd and Ru(Phen-3NPy2)Pd are used as catalysts precursors than in the case of mixed catalytic system Ru(bpy)3(PF6)2/(RNPy2)PdCl2.

An overview of the main scientific achievements of Russian universities in the field of organic chemistry over the period 2018–2023 is presented.

Complexes [(bpy)2Ru(BL)](PF6)2 (Ru(BL), BL=N,N-di(pyridin-2-yl)-1,10-phenanthrolinamine) have been investigated in the coupling reaction of aryl halides and sodium arylsulfinates under visible light irradiation. The position (3, 4 or 5) of the nickel-coordinating di(pyridin-2-yl)amine fragment in the 1,10-phenanthroline core has a strong influence on the activity of the catalytic system. The advantage of binding fragments of photocatalyst and metal complex into one molecule in the systems with bridging ligands N,N-di(pyridin-2-yl)-1,10-phenanthrolin-3-amine (BL1) and N,N-di(pyridin-2-yl)-1,10-phenanthrolin-4-amine (BL2), in comparison with mixed catalytic systems, is shown. With Ru(BL2) photocatalysts it is possible to reduce the loading to 0.1 mol%, instead of the commonly used 1-2 mol%, and to eliminate the use of the additional ligand for nickel. Under these conditions, more than 20 diarylsulfones of different structures were synthesized in 25-95% yields. image

Using palladium-catalyzed arylation of (S)-2,2′-diamino-1,1′-binaphthalene (BINAM) with the halogen derivatives of naphthalene, anthracene, and anthraquinone, the corresponding N,N′-diaryl derivatives were synthesized. The dependence of the yields of the compounds on the structure of the initial halogen derivatives was shown. The synthesized compounds were studied in fluorescent enantioselective detection of amino alcohols. The synthesized derivatives demonstrate a response in the case of complex formation with some amino alcohols, but the response is most pronounced for the derivative with anthraquinone substituents. This detector can recognize enantiomers of leucinol, 2-phenylglycinol, and prolinol by different changes in the fluorescence enhancement in the presence of opposite optical isomers. In the case of 2-amino-1-propanol, fluorescence enhancement is observed only in the presence of the (S)-isomer.