Vol 93, No 7 (2023)

A N -phenyl-substituted morpholine adduct of C₆₀ fullerene, 1,9-[4′-phenylmorpholine]-1,9-dihydro-(C₆₀-I_h) [5,6]fullerene, was obtained for the first time with a yield of 56% in the reaction of 2-phenylaminoethanol with fullerene in the presence of LiOH and Pb(OAc)₄ at room temperature for 1 h. The amino alcohol with an electron donor group (2-methylaminoethanol) in the reaction with fullerene showed a higher reactivity: the product 1,9-[4′-methylmorpholine]-1,9-dihydro-(С₆₀-I_h)[5,6]fullerene was isolated in 68% yield. The presence of electron-withdrawing groups at the α- or β-carbon atom relative to the nitrogen atom in amino alcohols [carboxylic (2-amino-3-hydroxypropanoic acid, serine) or carbonyl (aminoacetic acid) groups] does not contribute to the reactions with fullerene under the studied conditions.

The reaction of (1-ethoxyethylidene)malononitrile with cyanoacetamide or cyanothioacetamide yielded 6-amino4-methyl-2-(thio)oxo-1,2-dihydropyridine-3,5-dicarbonitriles. The resulting pyridine derivatives enter into an aminomethylation reaction with an excess of formaldehyde and primary amines with the formation of previously unknown 8-methyl-6-oxo-3-R-1,3,4,6-tetrahydro-2 H -pyrido[1,2- a ][ 1,3,5]triazine-7,9-dicarbonitriles. Further treatment of 6-amino-4-methyl-2-thioxo-1,2-dihydropyridine-3,5-dicarbonitrile and its oxygen analogue with excess formaldehyde leads to the formation of 3,10-dimethyl-1,8-dithioxo-5,6,12,13-tetrahydro-1 H ,8 H -dipyrido[1,2- a :1’,2’- e ][1,3,5,7]tetrazocin-2,4,9,11-tetracarbonitrile and 6,6’-[methylenedi(imino)]bis(4-methyl-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile), respectively. These compounds show a pronounced antidote effect against the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) in laboratory and field experiments on sunflower seedlings. Also, 6-amino-4-methyl-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile exhibits pronounced anticorrosion properties and is an adsorption-type corrosion inhibitor. The mechanism of anti-corrosion action was studied in detail using X-ray photoelectron spectroscopy.

A convenient method for the preparation of 5-aryl-2,2′-bipyridines with para -arylsulfanyl group in an aromatic substituent was proposed. The synthesis was performed using in situ generated aryne intermediates without the use of complex experimental procedures and expensive reagents/catalysts. The structure of one product was confirmed by XRD data. This approach is a new variant for the preparation of 5-aryl-2,2’-bipyridines with an extended conjugation system.

The reaction of 1,3-dipolar cycloaddition of a stable azomethine ylide formed from ninhydrin and L-proline to activated acetylenic phosphonates was studied. It was found that the reactions proceed under mild conditions with high regioselectivity with the formation of cycloadducts with a spiro[inden-2,3’-pyrrolysine]-1,3-dione backbone.

New tetraphosphoryl tripodal ligands on the triphenylphosphine oxide platform [2-Ph₂P(O)(CH₂) _n OC₆H₄]₃PO with different linker length ( n = 3, 4) were synthesized. Composition and structure were found by elemental analysis, IR, multinuclear (¹H, ¹³C, ³¹P) NMR spectroscopy, and X-ray diffraction. Extraction properties of the ligands were studied by the example of recovery of micro amounts of f -block elements from aqueous phase to 1,2-dichloroethane.

The effect of amino acid fragments in tetraphenylporphin derivatives on the pH range of porphyrin dominance as a dication was studied. For this purpose, the protonation processes of unsymmetrically substituted derivatives of 5,10,15,20-tetraphenylporphyrin: 5-(4′-aminophenyl)-10,15,20-triphenylporphine, 5-(4′-tyrosinylamidophenyl)-10,15,20-triphenylporphine and 5-(4′-glycinacylaminophenyl)-10,15,20-triphenylporphine were analyzed in acetonitrile. It was found that in acidic acetonitrile solutions the pH range of dominance of the doubly protonated form depends on the nature of the substituent in the para -position on the periphery of the phenyl fragment of the porphyrin ring: electron-donating substituents expand the pH range of dominance of the porphyrin in the dication form, while electron-withdrawing substituents decrease it. The calculation of the energies of the molecular orbitals of the studied compounds by the DFT method with the B3LYP/cc-pVDZ set showed good agreement between the experimental results and the calculations.

Using 4-bromo-5-nitro- and 4,5-dichlorophthalonitriles, substituted phthalonitriles containing a fragment of 2-cyclohexylphenol and nitro- or 1-benzotriazolyl groups, as well as phthalonitrile containing two 2-cyclohexylphenoxy groups, were synthesized. Tetramerization of these precursors with zinc acetate hexahydrate gave the corresponding octa-substituted zinc phthalocyanines. Their spectral properties were studied.

The interaction of phthalimide with 2-picoline in the presence of zinc oxide synthesized 3-(pyridin-2-ylmethylene)isoindolin-1-one. Heating its mixture with an excess of phthalimide and zinc acetate leads to the formation of zinc 5-(2-pyridyl)tetrabenzoporphyrinate, which, upon treatment with acid, is converted to 5-(2-pyridyl) tetrabenzoporphyrin. The latter, when interacting with cobalt(II), copper(II), and iron(III) chlorides in DMF, forms the corresponding metal complexes. The composition and structure of the obtained compounds were confirmed by mass spectrometry, vibrational, ¹H NMR, and electron spectroscopy. The results of quantum-chemical calculations of complexes by the DFT method are presented. A correlation is established between the energy gap between the frontier orbitals and the positions of the first bands in the electronic absorption spectra. All the synthesized tetrabenzoporphyrins exhibit catalytic activity in the electroreduction of oxygen, the highest activity being exhibited by cobalt and copper complexes.

The reaction of 1,3,5-tris(diphenylphosphinyl)benzene (L) with MnI₂ in the presence of CuI (wet MeCN, 25°C, 30 min) leads to the formation of a complex [MnL₄(H₂O)₂][Cu₅I₇(CH₃CN)]·7MeCN with yield of 72%. The Mn²⁺ ion of this complex has a distorted Mn@O₆ octahedral environment formed by four L ligands and two coordinated water molecules. The [Cu₅I₇(CH₃CN)]^2- anion has an unprecedented structure of the {Cu₅I₇} backbone, which includes five copper atoms bound by bridging iodide ions (µ₂, µ₃, µ₄), as well as four short Cu···Cu contacts (<2.80 Å). It is shown that the synthesized complex at 298 K exhibits weak photoluminescence attributed to cluster-centered phosphorescence from the iodocuprate anion.