Ресурсный центр «Магнитно-резонансные методы исследования»

Е.А. Катленок, С.Н. Смирнов, А.Ю. Иванов, С.В. Макаренко, К.П. Балашев

“Влияние донорно-акцепторных свойств лигандов на спектроскопические и электрохимические характеристики смешанно-лигандных циклометаллированных комплексов Pt(II) и Ir(III) 2-фенилбензотиазола”

Оптика и Спектроскопия, 2017,122(3), 436-444
DOI:10.7868/S0030403417030126
Приведены результаты спектроскопических ЯМР 1Н, 13C, 195Pt, ИК, оптических и вольтамперометрических характеристик смешанно-лигандных комплексов Pt(II) и Ir(III) с металлированным 2-фенилбензотиазолом и трет-бутилизоцианидом (tBuNC), ацетонитрилом (AN), этилендиамином(En), О-этилдитиокарбонат- (Exn–) и диэтилдитиокарбонат-ионами (Dtc–). Показано, что изменение донорно-акцепторного взаимодействия с металлом лигандов tBuNC, AN, En, Exn–, Dtc– приводит к повышению энергии высшей заполненной молекулярной орбитали комплексов и сопровождается катодным смещением потенциала металл-центрированного окисления, батохромным смещением спин-разрешенного и спин-запрещенного оптических переходов переноса заряда металл-циклометаллированный лиганд и увеличением степени смешивания 1ПЗМЛ- и триплетного внутрилигандного состояния, ответственного за фосфоресценцию комплексов.

E.I. Evstigneyev, A.V. Kalugina, A.Yu. Ivanov, A.V. Vasilyev

“Contents of α-o-4 and β-o-4 bonds in native lignin and isolated lignin preparations”

J. Wood Chem. Technol, 2017,accepted
DOI:10.1080/02773813.2017.1297832

An analytical calculation method for the estimation of the contents of alkyl aryl ether bonds (α-O-4 and β-O-4) in lignin was developed. In the framework of the method, Alkyl–O–Aryl type bonds are described as coupled phenolic hydroxyls (OHphen). The method is based on the balance equation including the free and coupled OHphen contents in dissolved and residual lignins, on the one hand, and their respective contents in native lignin, on the other. The free OHphen content is calculated on the basis of the OHphen contents of dissolved and residual lignin, determined by the aminolysis method in the course of kraft cooking of softwood. The calculation results for soluble lignin preparations are in good agreement with the 13C NMR (nuclear magnetic resonance) spectral data for the solutions. The content of Alkyl–O–Aryl bonds in native softwood (pine, spruce) lignin was estimated at 79/100 PPU (phenylpropane unit). In isolated lignin preparations, the contents of these bonds decrease in the sequence: Freudenberg lignin (71/100 PPU)> Bjorkman lignin (61/100 PPU)> Pepper lignin (44/100 PPU). Dissolved alkaline lignin still contains small amounts of Alkyl–O–Aryl bonds (36/100 PPU in soda lignin and an average of 23/100 PPU in soda-AQ lignin, kraft lignin, and kraft-AQ lignin). Residual lignin which represents the fraction of native lignin with inter-unit bonds resistant to kraft pulping contains 66/100 PPU of such bonds. A relatively high content of Alkyl–O–Aryl bonds (61/100 PPU) is preserved in technical hydrolysis lignins.

A.S. Pankova, P.R. Golubev, A.F. Khlebnikov, A.Yu. Ivanov, M.A. Kuznetsov

“Thiazol-4-one derivatives from the reaction of monosubstituted thioureas with maleimides: structures and factors determining the selectivity and tautomeric equilibrium in solution”

Beilstein J. Org. Chem., 2016, 12, 2563-2569
DOI:10.3762/bjoc.12.251

2-(Alkyl(aryl)amino)thiazol-4(5H)-ones can regioselectively be prepared from monoalkyl(aryl)thioureas and maleimides. In solution, the former heterocycles exist in a tautomeric equilibrium with 2-(alkyl(aryl)imino)thiazolidin-4-ones and the substituent on the exocyclic nitrogen atom governs the ratio of these tautomers. Isomers with the alkyl group in the endocyclic position can be obtained from N-methyl(ethyl)thioureas. 2D NMR spectroscopy and DFT calculations rationalize experimental results.

M.N. Putintseva, O.Yu. Bakulina, A.Yu. Ivanov, P.S. Lobanov, S.K. Nikolskaya, I.E. Kolesnikov, D.V. Dar’in

“Double tandem cyclization of 4-(1-acyl-2,2-diaminovinyl)-6-arylpyrimidine-5-carbonitriles. Synthesis of novel peri-annulated azines”

Tetrahedron Lett., 2016, 57, 5192-5196
DOI:10.1016/j.tetlet.2016.10.020

A series of novel peri-fused azines, pyrimido[4,5,6-de]quinolino[2,3-b][1,8]naphthyridines and benzo[b]pyrimido[4,5,6-de][1,8]naphthyridines, were prepared via the base-promoted double tandem cyclization of 4-(1-acyl-2,2-diaminovinyl)-6-(haloaryl)pyrimidine-5-carbonitriles. This transformation represents a rare example of the one-pot synthesis of peri-annulated polycyclic structures from non-fused heterocycles. The synthesized pyrimido[4,5,6-de]quinolino[2,3-b][1,8]naphthyridines were found to be luminophores.

L.D. Funt, O.A. Tomashenko, A.F. Khlebnikov M.S. Novikov, A.Yu. Ivanov

“Synthesis, Transformations of Pyrrole- and 1,2,4-Triazole-Containing Ensembles, and Generation of Pyrrole-Substituted Triazole NHC”

J. Org. Chem., 2016, 81, 11210-11221
DOI:10.1021/acs.joc.6b02200

Unprecedented pyrrole- and 1,2,4-triazole-containing ensembles, substituted 1-(1H-pyrrol-3-yl)-4H-1,2,4-triazol-1- ium bromides and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazol-4-ium bromides, were prepared from 2H-azirines and triazolium phenacyl bromides using a simple procedure. N-(1H-Pyrrol-3-yl)-N′-benzyltriazolium bromides undergo reductive debenzylation on Pd/C to give substituted 1-(1H-pyrrol-3-yl)-4H-1,2,4-triazoles and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazoles in high yields. Betaines (triazoliumylpyrrolides) and pyrrolyltriazole NHCs, which are possible products of dehydrobromination of pyrrolyltriazolium salts, have comparable thermodynamic stabilities in nonpolar solvents according to calculations at the DFT B3LYP/6-31G(d) level. The carbene forms can be easily trapped by the reaction of salts with base in the presence of sulfur. The corresponding 1- and 4-(1H-pyrrol-3-yl)-1H-1,2,4-triazole-5(4H)-thiones are formed in high yields. In the absence of sulfur as a trap, the opening of the triazole ring occurs with the formation of derivatives of N-cyanoformimidamide. According to the DFT calculations the latter is most probably formed via a pyrrolyltriazoliumide intermediate, which is the minor component of the equilibrium triazoliumylpyrrolide−pyrrolyltriazole NHC−pyrrolyltriazoliumide. Blocking of the pyrrolyltriazoliumide intermediate formation, by introduction of a substituent at the 3-position of the triazole ring, made it possible to generate the first pyrrole-substituted triazole NHC.

Александр Иванов успешно прошел курс «NMR METHODS for LABELED PROTEINS» в рамках которого освещались принципы  и практические аспекты проведения многомерных экспериментов спектроскопии ЯМР.

M.S. Mishina, A.Yu. Ivanov, P.S. Lobanov, D.V. Dar’in

“A New Synthesis of 2-Aminoindoles and 6-Aminopyrrolo[3,2-d]pyrimidines from π-Deficient 1,2-Dihaloarenes and Geminal Enediamines”

Synthesis, 2016, 48, 2851-2862
DOI:10.1055/s-0035-1561645

An efficient approach for the synthesis of fused 2-aminopyrroles via geminal enediamines and π-deficient 1,2-dihaloarenes is presented. The two-step methodology includes aromatic nucleophilic substitution of the activated halogen of dihaloarene with enediamine C-nucleophilic center followed by Cu-catalyzed intramolecular N-arylation. This approach allows access to a variety of 2-amino-6-nitroindoles and 6-aminopyrrolo[3,2-d]pyrimidines (including N-mono- and N,N-disubstituted) in moderate and good yields under mild conditions.

M.A. Sandzhieva, A.N. Kazakova, I.A. Boyarskaya, A.Yu. Ivanov, V.G. Nenajdenko, A.V. Vasilyev

“Friedel–Crafts Alkylation of Arenes with 2-Halogeno-2-CF3-styrenes under Superacidic Conditions. Access to Trifluoromethylated Ethanes and Ethenes”

J. Org. Chem., 2016, 81, 5032-5045
DOI:10.1021/acs.joc.6b00419

The formation of the corresponding benzyl cations [ArHC⁺–CH(X)CF₃] takes place under protonation of E-/Z-2-halogeno-2-CF₃ styrenes [ArCH═C(X)CF₃, X = F, Cl, Br] in superacids. The structures of these new electrophiles were studied by means of NMR and theoretical DFT calculations. According to these data, in the case of bromo derivatives, the formed cations, most probably, exist as cyclic bromonium ions; however, in the cases of chloro and fluoro derivatives, open forms are more preferable. Subsequent reaction of these benzyl cations with arenes proceeds as Friedel–Crafts alkylation to afford 1,1-diaryl-2-halo-3,3,3-trifluoropropanes [Ar(Ar′)CH–CH(X)CF₃] in high yields (up to 96%) as a mixture of two diastereomers. The prepared halogenopropanes were easily converted into the corresponding mixtures of E-/Z-trifluoromethylated diarylethenes [Ar(Ar′)C═CCF₃] (in yields up to 96%) by dehydrohalogenation with base (KOH or t-BuOK). The mechanism of elimination (E₂ and Ecb) depends on the nature of the leaving group and reaction conditions.

E.A. Katlenok, A.A. Zolotarev, A.Yu. Ivanov, S.N. Smirnov, R.I. Baichurin, K.P. Balashev

“Complexes of Ir(III) and Pt(II) with Cyclometallated 2-Phenylbenzothiazole and Chelating Diethyldithiocarbamate and O-Ethyldithiocarbonate Ions: Structures and Optical and Electrochemical Properties”

Rus. J. Coord. Chem., 2016, 42, 178-186
DOI:10.1134/S1070328416030039

It is shown by X-ray diffraction analysis, IR spectroscopy, and 1Н, 13С{1H}, and 195Pt NMR spectroscopy that the Pt(II) and octahedral Ir(III) complexes with metallated 2-phenylbenzothiazole and chelating diethyldithiocarbamate and O-ethyldithiocarbonate ions have the square and cis-C,C structure, respectively. The highest occupied and lowest unoccupied molecular orbitals of the complexes determining their long-wavelength absorption, phosphorescence, and one-electron oxidation and reduction are assigned to those predominantly localized on the mixed p(S)/d(M) and π* orbitals of the metallated ligand. The cathodic shift of the oxidation voltammogram and the bathochromic phosphorescence shift of the Pt(II) complex with the О-ethyldithiocarbonate ion are attributed to the enhanced donor–acceptor interaction of the donor S atoms of the ligand with Pt(II). The structural data are deposited with the Cambridge Crystallographic Data Centre (CIF files CCDC nos. 1058768 (Ia) and 1058767 (IIb)).