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Atom Transfer Radical Polymerization (ATRP) is an effective catalytic process leading to well-defined polymers with desired properties. This process based on reversible deactivation of propagating chains has a lower rate in comparison with conventional radical polymerization, especially in the case of obtaining polymers with high molecular weights. Thus, the increase of the rate of this process with preserving control over molecular weight distribution is a challenging task. In this work, novel catalytic systems for Activators Generated by Electron Transfer (AGET) ATRP of acrylonitrile based on copper (II) bromide complexes were proposed. It was found that Rochelle salt (potassium sodium tartrate tetrahydrate) may be used as a reducing agent for regeneration of copper-based catalysts to increase the rate of the process. The provided UV-vis spectroscopy experiments have confirmed the reducing ability of tartaric anion. It was found that the use tandem catalytic system based on two copper complexes with different ligands also increases the polymerization rate. The performed experiments allowed us to develop a catalytic system for rapidly obtaining polyacrylonitrile polymers with desired molecular weights exceeding 100 kDa.

The effect of methyl substituents in the lower belt of dicarbollide ligands on the redox potential of ruthenacarboranes based thereof, as well as the ability of the metallacarboranes obtained to catalyze radical polymerization with atom transfer were studied. For this purpose, a new approach to the synthesis of closo-ruthenacarboranes based on substituted dicarbollide ligands was developed and six new complexes 3,3-(Ph2P(CH2)4PPh2)-3-H-3-Cl-9-Me-12-X-closo-3,1,2-RuC2B9H9, 3,3,8-(Ph2P(CH2)4PPh-μ-(C6H4-o))-3-Cl-9-Me-12-X-closo-3,1,2-RuC2B9H8 and 3,3,4,8-(Ph2P(CH2)4P-μ-(C6H4-o)2)-3-Cl-9-Me-9-X-closo-3,1,2-RuC2B9H7 (X = H, Me) were synthetized and characterized by single crystal X-ray diffraction, NMR and ESR spectroscopy and MALDI TOF mass-spectrometry. Comparison of the values of the redox potentials of the synthesized ruthenium complexes in 1,2-dichloroethane with the values previously found for the corresponding ruthenacarboranes based on the parent dicarbollide anion showed that the introduction of methyl substituents into the carborane cage led to a decrease in the redox potentials of the complexes, which made them more preferable catalysts for ATRP. Test experiments on the polymerization of MMA showed that the synthesized ruthenacarboranes were effective catalysts for ATRP, the most active being the complex with two methyl groups and two ortho-phenylenecycloboronated fragments.

A (series) range of potential dimorpholinoquinazoline-based inhibitors of the PI3K/Akt/mTOR cascade was synthesized. Several compounds exhibited cytotoxicity towards a panel of cancer cell lines in the low and sub-micromolar range. Compound 7c with the highest activity and moderate selectivity towards MCF7 cells which express the mutant type of PI3K was also tested for the ability to inhibit PI3K-(signaling pathway) downstream effectors and associated proteins. Compound 7c inhibited the phosphorylation of Akt, mTOR, and S6K at 125–250 nM. It also triggered PARP1 cleavage, ROS production, and cell death via several mechanisms. Inhibition of PI3Kα was observed at a concentration of 7b 50 µM and of 7c 500 µM and higher, that can indicate minority PI3Kα as a target among other kinases in the titled cascade for 7c. In vivo studies demonstrated an inhibition of tumor growth in the colorectal tumor model. According to the docking studies, the replacement of the triazine core in gedatolisib (8) by a quinazoline fragment, and incorporation of a (hetero)aromatic unit connected with the carbamide group via a flexible spacer, can result in more selective inhibition of the PI3Kα isoform.

In order to obtain molecular Ce(III) complexes which emit red light by f–d transitions the azolyl-substituted thiophenolates were used as the ligands. The thiophenolate Ce(III) complexes were synthesized by the reaction of Ce[N(SiMe3)2]3 with respective thiophenols 2-(2′-mercaptophenyl)benzimidazole (H(NSN)), 2-(2′-mercaptophenyl)benzoxazole (H(OSN)) and 2-(2′-mercaptophenyl)benzothiazole (H(SSN)) in DME media. The structures of the benzimidazolate (Ce(NSN)3(DME)) and benzothiazolate (Ce(SSN)3(DME)) derivatives were determined by X-ray analysis which revealed that the cerium ion in the molecules is coordinated by one DME and three anionic thiophenolate ligands. The lanthanum complex La(OSN)3(DME) has been synthesized similarly and structurally characterized. It was found that the solids of Ce(SSN)3(DME) and Ce(OSN)3(DME) exhibit a broad band photoluminescence peaking at 620 nm which disappears upon solvatation. With an example of OSN derivatives it was proposed that this behaviour is caused by the blue shift of the f–d transition of Ce3+ ions.

A novel method for synthesis of diamagnetic Ru(II) carborane clusters based on reduction of corresponding Ru(III) species by amines was developed. The interaction of paramagnetic 17-electron complex (1) with aliphatic amines in dichloromethane solution at 40 °C proceeds with the abstraction of chlorine atom from the ruthenium center and results in formation of corresponding 16-electron species. The latter can be stabilized by 2-electron ligands such as triphenylphosphine or acetonitrile through the formation of novel stable complexes of ruthenium (II): (2: L = PPh3; 4: L = CH3CN). A bis(ortho-phenylene)cycloboronated complex (6) may be obtained in a similar way from corresponding precursor. The related reaction conducted with diamagnetic closo-carborane cluster of ruthenium (IV) 3,3-Ph2P(CH2)4PPh2-3-H-3-Cl-closo-3,1,2-RuC2B9H11] (7) gives 3-CH3CN-3,3-Ph2P(CH2)4PPh2-closo-3,1,2-RuC2B9H11] (8). The obtained complexes were characterized by means of NMR and IR spectroscopy and mass spectrometry. A single-crystal X-ray diffraction study confirmed closo-structure of the obtained complexes and the presence of acetonitrile molecule as a ligand. The performed electrochemical investigation of the obtained ruthenacarboranes testified its ability to undergo reversible oxidation to Ru(III) species. The comparison of the properties of the obtained complex 2 with its analogue with shorter alkyl fragment in diphosphine moiety shows that the slight difference in the structure leads to the decrease of stability.

Anovel facile way of synthesis of closo-ruthenacarboranes with chelate 1,2-bis(diphenylphosphino)ethane (dppe) with high yields was proposed. It was found that the interaction of the three-bridged 5,6,10-{Cl(Ph3P)2Ru}-[5,6,10-(μ-H)3-10-H-exo-nido-7,8-C2B9H10] (1) with dppe in acetonitrile or CH2Cl2/acetonitrile mixture leads to the formation of novel diamagnetic ruthenacarborane cluster 3-СNMe-3,3-[κ2-dppe]-closo-3,1,2-RuC2B9H11 (2) along with some amount of ionic compound [trans-(CH3CN)RuCl(dppe)2]+[C2B9H12]− (3) which may be also converted to 2 increasing its total yield. The reaction of 2 bearing divalent ruthenium with carbon tetrachloride or HCl gives the known 17-electron paramagnetic complex 3-Сl-3,3-[κ2-dppe]-closo-3,1,2-RuC2B9H11 (4)..The detailed investigation of the previously described method of synthesis of 4 from 3-H-3Cl-3,3-(PPh3)2-closo-3,1,2-RuC2B9H11 (5) allowed us to characterize the forming by-products as 3-PPh3-3,3,8-(Ph2P(CH2)2PPh-μ-(C6[H4-о)-closo-3,1,2-RuC2B9]H10 (6) and 3-[κ1-dppe]-3,3-[κ2-dppe]-closo-3,1,2-RuC2B9H11 (7). The obtained ruthenacarborane clusters undergo reversible Ru(II)/Ru(III) transition. It was shown that the complexes 2, 4 and 6 show good activity as catalysts for Atom Transfer Radical Polymerization of methyl methacrylate.

Novel complexes of ruthenium with tridentate phosphine ligands: tris(diphenylphosphinomethyl)ethane and bis(2-diphenylphosphinoethyl)phenylphosphine were synthethised starting from the well-known exo-nido-ruthenacarborane [exo-5,6,10-{Ru(Ph3P)2Cl}-5,6,10-(μ-H)3-10-H-nido-7,8-C2B9H8] via ligand substitution followed by exo-nido- to closo-rearrangement in toluene. The novel compounds were characterized by NMR or EPR spectrometry, MALDI TOF mass-spectrometry and cyclic voltammetry. A single-crystal X-ray diffraction study confirmed closo-structure of the obtained complexes and the presence of η3-coordinated triphosphine ligands in it structures. The correlations between ligand structure and complex stability and reactivity were established. The possibility of application of ruthenacarboranes with tridentate phosphine ligands in Atom Transfer Radical Polymerization (ATRP) was explored. It was found out that complexes based on tris(diphenylphosphino)methane are the most suitable catalysts.

Alkoxides [Ln(OR)3(DME)]2 (R = CH(CF3)2, Ln = Sm (1), Yb (2)), [Ce(OR)3(Phen)]2 (3) (Phen = 1,10-phenanthroline), [Ce(OR′)3(DME)2]2 (R′ = C(CF3)3) (4), {Gd(OR′)3(DME)2} (5), {Ln2[O(CF3)2C–C(CF3)2O]3} (Ln = Ce (6), Gd (7)), {Ce2[O(CF3)2C–C(CF3)2O]3(Phen)2} (8), and {Ce[O(CF3)2C–C(CF3)2O][O(CF3)2–C(CF3)2OH](Phen)2} (9) were synthesized by the reactions of silylamides Ln[N(SiMe3)2]3 with respective fluorinated alcohols. The heterovalent trinuclear complex {Sm2(μ2-OR)3(μ3-OR)2Sm(OR)2(THF)2.5(Et2O)0.5} (10) was obtained by treatment of SmI2(THF)2 with ROK. The reaction of europium(II) and yttrium(III) silylamides with ROH afforded the heterobimetallic alkoxide {Eu2(μ2-OR)3(μ3-OR)2Y(OR)2(DME)2} (11) containing divalent europium. The molecular structures of 1, 2, 3, 9, 10 and 11 were determined by X-ray analysis. All the prepared cerium derivatives as well as the europium–yttrium isopropoxide upon UV excitation exhibited photoluminescence in the regions of 370–425 (for Ce3+) and 485 nm (for Eu2+) which was assigned to 4d→5f transitions.

A set of Y, Nd, Tm and Yb complexes containing, along with 3-(2-benzothiazol-2-yl)-2-naphtholate (L), the 8-oxyquinolate (Q), pentafluorophenolate, cyclopentadienyl (Cp) or methylcyclopentadienyl (CpMe) ligands were synthesized using Ln[N(SiMe3)2]3, Ln(Cp)3 or Ln(CpMe)3 as starting materials. Depending on molar ratio of initial reagents the mononuclear, dinuclear or tetranuclear products were isolated from the reaction mixtures. The complexes Y2(L)4(CpMe)2, Nd2(L)4(Cp)2, Yb(L)(Cp)2, Y2(L)3(Q)2(CpMe) and Y4(L)(Q)11 were structurally characterized. The synthesis routes and conditions governing the set of ligands in products and their nuclearity are discussed.

Quantum chemical calculations were carried out for exo-nido - and closo -ruthenacarborane clusters containing phosphine and diphosphine ligands. The calculated energies and geometric parameters of the complexes show that closo -ruthenacarboranes with seven- or eight-membered ω-diphosphaalkyl-substituted ruthenacycles are the most stable compounds in the studied series. The results explain the effect of the nature of the diphosphine ligand on the reactivity and catalytic activity of the ruthenacarboranes in ATRP processes.

The synthesis, characterization, photoluminescent (PL) and electroluminescent (EL) behavior of trivalent Sc, Nd, Gd, Er, Tm and Yb complexes with 3-(5-methylbenzoxazol-2-yl)naphthol (L-5Me) and 3-(6-methylbenzoxazol-2-yl)naphthol (L-6Me) ligands are reported. An X-ray analysis of Sc(L-5Me)3, Sc(L-6Me)3 as well as the non-methylated analogue Sc(L)3 has shown the monomeric structure of the complexes whereas the lanthanide naphtholates according to LDI-TOF data are dimers Ln2(L-5Me)6 and Ln2(L-6Me)6. The scandium complexes under photo- and electroexcitation revealed intense ligand-centered luminescence peaked at 522 nm. The PL and EL spectra of Nd, Tm and Yb compounds displayed moderate ligand-centered emission along with narrow bands of corresponding f–f transitions.

The heating of a mixture of 14-e [Ph2P(CH2)nPPh2]FeCl2 (n = 3 or 2) with the [K]+ salt of the [nido-7,8-C2B9H12]− mono-anion under gentle reflux in benzene affords either the paramagnetic (17-electron) complex [3,3-(dppp)-3-Cl-closo-3,1,2-FeC2B9H11] isolated in 15% yield or a mixture of the paramagnetic complex [3,3-(dppe)-3-Cl-closo-3,1,2-FeC2B9H11] (46% yield) and the diamagnetic complex [commo-8,8′-μ-(Ph2PCH2CH2PPh2)-3,3′-Fe{1,2-C2B9H10}2] (10% yield). All three novel ferracarboranes were characterized by spectroscopic (EPR or NMR) data and single-crystal X-ray diffraction.

Reactions of [ exo -5,6,10-{Cl(Ph 3 P) 2 Ru}-5,6,10-(μ-H) 3 -10-H- nido -7,8-C 2 B 9 H 8 ] ( 1 ) with 1,5-bis(diphenylphosphino)pentane ( 2 ) in benzene either at ambient temperature for ca 2 days or under gently reflux for 30 min in anaerobic conditions both proceed with the replacement of PPh 3 ligands on the ruthenium center with the diphosphine to form diamagnetic (18-electron) closo complex [3,3-{κ 2 -{Ph 2 P(CH 2 ) 5 PPh 2 }}-3-Cl-3-H- closo -3,1,2-RuC 2 B 9 H 11 ] ( 3 ). On heating in benzene, 3 in the presence of a small amount of CCl 4 affords stable paramagnetic (17-electron) species [3,3-{κ 2 -{Ph 2 P(CH 2 ) 5 PPh 2 }}-3-Cl- closo -3,1,2-RuC 2 B 9 H 11 ] ( 5 ) along with traces of ortho -phenylenecycloboronated closo complex, ( 7 ). The latter complex was prepared in higher yields by thermal treatment of either 3 or 5 under more severe conditions in toluene at 110 °C. Thermolysis of 7 in boiling toluene in the presence of a small amount of CCl 4 afforded the new paramagnetic complex ( 8 ), featuring bis( ortho -cycloboronation) of both P-phenyl groups located at the same phosphorus atom of the ruthenium bound dppt ligand; a minor amount of chloro-cage-substituted complex ( 9 ) was also isolated from the latter reaction as the by-product. All new closo -ruthenacarboranes obtained were characterized by a combination of analytical, multinuclear NMR (for even-electron species) or EPR (for odd-electron species) data and, in addition, by single-crystal X-ray diffraction studies of three paramagnetic complexes 5 , 7 and 8 .

In this article the features of controlled radical polymerization of stearyl methacrylate in the presence of copper-based compounds in combination with nitrogen-containing ligands such as tris[2-(dimethylamino)ethyl]amine and tris[(2-pyridyl)methyl]amine were studied. The ethyl 2-bromoisobutyrate was used as the initiator of the polymerization process. The synthesized polymers were characterized by gel permeation chromatography and MALDI-TOF time-of-flight mass spectrometry. It was found that the proposed catalytic systems allow conducting controlled radical polymerization of stearyl methacrylate according to the Atom Transfer Radical Polymerization mechanism at relatively mild temperature conditions. It was revealed that the nature of the organic ligand has a significant effect on the rate of polymerization and the molecular-weight characteristics of the synthesized samples. Using the copper(I) bromide catalytic system in combination with tris[(2-pyridyl)methyl]amine as a ligand at reagents molar ratio of 1:4, the polymerization of stearyl methacrylate proceeded with high reaction rate to deep conversions in a wide range of molecular weights. The observed linear growth of the molecular weight of the polymer with increasing conversion and low polydispersity index of the synthesized polymers being at the level of 1.19-1.29, considered as an evidence of the controlled mode of polymerization. The influence of the molecular weight characteristics of polymers based on stearyl methacrylate on the low-temperature properties of diesel fuel of specification24-2000 produced by OOO «LUKOIL-Nizhegorodnefteorgsintez» was evaluated using a low-temperature analyzer MX-700 (PE-7200I) in accordance with the requirements of Russian (GOST 5066-91 and GOST 20287-91) and the international (ISO-3016) standards for the quality of petroleum products. It was established that the synthesized polymers can be used as additives that reduce the temperature range of solidification of environmentally clean diesel fuels, while the molecular weight of polystearyl methacrylate has a significant effect on the depressor properties of the fuel.Forcitation:Simanskaya K.Yu., Grishin I.D., Grishin D.F. Synthesis of polymers based on stearyl methacrylate and their use as additives for diesel fuel. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 82-89