Publications by authors named "Mikhail N Bochkarev"

In order to prepare the first lanthanide coordination polymers (CPs) based on ditopic sulfide ligands, benzo[1,2-:4,5-']bisthiazole-2,6(3,7)-dithione (HL) was used as a linker. The reactions of lanthanide silylamides Ln[N(SiMe)] (Ln = Nd, Gd, Er, and Yb) with HL result in the formation of soluble dimethyl sulfoxide (DMSO) ionic salts [Ln(DMSO)][L] [Ln = Nd (), Gd (), Er (), and Yb ()]. Due to the lack of coordination of anionic ligands, compounds , , and do not show sensitized metal-centered photoluminescence (PL), while Gd compound shows weak phosphorescence at 77 K.

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A new mixed Eu(II)-Cu(I) iodide [Eu(DME)][CuI] (1) was synthesized by the reaction of an organosulphide salt of Eu(II) and CuI in DME media. X-ray analysis revealed that 1 is an ate-complex consisting of Eu(DME) dications and tetraiododicuprate dianions. Upon UV light excitation ( = 365 nm), the compound exhibits intense double-peaked photoluminescence (PL) at 445 and 500 nm.

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The complexes of La, Ce, Nd, Sm, Eu, Tb and Yb with benzoxazolyl-phenolate, benzothiazolyl-phenolate, benzoxazolyl-naphtholate, benzothiazolyl-naphtholate and 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione ligands were treated with n,γ-irradiation upon a sustained (45 h, absorbed dose of 120 krad, flux of neutrons 5·10 n/cm) and a pulse mode (3 ms, absorbed dose of 130 krad, flux of neutrons 3.6·10 n/cm). It was found that main characteristics of the compounds (shape of substance, color, IR absorption and photoluminescent spectra) have not changed.

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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(SiMe)] 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)(DME)) and benzothiazolate (Ce(SSN)(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.

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A comparative study of the photoluminescence (PL) and radioluminescence (RL) of lanthanide complexes with benzimidazolylphenolate (NON), 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate (TTA) and 1,3-acetylacetonate (acac) ligands revealed significant differences in the total and relative intensity of emission. The PL spectra contain both bands of metal-centered and ligand centred emission while X-ray excited compounds display only the bands of Ln3+ ions, the relative intensity of which differs from that in UV excited analogues. The RL intensity of all the studied complexes is about 300 times lower than that of PL.

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A set of Sc, Nd, Sm, Eu, Ho, Gd, Er, Yb complexes with perfluorinated 2-(benzothiazol-2-yl)phenolate ligands Ln(SON)(DME) were synthesized by the reactions of silylamides Ln[N(SiMe)] with phenol H(SON). The structure of the initial phenol, Sc, and Er complexes was established using X-ray analysis, which revealed that the obtained compounds are mononuclear, in contrast to the binuclear non-fluorinated analogues [Ln(SON)] synthesized earlier. All the obtained complexes, both in solid state and in tetrahydrofuran (THF) solutions, upon excitation by light with λ 395 or 405 nm show intense luminance of the ligands at 440-470 nm.

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To obtain new efficient lanthanide-based NIR luminophores perfluorinated 2-mercaptobenzothiazole was used as a ligand. The ate-complexes [(Ln(mbtF)4)-(Na(DME)3)+] of Nd (1), Sm (2), Tb (3), Er (4), Yb (5) and [(Y(mbtF)4)-(Li(DME)3)+] (6) were synthesized in high yields by the reactions of the respective silylamide compounds Ln[N(SiMe3)2]3 and M[N(SiMe3)2] (M = Li, Na) with 4,5,6,7-tetrafluoro-1,3-benzothiazol-2(3H)-thione (HmbtF) in DME media. The complexes 1-3 and 6 were structurally characterized by X-ray diffraction analysis.

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Herein, complexes [ZnL] (1), {(HO)Zn(μ-L)Yb[OCH(CF)]} (2), {[(CF)HCO]Zn(μ-L)Yb[OCH(CF)](μ-OH)} (3), and [(HO)Ln(L)] (Ln = Yb (4) and Gd (5)) containing a bridging Schiff-base ligand (HL = N,N'-bis(3-methoxy salicylidene)phenylene-1,2-diamine) were synthesized. The compounds 1-4 were structurally characterized. The ytterbium derivatives 2-4 exhibited bright NIR metal-centred photoluminescence (PL) of Yb ion under one- (λ = 380 nm) and two-photon (λ = 750 nm) excitation.

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To obtain luminescent lanthanide complexes with a low energy LMCT state the 2-(2'-mercaptophenyl)benzothiazolates, Ln(SSN), and 2-(2'-mercaptophenyl)benzoxazolates, Ln(OSN) (Ln = Gd, Yb), were synthesized by the reaction of amides Ln[N(SiMe)] with respective thiophenols. Ytterbium complexes were structurally characterized by X-ray diffraction analysis. Cyclic voltammetry revealed that the deprotonated mercaptophenyl ligands have significantly lower oxidation potentials than their phenoxy analogues and some β-diketones.

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A series of lanthanide complexes (Ln = Nd, Sm, Eu, Gd and Yb) with anionic 2-mercaptobenothiazolate (mbt) ligands were synthesized. Depending on the solvents chosen for the synthesis, Ln(mbt)3(THF)2 and Ln(mbt)3(Et2O) complexes were precipitated from THF and Et2O solutions respectively. The structure of Yb(mbt)3(Et2O) was determined by X-ray analysis.

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New 8-quinolinolate (Q) complexes of yttrium (1) and ytterbium (2) were synthesized by the reactions of Cp3Y and Yb[N(SiMe3)2]3 with 3 equiv. of 8-hydroxyquinoline in a DME solution. Single crystal X-ray analysis revealed the trinuclear molecular structure of the compounds Ln3Q9.

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The first monomeric anhydrous scandium tris(8-quinolinolate) complex 1 with the 2-amino-8-quinolinolate ligands and the Sc(2)Q(6) dinuclear complex 2 with the unsubstituted 8-quinolinolate ligands have been synthesized and characterized by X-ray analysis and DFT calculations. The intramolecular hydrogen bonds appear to be responsible for the unique monomeric structure of complex 1. The DFT-based analysis of the electron density topology reveals the (3,-1) critical points corresponding to the O···H and N···H bonds.

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Three members of a new class of electroluminescent, neutral, and monomeric scandium N,O-chelate complexes, namely, Sc(III)-tris-2-(2-benzoimidazol-2-yl)phenolate (1), Sc(III)-tris-2-(2-benzoxyazol-2-yl)phenolate (2), and Sc(III)-tris-2-(2-benzothiazol-2-yl)phenolate (3), have been prepared and X-ray characterized. DFT calculations have been performed. In contrast to the most frequently applied dual or multiple dopants in multilayer white OLED devices, all our simpler devices with the configuration of indium tin oxide/N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine/neat scandium complex/Yb exhibit close to near-white emission with a blue hue (CIE(x,y) = 0.

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The metal-organic complexes of Sc, Y, La and lanthanides, which were tested as luminescent materials in organic light emitting diodes (OLEDs), are collected. The performances of the devices are given. Advantages and drawbacks of organic derivatives of rare earth metals as emissive materials are considered.

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The redox reaction of [Yb(C(9)H(7))(2)(thf)(2)] with the diazabutadiene PhN==C(Me)--C(Me)==NPh (DAD) has been found to depend on the molar ratio of the reactants. Reaction in a 1:2 molar ratio affords the dinuclear mixed-valent complex [Yb(2)(mu-eta(5):eta(4)-C(9)H(7))(eta(5)-C(9)H(7))(2){mu-eta(4):eta(4)-PhNC(Me)==C(Me)NPh}] containing an indenyl ligand with an unusual mu-eta(5):eta(4) bridging coordination. Reaction of equimolar amounts of these compounds results in an organolanthanide-mediated reductive coupling of the DAD ligands and formation of the tetranuclear mixed-valent complex [Yb(2)(mu-eta(5):eta(4)-C(9)H(7))(eta(5)-C(9)H(7))(2){mu-eta(4):eta(4)-PhNC(CH(2))==C(Me)NPh}](2) with a novel tetradentate tetraimine ligand.

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In the course of comparing the reaction chemistry of (C5Me5)3U, 1, and its slightly less crowded analogue (C5Me4H)3U, 2, new syntheses of UI3, (C5Me4H)3U, (C5Me4H)3UCl, 3, and (C5Me5)3UCl, 4, have been developed. Additionally, (C5Me4H)3UI, 5, and (C5Me4H)2UCl2, 6, have been identified for the first time. A facile synthesis of unsolvated UI3 is reported that proceeds in high yield with inexpensive equipment from iodine and hot uranium turnings.

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Complexes of Dy(III) and Tm(III) with novel 1,1'-bis(iminoethyl)ethylamine ligands, [{(HN=CMe)2MeCNH2}Ln(MeCN)6]I3, were obtained by the reactions of LnI2 (Ln = Dy(II), Tm(II)) with acetonitrile.

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Two new starting materials for a new chemistry of low-valent lanthanide compounds are the first crystallographically characterized molecular complexes of the rare Nd ion, [NdI (thf) ] (1), and [TmI (thf)(dme) ] (2; dme=1,2-dimethoxyethane). These have a pentagonal-bipyramidal structure in which the two iodine atoms are in axial positions.

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A ligand-splitting transmetalation: The ansa-metalloacenes [(η -C H ) M(thf) ] (M=Yb, Ca) react with ZrCl or Me SiCl unexpectedly by splitting the ansa-bisacenyl ligand, leading to the formation of the zirconacycle [(η -C H )ZrCl (thf) ] (1) [Eq. (1)] and the 1,2-bistrimethylsilylacenaphthene (Me Si)C H , respectively.

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