M. A. Lopatin

Terbium-containing copolymers based on the norbornene functional derivatives. Synthesis, photoluminescent and electroluminescent properties

New carbazole- and terpyridine- containing norbornene derivatives were synthesized and structurally characterized. On the basis of these compounds by the method of metathesis polymerization copolymers were obtained with carbazole and terpyridine fragments in side chains. The synthesized copolymers react with terbium pyrazolonate complex to form the terbium-containing polymeric materials exhibiting the metalcentered photo- and electroluminescence.

Chemistry of the phosphorus-nitrogen ligands. Multiple isomeric transformations of the diphosphinohydrazine bearing 8-quinolyl substituent: P→C, P→N, and P→P migrations caused by different factors.

The reaction of 8-quinolylhydrazine with 2 equiv of Ph(2)PCl in the presence of Et(3)N gives 8-[(Ph(2)P)(2)NNH]-Quin (1) (Quin = quinolyl) in 84% yield. The heating of 1 at 130 °C for 1 h in toluene results in migration of the [Ph(2)PNPPh(2)] group to a carbon atom of the quinolyl fragment to form an isomer, 7-(Ph(2)P-N═PPh(2))-8-NH(2)-Quin (2). The same migration is caused by the addition of LiN(SiMe(3))(2) to 1. On the contrary, lithiation of 1 with n-BuLi followed by the addition of ZnI(2) (1:1) affords the aminoquinolyl-phosphazenide dinuclear complex [ZnI(8-Quin-NPPh(2)═N-PPh(2))-κ(3)N,N,P](2) (4), which is a result of P→N migration. Compound 1 itself reacts with ZnI(2) in THF to form 4 and protonated molecule 1·HI, which rearranges to the more stable iminobiphosphine salt (Ph(2)P-PPh(2)═N-NH-Quin-8)·HI. Zinc iodide reacts with 2 equiv of the lithium salt of 1 without rearrangement, to form homoleptic aminoquinolyl zinc complex Zn[{(Ph(2)P)(2)NN-Quin-8}-κ(2)N,N](2) (6). Solutions of 4 and 2 in dichloromethane show luminescence at 510 and 460 nm (quantum yields are 45% and 7%, respectively). DFT calculations were provided for possible isomers and their complexes.

Europium, terbium, and ytterbium 3-(3′-triethoxysilylpropyl)pentane-2,4-dionates. Synthesis and the formation of luminescent sol-gel films

Abstract3-(3′-Triethoxysilylpropyl)pentane-2,4-dione, (EtO)3SiCH2CH2CH2C[-C(O)CH3]2 (I), was synthesized from 3-allylpentane-2,4-dione, CH2 = CH-CH2-C[-C(O)CH3]2, and triethoxysilane, (EtO)3SiH, in the presence of Speier’s catalyst. The silylation occurred mainly at the terminal C atom of the allyl group. The corresponding europium(III), terbium(III), and ytterbium(III) β-diketonates were synthesized from compound I and appropriate metal isopropoxides and used to obtain transparent sol-gel films containing Eu3+, Tb3+, and Yb3+ cations. The film formation was studied by IR spectroscopy. It was found that moisture causes not only the hydrolysis and condensation of triethoxysilyl groups but also the hydration of the cation of the rare-earth metal. When the terbium complex was excited at the wavelength of one of the two peaks (230 and 308 nm) in the excitation spectrum, the cation fluoresced intensely at 491, 547, 585, and 623 nm due to the transitions 5D4 → 7F6, 5D4 → 7F5, 5D4 → 7F4, and 5D4 → 7F3, respectively. All these bands were narrow, the band at 547 nm being most intense. No emission from the organosilicon matrix at 440 nm was observed. The emission spectra of Eu3+-containing films showed, along with the bands at 593, 618, 667, and 700 nm due to the emission from the cation (5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3, and 5D0 → 7F4 transitions, respectively), an intense band at 491 nm due to the emission from the matrix.

Stoichiometric synthesis of fullerene compounds with lithium and sodium and analysis of their IR and EPR spectra

A modified method is proposed for preparing fullerene compounds with alkali metals in a solution. The compounds synthesized have the general formula MenC60(THF)x, where Me = Li or Na; n=1–4, 6, 8, or 12; and THF = tetrahydrofuran. The use of preliminarily synthesized additives MeC10H8 makes it possible to prepare fullerene compounds with an exact stoichiometric ratio between C60n− and Me+. The IR and EPR spectra of the compounds prepared are analyzed and compared with the spectra of their analogs available in the literature. The intramolecular modes Tu(1)-Tu(4) for the C60n− anion are assigned. The splitting of the Tu(1) mode into a doublet at room temperature for MenC60(THF)x (n=1, 2, 4) compounds indicates that the fullerene anion has a distorted structure. An increase in the intensity of the Tu(2) mode, a noticeable shift of the Tu(4) mode toward the long-wavelength range, and an anomalous increase in the intensity of the latter mode for the Li3C60(THF)x complex suggest that, in the fullerene anion, the coupling of vibrational modes occurs through the charge-phonon mechanism. The measured EPR spectra of lithium-and sodium-containing fullerene compounds are characteristic of C60− anions. The g factors for these compounds are almost identical and do not depend on temperature. The g factor for the C60n− anion depends on the nature of the metal and differs from the g factor for the C60− anion.

Some reactions of dimeric silicon phthalocyanines under alkaline conditions

Reactions of bis(hydroxy)- and bis(trimethylsiloxy)diphthalocyaninato silicon with KOH were studied in o-xylene or oligosiloxane in the presence of crown ether 15-cr-5 in vacuo at 190-200 °C by the means of electronic, EPR and 1H NMR spectroscopy. Under gradual removing of H2O, consecutive formation of paramagnetic silicon diphthalocyanine monoanions (λmax580 nm), and diamagnetic silicon diphthalocyanine dianions (λmax 550 nm) have been observed. The dianions react with H2O to regenerate silicon diphthalocyanine monoanions and then the starting silicon diphthalocyanine. Reaction of the dianion with O2 results in a decomposition of silicon diphthalocyanine. 1H NMR spectra of silicon diphthalocyanine dianion have proven the absence of a ring current in the π-electron system of the dianion.

The thermodynamic properties of bis(η6-ethoxybenzene)chromium fulleride from T → 0 to 340 K

The temperature dependence of the heat capacity of crystalline bis-(η6-ethoxybenzene)chromium fulleride [(η6-(EtOPh))2Cr]·+[C60]·− was studied for the first time by adiabatic vacuum calorimetry over the temperature range 6–340 K with errors of ±0.2%. The temperature dependence of the EPR signal parameters of bis-(η6-ethoxybenzene)chromium fulleride was studied for the first time from 120 to 340 K. A reversible endothermic transformation was observed between 160 and 250 K during heating; it was caused by the dissociation of the [(C60)2]2− dimer and the formation of the [(η6-(EtOPh))2Cr]·+[C60]·− fulleride; its standard thermodynamic characteristics were estimated and analyzed. The experimental data were used to calculate the standard thermodynamic functions, including the heat capacity, enthalpy, entropy, and Gibbs function of the fulleride dimer from T → 0 to 160 K and the [(η6-(EtOPh))2Cr]·+[C60]·− monomeric complex over the temperature range 250–340 K. The standard thermodynamic properties of the fulleride studied, fullerides studied earlier, and fullerite C60 were compared.

Synthesis, structure, and thermolysis of (fullerene)(toluene)dicarbonylchromium

Fullerene C 60 has 30 essentially localized double bonds and can form η 2 complexes with transition metals. Molybdenum and tungsten π complexes of dihaptocoordinated fullerene with different ligands, such as CO, phenanthroline, α , α -dipyridyl, triphenylphosphine, and maleic and fumaric acid esters, have been prepared and structurally characterized [1–4]. The η 2 -C 60 complex with the (diphosphine)tricarbonylchromium moiety has been characterized by spectral methods [5]. As is known, (arene)tricarbonylchromium complexes can exchange the CO group for alkenes when exposed to UV irradiation [6]. Therefore, we studied the interaction of C 60 with (toluene)tricarbonylchromium under UV irradiation.

Synthesis of europium(III) phenanthroline-β-diketonate silicon-containing complex. Photoluminescence in solution and in sol-gel film

A phenanthroline benzoyltrifluoroacetonate europium complex showing a bright red photoluminescence at a wavelength 616 nm was synthesized by reacting 3-isocyanatopropyltriethoxysilane with anhydrous europium(III) tris(benzoyltrifluoroacetonate) and then with phenanthroline.

Preparation of antireflection coatings from silicon dioxide on glass and quartz by the sol-gel method with oligoethers

Antireflection coatings with a low refractive index (1.18–1.23) have been prepared on silicate glass and optical quartz from mesoporous silicon dioxide synthesized by the sol-gel method in the presence of oligoethers. The optimum concentration of the oligoester in the sol is equal to 1.5–2.5 wt %. For the single-layer double-sided coating, the maximum transmission is equal to 99.0% for the silicate glass and 99.9% for quartz.

Synthesis of C-functionalized acetylacetone and its europium complex. Preparation and study of luminescence of europium-containing sol-gel films

New fuctionalized ligand 3-(3′-triethoxysilylpropylaminocarbonyl)pent-2-on-3-en-4-ol (EtO)3SiCH2·CH2CH2NHC(O)-C[C(O)CH3][=C(OH)CH3] (I) containing ketoenol and triethoxysilyl groups is synthesized from 3-triethoxysilylpropyl isocyanate (EtO)3SiCH2CH2CH2N=C=O and acetylacetone. The reaction is accompanied by the formation of 2-(3′-triethoxysilylpropylaminocarboxy)-pent-2-en-4-one (EtO)3SiCH2CH2·CH2NHC(O)-OC(CH3)=CH-C(O)CH3 (II), the product of addition of acetylacetone enol form to isocyanate group. The ratio of amide I and urethane II forms is 7:3. Europium(III) tris[3-(3′-triethoxysilylpropylaminocarbonyl) pent-2-on-3-en-4-olate] is prepared from I and Eu(i-OPr)3. An alternative pathway consists in the reaction of europium tris(acetylacetonate) with 3-triethoxysilylpropyl isocyanate. Conditions of formation of transparent europium-containing sol-gel films were developed. Thermal stability and photoluminescence of the films were investigated.