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The new ligand 8,10-di-tert-butylbenzo[b][1,10]phenanthrolin-11-ol and its lanthanide complexes were obtained and their photoluminescence and electrochemical properties were studied.

The heteroligand complexes CpLn(BQ)2(DME) (BQ = 10-oxybenzo[h]quinoline, Cp = cyclopentadienyl, Ln = La (1), Nd (2), Sm (3), Gd (4)) were synthesised by the reaction of Cp3Ln with (BQ)H. The complexes of La, Nd and Sm were structurally characterised. In the case of ytterbium the reaction affords Cp2Yb(BQ)(DME) (5) and homoligand binuclear complex Yb2(BQ)6 (6) iregardless of the molar ratio of initial reagents. Upon UV excitation all the complexes gave rise to fluorescence of ligands in the visible region. The photoluminescent spectrum of compound 1 also contains a phosphorescent band with a lifetime longer than 10 ms. The complexes of Nd, Sm and Yb along with ligand emission display metal-centered luminescent f–f transitions.

A set of novel ditopic 2-mercaptothiazoles has been synthesized. Depending on the nature of the bisthiazoles their sodium salts can form coordination compounds or 2D polymers.

Zinc complexes with oxyacridine ligands (Zn(Acr)2 and [Zn(Acr)Et]2) are synthesized, and their structures are determined by X-ray structure analysis (CIF files CCDC nos. 2063229 and 2063230, respectively). The complexes exhibit a medium-intensity emission with maxima at 700 and 630 nm upon photoexcitation (λ = 405 nm). Both compounds also manifest weak electroluminescence properties. The complexes with methyl substituents in the ligands are the most luminescence-active of the whole series of the synthesized zinc compounds with the oxyacridine ligands Zn(AcrR)2 and [Zn(AcrR)Et]2 (R = Me, Br, H). The results of the MTT assay show a moderate cytotoxic activity of the synthesized compounds.

In the search for new f–d luminescent complexes of Eu(II) and Yb(II) the metathesis reactions of diiodides of these metals with perfluorinated 2-mercaptobenzothiazolates of alkali metals were studi...

Sm, Er, and Yb complexes containing anionic (4,5,6,7-tetrafluorobenzothiazol-2-yl)-2-(3,4,5,6-tetrafluoro)phenolate (SONF) and 3-(2-benzothiazol-2-yl)-2-naphtholate (NpSON) and neutral 1,10-phenathroline or 2,2'-bipyridine ligands were synthesized. The structures of complexes Yb(SONF)2-(NpSON)(DME)1.5 (II) and previously synthesized Er(SONF)3(DME) (I) were determined by X-ray diffraction (CIF files CCDC nos. 1972769 and 1972770, respectively). Upon excitation by light at λ 405 nm, all complexes showed luminescence of the ligands and Ln3+ ions. The OLED devices based on samarium complexes showed moderate intensi metal-centered emission of moderate intensity at a 19 V voltage.

A new mixed Eu(II)-Cu(I) iodide [Eu(DME)4][Cu2I4] (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)4 dications and tetraiododicuprate dianions. Upon UV light excitation (λ = 365 nm), the compound exhibits intense double-peaked photoluminescence (PL) at 445 and 500 nm. The relative intensity of these peaks changes dramatically when the temperature changes in the range of 180-250 K. To understand the nature of the found PL thermochromism, the structure and time-resolved PL of 1 were studied at various temperatures. The time-resolved PL studies of 1 at various temperatures revealed the presence of two luminescent centers which are excited by the capture of an electron from the conduction band. The ratio of intensities at 445 and 500 nm (R = I445/I500) in the PL spectra of 1 changes by almost two orders of magnitude and the relative sensitivity S (S = (∂R/∂T)/R) exceeds 5% per K in the range of 190-245 K that makes this compound a promising luminescent thermometer for the range where ammonia exists in a liquid state.

The synthesis of complexes LnI(C6F5O)2 and LnCp(L)2 (Ln = Er, Yb; L = C6F5O, SONF), which are convenient precursors for the preparation of heteroligand bimetallic complexes, is described. The structures of YbI(C6F5O)2(DME)2 (I), CpEr(C6F5O)2(DME)[(C2H5)2O] (III), and CpYb(SONF)2(DME) (VI) were established by X-ray diffraction (CIF files CCDC (nos. 1902963 (I), 1902964 (III), and 1902965 (VI)). The developed methods were used to prepare heteroligand bimetallic Yb(III)–Er(III) complexes (C6F5O)2Yb[µ-(CF3)2CHO]2Er(C6F5O)2 and {(SONF)2Yb[µ-(CF3)2CHO]2-Er(SONF)2}x, which showed metal-centered emission inherent in Yb3+ and Er3+ ions λem = 985 and 1540 nm, respectively. This suggests that the obtained compounds can serve as promising upconversion materials.

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 5·1013 n/cm2) and a pulse mode (3 ms, absorbed dose of 130 krad, flux of neutrons 3.6·1013 n/cm2). It was found that main characteristics of the compounds (shape of substance, color, IR absorption and photoluminescent spectra) have not changed. With an example of cerium complex [Ce(OON)3]2 it was revealed that the molecular structure of compounds after strong pulse irradiation also does not changed. However, computer simulations of neutron exposure on the same complexes showed significant shift of metal atoms and ligands. Possible reasons for the detected discrepancy between experimental and calculated data are discussed.

The calculation of defects in the structures of the Sc, La, Nd, Sm, Tb, and Yb complexes with substituted phenolate and naphtholate ligands formed under the action of neutrons with a mean energy of 2 MeV shows that the shifts of the target atoms depend on their masses and can achieve 1 μm for O, N, and S. A similar result is obtained for the calculation of the destruction of the Eu(TTA)3(DME)2 complex (HTTA is thenoyltrifluoroacetone). However, the treatment of the samples with the n,γ radiation does not result in destruction. Possible reasons for the found divergence between the calculated and experimental data are discussed.

Three-nuclear clusters Nd2LnI5(S2)(S2N2)(THF)9 (Ln = Tb, Tm) were prepared by the disproportionation reaction of iodide-nitride [(NdI)3N2](THF)6 with LnI3(THF)3 in the presence of sulfur. Molecule of the cluster contains a flat inorganic core formed by two Nd and Ln atoms connected by dithiadiazine group. One of the Nd atoms is bound to the Ln3+ ion, besides terminal N atom of the bridge S2N2 fragment, by a bridge fragment S2. The second Nd atom is coordinated by two iodine anions and SN group forming unusual NdSN tree-member cycle. Structure of inorganic framework of the complexes is similar to that of earlier obtained monometallic analogues Ln3I5(S2)(S2N2)(THF)10 (Ln = Nd, Dy). In both new clusters the Ln atoms have the same coordination surrounding consisting of one iodine anion, S2 group and N atom of dithiadiazine ligand and occupy in the framework Nd2Ln(S2)(S2N2) the same position which corresponds to the lowest energy of the molecule. The nitride [(NdI)3N2](THF)6 in the presence of sulfur easy reacts as well with triiodides of La and Sm. Products isolated in these reactions do not form crystals suitable for X-ray study but the data of elemental analysis, fragment analysis, the found Nd: Ln ratio, spectroscopic and magnetic measurements allow to conclude that the structure of La, Sm products is similar to that of the above Tb, Tm analogs.

Heterolanthanide clusters Nd2LnI5(S3)(S2N2)(THF)9 (Ln = Dy, Yb) are synthesized by the reactions of (NdI)3N2 with DyI3 or YbI3 and sulfur in a THF solution. X-ray diffraction analysis revealed that the structure of the complexes is similar to the structure of Nd2LnI5(S3)(S2N2)(THF) 9 obtained earlier (Ln = Tb, Tm). The ion Dy3 + in the molecule is coordinated by the iodine atom, the S2 group and the terminal N atom in the resulting S3N2 ligand. Cluster Nd2YbI5(S3)(S2N2)(THF)9 of the same structure was obtained as well when YbI2 was used instead of YbI3. Possible pathways of the reactions are discussed. UV excitation of Nd2DyI5(S3)(S2N2)(THF)9 causes low-intensity emission of Dy3+ ions: two bands at 480 and 580 nm. Magnetic measurements showed no exchange interaction in the obtained clusters.

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 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. Increasing the cathode current and tube voltage enhances the RL efficiency insignificantly. Simultaneous irradiation of the sample with X-ray and UV radiation leads to a corresponding increase in the intensity of emission. A possible mechanism of RL of organo-lanthanide complexes is discussed.

A series of homo and heterometallic La, Li and Na complexes with 2-(2-benzoxyazol-2-yl)phenolate (L) ligands were synthesized using La[N(SiMe3)2]3 and M[N(SiMe3)2] (M = Li, Na) or La(Cp)3 as starting materials for La2(L)6 (1), La2(L)6(bipy) (2), La(L)2Cp(DME) (3), La2Li(L)7 (4), Li(L) (5), Na(L) (6). Photoluminescent (PL) properties of these compounds, staring phenol H(L) as well as previously obtained complex LaNa(L)4(DME)2 (7) were studied at 300 and 77 K. Molecular structure of 2, 3 and 4 were determined by X-ray analysis. All the compounds in THF solution at 300 K upon UV excitation (370 nm) revealed a bright fluorescence in the range 430–460 nm and moderate phosphorescence as a shoulder at about 500 nm. The total quantum yield (QY) is 1–35%. At 77 K all lanthanum compounds (except 3) in THF solution exhibit weak or moderate fluorescence but intense phosphorescence (τ 3.5 – 95.8 ms). The PL spectra of solid samples at 300 K strongly differ from those of solutions, apparently due to the effects of crystal packing, the shape and size of the crystals. The emission of H(L) is most intensive but the PL of 1 has lowest efficiency. It is assumed that phosphorescence occurs from excimers and exciplexes, the formation of which in the compounds studied has been confirmed by X-ray diffraction analysis.

In the search for a way to organic up-converter materials the complex [(OON)2Er(THF)](μ-O)[(OON)2Yb(THF)] with the (benzoxazol-2-yl)phenolate (OON) ligand was synthesized. Upon excitation by laser with λex 405 nm light the complex displayed only emission of the Yb3+ ion indicating the lack of energy transfer from Yb to Er. To develop a method for preparation of other up-converter materials the complexes [Yb4(SON)8(μ4-O)(OH)2 and [Eu4(OON)10Li2(3-O)2] with (benzothiazol-2-yl)phenolate (SON) and (benzoxazol-2-yl)phenolate ligands were synthesized using water as a co-reagent. The X-ray study revealed that the clusters contain μ2-O, μ3-O and μ4-O bridges and short Ln…Ln contacts. These modelling syntheses showed that the method is applicable for preparation of potential up-convertion materials with Ln-O-Ln’ groupings.

Mononuclear terbium and erbium complexes of the composition Ln(mbtF)3phen and the dinuclear complex Tb2(mbtF)4(OH)2(phen)2 (mbtF is 4,5,6,7-tetrafluoro-2-mercaptobenzothiazolate, phen is 1,10-phenanthroline) were synthesized. The structures of the complexes Er(mbtF)3phen and Tb2(mbtF)4(OH)2(phen)2 were determined by X-ray diffraction. In the solid state, the terbium and erbium complexes exhibit intense metal-centered photoluminescence. Based on the complexes Ln(mbtF)3phen, double-layer organic light-emitting diodes (OLEDs) were assembled. These OLEDs exhibit electroplex emission with a band maximum at 630 nm.

The thermal decomposition of cluster Nd3I5(S2)(S2N2)(THF)10 (I) at 50–400°C affords a mixture of products among which tetrahydrofuran (THF), sulfur, diiodine, HI, H2S, CS2, S3N6, S3N5, MeI, thiophene, tetrahydrothiophene, diiodobutane, iodobutene, and NdI3 are identified. The treatment of Ln3I5(S2)(S2N2)(THF)10 (Ln = Nd (I), Dy (II)) with phenanthroline (Phen) in THF at room temperature results in the partial substitution of ТНF to form new complexes Ln3I5(S2)(S2N2)(THF)4(Phen)3. The dissolution of compound I in pyridine gives a pyridine (Py) complex Ln3I5(S2)(S2N2)(THF)3(Py)7. The dissolution of compounds I and II in acetonitrile at 20°C is accompanied by the fast rearrangement and fragmentation of the complexes to form LnI3(MeCN)6, [LnI(S2)(MeCN)], and [LnI(S2N2)(MeCN)]. Complex I in THF does not react with white phosphorus, carbon monoxide, fullerene C60, and chromium hexacarbonyl.

In an attempt to get more insight into the way of formation of recently obtained unusual iodide-sulfide-nitride clusters Ln 3 I 5 (S 2 )(S 2 N 2 )(THF) 10 (Ln = Nd ( 1 ), Dy ( 2 )) and modify this synthesis reactions of dysprosium iodide-nitride with sulfur were carried out in various conditions. It was found that the reaction of as prepared dysprosium iodide-nitride [(DyI 2 ) 3 N] x with sulfur in THF yields ionic complex {[DyI 2 (THF) 5 ] + [DyI 2 S 5 (THF) 2 ] − } ( 3 ) anionic part of which contains six-membered cycle DyS 5 . The same reaction in iso -propylamine medium affords ionic iodide-sulfide{[( i PrNH 2 ) 4 Dy(μ- η 2 :η 2 - S 2 )] 2 } 2+ [I − ] 2 ( 4 ) containing bipyramide core formed by two apical Dy 3+ cations and two equatorial S 2 fragments. The nitride [(DyI) 3 N 2 ] in THF does not interact with sulfur but upon addition of triiodide DyI 3 the reaction affords cluster 2 in moderate yield.

A set of new heterometallic complexes of composition of ErYb(L) 6 and Er 0.67 Yb 1.33 (L) 6 (L = 3-(2-benzothiazol-2-yl)-2-naphtholate (NpSON), pentafluorophenolate (C 6 F 5 O) and hexafluoro-iso-propoxide ((CF 3 ) 2 CHO) were synthesized and characterized by X-ray diffraction (L= (CF 3 ) 2 CHO), MALDI-TOF, 19 F NMR (L= C 6 F 5 O, (CF 3 ) 2 CHO), IR and elemental analyses. All the compounds exhibited emission of Er 3+ at 1530 nm upon direct excitation of Yb 3 + by the laser irradiation with λ ex = 910 and 980 nm that shows the intramolecular energy transfer Yb 3+ →Er 3+ . In the luminescence spectra of Er 0.67 Yb 1.33 [(CF 3 ) 2 CHO] 9 besides the band at 1530 nm the short-wavelength emission at 550 nm was found, which indicates upconversion phenomenon. Excitation of ytterbium in the mixture of monometallic iso -propoxides Er 2 [(CF 3 ) 2 CHO] 6 and Yb 2 [(CF 3 ) 2 CHO] 6 does not lead to luminescence of erbium ions which confirms intramolecular character of energy transfer in Er 0.67 Yb 1.33 [(CF 3 ) 2 CHO] 6 .

The syntheses of the 2,6-di-tert-butyl-4-(2-hydroxybenzylideneamino)phenolate (L) complexes of Gd (I), Nd (II), Er (III), Yb (IV), Tm (V), Sm (VI), and Tb (VII) are described. The structures of the Gd and Er complexes are determined by X-ray diffraction analysis (CIF files CCDC nos. 1558820 (I) and 1558819 (III)). All synthesized compounds exhibit ligand-centered photoluminescence in a range of 405–485 nm. In addition, the luminescence spectra of solid samples of the neodymium and ytterbium complexes contain narrow bands of f–f transitions characteristic of Nd3+ and Yb3+ ions.

In search of new fully fluorinated ligands which effectively sensitized the lanthanide luminescence the 4,5,6,7-tetrafluoro-1,3-benzothiazol-2(3Н)-thione (HmbtF) was proposed. Based on this ligand a set of new complexes LnL3(THF)2 (Ln1) (Ln = Nd, Gd, Tb, Dy, Er, Yb) was synthesized and their luminescence were studied. The structure of the compounds was established with an example of Gd derivative. The triplet state energy of mbtF was found to be 21500 cm−1 that enables the resonant energy transfer to Dy3+, Tb3+, Nd3+ and Er3+ ions and stipulates metal-centered emission of some complexes. In case of Yb1 the observed luminescence of Yb3+ ion probably occurs due to the non-resonant energy transfer.

In this work we investigate the chemical composition of an archetypal thin-film organic device with the Ag/LiF cathode using the time-of-flight secondary ion mass spectrometry (ToF-SIMS) with depth profiling. The LiF cathode underlayer is partly decomposed because a significant amount of lithium is released into the bulk of the multilayer device. The released lithium diffuses all the way to the substrate, accumulating, as revealed by ToF-SIMS depth profiles, at the interfaces rather than uniformly doping the underlying layers. Particularly, the bottom anode becomes chemically modified.

Composite materials (CM) consisting of polysiloxane rubber filled with lanthanide acetylacetonates, acetates, carboxylates and bismuth (III) and thorium (IV) fluorides were tested as X-ray shielding materials. It has been established that materials containing bismuth and thorium fluorides are superior in protective properties to the other studied materials, as well as to the convenient composites based on lanthanide oxides. The values of half value layer (HVL) of the materials based on BiF3(H2O) (79% wt) and ThF4(H2O) (69% wt) at X-ray irradiation with photon energy range 10–45 keV reach 0.20 mm. The obtained materials are flexible and thermally stable up to 300 °C.

A number of new zinc complexes with 1,3-di‑tert‑butyl‑7-methylacridin-4-olate or 1,3-di‑tert‑butyl‑7-bromoacridin-4-olate ligands Zn(AcrMe)2, Zn(AcrMe)2(DMSO), Zn(AcrMe)2(Py)2, [Zn(Et)(AcrMe)]2, Zn(AcrBr)2, Zn(AcrBr)2(DMSO) and [Zn(Et)(AcrBr)]2 were synthesized by the reaction of respective acridinol with Et2Zn and structurally characterized. All compounds exhibited photoluminescence in the form of a single band in the 600 - 700 nm region. Compounds Zn(AcrMe)2 and [Zn(Et)(AcrMe)]2 displayed also weak electroluminescent properties. It is found that introduction of both alkyl or bromine substituents into acridine rings cause the hypsochromic shift of emission band. The resistance of organozinc complexes to strong ionizing radiation was studied using the example of [Zn(Et)(AcrMe)]2. X-ray diffraction study showed that the molecular structure of the complex did not change after strong neutron-gamma irradiation for 45 h.

A series of rare-earth metal carboxylates M(RCOO) 3 (M = La ( 1 ), Eu ( 2 ), Gd ( 3 ), Tb ( 4 ), Er ( 5 ); R = 3,5-di- tert -butyl-4-hydroxyphenyl) was synthesized and characterized by elemental analysis, NMR, IR spectroscopy and MALDI-TOF spectroscopy. The photoluminescent (PL) properties of 1 – 5 were investigated. The electron transfer reactions were examined in CUPRAC-test. The radical scavenging activity of the complexes was measured spectrophotometrically using a DPPH-test. The EC 50 values for complexes are varied from 32 to 57 μM while the EC 50 for RCOOH is 79 μM. The inhibition of lipoxygenase (LOX-1B) in the presence of compounds was evaluated. It was found that complexes are weak inhibitors, while RCOOH is inactive. The lanthanum complex was found to be the most efficient inhibitor of lipoxygenase. Thus, the lanthanide carboxylates with 2,6-di- tert -butylphenol moiety could be used as potential antioxidants and luminescent materials.

New two- and trivalent europium complexes with dithio- and diselenodiphenylphosphinate ligands (S2PPh 2 - and Se2PPh 2 - ) have been synthesized as precursors for nanoparticles. Two-valent europium compounds have been characterized via X-ray diffraction. Their photoluminescence properties have been studied as well. EuS colloidal nanoparticles have been obtained via the thermolysis of Eu(S2PPh2) n (n = 2, 3) in a hexadecylamine medium at 310°C. The average size of objects is found to be 40–70 nm. As is established, the valent state of a lanthanide in the complex exerts no influence on the size of the forming nanoparticles or on the luminescence spectrum of colloidal solutions.

Herein, complexes [ZnL]2 (1), {(H2O)Zn(μ-L)Yb[OCH(CF3)2]3} (2), {[(CF3)2HCO]Zn(μ-L)Yb[OCH(CF3)2](μ-OH)}2 (3), and [(H2O)Ln2(L)3] (Ln = Yb (4) and Gd (5)) containing a bridging Schiff-base ligand (H2L = 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 Yb3+ ion under one- (λex = 380 nm) and two-photon (λex = 750 nm) excitation. The superior luminescence properties of complex 2, which was suggested as a marker for NIR bioimaging, were explained via the strong absorption of the 375 nm LMCT state of the ZnL chromophore, efficient energy transfer from ZnL towards Yb3+ through a reversible ligand-to-lanthanide electron transfer process, and absence of luminescence quenchers (C-H and O-H groups) in the first coordination sphere of the rare-earth atom.

Heterometallic complexes Ln(L1)5Zn (Ln = Sc, Sm, Gd) were obtained by the reactions of silylamides Ln[N(SiMe)2]3 with 2-(benzoxazol-2-yl)phenol (HL1) in the presence of diethylzinc. Similar reactions with 3-(benzothiazol-2-yl)-2-naphthol (HL2) led to the formation of complexes Ln(L2)5Zn (Ln = Nd, Er, Gd, Yb). The introduction of the zinc-containing fragments provided a considerable increase of photo- and electroluminescence intensity of the scandium complex.

The samarium complexes Sm(S2PPh2)3(THF)2 (1) and Sm(Se2PPh2)3(THF)2 (2) with soft-donor dithia- and diselenophosphinate ligands were synthesized and their photophysical properties were studied in detail. Both complexes displayed the metal-centered photoluminescence (PL) in visible and NIR regions corresponding to (4)G5/2→(6)HJ (J=5/2, 7/2, 9/2, 11/2, 13/2, 15/2), (6)FJ (J=1/2, 3/2, 5/2, 7/2, 9/2, 11/2) f-f transitions of Sm(3+). Luminescence decay curves exhibit an initial short build-up region and can be described by double or triple exponential function owing to multiphonon relaxation from the (4)F3/2 energy level to the (4)G5/2 one and reversible energy transfer from the Sm(3+) excited states to the triplet ((3)T1) state of phosphinate ligand. A Judd-Ofelt analysis was performed to estimate PL quantum efficiency (QE), branching ratios (β) and induced-emission cross section (σem) of the compounds obtained. It was found that the Judd-Ofelt parameter Ω2 of 1 is significantly greater than that of 2. This feature is responsible for large values of β (50.98%) and σem (4.29×10(-21)cm(2)) which suggest 1 as a good candidate for the development of samarium doped polymethylmethacrylate (PMMA) laser medium acting on the (4)G5/2→(6)H9/2 transition at 645nm. The estimated room-temperature PL QE of 1 and 2 equals to 1.9 and 0.17%, respectively.

The reaction of NdN and SmN with iodine gave the iodide-nitrides (NdI2)3N(DME)4 and (SmI)3N2(THF)2, which are inert towards sulfur, in contrast to the neodymium and dysprosium iodide-nitrides prepared by the reaction of LnI2 with N2. Reaction of NdN and SmN with C6F5OH and CpH gave the organolanthanide derivatives Ln(C5F5O)3(THF)n (Ln = Nd or Sm) and Cp3Sm with moderate and low yields, respectively. Phenylacetylene and styrene do not react with SmN.

The basic physicochemical properties and molecular structure of bis-(thrimethylsiloxy). phthalocyaninato silicon [SiPc(OSiMe3)2] are investigated. The temperature of melting of this complex was measured by the DSC method in the temperature interval 20–520 °C (Tm =497 °C). Thermogravimetric analysis data showed mass loss occurs in the temperature range 275−500 °C. The mass loss in this temperature range is 96 %. Mass spectrometric studies of the composition of the gaseous phase of [SiPc(OSiMe3)2] was performed in the temperature range up to 450 °C. It was found that the complex is sublimated in monomeric form. The vapor pressure of the compound was determined as a function of temperature by the Knudsen effusion method. Based on the data obtained, the thermodynamic parameters of the sublimation process are calculated. The X-ray diffraction study revealed that molecular geometric parameters of [SiPc(OSiMe3)2] are varied slightly upon changing of temperature. The photovoltaic properties of [SiPc(OSiMe3)2] studied with heterojunction solar cell of configuration of ITO/complex /C60/Bphen/Al. The operating characteristics of the cell turned out comparable with the characteristics of earlier designed analogues devices based on phthalocyanine complexes of Cu, Zn and Sn.

The cathodoluminescence (CL) of organo-lanthanide complexes is studied as a modeling of beta luminescence. It is found that complexes of Sc, La, and lanthanides with anionic OO, ON bidentate and O-monodentate ligands under excitation by fast electrons display luminescence of various intensities. In the spectra of Sc, La, Nd, Er, and Tm compounds, only broadened bands of the ligands peaked about 450 nm are observed. A similar spectrum gives anthracene, which is used as a reference compound. In contrast, the emission spectra of Eu and Tb compounds contain only the narrow bands of f–f transitions characteristic of these metals. The spectra of Sm, Dy, and Yb derivatives exhibit both the bands of ligands and weak metal-centered luminescence. X-ray luminescence (RL) of several terbium complexes is also investigated. A comparison of the photoluminescence, CL and RL spectra of the studied compounds reveals a similarity of the shape of the spectra but a significant difference in their intensities. Terbium compounds show record scintillating activity. Possible mechanisms of luminescence of organo-lanthanide complexes upon different types of excitation are discussed.

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. It has been shown that the mbtF ligands sensitize the luminescence of Nd, Sm, Tb, Er and Yb ions upon mild UV or blue light excitation. The NIR luminescence of crystalline compounds 1, 2, 4 and 6 has been studied by time-resolved techniques. As expected, the compounds exhibit prolonged NIR luminescence due to the removal of C-H groups from lanthanide centers and the absence of C-O bonds in the coordination sphere of the lanthanides. The synthesized compounds are promising materials for NIR laser applications.

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.

The o-iminobenzoquinone complexes of lanthanum, samarium, and ytterbium, Ln(L)3 (L = 3,5-ditert- butyl-1,2-quinone-1-(2-oxy-3,5-di-tert-butylphenyl)imine) are synthesized. In order to study the photovoltaic properties of the obtained complexes and previously synthesized similar complexes of zinc and aluminum M(L)2 prototypes of photovoltaic cells are prepared on their basis. An examination of the fabricated devices has revealed that nanolayers of all the compounds, except for ytterbium complex, exhibited photovoltaic properties. The best results of energy conversion are achieved for single-layer cells containing zinc complex as a photoactive material (Open-circuit voltage U OC = 1.01 V, short-circuit current J SC = 5.2 nA/cm2).

Photoluminescent (PL) and electroluminescent (EL) properties of heteroleptic complexes of Yb 3+ containing the 3-(2-benzothiazol-2-yl)-2-naphtholate (L), 8-oxyquinolate (Q), pentafluorophenolate (OC 6 F 5 ), or cyclopentadienyl (Cp) ligands were studied. All the complexes revealed NIR emission of Yb 3+ ion of different intensity. The obtained data indirectly confirm the fact that the excitation of the ytterbium in naphtholate complexes proceeds due to intramolecular reduction–oxidation mechanism.

The Schiff base NNO ligand 1-(furan-2-yl)-N-[(2-methyl-1H-imidazol-4-yl)methylene]methanamine was synthesized and structurally characterized by XRD crystallography, mass spectrometry, and NMR spectroscopy. Quantum-chemical calculations revealed conformational flexibility of the ligand backbone to give two different conformations with nearly equal ground-state energies. The orientation of two nitrogen atoms and the oxygen atom in one conformation is a good fit for the NNO tridentate coordination mode, whereas the other would allow the NN coordination mode only. Two lanthanide complexes [Ln(tta)3(NNO)] (Ln = EuIII and LuIII; tta = thenoyltrifluoroacetone) were prepared and studied spectroscopically. The structures of the complexes were optimized by the DFT approach. The NNO ligand in the Eu complex displays tridentate NNO coordination, whereas the ligand is only NN-coordinated in the Lu complex. The Eu complex shows bright red metal-centered phosphorescence under excitation into the ligand (π–π*) absorption bands with a quantum yield of ca. 80 % and a lifetime of 580 μs. A mechanism for energy transfer between the ligands and metal centers was suggested and confirmed by DFT and time-dependent DFT (TDDFT) studies. An organic light-emitting diode (OLED) device based on the Eu complex incorporated into a poly(9-vinylcarbazole) (PVK) matrix was prepared. A study of the characteristics of the device revealed electrochromism of the system owing to variations in the efficacy of metal-centered and matrix emission at different strengths of applied electric field.

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.

Saturated vapor pressure of lithium pentafluorophenolate and the lanthanide complexes as a function of temperature has been determined by the Knudsen effusion method. Processing of the pressure data allowed the calculation of thermodynamic parameters of the compounds sublimation. Mass spectra and differential scanning calorimetry data are presented.

A series of square planar [Pt(N^C)(NHC)L] complexes containing cyclometallated N^C ligands (phenylpyridine and benzoquinoline) and N-heterocyclic carbene (NHC) – N^C = 2-phenylpyridine, 7,8-benzoquinoline; NHC = 1,3-dibenzylbenzimidazolium, 1,3-diethylbenzimidazolium, 1,3-dibenzylimidazolium; L = Cl, Br, –C2Ph – have been synthesized in moderate to good yields. The complexes obtained were characterized using chemical analysis, MS-ESI spectrometry, NMR spectroscopy and X-ray crystallography. The complexes display moderate to strong phosphorescence in solution (Q.Y. 0.3–7.9%) and in the solid state (Q.Y. 2.7–16.0%), which is related to metal modulated intraligand π–π* transitions located at the aromatic system of cyclometallated ligands with some contribution of the MLCT excited state. Emission lifetimes fall in the range of 0.2–1.5 μs in solution and amount up to 13 μs in the solid state. Analysis of the spectroscopic data together with the density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations clearly support this assignment and show negligible contribution of the auxiliary ligands to the emissive excited states. The compounds obtained were also used to prepare organic light emitting diode (OLED) devices, which display good luminance efficiency emitting in the green area of the visible spectrum.

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. Photophysical properties of the complexes were studied. It was found that under photoexcitation Nd and Yb derivatives exhibit bright metal-centered luminescence in the NIR region while Sm(mbt)3(THF)2 demonstrates intensive visible emission corresponding to (4)G5/2 → (6)HJ (J = 5/2, 7/2, 9/2, 11/2) f-f transitions of Sm(3+) along with NIR emission of moderate intensity. In the case of europium compounds as well as Sm(mbt)3(Et2O) no luminescence was detected. It is assumed that the difference in photoluminescence of Yb and Eu complexes can be explained by an intramolecular electron transfer process, which efficiently proceeds in these compounds.

Herein, complexes [ZnL]

To obtain luminescent lanthanide complexes with a low energy LMCT state the 2-(2'-mercaptophenyl)benzothiazolates, Ln(SSN)3, and 2-(2'-mercaptophenyl)benzoxazolates, Ln2(OSN)6 (Ln = Gd, Yb), were synthesized by the reaction of amides Ln[N(SiMe3)2]3 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. The photophysical properties of Gd and Yb compounds were studied both in solution and in the solid state. The fluorescence spectra of the compounds in solution display the bands of the keto and enol forms of the ligands. No energy transfer from the organic part to Yb3+ has been detected in solutions of both Yb complexes, whereas in solids an intense metal-centered emission in the near infrared region was observed. The solid Gd compounds exhibited room temperature phosphorescence caused by unusually efficient intersystem crossing facilitated by the essentially reducing properties of OSN and SSN ligands. To explain the sensitization process occurring in solids Yb2(OSN)6 and Yb(SSN)3 a specific non-resonant energy transfer mechanism via a ligand to metal charge transfer state has been proposed. Based on the Yb derivatives, NIR-emitting OLEDs with 860 μW cm-2 maximal irradiance were obtained. Their Gd counterparts showed bright electrophosphorescence (up to 1350 cd m-2) in the devices containing doped emission layers.

The monophthalocyanine complexes of samarium and terbium containing axial 2-mercaptobenzothiazole (PcSm(MBT) (1)), 2-(2-benzoxazol-2-yl) phenolate (PcTb(OON) (2)) or 2-(2-benzothiazol-2-yl)phenolate (PcTb(SON) (3)) ligands were synthesized and identified by elemental, LDI-TOF and X-ray (for 1) analysis. Photoluminescence (PL) and electroluminescence (EL) spectra of the compounds contained only emission bands of phthalocyanine and axial ligands but did not contain the bands of f-f transitions. It was found that among the complexes 1, 2, 3 the latter had highest photoconductivity (~10−7 S/cm) and photovoltaic properties. An organic photovoltaic device (OPV) of configuration of ITO/3/C60/Alq3/Al revealed open-circuit voltage (VOC) of 0.24 V and short current density (ISC) of 0.3 μA/cm2 under illumination by a xenon lamp at 17 mW/cm2.