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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.

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.

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.

Three new sterically hindered acridin-4-ols have been prepared by alkylation of anilines with 3,5-di-tert-butyl-6-methoxymethylcatechol followed by oxidation of the reaction mixture. Formation of the acridine moiety was found to occur in the course of oxidation of the intermediate (anilinomethyl)catechol on contact with air in the Et2O/H2O–KOH system. The molecular structure of two acridin-4-ols was determined by single-crystal X-ray diffraction.

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.

Temperature dependences of the saturated vapor pressure of lanthanum complexes based on 2-(2-benzoxazol-2-yl)phenolate ligand have been obtained using the Knudsen effusion method. The thermodynamic parameters of vaporization have been calculated from the p−T data. Mass spectra and differential scanning calorimetry data have been obtained.

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.

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.

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.

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.

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 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.

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.

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.

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.

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]

The ethyl complexes of dysprosium DyI2Et(DME)2 and DyIEt2(DME)2 were synthesized by the reaction of DyI2 with ZnEt2 in dimethoxyethane. The complexes were isolated as pale yellow crystals. According to the X-ray diffraction data, these compounds contain, in addition to DyI2Et(DME)2 and DyIEt2(DME)2, triiodide DyI3(DME)2 (1). The reactions of CdMe2 with NdI2, DyI2, and TmI2 proceed in a similar way and afford methyl iodide complexes of lanthanides. The reaction of GaEt3 with DyI2 gave the ionic complex of trivalent dysprosium [GaEt4]−[DyI2(THF)5]+ (2).

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.

(2-Benzox(thi)azol-2-yl)phenolate and -naphtholate ate complexes of Sc, Y, La, Sm, Tb, and Yb are synthesized. The structure of (benzoxazolyl)phenolate complexes of La, Sm, and Yb are determined by X-ray diffraction analysis. All synthesized compounds manifest ligand-centered photo- and electroluminescence in a range of 510–540 nm. In addition, the spectra of the samarium and terbium complexes exhibit narrow bands of f-f transitions characteristic of Sm3+ and Tb3+ ions.

A series of Pr, Nd, Ho, Er, Tm, and Yb complexes with 3-(2-benzoxazol-2-yl)-2-naphtholate and 3-(2-benzothiazol-2-yl)-2-naphtholate ligands was synthesized. The structure, as well as the photo- and electroluminescent properties of these complexes were studied. An extraordinary bright emission of Yb3+ was detected. To explain the phenomenon, a novel excitation mechanism involving intramolecular electron transfer was proposed.

The complexes of trivalent lanthanides Ce, Sm, Eu, Gd, Tb, Dy with 2-(2-benzoxyazol-2-yl)phenolate (OON), 2-(2-benzothiazol-2-yl)phenolate) (SON) and 2-(2-benzoimidazol-2-yl)phenolate (NON) ligands were synthesized by the reactions of silylamides Ln[N(SiMe3)2]3 with respective phenol. Heteroleptic complex Tb(NON)2(SON) was obtained when Tb[N(SiMe3)2]3 was treated simultaneously with NONH and SONH. X-ray analysis of Ce(OON)3, Eu(OON)3, Sm(SON)3, Gd(NON)3, Dy(NON)3 and Tb(NON)2(SON) revealed that all the compounds are dimers with two bridging and four terminal XON ligands (XON)2Ln(μ-XON)2Ln(XON)2. In the heteroleptic complex the SON ligands are bridging but the NON groups are terminal. The molecules of the complexes in crystals are stacked with short intra- and intermolecular distances between planar ligands. This feature is reflected in the luminescence spectra of Gd, Tb (with SON ligands) and Dy complexes. Photo- and electroluminescence spectra of Ce, Gd and Dy derivatives showed only ligands emission in the region from 430 to 530 nm. The spectra of Sm and Tb complexes contain as well the bands of f-f transitions typical for corresponding metal ion. The complexes of Eu revealed no luminescence.

Unprecedented complexes of the composition Ln3I5(S2N2)(S2)(THF)10 were obtained in the reactions of neodymium and dysprosium iodide-nitrides with sulfur. The inorganic core of the molecules contains the cyclic fragments Ln(μ-S2)Ln, LnSNSN and LnSN. Ten of the fourteen atoms of the core are coplanar, the remaining four S2 and I2 atoms lie in the other two orthogonal planes. The dysprosium complex upon excitation with UV light exhibits the metal-centered luminescence characteristic of the Dy(3+) ion. Geometric parameters of the molecules, computational data, electron spectroscopy and fluorescence suggest the existence of some conjugation in the mentioned heterocycles.

A new class of Sc, Eu, and Tb complexes with N,O-chelate ligands was synthesized for the first time. The mass spectra, thermogravimetric analysis, differential scanning calorimetry data, as well as the data on the saturated vapor pressure of the compounds were obtained. The main thermochemical parameters of the compounds were calculated.

Efficient yellow–green electroluminescence emission at λmax = 530 nm with CIE coordinates x = 0.3913, y = 0.4947 was obtained with organic light-emitting devices based on tris(2-methyl-8-quinolinolate) scandium (1). The device with the configuration of indium tin oxide/N,N′-bis(3-methylphenyl)-N,N′-diphenylbenzidine/1/Yb exhibits current efficiency of 3.1 cd/A and power efficiency of 1.8 lm/W at a luminance of 100 cd/m2. The DFT calculations demonstrate that structural changes of the scandium complex 1 influence the electroluminescence spectrum, the better agreement with experimental data being achieved when monodentate ligands are taken into consideration.

The luminescent properties of homoleptic scandium complexes with 2-substituted 8-hydroquinolines bearing the substituent groups H (1), CH3 (2), CN (3), and NH2 (4) were studied for use as emission layers in organic light-emitting diodes. It was found that the introduction of a substituent into the 2-position makes its possible to effectively shift the emission maximum to the blue or red region: to 530 nm (yellow-green) by 1 and 2, 615 nm (orange) by 3, and 495 nm (blue-green) by 4. The structure and the optical properties of the complexes were determined by density-functional-theory quantum-chemical calculations. The theoretical spectra agree well with the experimental photoluminescence spectra.

The rare earth metal isoindolinates Ln(iPrL)3 (Ln = Sc (1), Y (2), Eu (3), Dy (4), Yb (5); iPrL = 1,3-bis(isopropylimino)isoindolinate anion) and [(MeL)Ce]2(μ-MeL)4 (6) (MeL = 1,3-bis(methylimino)isoindolinate anion) were synthesized by reactions of the amides Ln[N(SiMe3)2]3 with 1,3-bis(isopropylimino)isoindoline (iPrLH) or 1,3-bis(methylimino)isoindoline (MeLH), respectively. The X-ray diffraction study revealed that in monomeric molecules of the isopropyl-substituted compounds 2 and 4 the cations Ln3+ are η2-coordinated by three isoindolinate ligands. The methyl-substituted 6 exists in a crystal as a dimer containing two terminal η2-coordinated ligands and four bridging isoindolinate ligands two of which are bonded to Ce atoms in η3 fashion (η:η:η-N,N,N) but two others in η4 manner (η:η2:η-N,N,N). All the obtained complexes in solutions exhibited ligand-centered photoluminescence, the spectra of which consist of one broadened band with a maximum at 400–450 nm.

The reactions of phthalonitrile with MeNH2, PrnNH2, and PriNH2 in the presence of catalytic amounts of LnI3 (Ln = Nd or Dy) or LnI3(THF)3 (Ln = Gd or Nd) afford 1,3-bis(alkylimino)isoindolines (Alk = Me (1), Prn (2), or Pri (3), respectively). Under analogous conditions, 2-aminopyridine gives 1,3-bis(2-pyridylimino)isoindoline (4). The X-ray diffraction study of compound 3 showed that, in the crystalline state, this compound exists as the isomer, 1-isopropylamino-3-(isopropylimino)isoindole.

The acetamidinates {[MeNC(Me)NMe]2Ln}2[μ-η2-η2-MeNC(Me)NMe]2 (Ln = Y (1), Dy (2)) and {[PrnNC(Me)NPrn]2Y}2[μ-η2-η2-PrnNC(Me)NPrn]2 (3) have been prepared by the reactions of amides Ln[N(SiMe3)2]3 with respective N,N′-disubstituted amidines MeNC(Me)NHMe or PrnNC(Me)NHPrn. The reaction of Er[N(SiMe3)2]3 with excess of monosubstituted amidine HNC(Me)NHPri or in a ratio of 1:2 resulted in the formation of compound {Er[NC(Me)NHPri]3}x (4). The same reaction with 1:1 ratio yielded heteroleptic complex {Er[N(SiMe3)2]2[NC(Me)NHPri]}x (5). The complexes 1, 2 and 3 have similar structures and contain four terminal and two μ-η2:η2-N,N-bridging amidinate groups binding the metal atoms. Volatility of 1, 2 and 3 is comparable to that of known monomeric La[PriNC(R)NPri]3. Compound 1 efficiently catalyzes the ring-opening polymerization of rac-lactide to give polylactide with Mn 53 085 and polydispersity 1.84.

Amination of acetonitrile by the amines MeNH2, PrnNH2, PriNH2, ButNH2, and Et2NH is efficiently promoted by the lanthanide iodides LnI2 (Ln = Nd, Dy, Tm), LnI3 (Ln = Pr, Nd, Dy) and LnI3(THF)3 (Ln = Pr, Nd, Dy). The formed mono- and N,N′-disubstituted amidines MeC( NH)NHR (R = Pri, But), MeC( NH)NEt2, MeC( NR)NHR (R = Me, Prn) were isolated mainly as the complexes with starting iodide of general composition LnI2(amidine)x (1) or LnI3(amidine)x (2) (x = 3–8). In the products 1, which evidently are the mixtures of LnI2+, LnI 2 + and LnI3 derivatives, the metal exists in trivalent state but one of the ligands actually is amidinate anion. A part of the generated amidines remains in the reaction solutions in free form. Heating of the 1 and 2 in vacuum at 150–200 °C affords corresponding amidine and the complexes with reduced amount of the amidine ligands LnI2(amidine)y (3) or LnI3(amidine)y (4) (y = 2–3). The products 3 and 4 displayed the same catalytic activity in the acetonitrile-amine cross-coupling as the initial iodides. SmI2 and especially YbI2 revealed lower activity. The structure of isopropylacetamidine (5), tert-butylacetamidine (6) and {Dy[MeC( NH)NEt2]6}I3(MeCN) (7) were determined by X-ray diffraction analysis.

The reactivity of neodymium diiodide, NdI2 (1), towards organosilicon, -germanium and -tin halides has been investigated. Compound 1 readily reacts with Me3SiCl in DME to give tri- methylsilane (6 %), hexamethyldisilane (4 %) and (Me3Si)2O (19 %). The reaction with Et3SiBr in THF results in formation of Et3SiSiEt3 (17 %) and Et3SiOBu n (34 %). Alkylation of Me3SiCl with Pr n Cl in the presence of 1 in THF affords Me3SiPr n (10 %), Me3SiOBu n (52 %) and Me3SiSiMe3 (1 %). The main product iden- tified in the reaction mixture formed upon interaction of 1 with dichlorodimethylsilane Me2SiCl2 in THF is di-n-butoxydimethyl- silane Me2Si(OBu n )2 (54 %) together with minor amounts of Me2Si(OBu n )Cl. The reaction of 1 with Me3GeBr under the same conditions produces Me3GeGeMe3 (44 %), Me3GeH (3 %), and Me3GeI (7 %). An analogous set of products was obtained in the reaction with Et3GeBr. Treatment of trimethyltin chloride with 1 causes reduction of the former to tin metal (74 %). Me3SnH (7 %) and hexamethyldistannane (11 %) were identified in the volatile products. The reaction of 1 with Me3SiI provides straightforward access to hepta-coordinated NdI3(THF)4 (2), the structure of which was determined by X-ray diffraction.

The reactions of NdI2 (1) with aryl halides, PhX (X = Cl, Br, I), in THF afford benzene and a minor amount of biphenyl. Benzyl chloride under the same conditions yields 1,2-diphenylethane, toluene and PhCH2I due to Cl/I exchange. Alkyl halides C7H15Br and cyclo-C6H11Cl are reduced to the corresponding hydrocarbons. t-BuCl affords a mixture of isobutane/isobutylene. Chlorotrimethylsilane is converted into Me3SiH, hexamethyldisilane and Me3SiO(CH2)4CH3 in 10%, 8% and 31% yields respectively at room temperature but 1%, 2% and 88% yields at −60 °C. In benzene, the interaction of 1 with benzyl chloride proceeds at 80 °C to give diphenylmethane in 66% yield. Without solvent the same reaction leads to formation of the oligomers PhCH2(p-C6H4CH2)nC6H4CH2Cl. Heating 1 in benzene with n-BuCl or cyclo-C6H11Cl affords mono- and disubstituted products, RC6H5 and 1,4-R2C6H4. The n-Bu groups in the reaction transform into sec-Bu isomers. Iodobenzene, bromobenzene, Me3SiCH2Cl and Me3SiCl are inert towards 1 in benzene.

Reactions of DyI2 with (C6F5)3GeH, (C6F5)3GeBr, and (C6F5)2GeBr2 gave rise to the hyperbranched polymer [(C6F5)2Ge(C6F4)]n (4) in 22% to 65.7 yields. The major product of the reaction with (C6F5)3GeBr was perfluorinated hexaphenyldigermane in 61% yield. Under the same conditions, the germylmercury compound [(C6F5)3Ge]2Hg yielded the ionic complex { [(C6F5)3Ge]3Hg}−[DyI2]+. Hexaphenyldigermane slowly reacted with DyI2 even at elevated temperature to give polymer 4 in 8% yield. Perfluorinated tetraphenylgermane and nonfluorinated phenylgermanes Ph3GeH, Ph3GeGePh3, and (Ph3Ge)2O did not react with DyI2 but they initiated its reaction with THF.

The reactions of LnI2 (Ln = Nd, Dy, Tm) with benzonitrile are accompanied by disproportionation, resulting in the formation of triiodides LnI3(PhCN)4 and an intractable mixture of monoiodine derivatives LnI(R)R". Hydrolysis of the mixture gives 2,4,6-triphenyl-1,3,5-tiazine, 2,3,5,6-thetraphenyl-1,4-pyrazine, and 2,4,5-triphenylimidazole. The reaction of dysprosium diiodide with acrylonitrile gives a metal-containing polymer with a molecular weight of 2700. Treatment of the polymer with water results in separation of DyI2(OH)(H2O)x to give metal-free polyacrylonitrile with a molecular weight of 2400.

ansa-Metallocene derivative (η5-Gaz)2Ca(THF)2 (1) (Gaz = 1,4-dimethyl-7-isopropylazulene) was synthesized by the reaction of CaI2(THF)2 with two equivalents of potassium and two equivalents of guaiazulene in THF. The ytterbium analog ansa-(η5-Gaz)2Yb(THF)2 (2a) was synthesized by the reduction of guaiazulene with ytterbium naphthalenide in THF. The recrystallization of 2a from pyridine leads to the exchange of the coordinated solvent molecules and gives ansa-(η5-Gaz)2Yb(NC5H5)2 (2b). The molecular structures of 1, 2a, and 2b were determined by X-ray diffraction analysis. The crystals of 1, 2a, and 2c consist of a racemic mixture of both R,R- and S,S-enantiomers. The calcium and ytterbium atoms η5-coordinate the five-membered rings of the guaiazulene ligands. The 1H NMR spectroscopic and X-ray diffraction data unambiguously confirm the exclusive formation of N2-symmetric ansa-metallocenes in these reactions. The reaction of compound 1 with Me3SiCl in THF occurs with retention of the N—N bond between two guaiazulene moieties and affords bis(1,4-dimethyl-3-trimethylsilyl-7-isopropylazulene) (3) in high yield.

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) = 0.2147, 0.2379) in the case of 1, a cyan hue (0.2702, 0.3524) in the case of 2, and a yellowish hue (0.3468; 0.4284) in the case of 3.

The reactions of phthalonitrile with MeNH2, PrnNH2, and PriNH2 in the presence of catalytic amounts of LnI3 (Ln = Nd or Dy) or LnI3(THF)3 (Ln = Gd or Nd) afford 1,3-bis(alkylimino)isoindolines (Alk = Me (1), Prn (2), or Pri (3), respectively). Under analogous conditions, 2-aminopyridine gives 1,3-bis(2-pyridylimino)isoindoline (4). The X-ray diffraction study of compound 3 showed that, in the crystalline state, this compound exists as the isomer, 1-isopropylamino-3-(isopropylimino)isoindole.

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. The LDI-TOFMS investigation displayed that under the laser impact the compounds split off Q(-) anions to give Ln3Q8(+), Ln2Q5(+) and LnQ3(+) moieties. In the negative mode spectra the anions Q(-) and LnQ4(-) were observed. The DFT calculations showed the decreased stability of cationic Ln-quinolinolate as compared with their anionic counterparts. Complex 2 which is used as an emitter in a three-layer OLED displayed a metal-centered emission at 979 nm and an intensity of 50 μW cm(-2) at 15.5 V.