Four novel copper(II) complexes of N-quinolyl or N-naphthyl substituted (3-aminovinyl ketones, derivatives of either benzoylacetaldehyde or benzoylacetone were synthesized. Their structures and physico-chemical properties were studied using single-crystal XRD analysis, XANES and EXAFS, IR, EPR, and UV-Vis spectroscopy, magnetic measurements, and DFT calculations. All investigated metal chelates have the ML2 composition. The square-planar coordination geometry in the N-naphthyl substituted copper(II) ketoiminate complexes is formed by bidentate NO coordination of the deprotonated (3-aminovinyl ketones. Both copper(II) N-quinolyl substituted ketoiminate complexes have square-pyramidal coordination geometry with one of two deprotonated (3-amino- vinyl ketone ligands coordinated as NNO tridentate. In the copper(II) complex of N-quinolyl substituted (3-aminovinyl ketone derived from benzoylacetaldehyde, the remaining coordination sites are occupied with the enamine and quinoline nitrogen atoms of the second ligand. On the other hand, in the copper(II) complex prepared from its (3-methyl derivative the second ligand coordinates through the azomethine nitrogen and the enamine ketone oxygen. Antibacterial, antifungal, and protistocidal activity of compounds was tested. The (3-methyl substituted N-quinolyl-(3-aminovinyl ketone and its copper(II) complex exhibit the most pronounced biological activity.

The article represents a translation of Section 6.2 of the monograph authored by A.S. Burlov, V.G. Vlasenko, D.A. Garnovskiy, A.I. Uraev, E.I. Maltsev, D.A. Lypenko, and A.V. Vannikov, Electroluminescent Organic Light-Emitting Diodes Based on Metal Coordination Compounds, Rostov-on-Don: Yuzhn. Fed. Univ., 2015; ISBN 978-5-9275-1469-4 (see Additional Information), dedicated to reviewing the photoluminescence and electroluminescence properties of metal complexes based on (Zn, Cd, Al, Sc, Be, B) with azoles (2-(2-hydroxyphenyl)benzothiazoles, 2-(2-hydroxyphenyl)benzoxazoles, 2-(2-hydroxyphenyl)benzimidazoles, azaindoles, oxadiazoles, and their derivatives) as ligands. Modifying such ligands by introducing electron-donating substituents into various positions of the phenyl fragments leads to significant changes in their electroluminescence characteristics. Metal complex compounds with ligands of this type are widely used for creating OLED devices emitting white light.

This review article explores and analyzes published data on the photoluminescence and electroluminescence characteristics of rare earth element (REE) complex compounds, which are promising materials for creating highly efficient OLED devices. Distinguishing features of such compounds include their narrow emission bands, Stokes shift, long lifetime, and high quantum yields, enabling high resolution and color purity in constructed OLED devices. Using REE complexes as emissive layers in light-emitting diodes ensures significant color saturation and high device efficiency.

The article represents a translated, revised, and updated Section 6.3 of the monograph by A.S. Burlov, V.G. Vlasenko, D.A. Garnovskiy, A.I. Uraev, E.I. Maltsev, D.A. Lypenko, and A.V. Vannikov, Electroluminescent Organic Light-Emitting Diodes Based on Metal Coordination Compounds, Rostov-on-Don: Yuzhn. Fed. Univ., 2015; ISBN 978-5-9275-1469-4 (see Additional Information). This section is dedicated to reviewing the photoluminescence and electroluminescence properties of metal complexes based on bi- and polydentate ligands of the azomethine type (Schiff bases). Many metal complexes of Schiff bases find wide use as luminescent materials. One of the applications of these compounds is the use as emissive layers or dopants for manufacturing OLED. The photo- and electroluminescence properties of a series of the metal complexes with the ligands based on the derivatives of hydroxybenzaldehyde, 2-(N-tosylamino)benzaldehyde, 1‑phenyl-3-methyl-4-formylpyrazol-5-one, and some others are reviewed. The systematic categorization of these compounds extends beyond their photophysical properties to consider the electroluminescence characteristics observed in OLED devices employing them as the basis. By modifying known azomethine-type ligand systems, one can obtain metal complex compounds with exceptional thermal stability, solubility, and quantum efficiency. These characteristics enable their use as luminescent materials in highly efficient OLED devices.

The review is devoted to analysis of photo- and electroluminescent properties of metal complexes (Al, Be, Mg, Ga, In, Zn, and B) based on substituted quinoline derivatives. Literature data shows that changing the substituents in quinoline ligands and the metal complexing agent can affect the color and intensity of photoluminescence in the corresponding metal complexes. OLED devices fabricated based on these complexes have exhibited high brightness and efficient electroluminescence across a broad spectral range from red to blue. Furthermore, these compounds possess excellent electron-transport properties, enabling their utilization as conductive layers in OLEDs.

This review summarizes the results of the synthesis, photoluminescence, and electroluminescence of the main classes of cyclometallated iridium(III) complex compounds. The primary focus of the review is on heteroleptic iridium(III) complexes, which contain two equivalent C^N ligands and an additional auxiliary ligand. Numerous examples demonstrate that the selection and modification of the ligand systems in iridium(III) complexes, using various donor or acceptor groups, alter significantly their spectral characteristics, often achieving record levels of brightness and emission efficiency for OLED devices manufactured based on them.

A series of novel Zn(II) bischelate complexes based on azomethines of 2-(N-tosylamino)benzaldehyde and aromatic amines (aniline, 4-methylaniline, 4-methoxyaniline, 2-methoxylaniline, and 4-ethoxylanine) were designed and synthesized with the aim of studying their photo- and electro-luminescent properties. The structures of the synthesized azomethines and their complexes were studied by elemental analysis, infrared (IR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. The structure of the Zn(II)-complexes was determined using X-ray diffraction analysis. In the solid state, azomethines exhibit bright luminescence in the yellow part of the spectrum with high emission efficiency and quantum yields of approximately 50 %. Zinc complexes based on them exhibit noticeable luminescence in the solid state and in solutions of methylene chloride. Compared to azomethines, the luminescence maxima of Zn(II) complexes are hypsochromically shifted, and they exhibit pronounced blue-green luminescence. The OLED devices based on zinc(II) complexes emit strong bluishgreen light with a peak maximum at 478-490 nm. The device with the best parameters has a maximum luminance of 2103 cd/m2, a current efficiency of 14.0 cd/A, and an overall efficiency of 4.8 %, with a turn-on voltage of 3.6 V.

Two new Schiff base compounds of N‐{2‐[(E)‐сyclohexyliminomethyl]phenyl}‐4‐methylbenzenesulfonamide, N‐{2‐[(E)‐(4‐сyclohexylphenyl)iminomethyl]phenyl}‐4‐methylbenzenesulfonamide and their Zn(II) complexes have been synthesized and characterized by elemental analysis, FT‐IR and UV–Vis spectra, and single crystal X‐ray determination. In both complexes, Zn2+ ions have a tetrahedral environment with two nitrogen atoms of the tosylamide groups and two nitrogen atoms of the imine fragment. Time‐dependent density functional theory calculations have been performed on two zinc(II) complexes in order to assign their experimental UV–visible absorption bands. Zinc(II) complexes showed thermal stability up to 335–340°C under a nitrogen atmosphere by thermogravimetric analysis (TGA). The photoluminescent spectra show that both Zn(II) complexes in the solid state at room temperature emit blue luminescence with high emission quantum yields of 20% and 29%. The doped devices with configurations of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS)/N,N′‐Di(1‐naphthyl)‐N,N′‐diphenyl‐(1,1′‐biphenyl)‐4,4′‐diamine (NPD)/4,4′‐N,N′ ‐dicarbazolebiphenyl (CBP):Zinc(II) complex (5%)/1,3,5‐tris(N‐phenylbenzimidazole‐2‐yl) benzene (TPBI)/LiF/Al have been fabricated and investigated. The doped device based on the complex with the сyclohexylphenyl substituent of the ligand showed the best electroluminescent characteristics with maximum brightness Lmax of 3415 cd/m2, maximum current efficiency of 2.8 cd/A, and power efficiency of 1.9 lm/W, while the doped device with emitter on the base of the complex with the сyclohexyl substituent showed slightly worse electroluminescence (EL) performance with Lmax of 2105 cd/m2, maximum current efficiency of 2.1 cd/A, and power efficiency of 1.6 lm/W.

Two Zn(II) and Ni(II) complexes derived from the N-[2-(2-diethylphosphonylethyliminomethyl)phenyl]-4methylbenzenesulfonamide ligand (HL) with stoichiometry ML2 (M = Zn, Ni) have been synthesized. Their structures have been established using elemental analysis, IR, 1H NMR, UV-Vis spectroscopy, and synchrotron single-crystal X-ray diffraction. The Zn(II) and Ni(II) metal sites therein adopt the tetrahedral configuration. The DMSO and toluene solutions of the Zn(II) complex manifest photoluminescence in the blue-violet spectral range characterized by PL maxima at 436 and 432 nm and quantum yields of 0.15 and 0.30, respectively.

β-Aminovinyl ketone (2-nitro-3-(8-quinolylamino)prop-2-enal) was synthesized by condensation of nitromalondialdehyde with 8-aminoquinoline. The reactions of β-aminovinyl ketone with copper, nickel, and cobalt acetates in methanol gave metal complexes. The spectral and magnetic characteristics of preparatively isolated compounds were studied. The structure of cobalt(II) chelate was determined on the basis of X-ray diffraction study (CIF file CCDC no. 2109263).

Zn(II) and Cd(II) complexes based on N-[2-(diethylaminoalkyliminomethyl)-phenyl]-4-methyl-benzenesulfonamide (HL) of composition ML2 and MHLCl2 were synthesized. The structures of the complexes were established by elemental analysis, IR, H-1 NMR, UV spectroscopy, X-ray absorption spectroscopy (EXAFS), and X-ray crystallography. The complexes demonstrate photoluminescent properties in the blue-violet region of the spectrum with the maxima of the PL bands at 426-448 nm and quantum yields of 0.2-0.34.

New Zn(II) complexes of bidentate Schiff base ligands were synthesized and characterized by 1H NMR, IR spectroscopy, and elemental analysis. The single‐crystal X‐ray diffraction study revealed that all compounds can be represented as mononuclear zinc(II) complexes with two bidentate organic ligands coordinated to the central metal atom by two oxygen and two nitrogen atoms. The photophysical properties of the complexes were investigated by UV–vis and photoluminescence spectroscopy in dimethyl sulfoxide (DMSO) solutions. It was found that the positions of maxima of the long‐wavelength absorption bands and photoluminescence depend strongly on the substituent in the aldehyde and amine fragments. The nature of the bands of electronic absorption spectra in DMSO solutions was interpreted using the results of quantum chemical calculations in the time‐dependent density functional theory (TD‐DFT) approximation. The light emission performance of the complexes in organic light‐emitting diodes was investigated. The electroluminescence (EL) spectra maxima of all three complexes are located in the visible range from 470 to 550 nm. The absence of additional spectral maxima or shoulders in the EL bands means that neither exciplex nor excimer states form, and the observed EL bands are due to the intrinsic radiation of the zinc(II) complexes. EQEs were measured for these three complexes. The maximum value, close to 3%, was obtained in the case of a structure with a maximal brightness of 8000 cd m−2 at 17 V.

The aminomethylene derivatives of pyrazole-5-one (6) and pyrazole-5-thione (7) were synthesized in the reaction of 2-aminophenol (4) with corresponding 1-phenyl-3-methyl-5-X-pyrazole-4-carbaldehyde (1, X = hydroxy) or (2, X = sulfanyl). Reaction of 2-aminobenzenethiol (5) with 1-R-3-methyl-5-sulfanylpyrazole-4-carbaldehydes (2, R = phenyl and 3, R = isopropyl) results in the formation of disulfide compounds 8 and 9. The structures of compounds 6-9 were determined by IR and NMR spectroscopy and elemental analysis. The reaction of each ligand 6-9 with copper(II) acetate monohydrate in ethanol resulted in dinuclear metal-chelates with Cu2N2O4, Cu2N2O2S2, Cu2N2S4 chromophores. All complexes were characterized with C, H, N elemental analysis, FT-IR, ESR and X-ray absorption spectroscopy. The structures of the complexes 11 and 13 were determined by X-ray single-crystal diffraction. The variable-temperature magnetic susceptibility measurements in the 2-300 K temperature range were performed and the influence of the type of bridging atoms on the magnetic and spectral properties was discussed. The nature of magnetic and spectral properties of the copper chelates was analyzed using DFT quantum-chemical calculations within broken-symmetry and time dependent (TD DFT) approximations, correspondingly. (C) 2020 Elsevier Ltd. All rights reserved.

A series of Zn(II) complexes of the tridentate azomethine ligands, condensation products of 2‐(N‐tosylamino)benzaldehyde and 2‐aminoalkylpyridines, were synthesized by chemical and electrochemical methods. All compounds were characterized on the basis of C, H, N elemental analysis, Fourier‐transform infrared, 1H nuclear magnetic resonance, UV–Vis, and photoluminescence studies. The local atomic structures of complexes were determined from analysis of extended X‐ray absorption fine structure and X‐ray absorption near‐edge structure of Zn K‐edges. The molecular structure of chloro‐{4‐methyl‐N‐[2‐[(Z)‐2‐pyridyl)ethyliminomethyl]phenyl]benzenesulfamide}zinc(II) was determined by X‐ray single‐crystal diffraction. The fluorescence spectra show that these complexes in dimethyl sulfoxide solutions at room temperature emit bright blue luminescence at 435–461 nm with fluorescence quantum yields in the range of 0.20–0.31. The assignment and the nature of the bands in experimental UV–Vis spectra of complexes were analyzed using time‐dependent density functional theory calculations B3LYP/6‐31G(d). The azomethines and complexes of zinc have been screened for their antibacterial, protistocidal, and fungistatic activities against Penicillium italicum, Colpoda steinii, Escherichia coli 078, and Staphylococcus aureus P‐209, and the results are compared with the activity of furazolidone, chloroquine, and Fundazol.

•The structures and bioactivity of Co(II), Ni(II), Cu(II) complexes were studied.•The molecular structures of complexes were determined by the X-ray diffraction method.•The antibacterial, protistocidal, and fungistatic activities of the Co(II), Ni(II), and Cu(II) complexes have been screened.

Осуществлен синтез комплекса Ni(II) на основе (4Z)-4-[(2-диэтиламиноэтиламино)мети­лен]-5-метил-2-фенилпиразол-3-она (НL) — продукта конденсации 5-гидрокси-3-метил-1-фенилпиразол-4-карбальдегида с N,N-диэтилэтилендиамином. Методами элементного анализа и ИК спектроскопии установлено, что комплекс никеля имеет состав Ni(L) CH3COO·CH3OH·H2O. Кристаллическое и молекулярное строение комплекса определено методом монокристальной рентгеновской дифракции. Из данных РСА следует, что в монохелатном комплексе Ni(II) реализуется искаженное октаэдрическое строение за счет связей с монодентатным ацетат-анионом и молекулами метанола и воды.

Refluxing of equimolar amounts of 2,2'-bipyridine (bipy) and N, N, S-tridentate basic form of the Schiff base N-[2-[[3-methyl-1-phenyl-5-thioxo-pyrazole-4-ylidenemethyl]amino]phenyl]-4-methylbenzenesulfonamide (H2L) with corresponding metal acetate hydrate (Cu, Ni, Zn, Cd) in acetonitrile-methanol solution (1:1) give rise to the formation of mononuclear mixed ligand complexes with a common formula [M(L)bipy]center dot(CH3CN) (M = Cu(II), Ni(II), Zn(II)) (1-3) and binuclear cadmium(II) heteroleptic compound with the composition [Cd-2(L)(2)(bipy)(2)]center dot(CH3CN)(2)(CH3OH)(2) (4). All compounds were characterized by C, H, N elemental analysis, FT-IR, H-1 NMR, and magnetic measurements. The structures of the ligand H2L and complexes 1, 3 and 4 were determined by X-ray single-crystal diffraction. The metal center in 1, 3 is surrounded with imine and amide nitrogen, sulfur of thiol group of H2L and two nitrogen of 2,2'-bipy employing as the auxiliary ligand. The crystal structure of binuclear cadmium complex reveals unexpected mu(2)-O sulfonamido bridges. The time-dependent density functional theory (TD-DFT) calculations have been performed to explore the assignment and the nature of the bands in experimental UV-vis absorption spectra of adducts 1-4. (C) 2020 Elsevier Ltd. All rights reserved.

(4Z)-4-[(2-Furylmethylamino)methylene]-5-methyl-2-phenylpyrazol-3-one (HL) and its Cu(II), Ni(II), Co(II), Zn(II), and Pd(II) complexes with the ML2 composition are synthesized. The structures of the complexes are studied by elemental C,H,N analysis, IR spectroscopy, magnetochemical measurements, and quantum chemistry. The crystal structures of the copper(II) and cobalt(II) complexes are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2177619 and 2177622, respectively). Two deprotonated ligands are coordinated to the metal ions via the chelate mode by the nitrogen atom of the imino group and the oxygen atom of the hydroxy group of the ligand. The geometry of the copper(II) ion environment corresponds to a distorted planar square, whereas the cobalt(II) ion exists in a distorted tetrahedral environment. In the series of the compounds studied, fluorescence with a maximum at 431 nm and a quantum yield of 0.29 is observed for the Zn(II) complex in a solution of CH2Cl2. The synthesized enamine and metal complexes are tested for antibacterial, protistocidal, and fungistatic activities. All compounds are shown to have no fungistatic and antibacterial activities, and only a weak protistocidal activity is found for the copper and zinc complexes.