Using density functional theory (B3LYP/6-311++G(d,p)) and NBO analysis, the effect of methylation on the conformation and electronic structure of beta-aminovinyl ketones bearing quinoline and naphthalene substituents was investigated. Methylation at the 3-position leads to significant twisting of the aromatic fragment due to steric repulsion, increasing the dihedral angle to similar to 30 degrees (quinoline) and similar to 50 degrees (naphthalene). Relative energy profiles confirm that twisted conformations are global minima. Thermodynamic analysis reveals that methylation stabilizes the twisted conformation by 2.4-3.1 kcal/mol (Delta G). NBO analysis shows that the methyl group enhances hyperconjugative interactions within the vinylketone fragment but weakens n -> pi* conjugation of the nitrogen lone pair with the aromatic system. Additional stabilization is provided by a strong intramolecular N-H & centerdot;& centerdot;& centerdot;O hydrogen bond. A correlation between the torsion angle and the hypsochromic shift of the long-wavelength absorption band confirms that methylation effectively modulates both conformation and optical properties.

This study reports the synthesis and comprehensive characterization of two novel dinuclear copper(II) complexes derived from 2-(5-methoxy-1-methylbenzimidazol-2-yl)-1-(4-methoxyphenyl)ethanol (HL). The reaction of HL with copper(II) acetate hydrate and copper(II) nitrate trihydrate in tetrahydrofuran yielded dinuclear complexes formulated as [CuL(CH3COO)]2 & sdot;2MeCN (1) and [CuLH(NO3)DMF]2 & sdot;DMF (2), respectively. The compounds were characterized by elemental analysis, IR and 1H NMR spectroscopy, and single-crystal X-ray diffraction analysis. Structural elucidation revealed that both complexes feature a Cu2O2 rhombic core with the copper centers bridged by alkoxide oxygen atoms. Magnetic susceptibility measurements in the temperature range of 5-300 K demonstrated strong antiferromagnetic exchange interactions in both complexes, with exchange coupling constants of J =-401 +/- 11 cm-1 for 1 and J =-445 +/- 5 cm-1 for 2. Broken-symmetry density functional theory (BS-DFT) calculations corroborated the experimental magnetic data and provided insight into the electronic structure and magnetic exchange pathways. The observed differences in magnetic behavior are discussed in relation to structural variations induced by the different coordinating anions.

The possibility of the formation of amino-substituted derivatives [B10H9N(MBzim)CH2MBzim]2- (MBzim is 1-methylbenzimidazole) and [B10H9N+H(MBzim)CH2Bzid-]2- (Bzid is benzimidazolide) during the cadmium(ii) complexation with N,1-bis(1-methylbenzimidazol-2-yl)methanimine (L1) and N-(benzimidazol-2-yl)-1-(1-methylbenzimidazol-2-yl)methanimine (L2) with a -CH 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 N- linker group in the presence of a closo-decaborate anion has been demonstrated for the first time. The substitution likely results from the metal-promoted formation of the carbocation [Cd(MBzim)HC+-N-R]2+ (R = MBzim or Bzim), which acts as an electrophilic inducer in the EINS reaction with the [B10H10]2- anion. As a result, binuclear complexes {Cd(CH3CN)[B10H9N(MBzim)CH2MBzim]}2 and {Cd(DMF)[B10H9N+H(MBzim)CH2Bzid-]}2 have been obtained and characterized. A method for obtaining soluble salts Cat2[B10H9N(MBzim)CH2MBzim] and Cat2[B10H9N+H(MBzim)CH2Bzid-] (Cat = Na+, Bu4N+) has been proposed. The heteroleptic complex {CdL2(DMF)[B10H10-kappa 3B1,B2,B3]}, in which the benzimidazole derivative acts only as a ligand, has been obtained and characterized as a result of complexation with 1-isopropyl-N-((1-methyl-1H-benzo[d]imidazol-2-yl)methyl)-1H-benzo[d]imidazol-2-amine (L3) with a -CH2-NH- linker group. X-ray diffraction analysis revealed the structural features of the synthesized compounds, namely the coordination of bis(benzimidazoles) resulting in the formation of a seven-membered chelate ring, and the facial coordination of the closo-decaborate anion, which is rare for cadmium(ii).

This work presents the synthesis and comprehensive study of a novel series of zinc(II) coordination compounds based on azomethine ligands derived from N-[2-(hydroxyalkyliminomethyl)phenyl]-4-methylbenzenesulfonamides. The ligands incorporate aliphatic spacers of varying length (CH2)n (n = 2–6), enabling a systematic investigation of the spacer’s influence on the structural, thermal, photophysical, and electroluminescent properties of the resulting complexes. The complexes were characterized by elemental analysis, and IR and NMR spectroscopy. Single-crystal X-ray diffraction analysis confirmed the formation of chelate complexes, where the Zn(II) ion adopts a distorted tetrahedral geometry, coordinated by two bidentate ligands via the nitrogen atoms of deprotonated sulfonamide and azomethine groups. Elongation of the methylene spacer does not significantly alter the core coordination geometry (Zn–N bond lengths, bond angles) or the dominant intermolecular interactions (hydrogen bonds, π–π stacking) governing crystal packing. These structural findings are strongly supported by density functional theory (DFT/B3LYP) calculations. In the solid state, the complexes exhibit intense blue photoluminescence with emission maxima ranging from 435 to 466 nm. The photoluminescence quantum yields (PLQY) vary from 7.4 to 21.5

Two Zn(II) coordination compounds based on glaucine-derived Schiff bases were synthesized and investigated as potential materials for dye-sensitized solar cells (DSSCs). The structures of all compounds were established by X-ray diffraction analysis and quantum chemical modeling (DFT/TD-DFT). Their photophysical properties (absorption and luminescence spectra in solution and the solid state), electrochemical characteristics, and photovoltaic parameters in DSSC devices were studied. The highest power conversion efficiency (PCE similar to 5.18%) was demonstrated by the free ligands, which is attributed to their favorable absorption spectrum and optimal alignment of energy levels relative to the conduction band of TiO2 and the redox couple of the electrolyte. The Zn(II) coordination compounds exhibited significantly lower efficiency (similar to 2.1%). Impedance spectroscopy results indicated more efficient charge transfer at the TiO2/dye/electrolyte interface for the organic derivatives.

New Zn(II) and Cd(II) complexes based on N-[2-[(E)-2-furylmethyliminomethyl]phenyl]-4-methyl-benzenesulfonamide were synthesized. The structures and physicochemical properties of the complexes were studied using single-crystal X-ray diffraction analysis, 1H nmR, IR, and UV-Vis spectroscopy and DFT calculations. It was shown that the two deprotonated ligands chelate the metal ions through the nitrogen atoms of the tosylamine and azomethine fragments. The coordination geometry around the Zn(II) and Cd(II) ions is highly distorted tetrahedron. Hirshfeld surface analysis was used to visualize and quantify intermolecular interactions, including hydrogen bonds, van der Waals forces, and pi-pi stacking in the crystal structures. The photoluminescent properties of the complexes were also investigated.

The results of the synthesis and investigation of two copper(II) complexes based on 1-phenyl-3-(8-quinolylamino)but-2-en-1-one (HL) are presented. Both complexes were characterized by elemental analysis and IR spectroscopy. The crystalline and molecular structure of copper(II) complexes was determined using single-crystal X-ray diffraction analysis. Depending on the synthesis method (with or without the addition of sodium methoxide in a methanol solution), two different types of crystal structures with compositions CuL2 and CuLCOOCH3 were obtained. The Hirschfeld surface analysis method was used to analyze interactions between molecules in crystals, which made it possible to visualize and quantify hydrogen bonds, van der Waals forces, and π-π stacking interactions in these compounds. This study demonstrated that the structure of the complex is dependent on the synthesis conditions that affect the coordination environment of copper(II) ions and the characteristics of intermolecular interaction.

A systematic study of silver(I) complexation with benzimidazole containing compounds L: imines Bz-CH=N-C6H5 (L1: Bz is 1-methylbenzimidazole, C6H5 is phenyl; L2: Bz is 1-benzylbenzimidazole, C6H5 is phenyl) and amines Bz-CH2-NH-X (L3: Bz is 1-methylbenzimidazole, X is 4-metoxyphenyl (C6H4OCH3), L4: Bz is 1-benzylbenzimidazole, X is 4-chlorophenyl (C6H4Cl)) has been carried out. The effect of the ratio of the initial reagents Ag+: L, the type of linker group or substituent at the nitrogen atom of the imidazole ring in the organic ligand on the composition and structure of the resulting compounds has been determined. Benzimidazolecontaining mononuclear molecular silver(I) complexes [AgL1(CH3CN)NO3] (1), [Ag(L1)2NO3] (2), [AgL2NO3] (3), as well as mononuclear cationic complexes in the composition of salts [AgL2]NO3 (L = L2 (4), L3 (5), L4 (6)) have been obtained and characterized. The structural features of the synthesized compounds have been analyzed based on X-ray diffraction analysis data.

Silver(I) complexation with substituted (benzoimidazol-2-yl)methanamines Bz–CH2–NH–R (Bz is 1-methylbenzimidazole, R is anisole (L1) or 1-isopropylbenzimidazole (L2)) in the presence of boron cluster anions [BnHn]2– (n = 10, 12) has been studied for the first time. The influence of substituent R in the benzimidazole derivative on the composition and structure of the resulting compounds has been determined. Coordination compounds [Ag(L1)2]xAn (x = 1, An = Ag[B10H10]mm–; x = 2, An = [B12H12]2–), featuring closo-borate anions in the outer coordination sphere and monodentately coordinated ligands L1, have been synthesized and structurally characterized. Additionally binuclear complexes [Ag2(L2)2[µ-BnHn]] have been obtained, in which L2 is coordinated bidentately, forming a seven-membered metallacycle, while anions [BnHn]2– (n = 10, 12) act as bridging ligands. The structural features of the synthesized compounds have been analyzed, including the coordination mode of the organic ligands and the occurrence of positional and bond isomerism in compounds with coordinated boron cluster anions.

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.

Light-emitting diodes are budget-friendly solid-state light sources that find use in the very diverse areas: from lighting to data display devices. The history of the discovery of the electroluminescence phenomenon and development of the technology of inorganic (LED) and organic light-emitting diodes (OLED) is presented. Today, there has been a widespread transition to light-emitting diode sources based on inorganic semiconductors, ensuring significant energy savings. However, OLED technologies continue to undergo intensive development. Advantages of OLED over other light sources and areas of their practical use are considered. We discussed the fundamental principles of manufacturing organic light sources with a white emission spectrum, based on low-molecular-weight and polymeric compounds, and considered various approaches for developing polymeric materials with a white emission spectrum. Prospects of the development of the market of OLED light sources are evaluated.

Осуществлён синтез двух новых комплексов никеля(II) бензоилгидразона 2-(N-тозиламино)бензальдегида (H2L) c дополнительными гетероциклическими донорными лигандами L1=2,2'-бипиридин и L2=1,10-фенантролин. Строение и состав полученных соединений установлены методом элементного анализа, 1Н ЯМР, ИК-спектроскопии. Кристаллическое и молекулярное строение комплексов Ni(II) определено с помощью РСА. Показано, что аддукты имеют димерное строение состава Ni2L2L1(CH3OH) и Ni2L2L2(CH3OH). В обоих аддуктах один из ионов никеля(II) находится в искаженном плоско-квадратном окружении, тогда как другой ион никеля(II) имеет октаэдрическое окружение за счет дополнительной координации 2,2'-бипиридина или 1,10-фенантролина и молекулы метанола. Исследована биологическая активность комплексов. Обнаружено, что оба аддукта проявляют протистоцидную активность в отношении Colpoda steinii, причем Ni2L2L1(CH3OH) в два раза менее активен, а Ni2L2L2(CH3OH) в два раза более активен по сравнению с препаратом сравнения хлорохином.

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.

ratiometric luminescent thermometers, particularly lanthanide-based, become very important, and long wavelength range is of particular interest due to low signal scattering. With this in mind, a series of new red and NIR emitting lanthanide Schiff base complexes were synthesized and characterized in detail for use as components of luminescent thermometers. Red-emitting europium complexes demonstrated high temperature sensitivity (up to 7 %/K) in the cryogenic temperature range (80-200 K), where the ligand-to-europium luminescence intensity ratio (LIR) was used as a signal. In contrast, NIR emitting ytterbium complexes demonstrated no sensitivity in the cryogenic range; however, their luminescence was sensitive to high temperatures (300-600 K), which is currently of particular interest. Ytterbium and europium complexes were also tested in OLEDs, and due to high temperature sensitivity, europium complexes were used for the first electroluminescent thermometers.

Silver(I) complexation with boron cluster anions [BnHn]2- (n = 10, 12) and chelating 1-substituted-2-aldiminebenzimidazoles 1-(1-methylbenzimidazol-2-yl)-N-phenylmetanimine (L1) and 1-(1-benzylbenzimidazol-2-yl)-Ncyclohexylmethanimine (L2) in systems AgNO3/[BnHn]2- /L and {Ag2[BnHn]}m/L, as well as with azaheterocyclic ligands 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen) in the system AgNO3/[BnHn]2- /L has been first studied. The effect of the organic ligand on the composition and structures of the resulting compounds has been shown. As a result, binuclear complexes [Ag2L2[mu-BnHn]] with bridging boron cluster anions with various combinations of coordination modes (edge-edge and edge-face for the [B10H10]2- anion, edge-atom and nontrivial asymmetric for the [B12H12]2- anion) have been synthesized and structurally characterized for benzimidazole derivatives L1 and L2. When using bipy or phen as ligands, polymeric complexes {Ag2L[B10H10]}m or {Ag2L2[mu-B12H12]}m have been obtained.

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.

Basic processes of the electroluminescence phenomenon in OLED structures are described. The conventional theoretical models for injection, transport and recombination of charge carriers and their relationship with the obtained experimental data are discussed. The mobility of charge carriers is a key characteristic of the electron and hole transport. Methods for measuring mobility that adequately reflect the transport of charge carriers in OLEDs are considered.

The photochemical and photophysical properties of the new ligand N-[2-(5,6-dihydrobenzimidazo[1,2-c]quinazoline-6-yl)phenyl]-4-methylbenzolsulfamide (1) and its zinc complexes, namely [2-[(E)-[2-(1H-benzimidazol-2-yl)phenyl]iminomethyl]-N-(p-tolylsulfonyl)anilino]chloro-zinc (3) and acetoxy-[2-[(E)-[2-(1H-benzimidazol-2-yl)phenyl]iminomethyl]-N-(p-tolylsulfonyl)anilino]zinc (4) were studied using UV spectroscopy, time-resolved luminescence and stationary photolysis. Compound 1 combines the properties of Schiff bases and benzimidazole derivatives, both known as good luminophores. The structures of compounds in the crystalline state were determined by means of XRD. Ligand 1 demonstrates high photoluminescence quantum yields (PLQY) in solutions, while for the soluble zinc complex 3 it drops in an order of magnitude. PLQY in the solid state for all the compounds are moderate (0.2–0.3). For complex 3 the PLQY in the solid state is ca. 3 times higher than in solutions, demonstrating the effect of aggregation-induced enhancement of luminescence. The approach based on combining properties of the two classes of luminophores seems prospective for further development of luminescent materials.

A number of new copper(II) complexes of 2-(N-tosylamino)benzaldehyde benzoylhydrazone (H2L) CuLLn (n = 1–6) with heterocyclic donor ligands (L1 = 1-propyl-2-aminobenzimidazole, L2 = 1‑hexyl-2-aminobenzimidazole, L3 = 1-octyl-2-aminobenzimidazole, L4 = 2,2'-bipyridine, L5 = 1,10-phenanthroline, and L6 = 2-aminopyridine) is synthesized. The structures and compositions of the synthesized compounds are determined by elemental analysis, 1Н NMR spectroscopy, IR spectroscopy, and magnetochemistry. The molecular structures of complexes CuLL1,2,4−6 are determined by XRD (CIF files CCDC nos. 2341480 (CuLL1), 2341468 (CuLL2), 2341478 (CuLL4), 2341477 (CuLL5), and 2341479 (CuLL6)). The biological activity of the complexes is studied. The adducts with L1, L2, and L6 exhibit a significantly higher anti-protist activity than chloroquine used as the reference compound.

A new azomethine compound 4-methyl-N-[2-pentafluorophenyliminomethyl)phenyl]methylbenzenesulfamide and a Cu(II) complex based on it are obtained and characterized by 1H NMR, IR spectroscopy and the elemental analysis. Crystal structures of azomethine and its complex are analyzed by single crystal X-ray diffraction (XRD). From the single crystal XRD data it is found that the Cu(II) complex crystallizes in the triclinic space group P1̅ . The unit cell contains two crystallographically independent mononuclear molecules with similar geometries. In the complex, copper ions have a distorted tetrahedral environment of four nitrogen atoms, which is formed by two bidentate coordinated azomethine ligands. From magnetic measurements it is found that the Cu(II) complex is paramagnetic.