Synthesis, structure and luminescence property of the ternary and quaternary europium complexes with furoic acid

A ternany europium complex with furoic acid (α-FURA) and 1,10-phenanthroline(phen), [Eu(α-FURA)₃phen]H₂O(I) and a quaternary europium furoate complex with 1,10-phenanthroline and nitrate, Eu(α-FURA)₂NO₃phen(II) were synthesized and characterized by X-ray diffraction. The two europium ions in each of the complexes (I) and (II) are held together by four carboxylato groups with the two modes, namely bidentate bridging and tridentate bridging, and each europium ion is further bonded to two nitrogen atoms from 1,10-phenanthroline and one chelated bidentate furoate group for the complex (I) and one chelated nitrato group for the complex (II), making a coordination number of 9. Luminescence spectra observed at 77 K show that the europium ion site in the crystals of the complexes (I) and (II) has low symmetry and lifetimes of the solid complexes (I) and (II) are 1.13 and 1.20 ms, respectively.     

Luminescence and magnetic properties of europium(III) nitrate complex with 1,10-phenanthroline

Luminescent and magnetic properties of the europium nitrate complex with 1,10-phenanthroline synthesized in the traditional way by precipitation from water-ethanol medium and by the method of mechanical activation were investigated. Correlations between luminescent and magnetic properties of the complex compounds were revealed. The higher value of molar magnetic susceptibility ??_m was shown to be typical for the highly dispersed europium compound obtained by mechanochemistry method due to the presence of the paramagnetic ion Eu²⁺.     

Molecular structure of paramagnetic <Emphasis Type="Italic">bis</Emphasis>-diisobutyl dithiophosphinate complexes of lanthanides(III) with 1,10-phenanthroline in solution by the data of NMR relaxation spectroscopy

NMR relaxation spectroscopy (RS) is used to examine the molecular structure of paramagnetic bis-diisobutyl dithiophosphinate complexes of lanthanides (by the example of europium and lutetium) with 1,10-phenanthroline in CDCl₃ solution. The results obtained are consistent with the results of studying the molecular structure of bis-diisobutyl dithiophosphinate complexes of yttrium with 1,10-phenanthroline in the crystalline phase by XRD.     

La(III) and Eu(III) 2-D coordination polymers of 5-nitroisophthalic acid (H2Nip) and 1,10-phenanthroline (phen), [M(phen)(HNip)(Nip)] n

Lanthanum(III) and europium(III) complexes of 1,10-phenanthroline (phen) with 5-nitroisophthalate, [La(phen)(HNip)(Nip)] _n (1) and [Eu(phen)(HNip)(Nip)] _n (2), have been synthesized and characterized by elemental analysis and IR spectroscopy and studied by X-ray crystallography. The single crystal X-ray analyses show that both lanthanum(III) and europium(III) are coordinated by two nitrogens of phen and six oxygens from “Nip^2?” and “HNip^?”, resulting in a distorted square antiprism.     

Mechanochemical synthesis of nanosized europium nitrate with 1,10-phenanthroline

Mechanochemically synthesized europium nitrate with 1,10-phenanthroline (Phen) is formed into globules with sizes of 100–300 nm, which are assembled into larger globular aggregates or packed into layers. The increasing mechanical activation time induces sintering, generating porous aggregates with micro-and nanopores. Eu²⁺ paramagnetic centers, detectable by ESR, are generated by mechanical grinding. Possibly, they are positioned on the surfaces of nanoglobules. The complex Eu(NO₃)₃ · 2Phen synthesized conventionally from aqueous ethanol consists of needle-shaped microcrystallites. They do not give rise to ESR spectra.     

Synthesis,crystal structure,and luminescence of a quaternary binuclear europium complex [Eu2(phth)2(Hphth)2(phen)2(H2O)4]

A quaternary binuclear europium complex [Eu₂(phth)₂(Hphth)₂(phen)₂(H₂O)₄] (H₂phth?=?phthalic acid, phen?=?1,10-phenanthroline) has been synthesized. The structure was determined by X-ray crystallography which reveals that it is binuclear with each europium nine-coordinate. Intermolecular hydrogen bonds link the complex units to form a 3D supermolecular network. Its properties have been studied by means of luminescence spectrum and thermal analysis. Fluorescence spectra show that the complex exhibits strong red emission.     

Mechanochemical synthesis of mixed-ligand europium β-diketonates with nitrogen-containing neutral ligands

The solid-phase reaction between europium salts of β-diketones and nitrogen-containing neutral ligands in a planetary mill produces luminescent mixed-ligand compounds Eu(β-dic)₃ · D, where β-dic stands for dibenzoylmethane (DBM), benzoylacetone (BA), thenoyltrifluoroacetone (TTA), or benzoyltrifluoroacetone (BTFA); and D stands for 1,10-phenanethroline (Phen), 2,2-dipyridyl (Dipy), or diphenylguanidine (DPG). The mechanosynthesis and yield of lanthanide β-diketonates are studied as affected by the treatment parameters and the nature of the reagents. Powder X-ray diffraction demonstrates a staged course of the mechanochemical synthesis. Examination of formation-rate curves shows that grinding/stirring is the rate-controlling stage of the process. Thermogravimetric analysis (TGA) shows that the mechanosynthesis can proceed in the self-propagation mode. The relative luminescence intensity is determined as a function of treatment time. Particles of the mechanically activated mixture have sizes of 10–100 μm.     

Luminescent 1,10-Phenanthroline β-Diketonate Europium Complexes with Large Second-Order Nonlinear Optical Properties

Substitution of the diglyme ligand of [Eu(hfa)₃(diglyme)] (where hfa is hexafluoroacetylacetonate) with a simple 1,10-phenanthroline leads to a six-fold increase of the product μβ_EFISH, as measured by the Electric-Field-Induced Second Harmonic generation (EFISH) technique. Similarly, [Eu(tta)₃(1,10-phenanthroline)] (where Htta is 2-thenoyltrifluoroacetone) is characterized by a large second-order NLO response. Both 1,10-phenanthroline europium complexes have great potential as multifunctional materials for photonics.     

Heteroligand complexes of lanthanides with 4-formyl-3-methyl-1-phenylpyrazol-5-one and 1,10-phenanthroline

Complexes of the general formula LnL₃ · Phen (Ln = Nd, Sm, Eu, Gd, Tb, Dy, and Yb; HL = 4-formyl-3-methyl-1-phenylpyrazol-5-one, Phen = 1,10-phenanthroline) were obtained and examined by IR spectroscopy and thermogravimetry. The structure of the complex TbL₃ · Phen was studied by X-ray diffraction. The coordination polyhedron of terbium is a distorted square antiprism made up of six O atoms of three 4-formylpyrazol-5-one anions and two N atoms of the 1,10-phenanthroline molecule. Polycrystalline samples of the complexes studied show emission in the spectral ranges characteristic of Ln(III).     

Mechanochemical synthesis of thenoyltrifluoroacetone-1,10-phenanthroline europium complex

The paper considers the possibilities for mechanochemical synthesis of rare earth complexes. The complex Eu(TTA)₃·phen (HTTA — 2-thenoyltrifluoroacetone, phen — 1,10-phenanthroline) is synthesized by mechanical treatment of a mixture of EuCl₃.6H₂O, HTTA, phen and NaOH in planetary ball mill Pulverisette 7 for 30 min at 800 min^?1. The non reacted starting reagents and reaction side products are separated by treating activated mixture with water-ethanol solution following a procedure proposed in the literature. The elemental composition, X-ray diffraction pattern, IR spectra, optical properties (excitation and emission spectra, luminescence lifetime) and morphology of the mechanochemically synthesized complex are compared with those of the complex prepared from solution by the conventional method. The results confirm close similarity in the molecular structure and identity of the elemental composition, X-ray diffractograms and fluorescence properties of the compounds prepared by both methods.      

Electronic structure of adducts of Nd(III) carboxylate complexes determined by DFT and XPS methods

X-ray photoelectron spectroscopy and quantum chemistry methods are used to study Nd(tol)₃ and Nd(сor)₃ carboxylate complexes and their adducts with 1,10-phenanthroline (Nd(tol)₃Phen and Nd(сor)₃Phen₂). The electronic structure and specific features of the nature of chemical bonds are studied, as well as the effect of 1,10-phenanthroline on the electronic structure of the adduct. We propose the band assignment of the valence band of the XPS spectra of all compounds.     

Photochemical properties of mixed-ligand complexes europium carboxylates

The photochemical behavior of mixed-ligand complexes of europium carboxylates with nitrogen-and phosphorus-containing neutral ligands of island and dimer types, Eu(L)₃ · xD · nH₂O and [Eu(L)₃ · xD]₂ · nH₂O (L is the trifluoroacetate, toluate, or cinnamate anion), was studied. During UV irradiation of the complexes of europium carboxylates with 1,10-phenanthroline and 2,2′-dipyridyl, a luminescence buildup was observed. EPR measurements demonstrated that the observed buildup of luminescence from europium occurs in parallel with the increase of the concentration of radical anions formed from neutral ligands.     

Synthesis,characterization, and crystal structure of a copper(II) complex of 1,10-phenanthroline and succinate

A mixed ligand complex of Cu(II) with 1,10-phenanthroline and succinate has been synthesized from the reaction of hydrated copper nitrate, succinate, and 1,10-phenanthroline. The nature of bonding and the structure of the complex were characterized by elemental analyses, infrared spectrum, TGA/DTA, and X-ray diffraction. The crystal crystallizes in triclinic space group P 1. The complex is polymeric and the geometry around each copper varies from square planar to distorted square pyramidal or octahedral. Each copper coordinates two oxygens of succinate and two nitrogens of 1,10-phenanthroline. The thermal decomposition of the complex has also been studied by TGA and DTA under inert atmosphere.     

Mechanochemical activation of aluminum. 4. Kinetics of mechanochemical synthesis of aluminum carbide

The kinetics of mechanochemical synthesis of aluminum carbide Al₄C₃ from elements was studied with X-ray diffraction analysis, low-temperature argon adsorption, laser granulometry, chemical analysis, X-ray photoelectron spectroscopy, and electron scanning microscopy. The conversion was presented as a function of energy consumption (dose) upon the mechanical treatment of mixtures of aluminum and graphite powders with the composition Al-15 wt % C and Al-30 wt % C. A multistage mechanism of the mechanochemical reaction was revealed, and the following stages were separated and characterized: (i) independent grinding and mixing of reagents, (ii) formation of molecular-dense Al/C composites based on nanosized aluminum particles, (iii) chemical interaction of components with the formation of interatomic Al-C bonds, and (iv) crystallization of Al₄C₃ carbide. The formation of amorphous nuclei of aluminum carbide occurs on the contact surface of aluminum nanoparticles with carbon.     

The Fluorescent Properties of Heteroligand Europium Cinnamates

Heteroligand europium cinnamates with nitrogen- and phosphorus-containing neutral ligands were studied by luminescent and X-ray electron spectroscopy. A tendency toward an increase in the electron density on Eu³⁺ was observed when neutral ligands were coordinated by donor nitrogen atoms. The Δν₀, ΔF ₁, and I(F ₀)/I(F ₂) values monotonically decreased as the donor properties of neutral ligands increased because of strengthening of the interaction of Eu³⁺ with the ligands.     

Synthesis and reactions of 1,10-phenanthroline-2(1H)-thione: a facile synthesis of 2,2′-thiobis-1,10-phenanthroline

Treatment of 2-chloro-1,10-phenanthroline with NaSH hydrate in DMF, Na₂S nonahydrate in DMF or thiourea in refluxing ethanol readily afforded 1,10-phenanthroline-2(1H)-thione. This thione undergoes reaction with 1,2-dibromoethane to yield a thiazole bromide salt. Upon heating the thione in diphenyl ether with 2-chloro-1,10-phenanthroline, the hydrochloride salt of 2,2′-thiobis-1,10-phenanthroline precipitated and could be converted into the corresponding free base on treatment with aqueous base. Heteroaryl substituted sulfides could be prepared by treatment of 2-chloro-1,10-phenanthroline with pyridine-2-thione or pyrimidine-1-thione with potassium carbonate in DMF.     

Crystal structures and antibacterial properties of Cu(II) complexes containing an unsymmetrical N2O Schiff base ligand and bidentate N-donor heterocyclic co-ligands

Abstract

Three new Cu(II) Schiff base complexes with bidentate N-donor heterocyclic co-ligands, 2,2'-bipyridine (1), 1,10-phenanthroline (2), and 2,9-dimethyl-1,10-phenanthroline (3), were synthesized and characterized by FT-IR and UV-vis spectroscopy. Molecular structures of [C₂₀H₂₁CuN₄O](ClO₄) (1) and [C₂₄H₂₅CuN₄O](ClO₄) (3) were characterized by single-crystal X-ray crystallography. The Schiff base ligand is an N₂O-type ligand, which is the mono-condensed form of the reaction between 1,3-propanediamine and salicylaldehyde. The antibacterial activities of these complexes were investigated against one gram positive and four gram negative bacteria. Considerable antibacterial activity was obtained against both gram type bacteria. Complexes 2 and 3 with 1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline, respectively, showed better antibacterial activity compared to 1 which has the 2,2'-bipyridine co-ligand.     

Cationic Lanthanide Luminescent Copolymer: Design,Synthesis and Interaction with DNA

Polymerizable rare earth complex Eu(AA)₃Phen was synthesized by complexion of europium ion, acrylic acid (AA), and 1,10-phenanthroline (Phen). The structure and fluorescence properties of the complex were studied by elemental analysis, ¹H-NMR spectroscopy, and fluorescence spectroscopy. Eu-containing copolymer poly(PEGMA-co-MMA-co-METAC-co-Eu(AA)₃Phen) (PPMMEu) was then synthesized by free radical copolymerization of Eu(AA)₃Phen and other functional monomers including poly(ethylene glycol) methyl ether methacrylate (PEGMA) and [2-(Methacryloyloxy) ethyl] trimethylammonium chloride (METAC). ¹H-NMR spectroscopy and fluorescence spectroscopy were used to characterize the copolymer and the interactions between the copolymer and DNA was investigated by TEM, fluorescence spectroscopy, and agarose gel electrophoresis. The desired luminescent cationic copolymer was successfully obtained. The copolymer can form micelles in water solution and can efficiently bind to DNA molecules through electrostatic interaction. The results suggest the potential use of PPMMEu in bioprobes and gene vectors.     

Fluorescence properties of mixed-ligand europium carboxylates

Mixed-ligand binuclear and mononuclear europium carboxylate complexes with nitrogen-and phosphorus-containing neutral ligands have been studied by luminescence and X-ray photoelectron spectroscopy. The coordination of neutral ligands through the nitrogen donor atom leads to an increase in electron density at the Eu³⁺ atom. In groups of carboxylates of the same type, the coordination of neutral donor ligands leads to an increase in the relative intensity of the ⁵ D ₀-⁷ F ₄ electric dipole transition. Analysis of the luminescence excitation spectra points to the presence of two excitation energy transfer channels for mixed-ligand europium trifluoroacetate and toluate complexes and of one channel for europium cinnamate complexes with neutral ligands.     

Thermodynamics and Fluorescence Spectra of 1,10-Phenanthroline in Micelles of Poly (Ethylene Oxide)-Type Nonionic Surfactant

The distribution of 1,10-phenanthroline (phen) in micellar solutions of the nonionic surfactants Triton X and C₁₂E _n with varying poly (ethylene oxide) chain lengths has been studied by potentiometry, calorimetry, and fluorometry at 298 K. Micelles accommodate 1,10-phenanthroline according to the reaction, phen + Y_m = Y_m(phen), where Y_m denotes a surfactant molecule aggregated in micelles. The constant K _m for the reaction of Triton X increases as a linear function of n*, the number of ethylene oxide (EO) groups, as K _m = K_EO n* + K_c. Nonzero K _EO and K _c values suggest a heterogeneous inner structure of the micelle, i.e., the hydrophobic core surrounded by a hydrophilic poly (ethylene oxide) (PEO) shell. On the basis of molar volumes, the intrinsic thermodynamic parameters of transfer of 1,10-phenantholine were extracted. The enthalpy and entropy of transfer of 1,10-phenanthroline from the PEO shell to the core are found to be small and negative. By using K _EO and K _c values for C₁₂E _n obtained by fluorometry, individual fluorescence spectra of 1,10-phenanthroline in the PEO shell and core were extracted. The fluorescence intensity of 1,10-phenathroline accommodated in the core, like in organic solvents, is significantly reduced relative to that in water. These facts indicate that the aromatic rings of 1,10-phenanthroline penetrate into the hydrophobic core, while its hydrophilic N site is still hydrated in the PEO shell.