Luminescent properties of PP and LDPE films and rods doped with the Eu(III)‐La(III) complex

The work is devoted to luminescent properties of trivalent lanthanide complexes dispersed in thermoplastic host matrices. Polyethylene films and polypropylene‐rods, both doped with these complexes, were manufactured using an extrusion technique. Two kinds of dopants were used: Eu(III)‐thenoyltrifluoroacetone‐1,10‐phenanthroline complex (1) and Eu(III)‐La(III)‐1,10‐phenanthroline complex (2). Absorption, excitation, emission spectra and lifetime of luminescence were studied. The impact of the polymer matrix on the emission spectra was investigated. Emission spectra of the films were studied at room and helium temperatures. Time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) surface mapping showed that in the Eu(III)‐La(III) complex europium forms islands (clusters) with a dimension of 1 µm, whereas lanthanum was dispersed more uniformly in the polymer matrix. Dependence of emission intensity on the excitation was determined. Copyright © 2006 John Wiley & Sons, Ltd.     

三种新的铕(III)三元配合物的合成及发光性质研究

合成了吡嗪 [2 ,3 f]并邻菲罗啉及其一系列衍生物 ,作为第二配体 ,并以二苯甲酰甲烷为第一配体 ,合成了 3种新的铕 (III)三元配合物 .通过元素分析、红外光谱、核磁共振光谱确定了它们的组成 ,研究了三种配合物的热稳定性、成膜性能和光致发光性能 (发光强度、荧光量子效率和寿命 ) ,并初步从理论上探讨含有不同基团的第二配体的结构对铕 (III)配合物发光的影响 ,结果表明 :这三种铕 (III)三元配合物均为优良的红色发光材料 ,而且在真空条件下均形成均衡的薄膜 ,这为以这三种铕 (III)配合物作为发光层材料制作有机电致发光器件提供了认识基础     

Sublimable Cationic Iridium(III) Complexes with 1,10‐Phenanthroline Derivatives as Ancillary Ligands for Highly Efficient and Polychromic Electroluminescence

A novel series of four sublimable cationic iridium(III) complexes have been prepared with 1,10‐phenanthroline derivatives as ancillary ligands and the same negative counter‐ion, tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate, which has a large steric hindrance and widely dispersed charges, thereby increasing the ionic radii, reducing the electrostatic interaction, and thus improving the volatility. Their structural, photophysical, electrochemical, and thermal properties have been fully characterized. Upon excitation, these compounds show polychromic emission varying from green to orange in solution, which are blue‐shifted in the solid state to different extents due to π–π conjugate effects in the ancillary ligands and the resulting molecular aggregation. OLEDs fabricated by vacuum evaporation deposition demonstrated desirable device performance with high efficiency and brightness, exhibiting various electroluminescent colors dependent upon doping concentration.     

Synthesis of Cobalt(III) Ammine Complexes as Explosives for Safe Priming Charges

Physicochemical and explosive properties of Co(III) pentammine complexes containing in the inner coordination sphere monodentate polynitrogen heterocyclic ligands, 1-methyl-5-aminotetrazole and 1,5-diaminotetrazole, were studied, and it was shown that these compounds can be used in priming charges.     

Protonation of Chloro-, Bromo- and Iodo-pentacyanocobaltate(III) Complexes

The reactions between Fe(Phen)₃²⁺[phen = tris-(1,10) phenanthroline] and Co(CN)₅X³⁻ (X = Cl, Br or I) have been studied in aqueous acidic solutions at 25 °C and ionic strength in the range I = 0.001–0.02 mol dm⁻³ (NaCl/HCl). Plots of k₂ versus √I, applying Debye–Huckel Theory, gave the values −1.79 ± 0.18, −1.65 ± 0.18 and 1.81 ± 0.10 as the product of charges (Z_AZ_B) for the reactions of Fe(Phen)₃²⁺ with the chloro-, bromo- and iodo- complexes respectively. Z_AZ_B of ≈ −2 suggests that the charge on these Co^III complexes cannot be −3 but is −1. This suggests the possibility of protonation of these Co^III complexes. Protonation was investigated over the range [H⁺] = 0.0001 −0.06 mol dm⁻³ and the protonation constants K_a obtained are 1.22 × 10³, 7.31 × 10³ and 9.90 × 10² dm⁶ mol⁻³ for X = Cl, Br and I, respectively.     

Kinetics of substitution in two water soluble cobalt(III)-porphyrins

Summary Kinetics of substitution of thiocyanate and pyridine in the axial positions of tetra(p-trimethylammoniumphenyl)porphinatocobalt(III) and tetra(p-sulfonatophenyl)porphinato cobalt(III) were investigated at pH 4.00 and ionic strength 0.1 M (NaNO₃) in aqueous solution. These reactions were found to be as facile as other such reactions of cobalt(III) porphyrins even though a new synthesis was employed in the present study. The rates of these reactions are proportional to the base strength of the parent free base porphyrin. Electrostatic attraction between the ligand and the porphyrin peripheral charges were also found to enhance the rates. The cause of labilization is believed to be primarily electronic and not steric.     

Synthesis and spectroscopic characterization of ternary complexes of copper(II) glycylglycine and substituted phenanthrolines

Summary Complexes of Cu(glygly)phen ygly = glycylglycine; phen = 4,7-dimethyl [(1)], 5,6-dimethyl [(2)], 5-NO₂[(3)], 5-Cl[(4)], 2-oxazolinyl (2-ox) [(5)] Phenanthroline and bis(2-oxazolinylphenanthroline)-copper(II) [(6)] were synthesized and characterized by conductivity measurements, e.p.r., i.r. and reflectance electronic spectroscopies.A broad u.v.-vis. band in the 620–640 nm range and a shoulder at ca. 825 nm suggest that these complexes are five-coordinate. The e.p.r. spectra indicate a stronger equatorial ligand field in the ternary complexes which is absent in the binary Cu-phen complexes, suggesting square pyramidal coordination, whose base contains the three donor atoms from glygly (O, N, N) and one donor from the phenanthroline nitrogen atom. The other nitrogen-containing ligand of the phenanthroline is in an apical position.The spectroscopic results can be correlated with electronic and steric effects attributable to the different substituents on the phenanthroline ligands.Only small variations in the structure of the ternary complexes occur as a function of the electronic effects of substituents on the aromatic phenanthroline ring ligands. Steric hindrance predominates in determining coordination geometry around copper(II).     

New copper(I) isocyanide complexes containing other donor ligands

The preparation and physical properties of some new copper (I) isocyanide complexes containing other neutral donor ligands such as Ph₃P, pyridine(Py), 1,10- phenanthroline (Phen), bipyridine (Bipy), or 1,2-bis(diphhenylphosphino)ethane (Dipphos) are described. Possible structures for these new complexes, in the solid state and in solution, are discussed.     

Cationic bis-cyclometallated iridium(III) phenanthroline complexes with pendant fluorenyl substituents: synthesis, redox, photophysical properties and light-emitting cells

We report the synthesis, characterisation, photophysical and electrochemical properties of a series of cationic cyclometallated Ir(III) complexes of general formula [Ir(ppy)(2)(phen)]PF(6) (ppy=2-phenylpyridine, phen=a substituted phenanthroline). A feature of these complexes is that the phen ligands are substituted with one or two 9,9-dihexylfluorenyl substituents to provide extended pi conjugation, for example, the 3-[2-(9,9-dihexylfluorenyl)]phenanthroline and 3,8-bis[2-(9,9-dihexylfluorenyl)]phenanthroline ligands afford complexes 6 and 9, respectively. A single-crystal X-ray diffraction study of a related complex 18 containing the 3,8-bis(4-iodophenyl)phenanthroline ligand, revealed an octahedral coordination of the Ir atom, in which the metallated C atoms of the ppy ligands occupy cis positions. The complexes 6 and 9 displayed reversible oxidation waves in cyclic voltammetric studies (E(ox)(1/2)=+1.18 and +1.20 V, respectively, versus Ag/Ag(+) in CH(2)Cl(2)) assigned to the metal-centred Ir(III)/Ir(IV) couple. The complexes exhibit strong absorption in the UV region in solution spectra, due to spin-allowed ligand-centred (LC) (1)pi-pi* transitions; moderately intense bands occur at approximately 360-390 nm which are red-shifted with increased ligand length. The photoluminescence spectra of all the complexes were characterised by a broad band at lambda(max) approximately 595 nm assigned to a combination of (3)MLCT and (3)pi-->pi* states. The long emission lifetimes (in the microsecond time-scale) are indicative of phosphorescence: the increased ligand conjugation length in complexes 9 and 17 leads to increased lifetimes for the complexes (tau=2.56 and 2.57 micros in MeCN, respectively) compared to monofluorenyl analogues 6 and 15 (tau=1.43 and 1.39 micros, respectively). DFT calculations of the geometries and electronic structures of complexes 6', 9' (for both singlet ground state (S(0)) and triplet first excited (T(1)) states) and 18 have been performed. In the singlet ground state (S(0)) HOMO orbitals in the complexes are spread between the Ir atom and benzene rings of the phenylpyridine ligand, whereas the LUMO is mainly located on the phenanthroline ligand. Analysis of orbital localisations for the first excited (T(1)) state have been performed and compared with spectroscopic data. Spin-coated light-emitting cells (LECs) have been fabricated with the device structures ITO/PEDOT:PSS/Ir complex/Al, or Ba capped with Al (ITO=indium tin oxide, PEDOT=poly(3,4-ethylenedioxythiophene), PSS=poly(styrene) sulfonate). A maximum brightness efficiency of 9 cd A(-1) has been attained at a bias of 9 V for 17 with a Ba/Al cathode. The devices operated in air with no reduction in efficiency after storage for one week in air.     

Synthesis,Characterization, Antibacterial and Antifungal Activity of Yttrium(III) Complexes Including 1,10‐Phenanthroline

Two rare metal coordination complexes of yttrium(III) including 1,10‐phenanthroline, Y(phen)₂(NO₃)₃ and (phenH)₂[Y₂(pydc)₃(NO₃)₂·6H₂O] (phen=1,10‐phenanthroline, pydc=2,6‐pyridinedicarboxylate), and a proton transfer compound (phenH⁺)₂(pydc^2?) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra (IR), nuclear magnetic resonance (NMR) and thermal analysis. The proposed structures of yttrium complexes were exhibited. The in vitro biological activities of the newly synthesized complexes have also been investigated against Bacillus coli, Staphylococcus aureus and Candida albicans. The results showed that yttrium(III) complexes including 1,10‐phenanthroline exhibited better antibacterial/antifungal activity than their ligands and corresponding compounds.     

Interactions between Co(III) and Ni(II) complex ions and polyelectrolytes

An investigation has been carried out of the interaction of optically active tris(ethylenediamine)–Co(III) and of tris(o-phenanthroline)–Ni(II) complex ions with different polyelectrolytes in dilute aqueous solution. Optical rotatory dispersion measurements reveal that binding of the Co(III) complex ions occurs with a noticeable degree of specificity which in addition to depending on the nature of the fixed charges is also affected by the chemical constitution of the polyelectrolytes chain backbones. The dependence of tris(ethylenediamine)–Co(III) optical activity on polyelectrolyte concentration also exhibits interesting features. Polarimetric measurements of the rate of racemization of tris(o-phenanthroline)–Ni(II) ions in the presence of different polyelectrolytes lead to similar conclusions. Sodium dextran sulfate is shown to interact selectively with one of the antipodes of tris(phenanthroline)–Ni(II) complex.     

Lanthanide(III) Complexes of Tris(amide) PCTA Derivatives as Potential Bimodal Magnetic Resonance and Optical Imaging Agents

Lanthanide complexes of two tris(amide) derivatives of PCTA were synthesized and characterized. The relaxometric and luminescence properties of their lanthanide complexes were investigated as bimodal magnetic resonance (MR) and optical imaging agents. Luminescence studies show that one of the Tb^III complexes dimerizes in solution at low millimolar concentrations, whereas the other may have a higher than expected coordination number in solution. The corresponding Gd^III complexes display unusually high T₁ relaxivities and enhanced kinetic inertness compared to GdPCTA. These features suggest that these new chelates may be suitable for in vivo applications. The fast water‐exchange rates observed for these complexes make them unsuitable as paramagnetic chemical exchange saturation transfer (PARACEST) agents.     

Novel Water-Soluble 4,4-Disubstituted Ruthenium(III)-Salen Complexes in DNA Stranded Scission

Salen-type Ru(III) complexes are found to be capable of reacting with physiologically acceptable oxidants. The water solubility and DNA affinity of these Ru(III)-salen complexes are enhanced by the utilization of a variety of charged groups through the formation of peptide bonds. In the presence of hydrogen peroxide, modified Ru(III)-salen complexes are capable of nicking DNA. In addition, the reactivity in DNA cleavage increases along with the total number of positive charges retaining in Ru(III)-salen complexes and less influence in the electronic effect. Using ³²P-end-labeled oligonucleotides and high resolution polyacrylamide gel electrophoresis, Ru(III)-salen complexes are found to randomly cleave DNA regardless of the DNA secondary conformation such as bulge, inter-loop, or double-stranded regions. The possible reactive species of Ru(III)-salen complexes in DNA cleavage is considered as the hydroxyl radical and high valent oxoruthenium(IV) species according to the UV titration, quenching studies, and reaction with varied oxidants.     

Cyclometalated Iridium(III) Complexes as Two‐Photon Phosphorescent Probes for Specific Mitochondrial Dynamics Tracking in Living Cells

Five cyclometalated iridium(III) complexes with 2‐phenylimidazo[4,5‐f][1,10]phenanthroline derivatives ( IrL1 – IrL5 ) were synthesized and developed to image and track mitochondria in living cells under two‐photon (750 nm) excitation, with two‐photon absorption cross‐sections of 48.8–65.5 GM at 750 nm. Confocal microscopy and inductive coupled plasma‐mass spectrometry (ICP‐MS) demonstrated that these complexes selectively accumulate in mitochondria within 5 min, without needing additional reagents for membrane permeabilization, or replacement of the culture medium. In addition, photobleaching experiments and luminescence measurements confirmed the photostability of these complexes under continuous laser irradiation and physiological pH resistance. Moreover, results using 3D multicellular spheroids demonstrate the proficiency of these two‐photon luminescent complexes in deep penetration imaging. Two‐photon excitation using such novel complexes of iridium(III) for exclusive visualization of mitochondria in living cells may substantially enhance practical applications of bioimaging and tracking.     

Syntheses, luminescence switching, and electrochemical studies of photochromic dithienyl-1,10-phenanthroline zinc(II) bis(thiolate) complexes

A series of zinc(II) diimine bis(thiolate) complexes with photochromic diarylethene-containing phenanthroline ligands was synthesized, and their photophysical and photochromic properties were studied. The X-ray crystal structures of two of these complexes have been characterized. All complexes exhibit strong 3LLCT phosphorescence at 510-620 nm in the solid state at 77 and 298 K and in EtOH-MeOH glass at 77 K. Detailed studies revealed that the absorption, emission, and electrochemical properties of the complexes could be readily switched via the photochromic ring-closing and ring-opening reactions.     

Chiral Sensing of Various Amino Acids Using Induced Circularly Polarized Luminescence from Europium(III) Complexes of Phenanthroline Dicarboxylic Acid Derivatives

Circularly polarized luminescence (CPL) was observed from [Eu(dppda)₂]^? (dppda=4,7‐diphenyl‐1,10‐phenanthroline‐2,9‐dicarboxylic acid) and [Eu(pzpda)₂]^? (pzpda=pyrazino[2,3‐f][1,10]phenanthroline‐7,10‐dicarboxylic acid) in aqueous solutions containing various amino acids. The selectivity of these complexes towards amino acids enabled them to be used as chiral sensors and their behavior was compared with that of [Eu(pda)₂]^? (pda=1,10‐phenanthroline‐2,9‐dicarboxylic acid). As these Eu^III complexes have achiral D_2d structures under ordinary conditions, there were no CPL signals in the emission assigned to f–f transitions. However, when the solutions contained particular amino acids they exhibited detectable CPL signals with g_lum values of about 0.1 (g_lum=CPL/2 TL; TL=total luminescence). On examining 13 amino acids with these three Eu^III complexes, it was found that whether an amino acid induced a detectable CPL depended on the Eu^III complex ligands. For example, when ornithine was used as a chiral agent, only [Eu(dppda)₂]^? exhibited intense CPL in aqueous solutions of 10^?2 mol dm^?3. Steep amino acid concentration dependence suggested that CPL in [Eu(dppda)₂]^? and [Eu(pzpda)₂]^? was induced by the association of four or more amino acid molecules, whereas CPL in [Eu(pda)₂]^? was induced by association of two arginine molecules.     

Complexation and Electronic Spectra of Neodymium(III)–Amino Acid–1,10-Phenanthroline Systems in Aqueous Solution

Complexation of neodymium(III)-glutamate(glu)-phenanthroline(phen), neodymium(III)-aspartate(asp)-phenanthroline(phen) ternary systems and the corresponding binary systems in aqueous solution are discussed at various values of pH. Based on change regularity of hypersensitive transition intensities, the neodymium(III)-aspartate-phenanthroline ternary complex has a general formula of Nd(asp)₃phen, but the composition of the complex of Nd(III) with glutamate and phenanthroline is complicated and has not been determined. The electronic spectra of these complexes were studied, Slater-Condon parametersF _k ^s and the Lande parameter ξ_4f were obtained. The rms deviation between calculated and observed energy levels is less than 43 cm⁻¹. Bonding in these complexes are also investigated and bonding parameters calculated. The results show that Nd(III) and amino acids form complexes by ionic linkage with carboxylic oxygens, but with some weak covalency. Besides, the degrees of covalency in ternary complexes are larger than those in binary complexes.     

Crystal Structures and Thermal Behaviour of Lanthanide(III) Hexanoate 1, 10‐Phenanthroline Complexes, [M(C5H11CO2)3(phen)] and [Tm(C5H11CO2)2(NO3)(phen)]

Lanthanide(III) hexanoate 1, 10‐phenanthroline complexes crystallise in the space group P2₁/n. The compounds consist of dimers, whereby two lanthanide ions are held together by two bidentate bridging and two tridentate bridging carboxylate groups. The first coordination sphere of the lanthanide ions is completed by one bidentate chelating carboxylate group and by one bidentate 1, 10‐phenanthroline molecule, resulting in the coordination number 9. The dimers have a spherical form, which has important consequences for the thermal properties of complexes. The basic idea behind the preparation of this type of compounds is the stabilisation of the ionic lanthanide layer, so that the smaller lanthanide ions (from which the normal alkanoates do not show mesomorphism because they are too small) show liquid crystallinity. The stabilisation of the ionic layer was successful, expressed by the high melting temperatures, but mesomorphism is not observed. The absence of mesomorphism is related to the isotropic structure of the compounds. A lower symmetry is obtained when a hexanoate group is replaced by a nitrate group. Thulium(III) dihexanoate nitrate 1, 10‐phenanthroline crystallises in the space group P1¯. However, this compound also shows a spherical dimeric structure, but no mesomorphism.     

Luminescent Complexes of Europium (III) with 2-(Phenylethynyl)-1,10-phenanthroline: The Role of the Counterions

New antenna ligand, 2-(phenylethynyl)-1,10-phenanthroline (PEP), and its luminescent Eu (III) complexes, Eu(PEP)₂Cl₃ and Eu(PEP)₂(NO₃)₃, are synthesized and characterized. The synthetic procedure applied is based on reacting of europium salts with ligand in hot acetonitrile solutions in molar ratio 1 to 2. The structure of the complexes is refined by X-ray diffraction based on the single crystals obtained. The compounds [Eu(PEP)₂Cl₃]·2CH₃CN and [Eu(PEP)₂(NO₃)₃]∙2CH₃CN crystalize in monoclinic space group P2_1/n and P2_1/c, respectively, with two acetonitrile solvent molecules. Intra- and inter-ligand π-π stacking interactions are present in solid stat and are realized between the phenanthroline moieties, as well as between the substituents and the phenanthroline units. The optical properties of the complexes are investigated in solid state, acetonitrile and dichloromethane solution. Both compounds exhibit bright red luminescence caused by the organic ligand acting as antenna for sensitization of Eu (III) emission. The newly designed complexes differ in counter ions in the inner coordination sphere, which allows exploring their influence on the stability, molecular and supramolecular structure, fluorescent properties and symmetry of the Eu (III) ion. In addition, molecular simulations are performed in order to explain the observed experimental behavior of the complexes. The discovered structure-properties relationships give insight on the role of the counter ions in the molecular design of new Eu (III) based luminescent materials.