Electronic structure of adducts of Eu(III) <Emphasis Type="Italic">TRIS</Emphasis>-β—diketonates with phenanthroline: photoelectron and theoretical studies

By UPS spectroscopy of vapor, XPS spectroscopy of the condensed phase, and quantum chemical methods the adducts of tris-β-diketonates Eu(асас)₃Phen and Eu(hfас)₃Phen are studied. The electronic structure and features of the nature of chemical bonds in the adducts are established. The geometric structure of the studied compounds in the gas phase is determined. A procedure is developed that helps to assign the bands in gas-phase HeI photoelectron spectra and also in the valence band of the XPS spectra. Quantum chemical calculations (DFT) make it possible to find the regular changes in the electronic structure of the chelate complexes depending on ligand fluorination, to study the effect of a 1,10-phenanthroline molecule on the electronic structure of the chelate rings, and also to analyze the electronic effects caused by trifluoromethyl substitution for methyl groups in the ligand.     

Carbonylrhodium(I) complexes with heterocyclic nitrogen compounds

Crystalline complexes of rhodium(I) of the type [Rh(CO)₂(NN)] [RhX₂-(CO)₂] (NN  2,2'-bipyridyl, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-dipheynl-1,10-phenanthroline; X = Cl, Br) have been prepared. An ionic chain-like structure involving metal-metal interactions has been established by measurement of the reflectance spectra, absorption electronic spectra and electrical conductivities. The IR spectra have been examined over the 50–4000 cm^-1 range.     

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).     

Effect of heterocyclic diimine ligands with donor and acceptor substituents on the spectroscopic and electrochemical properties of Au(III) complexes

The composition, structure, and properties of a series of Au(III) complexes with heterocyclic diimine ligands [Au(N^N)Cl₂]⁺, where (N^N) = 2,2′-bipyridine (Bipy), 4,4′-dimethyl-2,2′-bipyridine (DmBipy), 2,2′-biquinoline (Bqx), 1,10-phenanthroline (Phen), 2,9-dimethyl-1,10-phenanthroline (DmPhen), and 4,7-diphenyl-1,10-phenanthroline (DphPhen), were characterized by ¹H NMR, electronic absorption, and emission spectroscopy and also by cyclic voltammetry. The influence of donor and acceptor substituents on the spectroscopic and electrochemical properties of the Au(III) complexes was revealed.     

Rhodium(I) carbonyl complexes with heterocyclic and nonheterocyclic nitrogen-donor ligands

Summary Complexes of the [Rh(N-N)(CO)₂][RhCl₂(CO)₂], [Rh(N-N)(CO)₂]BF₄ and Rh(N-N)(CO)₂Cl types where (N-N) = 2,9-dimethyl-1,10-phenanthroline (Me₂Phen), 4,7-diphenyl-1,10-phenanthroline (Ph₂Phen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Me₂2Ph₂Phen) or 2,2-biquinoline (biq), have been prepared and investigated. Benzidine (benz) ando-tolidine (tol) also form complexes of the first type. The complexes of the first two types behave as 11 electrolytes. While Ph₂Phen forms the four coordinate monocarbonyl Rh(Ph₂Phen)(CO)Cl complex, benzo(f)-quinoline (Q) yields the Rh(CO)₂ (Q)Cl compound. Triphenyl-phosphine and triphenylarsine react with the above complexes to form the well knowntrans-Rh(CO)ClL₂ where L = PPh₃ or AsPh₃. The i.r. and u.v.-visible spectra of the compounds are discussed.     

Formation Thermodynamics of Binary and Ternary Lanthanide(III) Complexes with 1,10-Phenanthroline and Chloride in N,N-Dimethylformamide

Formation thermodynamics of binary and ternary lanthanide(III) (Ln = La, Ce, Nd, Eu, Gd, Dy, Tm, Lu) complexes with 1,10-phenanthroline (phen) and the chloride ion have been studied by titration calorimetry and spectrophotometry in N,N-dimethyl-formamide (DMF) containing 0.2 mol-dm^–3 (C₂H₅)₄NClO₄ as a constant ionic medium at 25°C. In the binary system with 1,10-phenanthroline, the Ln(phen)³⁺ complex is formed for all the lanthanide(III) ions examined. The reaction enthalpy and entropy values for the formation of Ln(phen)³⁺ decrease in the order La > Ce > Nd, then increase in the order Nd < Eu < Gd < Dy, and again decrease in the order Dy > Tm > Lu. The variation is explained in terms of the coordination structure of Ln(phen)³⁺ that changes from eight to seven coordination with decreasing ionic radius of the metal ion. In the ternary Ln³⁺-Cl^–-phen system, the formation of LnCl(phen)²⁺, LnCl₂(phen)⁺, and LnCl₃(phen) was established for cerium(III), neodymium(III), and thulium(III), and their formation constants, enthalpies, and entropies were obtained. The enthalpy and entropy values are also discussed from the structural point of view.     

Synthesis,structure, DNA binding studies and nuclease activities of two luminescent neodymium complexes

Two neodymium(III) complexes, [Nd(Phen)(NO₃)₃(DMF)₂] (1) and [Nd(Phen)₂(NO₃)₃] (2) (phen = 1,10-phenanthroline; DMF = dimethylformamide), have been synthesized with a view to design artificial luminescent nucleases and nuclease mimics. The complexes were characterized by spectroscopic, powder, and single crystal XRD studies. The complexes, as expected, have luminescent properties. The DNA binding studies of both complexes have been carried out by spectroscopic studies e.g. electronic absorption (UV–Vis), fluorescence emission as well as viscosity measurements. The nuclease activity of the complexes has been established by gel electrophoresis using pUC19 circular plasmid DNA. The results of DNA binding as well as DNA cleavage activity and the model studies of interaction with pNPP indicate that both neodymium complexes demonstrate nuclease activity through phosphoester bond cleavage.     

Copper(II) complexes of entwined 2,9-di(o-substituted phenyl)-1,10-phenanthroline type ligands and intramolecular quenching in copper(I) complexes

Cu¹¹ complexes of 1,10-phenanthroline, disubstituted at the 2 and 9 positions or monosubstituted at the 2 position by phenyl moieties possessingortho substituents, were prepared and investigated by spectroscopic and electrochemical methods. The electronic spectral d-d band position varies from 14 500 to 13 200 cm⁻¹. E.s.r. g_‖ values are between 2.256 to 2.283 and A_‖ between 164 to 117×10⁻⁴ cm⁻¹. Thebis[2,9-di(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reversible one-electron electrochemical reduction (Cu¹¹/Cu¹) in the +0.536 to +0.825 V potential range versus s.c.e., whereas thebis[2-mono(o-substituted phenyl)-1,10-phenanthroline]Cu¹¹ complexes undergo reduction in the +0.360 to +0.405 V range; the redox couple is found to be quasireversible. Emission studies on copper(I) complexes show that onlybis[2,9-di(o-tolyl)-1,10-phen]Copper(I) complex exhibits emission properties. Emission behaviour of other structurally similar compounds is explored. TMC 2555     

Thermodynamic stability of neodymium nitrate complex with 1,10-phenanthroline

The thermodynamic stability of neodymium nitrate complex with 1,10-phenanthroline (Phen) was determined by mass spectrometry. The complex was formulated as Nd(NO₃)₃ · 2C₁₂H₈N₂ on the basis of elemental analysis. Mass spectrometry allowed us to characterize the decomposition of Nd(NO₃)₃ · 2C₁₂H₈N₂ thermodynamically. The formation enthalpy of this complex is ?1058.0 kJ/mol.     

Efficient Synthesis of 1,2-Bis(2,2′-bipyridinyl)ethane and 1,2-bis(1,10-phenanthrolinyl)ethane ligands by oxidative coupling of the corresponding monomeric methylene carbanions

Several dimeric 1,2-bis (2,2′-bipyridinyl)ethane (1,2,6,7, and 9 and 1,2-bis(1,10-phenanthrolinyl)) ethane (3,4, and 5) ligands have been synthesized in high yield by oxidative coupling of the corresponding monomeric methylene carbanions using as oxidating agents Br₂, I₂, and 1,2-dibromoethane. The structure of the compounds obtained from three tetramethyl-2,2′-bipyridines and one tetramethyl-1,10-phenanthroline have been assigned on the basis of their ¹H-NMR spectra. The electronic absorption and emission properties of these new ligands are reported. They display intense fluorescence spectra.     

Reaction with DNA and pharmacologic activity of 1,10-phenanthroline and electron-rich 1,10-phenanthrocyanine complexes of d-elements

Types of binding with DNA and pharmacologic activity of 1,10-phenanthroline and electron-rich 1,10-phenanthrocyanine complexes of d-elements are discussed. The relationship of the electronic and geometric structure of 1,10-phenanthroline complexes of transition metals to their interaction with DNA molecules is analyzed. The concept of redox-mediated antibacterial, antiviral, and antitumor activity of 1,10-phenanthroline complexes of d-elements is formulated.

     

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.     

Spectroscopic and Electronic Properties of Molybdacarborane Complexes with Non-innocently Acting Ligands

The molybdacarboranes [3-{L-κ²N,N}-3-(CO)₂-closo-3,1,2-MoC₂B₉H₁₁] (L=2,2′-bipyridine (2,2′-bpy, 1 a ) or 1,10-phenanthroline (1,10-phen, 1 b )) incorporating well-known potentially non-innocent ligands (CO, 2,2′-bpy, 1,10-phen) and the “non-spectator” nido-carborane ([η⁵-C₂B₉H₁₁]²⁻) ligand were prepared and fully characterised. High-resolution mass spectrometry, single-crystal X-ray diffraction methods, spectroscopy (IR, (resonance) Raman, NMR), cyclic voltammetry and spectroelectrochemistry (electrochemical properties) were supported by theoretical investigations of the electronic structure (DFT, CAS-SCF, TD-DFT).     

Synthesis and magnetic studies of phthalato-bridged oxovanadium(IV) binuclear complexes

Six new μ-phthalato binuclear oxovanadium(IV) complexes, namely [(VO)₂(PHTH)-(L)₂]SO₄ (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me₂ bpy); 5-nitro-1,10-phenanthroline (NO₂-phen); 5-chloro-1,10-phenanthroline (Cl-phen) and 5-methyl-1,10-phenanthroline (CH₃-phen), where PHTH is the phthalate dianion), have been synthesized and characterized by elemental analyses, IR, electronic spectra, magnetic moments at room temperature and molar conductivity measurements. The temperature dependence of the magnetic susceptibility of complexes [(VO)₂(PHTH)(phen)₂]SO₄ (1) and [(VO)₂(PHTH)(CH₃-phen)₂]SO₄ (2) was measured in 4—300 K range and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, ?=?2J?₁·?₂, giving the exchange integrals J=?12.8 cm^?1 for 1 and J=?7.9 cm^?l for 2. This indicates an antiferromagnetic spin-exchange interaction between the metal ions within each molecule.     

The Intercalation Reaction of 1,10-Phenanthroline with Layered Compound FePS3

The intercalation reaction of 1,10-phenanthroline with FePS₃ in ethanol and in the presence of anilinium chloride has been monitored in detail with the X-ray powder diffraction (XRD) method to study the reaction mechanism. It is revealed that during the intercalation period there are three phases: the 001 phase (corresponding to the perpendicular orientation of the 1,10-phenanthroline ring with the layer of the host FePS₃), the 001′ phase (standing for the parallel orientation of the 1,10-phenanthroline ring with the layer), and the 001″ phase (pristine FePS₃), but as the period of the reaction is prolonged, the 001′ and 001″ phases diminish gradually and finally disappear, and the 001 phase is intensified and a complete intercalate is obtained for Series A, in which excess 1,10-phenanthroline is used. However, for Series B in which the optimum amount of 1,10-phenanthroline is used, the 001 and 001″ phases diminish gradually, and another intercalate is obtained that exhibits the 001′ phase. Moreover, if the amount of phenanthroline used in the reaction is more than that in Series B but not in excess, another intercalate containing 001 and 001′ phases is obtained. In these intercalation reactions, the results of IR spectroscopy indicate that anilinium chloride serves only as the source of protons for 1,10-phenanthroline, but 1,10-phenanthroline acts as both the complexing agent of Fe²⁺ ions removed from FePS₃, confirmed by UV spectra of the filtrates, and the inserted guest, some of which exists in the form of protonated cation to maintain the charge balance of the intercalates. From the experimental evidence we find that the arranged orientation of 1,10-phenanthroline between the layers is controlled by the amount of guest used in the reaction, and a possible intercalation mechanism is proposed for the reaction.     

Solvent effects on the redox properties of tris-(1,10-phenanthroline)iron(II/III) complexes

The redox properties of the system Fe(tmphen)₃(II/III) (tmphen=3,4,7,8-tetramethyl-1,10-phenanthroline) have been studied in the solvents nitromethane, acetonitrile, propanediol-1,2-carbonate, dimethylformamide, dimethylacetamide, dimethylsulfoxide and of the systems Fe(phen)₃(II/III) (phen=1,10-phenanthroline) and Fe(niphen)₃(II/III) (niphen=5-nitro-1,10-phenanthroline) in the solvents nitromethane, acetonitrile, propanediol-1,2-carbonate and acetone. The redox potentials of Fe(tmphen)₃(II/III) are nearly independent of the solvent suggesting that the system might be used as a reference redox couple similar to the systems ferrocene/ferricinium or bisbiphenylchromium(0/I). In contrast the redox potentials of Fe(niphen)₃(II/III) show a significant decrease with increasing donor number of the solvent which can be explained by nucleophilic attack of solvent molecules at the iron. It is shown that such a mechanism is consistent with the known solvent and salt effects on the kinetics of dissociation of ferroin and ferriin type complexes.     

Neodymium(III) tris(1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)propane-1,3-dionato)(1,10-phenanthroline): Synthesis and photophysical properties

The reaction of NdCl₃ with 1,3-bis(1,3-dimethyl-1H-pyrazol-4-yl)propane-1,3-dione (HL) and 1,10-phenanthroline (Phen) in the presence of a base afforded complex [Nd(L)₃Phen] (I). Unstable solvate I · 2CH₂Cl₂ was obtained from a solution of the complex in dichloromethane, and its structure was determined by X-ray diffraction analysis. The photophysical properties of the complex were studied. Possible routes for the energy transfer in the course of photoluminescence were proposed.     

Bimetallic bis(diphenylphosphino)acetylene bridged copper(I) complexes with 1,10-phenanthroline derivatives: synthesis,crystal structure,and spectroscopic characterization

A new series of bimetallic bis(diphenylphosphino)acetylene-bridged copper(I) 1,10-phenanthroline complexes, [Cu₂(dppa)₂(L)₂](BF₄)₂; L?=?1,10-phenanthroline (1); 4-methyl-1,10-phenanthroline (2); 4,7-dimethyl-1,10-phenanthroline (3); and 2,9-dimethyl-1,10-phenanthroline (4), have been prepared and characterized by spectroscopic methods. The X-ray structures of 1 and 4 were determined. The structures consist of centrosymmetric bimetallic 10-membered chair-like dimetallacycles. In 1, intermolecular C–H?π interactions result in bending of the phenanthroline ligand and sterically induced lengthening of one Cu–P bond. In 1–4, the ³¹P NMR downfield coordination shift, relative to the free ligand, correlates with the basic strength of the 1,10-phenanthroline ligands.     

Rhodium and platinum complexes as catalysts for the polymerization of phenylacetylene

In polymerization reactions of phenylacetylene three different types of polyphenylacetylene (PPA) were prepared by using Rh and Pt complexes as catalysts in different reaction conditions. Type I PPA is obtained with [Rh (COD) Chel] PF₆ complexes (COD = cis,cis-cycloocta 1,5-diene; chel = 2,2′-bipyridine, 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 5,6-dimethyl-1,10-phenanthroline, 3,4,7,8-tetramethyl-1,10-phenanthroline) in bulk, benzene methanol, while type II PPA is obtained with the same catalysts in p-dioxane and type III PPA in the presence of [Pt (? C?CPh)₂(PPh₃)₂] in bulk. Type I, II, and III PPA exhibit different IR and ¹H-NMR spectra, which have been compared with literature data. Correlations proposed by different Authors between spectral properties of PPA and chain structures are also discussed.     

Synthesis,spectroscopic and structural characterizations of two new complexes of ruthenium with 2-(hydroxymethyl)benzimidazole and 1,10-phenanthroline ligands

The complexes [RuCl(CO)(PPh₃)₂(HBIm)] and [RuH(CO)(PPh₃)₂(1,10-phen)]Cl·H₂O·(CH₃)₂O have been prepared and studied by IR and UV–Vis spectroscopy, and X-ray crystallography. The complexes were prepared in the reactions of [RuHCl(CO)(PPh₃)₃] with 2-(hydroxymethyl)benzimidazole or 1,10-phenanthroline two hydrate in acetone. The electronic spectra of the obtained compounds have been calculated using the TDDFT method. The luminescence properties of these complexes were examined.