Phosphorus-containing Ligands Research Articles

Coupled hydrogenation of alkenes and arenes in the presence of catalytic systems based on cobalt Bis(acetylacetonate) and tributylphosphine

The effect of the composition of the catalytic systems based on Co(acac)2 and tertiary phosphines on the activity and efficiency of cobalt catalysts in the coupled hydrogenation of alkenes and arenes is reported. The process occurs in the presence of cobalt catalysts formed under the action of both organoaluminum compounds and tert-butoxy derivatives of complex aluminum hydrides. NMR and IR spectroscopic methods show that the interaction of the components of the catalytic systems yields mono- and/or trihydrido cobalt phosphine complexes, whose composition depends on the nature of the reducing agent and gas atmosphere. The homogeneous character of the process is hypothesized. The most probable schemes are proposed for the reaction mechanism, according to which the kinetic coupling of alkene (alkadiene) and arene hydrogenations is due to the fact that the reaction proceeds through a σ-alkyl or σ-alkenyl cobalt complex with two phosphorus-containing ligands.

Luminescence of ytterbium(III) cinnamate compounds

The spectral luminescent characteristics of mixed-ligand compounds of ytterbium (III) with cinnamic acid, nitrogen- and phosphorus-containing neutral ligands were studied by the methods of fluorescent spectroscopy. The luminescence intensity of the obtained compounds was measured and it was found that the highest intensity of luminescence has the polymeric ytterbium(III) cinnamate.

Mixed-ligand lanthanide complexes with acylpyrazolones and phosphorus-containing ligands

The reactions of lanthanum acetylacetonate with various phosphorus-containing pesticides, toxic gases, and products of their hydrolysis are modeled by quantum-chemical methods. In the most cases, the enthalpy of substitution for water by organophosphorus compounds is negative. The complexes are studied in solutions using ethyl (diethoxyphosphoryl) acetate as a model compound. The mixed-ligand lanthanide complexes with acylpyrazolones and ethyl (diethoxyphosphoryl) acetate are synthesized. The crystal structure is determined for the samarium complex.

A general synthesis of phosphaalkenes at zirconium with liberation of phosphaformamides

A general, atom-economical method for the synthesis of phosphaalkenes is reported via the net coupling of primary alkyl or aryl phosphines with aryl or alkyl isocyanides at zirconium. The phosphorus-containing ligand can be liberated as the phosphaformamide from zirconium by reaction with an organic electrophile.

Kinetics of homogeneous dehydrogenation of formic acid in the presence of supramolecular rhodium(III) complex with P-functionalized calix[4]resorcine

The kinetics of homogeneous dehydrogenation of formic acid in the presence of supramolecular rhodium(III) complex with P-functionalized calix[4]resorcine were studied in dioxane, tetrahydrofuran, dimethylformamide, and binary formamide-dioxane mixtures (volume ratio 10: 90, 20: 80, 30: 70) over a wide temperature range (40–90°C). The examined Rh(III) complex catalyzed the dehydrogenation process, and its catalytic activity was higher than that observed previously for rhodium complexes with non-macrocyclic phosphorus-containing ligands. The dehydrogenation rate constants were proportional to neither catalyst concentration nor dielectric constant of the medium, which is likely to be related to supramolecular nature of the Rh(III) complex. No micelle formation was observed in the examined systems.

PPM amount of Fe(iii)-mediated ATRP of MMA with phosphorus-containing ligands in the absence of any additives

MMA was polymerized via new oxidation-free ATRP by using ppm amounts of a Fe(III)-mediated ATRP system with four phosphorus containing ligands without any external reducing agent or free radical initiator. Well-controlled polymerizations were able to be achieved to produce PMMA with a high molecular weight (>300 000) and low polydispersity (PDI < 1.3) with a 10 ppm amount of FeBr3.

Luminescence of ytterium(III) β-diketonate complexes containing different ligands

The spectral and luminescent characteristics of ytterbium(III) β-diketonate complexes containing different nitrogen- and phosphorus-containing ligands are determined. The most intensive luminescence in the IR region is observed for the neutral phosphorus-containing ligands.

Luminescence of neodymium(III) carboxylate complexes with different ligands

The spectral and luminescent characteristics of neodymium(III) carboxylate complexes with different nitrogen- and phosphorus-containing neutral ligands were studied and the relationship between the intensity of luminescence and the composition of the coordination sphere was established. The most intensive luminescence of neodymium(III) compounds in the IR region was observed from the complexes with toluic and cinnamic acids.

Neodimium(III) luminescence in the mixed ligand compounds with β-diketones

The luminescent spectral characteristics of neodymium(III) tris- and tetrakis-β-diketonates and β-diketonate acido complexes were investigated. The dependence between the intensity of the luminescence and the composition of the coordination sphere of the complexes was revealed. The most intense luminescence in the IR region possess the neodymium(III) compounds which are the mixed ligand complexes with β-diketones and phosphorus-containing neutral ligands.

Comparison of different phosphorus-containing ligands complexing 68Ga for PET-imaging of bone metabolism

Abstract 99mTc-phosphonate structures are well established tracers for bone tumour imaging. Our objective was to investigate different 68Ga-labelled phosphonate ligands concerning labelling kinetics, binding to hydroxyapatite and bone imaging using μ-PET. Seven macrocyclic phosphorus-containing ligands and EDTMP were labelled in nanomolar scale with n.c.a. 68Ga in Na-HEPES buffer at pH∼4. Except for DOTP, all ligands were labelled with &gt;92% yield. Binding of the 68Ga-ligand complexes on hydroxyapatite was analysed to evaluate the effect of the number of the phosphorus acid groups on adsorption parameters. Adsorption of 68Ga-EDTMP and 68Ga-DOTP was &gt;83%. For the 68Ga-NOTA-phosphonates an increasing binding with increasing number of phosphonate groups was observed but was still lower than 68Ga-DOTP and 68Ga-EDTMP. μ-PET studies in vivo were performed with 68Ga-EDTMP and 68Ga-DOTP with Wistar rats. While 68Ga-EDTMP-PET showed uptake on bone structures, an excess amount of the ligand (&gt;1.5 mg EDTMP/kg body weight) had to be used, otherwise the 68Ga3+ is released from the complex and forms gallium hydroxide or it is transchelated to 68Ga-transferrin. As a result, the main focus of further phosphonate structures has to be on complex formation in high radiochemical yields with macrocyclic ligands with phosphonate groups that are not required for complexing 68Ga.

ChemInform Abstract: Complexes of Transition Metals with Phosphorus-Containing Ligands. Substituted (Benzoylmethylene)diphenyl-2-hydroxyphenyl Phosphoranes and Their Inner Complex Compounds.

ChemInform Abstract: Complexes of Transition Metals with Phosphorus-Containing Ligands. Substituted (Benzoylmethylene)diphenyl-2-hydroxyphenyl Phosphoranes and Their Inner Complex Compounds.

ChemInform Abstract: Synthesis and Magnetic Behavior of Paramagnetic Phosphorus-Containing Ligands and Their Metal Complexes

Abstract The synthesis of new paramagnetic phosphorus-containing compounds, (para-RAD-phenyl)diphenylphosphine and phosphine oxide (RAD = nitronylnitroxide. tBuNO), is described. Complexation of these phosphines with diamagnetic metal centres yields, for example, intermolecular ferromagnetic interactions with {Mo(CO)5(phosphine)}, antiferromagnetic interactions with {AuCl(phosphine)} and {PdCl2(phosphine)2}, a complex with multiple paramagnetic ligands. Ligation of nitronylnitroxide-containing phosphines to paramagnetic metals is hindered by catalytic nitrogen to phosphorus oxo-transfer to form the corresponding iminonitroxide-substituted phosphine oxide. A molecular square containing two nitronylnitroxide-substituted phosphine oxide ligands and two Mn(hfac)2 units is also described.

Propylene dimerization in the presence of nickel hydride complexes formed in situ

We study the influence of nickel hydride complexes formed in situ by reaction nickel(0) complexes having phosphorus-containing ligands with Bronsted acids in the presence of various modifiers on a catalyst turnover and selectivity in propylene dimerization. The activating action of boron trifluoride etherate is considered.

Luminescence and magnetic properties of mixed-ligand europium trifluoroacetates

The luminescence and magnetic properties of mixed-ligand europium trifluoroacetates with nitrogen- and phosphorus-containing neutral ligands [Eu(TFA)3 · 3H2O]2 and Eu(TFA)3 · 2D · nH2O were studied (here TFA is the trifluoroacetic acid anion, and D is Phen (1,10-phenanthroline), n = 1; DMF (dimethylformamide), n = 1; or TPPO (triphenylphosphine oxide), n = 3). The molar magnetic susceptibility increased in the series of complex compounds Eu(TFA)3 · 2Phen · H2O < [Eu(TFA)3 · 3H2O]2 < Eu(TFA)3 · 2DMF · H2O < Eu(TFA)3 · 2TPPO · 3H2O. Correlations were found between the luminescent and magnetic characteristics of the complex compounds.

“Through-space” nuclear spin–spin couplings in ferrocenyl polyphosphanes and diphosphino cavitands: A new way of gathering structural information in constrained P(III) ligands by NMR

Abstract Nuclear magnetic resonance is an invaluable technique for investigating a variety of important issues ranging from the determination of molecular structure to therapeutic medical imaging. In this respect, the indirect nuclear spin–spin coupling involving common nuclei such as 1 H, 13 C or 31 P provides, via the J constant, conclusive data for compound characterization in solution. This electron-mediated nuclear spin coupling is usually regarded as being transmitted by covalently bonded magnetic atoms. However, several experimental and theoretical studies, first focused on constrained organofluorides, and more recently devoted to phosphane ligands highlighted the existence of very intense J -couplings operating “through-space”. Herein, the intramolecular “through-space” 31 P 31 P and 31 P 13 C couplings are discussed in the light of recent examples found in constrained phosphorus-containing ligands such as phosphinocalixarenes , phosphinocyclodextrins and ferrocenyl phosphanes . The emphasis is put on the origin and transmitting mode of these nonbonded spin–spin couplings as well as on the relevant structural information they provide in solution.

Luminescence of europium trifluoroacetates

The luminescence spectral characteristics of mixed-ligand europium trifluoroacetates with nitrogen- and phosphorus-containing neutral ligands were studied at different temperatures. For several trifluoroacetates, the intensity of luminescence increased with temperature. The diffuse reflectance data were analyzed, and a mechanism of thermal luminescence buildup was suggested.

The influence of an intramolecular hydrogen bond on the 1,3-N,S-coordination of crown ether-containing N-phosphorylthiourea with NiII

Reaction of the lithium salt of N-phosphorylated thiourea [4′-benzo-15-crown-5]NHC(S)NHP(O)(OiPr)2 (HLI) with NiII leads to the chelate complex [NiLI2]. The metal center is found in a square-planar N2S2 environment formed by the CS sulfur atoms and the P–N nitrogen atoms of two deprotonated LI ligands. Reaction of [NiLI2] and its non-crown ether-containing analog Ni[PhNHC(S)NP(O)(OiPr)2]2 ([NiLII2]) with 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) leads to the [Ni(bipy)LI,II2] and [Ni(phen)LI,II2] heteroligand complexes. The coordination mode is preserved for the phosphorus-containing ligands. The extraction properties of the crown ether-containing compounds towards alkali metal picrates were investigated. The molecular structures of HLI, [NiLI2] and [Ni(bipy)LII2] were elucidated by X-ray diffraction.

New P-chiral polyfluoroalkyl phosphorodiamidite ligand in asymmetric transformations catalyzed by palladium and copper complexes

Chiral phosphorus-containing ligands having polyfloroalkyl substituents may be used for the preparation of metal complex catalysts which could be recycled via phase separation [1]. Following the approach proposed by us previously [2], we synthesized a new P-chiral polyfluoroalkyl phosphorodiamidite L as shown in Scheme 1. The product was stable on storage and readily soluble in organic solvents. It was tested as chiral auxiliary in palladium-catalyzed enantioselective amination of 1,3-diphenylprop-2-en-1-yl acetate (I) with dipropylamine according to the procedure described in [3] (Scheme 2). In all experiments, a steadily high enantioselectivity level was reached (ee 91– 95%), regardless of the L/Pd molar ratio (1 : 1 or 2 : 1) and reaction medium. However, the substrate conversion turned out to be quite sensitive to the solvent nature: it did not exceed 32% in tetrahydrofuran but was almost complete in methylene chloride.

Solid extractants prepared with ionic liquids and their use for recovery of actinides from nitric acid solutions

Solid extractants were prepared by noncovalent immobilization of phosphonium ionic liquids (ILs) on various polymeric materials, including fibrous materials. These sorption materials can be used for recovering Pu from 0.5–5 M HNO3. Immobilization of phosphorus-containing ligands on solid supports using phosphonium ILs yields a material recovering actinides from nitric acid solutions.

Phosphorus‐Containing Ligands for Iron(III)‐Catalyzed Atom Transfer Radical Polymerization

Living polymers: Iron(III) complexes with phosphorus-containing ligands are efficient catalysts for atom transfer radical polymerization in the absence of any radical initiator or reducing agent. The polymers produced have good molecular weights and narrow polydispersities as determined by gel permeation chromatography (see scheme). The controlled nature of the FeBr3/dppp system was confirmed by a chain-extension experiment. Mn,GPC in [g mol−1]. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.