Triphenylphosphine Complexes Research Articles

Rhodium(III)-triphenylphosphine complex with NNS donor thioether containing Schiff base ligand: Synthesis, spectra, electrochemistry and catalytic activity

New rhodium(III)-triphenylphosphine complex, [Rh(PPh3)(L)Cl2](PF6) (1) with thioether containing NNS donor ligand (L) (L = 2-(methylthio)-N-((pyridine-2-yl)methylene)benzenamine) has been synthesized and characterized. The pseudo octahedral geometry of the complex has been confirmed by single crystal X-ray analysis. The electronic structure, redox properties, absorption and emission properties of the complexes have been interpreted by DFT and TDDFT calculations. The complex effectively catalyzed the transfer hydrogenation reaction of ketones in 2-propanol and oxidation of alcohols in presence of NMO.

Bis(triphenylphosphine)silver(i) perrhenate, a cyclic dimer.

The 1 : 4 and 1 : 2 complexes of silver perrhenate and triphenylphosphine, [(Ph3P)4Ag](+) ReO4(-) and [(Ph3P)2AgReO4]2, have been prepared and their structures determined in the solid state by X-ray diffraction. The former is composed of independent ions, while in the latter the ions are aggregated into cyclic dimers. The silver centers are tetracoordinated including contact with two bridging perrhenate anions, setting this structure apart from that of its gold analogue [(Ph3P)2Au](+) ReO4(-) where the gold centers are strictly two-coordinate.

Hemilabile silver(i) complexes containing pyridyl chalcogenolate (S, Se) ligands and their utility as molecular precursors for silver chalcogenides

A series of silver triphenylphosphine complexes containing pyridyl chacogenolate (S, Se) ligands has been synthesized by employing [AgCl(PPh3)3] and [Ag2(μ-Cl)2(PPh3)4].

Au(i) π-bis(tert-butyldimethylsilyl)acetylene triphenylphosphine complex, an effective pre-catalyst for Au(i)-catalyzed reactions

A [Ph3PAu]+ η2-alkyne π complex is found to be shelf-stable and effective for a range of the Au(i)-catalyzed alkyne π activation reactions.

Bifunctional silver(I) complex-catalyzed CO2 conversion at ambient conditions: synthesis of α-methylene cyclic carbonates and derivatives.

The chemical conversion of CO2 at atmospheric pressure and room temperature remains a great challenge. The triphenylphosphine complex of silver(I) carbonate was proved to be a robust bifunctional catalyst for the carboxylative cyclization of propargylic alcohols and CO2 at ambient conditions leading to the formation of α-methylene cyclic carbonates in excellent yields. The unprecedented performance of [(PPh3)2Ag]2CO3 is presumably attributed to the simultaneous activation of CO2 and propargylic alcohol. Moreover, the highly compatible basicity of the catalytic species allows propargylic alcohol to react with CO2 leading to key silver alkylcarbonate intermediates: the bulkier [(Ph3P)2Ag(I)](+) effectively activates the carbon-carbon triple bond and enhances O-nucleophilicity of the alkylcarbonic anion, thereby greatly promoting the intramolecular nucleophilic cyclization. Notably, this catalytic protocol also worked well for the reaction of propargylic alcohols, secondary amines, and CO2 (at atmospheric pressure) to afford β-oxopropylcarbamates.

Gold(I)-triphenylphosphine complexes with hypoxanthine-derived ligands: in vitro evaluations of anticancer and anti-inflammatory activities.

A series of gold(I) complexes involving triphenylphosphine (PPh3) and one N-donor ligand derived from deprotonated mono- or disubstituted hypoxanthine (HLn) of the general composition [Au(Ln)(PPh3)] (1–9) is reported. The complexes were thoroughly characterized, including multinuclear high resolution NMR spectroscopy as well as single crystal X-ray analysis (for complexes 1 and 3). The complexes were screened for their in vitro cytotoxicity against human cancer cell lines MCF7 (breast carcinoma), HOS (osteosarcoma) and THP-1 (monocytic leukaemia), which identified the complexes 4–6 as the most promising representatives, who antiproliferative activity was further tested against A549 (lung adenocarcinoma), G-361 (melanoma), HeLa (cervical cancer), A2780 (ovarian carcinoma), A2780R (ovarian carcinoma resistant to cisplatin), 22Rv1 (prostate cancer) cell lines. Complexes 4–6 showed a significantly higher in vitro anticancer effect against the employed cancer cells, except for G-361, as compared with the commercially used anticancer drug cisplatin, with IC50 ≈ 1–30 µM. Anti-inflammatory activity was evaluated in vitro by the assessment of the ability of the complexes to modulate secretion of the pro-inflammatory cytokines, i.e. tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in the lipopolysaccharide-activated macrophage-like THP-1 cell model. The results of this study identified the complexes as auspicious anti-inflammatory agents with similar or better activity as compared with the clinically applied gold-based antiarthritic drug Auranofin. In an effort to explore the possible mechanisms responsible for the biological effect, the products of interactions of selected complexes with sulfur-containing biomolecules (L-cysteine and reduced glutathione) were studied by means of the mass-spectrometry study.

Effect of 2-Chloro-Substitution of Adenine Moiety in Mixed-Ligand Gold(I) Triphenylphosphine Complexes on Anti-Inflammatory Activity: The Discrepancy between the In Vivo and In Vitro Models

A series of gold(I) triphenylphosphine (PPh3) complexes (1–9) involving 2-chloro-N6-(substituted-benzyl)adenine derivatives as N-donor ligands was synthesized and thoroughly characterized by relevant methods, including electrospray-ionization (ESI) mass spectrometry and multinuclear NMR spectroscopy. The anti-inflammatory and antiedematous effects of three representatives 1, 5 and 9 were evaluated by means of in vitro model based on the expression of pro- and anti-inflammatory cytokines and influence of the complexes on selected forms of matrix metalloproteinases secreted by LPS-activated THP-1 monocytes and in vivo model evaluating the antiedematous effect of the complexes in the carrageenan-induced rat hind-paw edema model. In addition to the pharmacological observations, the affected hind paws were post mortem subjected to histological and immunohistochemical evaluations. The results of both in vivo and ex vivo methods revealed low antiedematous and anti-inflammatory effects of the complexes, even though the in vitro model identified them as promising anti-inflammatory acting compounds. The reason for this discrepancy lies probably in low stability of the studied complexes in biological environment, as demonstrated by the solution interaction studies with sulfur-containing biomolecules (cysteine and reduced glutathione) using the ESI mass spectrometry.

Catalyst Activity and Selectivity in the Isomerising Alkoxycarbonylation of Methyl Oleate

The synthesis of unsymmetrical diphosphine ligands (3a-g) with an o-tolyl backbone and tert-butyl, adamantyl, cyclohexyl and isopropyl substituents on the phosphorus moiety is described (1,2-(CH2PR2)(PR'2)C6H4; 3a: R=tBu, R'=tBu, 3b: R=tBu, R'=Cy, 3c: R=tBu, R'=iPr, 3d: R=Ad, R'=tBu, 3e: R=Ad, R'=Cy, 3f: R=Cy, R'=Cy, 3g: R=Ad, R'=Ad). The corresponding diphosphine-Pd(II) ditriflate complexes [(P^P)Pd(OTf)2] (5a-g) were prepared and structurally characterised by X-ray crystallography. These new complexes were studied as catalyst precursors in the isomerising methoxycarbonylation of methyl oleate, and were found to convert methyl oleate into the corresponding linear α,ω-diester (L) with 70-80% selectivity. The products of this catalytic reaction with the known [{1,2-(tBu2PCH2)2C6H4}Pd(OTf)2] complex (5h) were fully analysed, and revealed the formation of the linear α,ω-diester (L, 89.0%), the methyl-branched diester B1 (4.3%), the ethyl-branched diester B2 (1.0%), the propyl-branched diester B3 (0.6%) and all diesters from butyl- to hexadecyl-branched diesters B4-B16 (overall 4.8%) at 90 °C and 20 bar CO. The productivity of the catalytic conversion of methyl oleate with complexes 5a-g varied with the steric bulk of the alkyl substituent on the phosphorus. Ligands with more bulky groups, like tert-butyl or adamantyl (e.g., 5a, 5d, 5g), were more productive systems. The formation of the catalytically active hydride species [(P^P)Pd(H)(MeOH)](+) (6-MeOH) was investigated and observed directly for complexes 5a-e and 5g, respectively. These hydride species were isolated as the corresponding triphenylphosphine complexes (6-PPh3) and fully characterised, including by X-ray crystallography. The catalytic productivity of 6a-PPh3 was virtually identical to that of 5a, thereby confirming the efficient hydride formation of 5a under catalytic conditions.

Synthesis, characterization, structural analysis and DNA binding studies of nickel(II)–triphenylphosphine complex of ONS donor ligand – Multisubstituted thiosemicarbazone as highly selective sensor for fluoride ion

A new kind of Ni(II) complex of the type, [Ni(PPh3)(L)](1), {where L=chemosensor thiosemicarbazone=2-(3-bromo-5-chloro-2-hydroxybenzylidene)-N-phenyhydrazine-carbothioamide} have been synthesized and characterized by NMR, IR, UV–Vis spectroscopic methods and single crystal X-ray studies. Based on spectroscopic and X-ray crystallographic studies, a square planar structure has been proposed for the Ni(II) complex. The interaction between Ni(II) complex and CT-DNA has been investigated using UV–Vis, circular dichroism studies and gel electrophoresis. In UV studies, the observed strong hypochromism in absorption intensities and binding constant value (Kb=1.8×105) indicates significant interaction between the electronic states of the Ni(II) complex chromophore with that of DNA bases. With increasing concentration of Ni(II) complex, the peaks at 275 and 245nm of CT-DNA are shifted to 1–2nm without any change in the zero-cross over at 259nm in circular dichroism studies. These observations suggest that the complex bind to DNA through a non-intercalative mode due to the waggling of three phenyl rings of triphenyl phosphine group. The Ni(II) complex display significant hydrolytic cleavage of circular plasmid pUC18 DNA. At high concentration, the Ni(II) complex almost promotes the maximum conversion of DNA from form I to form II along with the appearance of form III. The newly synthesized thiosemicarbazone compound is a promising system for the development of new colorimetric probes for the detection of anions. Anion sensing ability of the receptor (L) with halide ions (F−, Cl−, Br− and I−) have been carried out in different solvents. The receptor shows a remarkable color change from colorless to dark orange in CH3CN solution on selective binding with fluoride ion. The anion recognition property of the receptor via hydrogen bonding interactions is monitored by UV–Vis titration and 1H NMR spectroscopy.

Catalytic and anticancer activities of sawhorse-type diruthenium tetracarbonyl complexes derived from fluorinated fatty acids

The reaction of fluorinated fatty acids, perfluorobutyric acid (C3F7CO2H), and perfluorododecanoic acid (C11F23CO2H), with dodecacarbonyltriruthenium (Ru3(CO)12) under reflux in tetrahydrofuran, followed by addition of two-electron donors (L) such as pyridine, 1,3,5-triaza-7-phosphatricyclo[3.3.1.1]decane, or triphenylphosphine, gives stable diruthenium complexes Ru2(CO)4(μ2-η2-O2CC3F7)2(L)2 (1a, L = C5H5N; 1b, L = PTA; 1c, L = PPh3) and Ru2(CO)4(μ2-η2-O2CC11F23)2(L)2 (2a, L = C5H5N; 2b, L = PTA; 2c, L = PPh3). The catalytic activity of the complexes for hydrogenation of styrene under supercritical carbon dioxide has been assessed and compared to the analogous triphenylphosphine complexes with non-fluorinated carboxylato groups Ru2(CO)4(μ2-η2-O2CC3H7)2(PPh3)2 (3) and Ru2(CO)4(μ2-η2-O2CC11H23)2(PPh3)2 (4). In addition, the cytotoxicities of the fluorinated complexes 1 were also evaluated on several human cancer cell lines (A2780, A549, Me300, HeLa). The complexes appear to be moderately cytotoxic, showing greater activity on the Me300 melanoma cells. Single-crystal X-ray structure analyses of 1a and 3 show the typical sawhorse-type arrangement of the diruthenium tetracarbonyl backbone with two bridging carboxylates and two terminal ligands occupying the axial positions.

English

The reaction of Ag(I) nitrate with triphenylphosphine in methanol in 1:1 molar ratios and recrystallization in toluene resulted in complex of the formula [Ag(PPh3)2NO3]∙C7H8. The compound is a mononuclear neutral complex in which the Ag atom is in a tetrahedral environment consisting of two triphenylphosphine ligands and a nitrate ion acting as a bidentate ligand. The compound crystallizes in the triclinic P`1 space group and the molecular structure of the compound contained a distorted toluene solvent of crystallization.   Key words: Triphenylphosphine complex, molecular structure, crystal structure, silver nitrate, toluene.

Investigation of Luminescence Characteristics of Osmium(II) Complexes in the Presence of Heparin Polyanions.

The luminescence characteristics of six osmium carbonyl complexes with phenanthroline (phen) or bipyridine (bpy) and pyridine (py), 4-phenylpyridine (4-phpy), or triphenylphosphine (PPh3) complexes in the presence of polyanion heparin were studied in both ethanol and aqueous solutions. The influence of heparin on the luminescence of the complexes is heavily dependent on the type of ligands in the complexes and the solvent used. In the ethanol solutions, the heparin solution enhanced the luminescence of the five osmium complexes, with the strongest enhancement to the 4-phenylpyridine complexes; linear curves were obtained in the luminescence enhancement ratio (F/F 0) versus the heparin concentration range of 1–40 μg/mL. In aqueous solutions, heparin quenching of the complexes was more significant; a linear quenching curve was obtained with [Os(phen)2CO(PPh3)](PF6)2 in the lower concentration range of 1–12 μg/mL. The interaction of these complexes with heparin in the solutions is discussed. The complexes are shown to be successful in the fast and sensitive detection of heparin in commercial injectable samples.

Structural and Magnetic Properties of Cobalt(II) Complexes of Triphenylphosphine

This work is related to the structural and mag- netic properties of the Co(PPh3)Cl2 metal complex for dif- ferent sintering times. The structural and physical proper- ties of the complex have been studied by using SEM, EDX, and magnetization techniques. SEM results clearly demon- strate that the grains of the complex are very well connected to each other and tightly packed. Magnetization measure- ments with respect to magnetic field and temperature show a paramagnetic behavior above 20 K for the all samples. Fur- thermore, the susceptibility (χ) as a function of temperature indicates a paramagnetic-antiferromagnetic phase transition with a negative value of the Curie-Weiss temperature, θ .I n addition, increasing sintering time appears to also enhance the effective magnetic moment, μeff.

Gold(I) Complexes Derived from Alkynyloxy-Substituted Anthraquinones: Syntheses, Luminescence, Preliminary Cytotoxicity, and Cell Imaging Studies

A series of mono- and dimetallic Au(I) triphenylphosphine complexes derived from 1,2-, 1,4-, and 1,8-dialkynyloxyanthraquinone have been prepared. The photophysical and cytotoxic behavior of the ligands and complexes have been explored, with all of the complexes showing both appreciable cytotoxicity against the MCF-7 carcinoma cell line and useful room-temperature anthraquinone-based visible luminescence, which allowed their successful application as fluorophores in cell imaging microscopy. The implications of the photophysical and toxicological properties for the design and investigation of gold-based anticancer agents are discussed.

Ruthenium(II)/(III) complexes of 4-hydroxy-pyridine-2,6-dicarboxylic acid with PPh3/AsPh3 as co-ligand: Impact of oxidation state and co-ligands on anticancer activity in vitro

With the aim to develop more efficient, less toxic, target specific metal drugs and evaluate their anticancer properties in terms of oxidation state and co-ligand sphere, a sequence of Ru(II), Ru(III) complexes bearing 4-hydroxy-pyridine-2,6-dicarboxylic acid and PPh(3)/AsPh(3) were synthesized and structurally characterized. Biological studies such as DNA binding, antioxidant assays and cytotoxic activity were carried out and their anticancer activities were evaluated. Interactions of the complexes with calf thymus DNA revealed that the triphenylphosphine complexes could bind more strongly than the triphenylarsine complexes. The free radical scavenging ability, assessed by a series of in vitro antioxidant assays involving DPPH radical, hydroxyl radical, nitric oxide radical, superoxide anion radical, hydrogen peroxide and metal chelating assay, showed that the Ru(III) complexes possess excellent radical scavenging properties compared to those of Ru(II). Cytotoxicity studies using three cancer lines viz HeLa, HepG2, HEp-2 and a normal cell line NIH 3T3 showed that Ru(II) complexes exhibited substantial cytotoxic specificity towards cancer cells. Furthermore, the Ru(II) complexes were found to be superior to Ru(III) complexes in inhibiting the growth of cancer cells.

3,5-Diacetyl-1,2,4-triazol bis( 4N-substituted thiosemicarbazone) palladium(II) complexes: Synthesis, structure, antiproliferative activity and low toxicity on normal kidney cells

Treatment of 4 N-monosubstituted bis(thiosemicarbazone) ligands of 3,5-diacetyl-1,2,4-triazol series with lithium tetrachloridopalladate gave the dinuclear complexes of general formula [Pd(μ-H 3L 1–5)] 2, but using dichloridobistriphenylphosphinepalladium(II) salt, the first mononuclear bis(thiosemicarbazone)–palladium–triphenylphosphine complexes of the 3,5-diacetyl-1,2,4-triazol series, [Pd(H 3L 1–5)PPh 3], have been obtained. All the compounds have been characterized by elemental analysis and by IR and NMR spectroscopy, and the crystal and molecular structures of dinuclear complexes [Pd(μ-H 3L 3)] 2 and [Pd(μ-H 3L 5)] 2 as well as mononuclear complexes [Pd(H 3L 1)PPh 3], [Pd(H 3L 2)PPh 3], [Pd(H 3L 3)PPh 3] and [Pd(H 3L 4)PPh 3] have been determined by X-ray crystallography. The new compounds synthesized have been evaluated for antiproliferative activity in vitro against NCI-H460, A2780 and A2780cisR human cancer cell lines. Subsequent toxicity study, on normal renal LLC-PK1 cells, shows that all compounds investigated exhibit very low toxicity on kidney cells with respect to cisplatin.

Synthesis, characterization and antimicrobial studies of mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones: Crystal structure of bis[{(μ 2-diazinane-2-thione)(diazinane-2-thione)(triphenylphosphine)silver(I) nitrate}

Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph 3P)Ag(thione) 2]NO 3 and [(Ph 3P) 2Ag(thione)]NO 3 were prepared and characterized by elemental analysis, IR and NMR ( 1H, 13C and 31P) spectroscopic methods. The crystal structure of one of the complexes, [Ag(Ph 3P)(Diaz) 2] 2(NO 3) 2 ( 1) was determined by X-ray crystallography. The title complex ( 1) is dinuclear, having each silver atom coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh 3 in a nearly tetrahedral environment, with an average P–Ag–S bond angle of 108.5°. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations and the results showed that the complexes exhibit a wide range of activity against two gram-negative bacteria ( E. coli, P. aeruginosa) and molds ( A. niger, P. citrinum), while the activities were poor against yeasts ( C. albicans, S. cerevisiae).

A catalytic process for the selective oxidation of alcohols by copper (II) complexes

Abstract Novel copper (II)–N–(2-pyridyl)–N'–(5-R-salicylidene) hydrazine triphenylphosphine complexes have been synthesized and characterized. The complexes were effective in the catalytic oxidation of primary and secondary alcohols in presence of periodic acid (H5IO6) as oxidant. The oxidation reactions were carried out in acetonitrile. Electrochemical electron transfer study reveals CuII–CuI reduction in methanolic solutions. A mechanistic study of the above reactions has been proposed.

In situ benzene-1,4-disulfonate ligand synthesis and electric conductivities of four silver 4-sulfobenzoate or benzene-1,4-disulfonate complexes

The reaction of 4,4′-bipyridine (bipy), AgNO 3 and 4-sulfobenzoate (4-sb) led to an unprecedented complex, {[Ag 2(4,4′-bipy) 2(H 2O) 2]·(1,4-bds)·(2H 2O)} n ( 1), in which benzene-1,4-disulfonate (1,4-bds) was synthesized in situ. This does not happen in the similar 1,2-bis(4-pyridyl)ethylene (bpe) system, where the complex {[Ag 2(bpe) 2(H 2O) 2]·(4-sb)·3H 2O} n ( 2) is formed. The same in situ reaction occurred when triphenylphosphine (PPh 3) was added into the bipy and silver reaction solution, resulting in the complex [Ag 2(PPh3) 4(1,4-bds)]. 2DMF ( 3). Complex 4, {[Ag 2(Ph 3P) 2(4-sb)(H 2O)]·(H 2O)} n , was synthesized similar to the synthesis of complex 3, without the presence of 4,4′-bipyridine. Complexes 1– 4 were characterized by single-crystal X-ray analyses, elemental analyses, IR spectra, TG analyses, fluorescence studies and electric conductivity. Complexes 1 and 2 are cation–anion species. Complexes 3 and 4 are silver triphenylphosphine complexes, where the phenyl embrace interactions play important roles. In 3, the six-fold phenyl embrace (6PEs) connect the molecules into a 1- d hybrid zig-zag infinite chain. Complex 4 is a one-dimensional branch-like polymer containing a 1- d necklace-like backbone made up of an [Ag 2(4-sb)(H 2O)] unit and PPh 3 ‘‘leaves”. Two new coordination modes for the 1,4-bds ligands and one for the 4-sb ligand are observed. Complexes 1– 3 are semi-conductors, while complex 4 is an insulator.

Synthesis, characterization and catalytic activity of Fe(III) complexes containing Schiff base and triphenylphosphine ligands

Abstract The oxidation of alcohols to carbonyls was investigated by an efficient catalyst system comprising of Fe(III)–Schiff base–triphenylphosphine complex. The complex chloroN-(2-mercaptophenyl)salicylideneiminebis(triphenylphosphine)iron(III) showed higher activity for oxidation of various alcohols under relatively mild conditions.