A 31P NMR STUDY OF TERTIARY PHOSPHINE COMPLEXES OF PLATINUM(II) AND PALLADIUM(II)

Complexes of the type NBu ₄ MCl ₃ PR ₃ R=P.Tolyl,Ph,Bu) (M = Pt, Pd) are prepared by the reaction of MCl ₂ or K ₂ [MCl ₄ ] by phosphine ligands. Addition of NBu ₄ Br or NBu ₄ I to these compounds, in dichloromethane results in a redistribution of halogens and formation of all six isomers of the type MBr _{3 ?X}Cl_XPR ₃ X= 0, 1, 2, and 3 which have been identified by ³¹ P- ¹ H NMR spectroscopy. The intensities show that the products are proportional to the statistical distribution.     

Edge-shared [M2Cl10]2? complexes of reaction between oxophilic group 4 metal and phosphorus ylides

The reactions between oxophilic group 4 metal chlorides, ??-keto ylides in THF, led to the formation of titanium, zirconium and hafnium edge-shared [M₂Cl₁₀]^2? complexes (1a?C3f). We describe that the reaction between MCl₄ (M = Ti, Zr and Hf) with phosphorus ylides produce edge-shared [M₂X₁₀]^2? complexes instead of O-coordination previously reported complexes. Adding dimethyl sulfoxide (DMSO) to these complexes in room temperature crystalline solid [M(DMSO)₈] · 4Cl · mH₂O · DMSO] (M = Ti (1g), Zr (2g) and Hf (3g); m = 0?C3) together with phosphonium salts in mother liquid were formed. The compounds were characterized by elemental analysis, IR and ¹H, ¹³C and ³¹P NMR spectroscopy.     

Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Three new oxime‐based palladacycles, namely [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(dppm)]ClO₄ ( 1 ), [Pd₂{C,N‐C₆H₄{C(Me)?NOH}‐2}₂(dppe)₂(μ‐dppe)](ClO₄)₂ ( 2 ) and [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(dppmS₂)]ClO₄ ( 3 ), were synthesized by the reaction of dinuclear oxime complex [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(μ‐Cl)]₂ with different diphosphine ligands (dppm, dppe and dppmS₂). The synthesized complexes were characterized using Fourier transform infrared, ³¹P NMR, ¹H NMR and ¹³C NMR spectroscopic methods and elemental analyses, and their molecular structures were elucidated using X‐ray crystallography. The structure of 2 is worthy of note as it is the first oxime palladacycle where there are both bridging (P–) and chelating (P^P) dppe ligands, giving rise to a dinuclear complex. The palladium atom is in a five‐coordinate, square pyramidal P₃NC environment, while in 3 the palladium atom is in a distorted square planar environment, coordinated by the oxime ligand and a chelating (S^S) dppmS₂ ligand. These complexes were employed as efficient catalysts for the Suzuki–Miyaura cross‐coupling reaction of several aryl bromides with phenylboronic acid. The in vitro cytotoxicity of the compounds was also evaluated against human tumour cell lines (HT29, A549 and HeLa) using the MTT assay method. The results indicate that the dinuclear complex 2 has greater catalytic and anticancer activity in comparison with the mononuclear complexes 1 and 3 .     

Synthesis of New Phosphonium Ylides Containing Thiophene and Furan Rings and Study of Their Reaction with Mercury(II) Halides: Spectral and Structural Characterization

Reactions of phosphonium ylides (4‐MeC₆H₄)₃PCHC(?O)(2‐C₄H₃S) (tptpy), Ph₃PCHC(?O)(2‐C₄H₃O) (fppy), and (4‐MeC₆H₄)₃PCHC(?O)(4‐BrC₆H₄) (bbtppy) with HgX₂ (X=Cl, Br, and I) in equimolar ratios in MeOH as solvent leads to the binuclear products 1 – 3 (Scheme 1). The bridge‐splitting reaction of the binuclear complex [{HgI₂(bbtppy)}₂] ( 3c ) by DMSO yields the mononuclear complex [HgI₂?(bbtppy) (DMSO)] ( 3d ) (Scheme 2). This bridge‐splitting reaction can also be a method for the synthesis of mononuclear products. C‐Coordination of the ylide and O‐coordination of DMSO are demonstrated by a single‐crystal X‐ray‐analysis of the mononuclear complex 3d . Characterization of the obtained compounds was also performed by means of elemental analysis and IR and ¹H‐, ³¹P‐, and ¹³C‐NMR spectroscopy. A theoretical study of some Hg^II complexes with phosphonium ylides is also reported.     

Synthesis,characterization, thermal,electrochemical, and DFT studies of mononuclear cyclopalladated complexes containing bidentate phosphine ligands and their biological evaluation as antioxidant and antibacterial agents

The non-symmetric phosphorus ylides and their Pd(II) complexes have been synthesized as potential antioxidant and antibacterial compounds and their structures were elucidated using a variety of physicochemical techniques. The reaction of 1 equiv non-symmetric phosphorus ylides, Ph₂PCH₂PPh₂C(H)C(O)PhX (X = Br (Y¹), Cl (Y²), NO₂ (Y³), OCH₃ (Y⁴)) with [Pd(dppe)Cl₂] (M¹), followed by treatment with 2 equiv AgOTf led to monomeric chelate complexes, [(dppe)Pd(Ph₂PCH₂PPh₂C(H)C(O)PhX)] (OSO₂CF₃)₂ (X = Br (C¹), Cl (C²), NO₂ (C³), OCH₃ (C⁴)), which contain a five-membered P,P chelate ring in one side and a five-membered P,C chelate ring in the other side. Palladium ion complexes were synthesized and investigated by cyclic voltammetry, FT-IR, UV–visible, multinuclear (¹H, ³¹P and ¹⁹F) NMR, thermal analysis and ESI-mass spectroscopic studies. Some complexes and ligands have been studied by powder XRD and single crystal X-ray diffraction techniques. FT-IR and ³¹P NMR studies revealed that the ylides Y are coordinated to the metal ions via the terminal phosphorus (P_c) of the ylides and methene group (CH). The proposed coordination geometry around the Pd atom in these complexes is defined as slightly distorted square planar by UV-Visible and DFT studies. Thermal stability of all complexes was also shown by TG/DTG methods. Furthermore, the electrochemical behavior of the complexes was investigated by cyclic voltammetry. The results indicate that all complexes are successfully synthesized from the initial ligands. All complexes were analyzed for their antioxidant properties by DPPH free radical scavenging assay. In addition, the antibacterial effects of the hexane-solved complexes were investigated by disc diffusion method against four Gram positive and negative bacteria. All complexes represented antibacterial activity against bacteria tested especially on Gram positive ones. A theoretical study on the structure, ¹H and ³¹P NMR chemical shifts and the interaction energy between the Pd²⁺ ion and ligands dppe and ylide Y is also reported.     

Fabrication of cerium oxide nanoparticles: characterization and optical properties

Ceria (CeO(2)) is a technologically important rare earth material because of its unique properties and various engineering and biological applications. A facile and rapid method has been developed to prepare ceria nanoparticles using microwave with the average size 7 nm in the presence of a set of ionic liquids based on the bis (trifluoromethylsulfonyl) imide anion and different cations of 1-alkyl-3-methyl-imidazolium. The structural features and optical properties of the nanoparticles were determined in depth with X-ray powder diffraction, transmission electron microscope, N(2) adsorption-desorption technique, dynamic light scattering (DLS) analysis, FTIR spectroscopy, Raman spectroscopy, UV-vis absorption spectroscopy, and Diffuse reflectance spectroscopy. The energy band gap measurements of nanoparticles of ceria have been carried out by UV-visible absorption spectroscopy and diffuse reflectance spectroscopy. The surface charge properties of colloidal ceria dispersions in ethylene glycol have been also studied. To the best of our knowledge, this is the first report on using this type of ionic liquids in ceria nanoparticle synthesis.     

Upgrading the Iranian national laboratory standard to conform to ISO 15189:2012

Accreditation and Quality Assurance - The Reference Health Laboratory (RHL) of Iran is the national authority responsible for making policies and plans for providing quality laboratory services...     

Synthesis and photovoltaic properties of a furan-diketopyrrolopyrrole-fluorene terpolymer

We report the synthesis of two solution-processable reduced band gap donor–acceptor conjugated polymers p(C8-DPP-F) and p(C12-DPP-F), composed from 9,9-dioctylfluorene as the donor moiety, diketopyrrolopyrrole (DPP) moiety as the acceptor moiety and furan bridges. Two different alkyl chains, n-dodecyl and n-octyl were used on the DPP moiety and the impact of this structural modification evaluated in detail. Both polymers exhibited similar optical and electrochemical properties with optical band gap of around 1.75 eV as result of LUMO levels near −3.4 eV and high-lying HOMO levels of ∼5.2 eV. Bulk heterojunction photovoltaic devices using these polymers electron donors along with PC₇₀BM as the electron acceptor, gave power conversion efficiency of 1.60% and 0.75% for p(C12-DPP-F) and p(C8-DPP-F) respectively.