Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization

The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.

Preparation of Platinum(II) Complexes with 1-β-D-Ribofuranosyl-1,2,4-triazole-3-carboxamide and its Deoxy-analogue

The platinum (II) complexes of the [Pt (N4,N7-Ribavirin) (DMSO) Cl], [Pt (N4,N7-De-oxyribavirin) (DMSO) Cl] were obtained by the reactions of cis-[Pt (DMSO)2 Cl2] and K[Pt (DMSO) Cl3] with 1-??-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (Ribavirin) and its deoxy-analogue (deoxyribavirin). The preparation of 1-(2'-deoxy-?-D-ribofuranosyl) -1,2,4-triazole-3-carboxamide was also performed through a four-step procedure, protection of 3', 5'-dihydroxyl group of Ribavirin with 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane (TPDS-Cl), phenoxythio-carbonylation of the 2'-hydroxyl group of 3', 5'-O-TPDS-Ribavirin with phenoxythiocarbonyl-chloride (PTC-Cl), reduction of 2′-O-phenoxythiocarbonyl ester of 3', 5'-O-TPDS-Ribavirin with tri-n-butyltin hydride and AIBN, deprotection of 3', 5'-O-TPDS-Ribavirin with tetrabutylammon-ium fluoride in THF.

Dioxygen Affinity and Catalytic Performance of Bis-(furaldehyde) Schiff Bases Co(II) Complexes in Cyclohexene Oxidation

Oxygenation constants and thermodynamic parameters DeltaH degrees and DeltaS degrees of cobalt (II) complexes with bis-(furaldehyde) Schiff bases (1, 2, 3, 4)were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could activate molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed.

Synthesis and Characterization of Chiral Mercury(II) and Cadmium(II) Complexes with 3,3'-Bipyridine-5,5',6,6'-tetramethyl-2,2'-dimethoxy-1,1'-biphenyl

Two homochiral mercury （1） and cadmium （2） complexes derived from chiral twisted biphenyl pyridine ligand （3,3＇-bipyridine-5,5＇,6,6＇-tetramethyl-2,2＇-dimethoxy-1,1＇-biphenyl） have been synthesized and characterized by IR, microanalysis, TGA, UV-Vis, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 2. For 1, a = 14.2038（16）, b = 14.3630（17）, c = 7.0257（8）, V = 1433.3（3）3, Mr = 878.91, Dc = 2.037 g/cm3, μ = 7.549 mm-1, F（000） = 824, the final GOF = 1.017, R = 0.0296 and wR = 0.0645 for 2925 observed reflections with I 2σ（I）. For 2, a = 14.212（3）, b = 14.392（3）, c = 7.0498（14）, V = 1442.0（5）3, Mr = 790.72, Dc = 1.821 g/cm3, μ = 2.924 mm–1, F（000） = 760, the final GOF = 1.075, R = 0.0340 and wR = 0.0834 for 3144 observed reflections with I 2σ（I）. The crystal structures of 1 and 2 are isostructural and each adopts a two-dimensional supramolecular network which contains the C–H···π interactions.

Synthesis, Structure and Norbornene Polymerization Catalyzed by o-Benzene Diimine Di-nuclear Palladium(Ⅱ) Complex

The title complex, C20H17N4Pd2Cl3·0.5CH3OH, crystallizes in the triclinic system, space group Pī with α = 9.927（6）, b = 11.079（6）, c = 11.233（6） ？, a = 73.970（12）, β = 85.738（16）, γ = 83.300（12）o, V = 1178.1（11） ？3, Mr = 648.55, Z = 2, Dc = 1.520 g/cm3, μ = 1.884 mm-1, F（000） = 634, the final R = 0.0460 and wR = 0.1280. This title compound was investigated for the catalytic behavior towards norbornene （NB） vinyl addition polymerization. And the complex exhibits good catalytic activity to catalyze norbornene polymerization using MAO as a cocatalyst.

The Novel Benzo-15-Crown-5 with Palladium(II) Complex: [Na(B15CS)]_2,[Pd(SCN)_4]

A novel Pd(II) Benzo-15-crown-5 complex [Na(B15CS)]_2[Pd(SCN)_4] has been isolated and characterized by IR and X-ray diffraction analysis. The crystal structure belongs to monoclinic, space group P2_1,/n with cell dimensions, a = l.0164(6), b = l.3743(3), c = l.4987(7) nm, β = 95.248(6) °, V = 2.0847 'nm_3, Z = 2, F(000) = 944, R = 0.053, Rw = 0.072. The compound consists of two [Na(B15CS)]+ complex canons and a [Pd(SCN)4_]^(2-) complex anion. Each sodium ion is coordinated by five crown ether oxygen atoms and one N atom from the SCN group of [Pd(SCN)_4]^(2-) to form stable neutral complex.

Chiral palladium complexes based on derivatives of benzylamine and 2α-hydroxypinan-3-one

Synthesized and characterized new chiral palladium complexes, some of which contain asymmetric donor nitrogen atom. Nitrogen-containing derivatives (+) - and (-)-2α-hydroxypinan-3-one- (1R,2R,5R)-3-(benzylimino)-2,6,6-trimethylbicy- clo[3.1.1]heptane-2-ol (HL1), (1S,2S,3S,5S)-3- (benzylamino)-2,6, 6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL2), (1R,2R,5R)-3-((S)-α-methyl- benzylimino)-2,6,6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL3), (1R,2R,3R,5R)-3-((S)-α-methyl- benzylamino)-2,6,6-trimethylbicyclo[3.1.1]- heptane-2-ol (HL4) -were studied as optically active ligands.

Preparation, Characterization and Antimicrobial Studies of Mn(II) and Fe(II) Complexes with Schiff Base Ligand Derived from 2-aminophenol and 3-formyl-2-hydroxy-6-methoxyquinoline

Schiff base derived from 2-aminophenol and 3-formyl-2-hydroxy-6-methoxyquinoline and its Mn(II) and Fe(II) complexes were synthesized and characterized by melting point and decomposition temperature, elemental analysis, molar conductivity, infrared (IR) spectral analysis, atomic absorption spectroscopy (AAS) analysis, solubility test, and magnetic susceptibility. The Fourier-transform infrared spectroscopy (FTIR) spectral data of the Schiff base determined showed a band at 1622 cm−1 and this was assigned to the v (C=N), which is a feature of azomethine group. The same band was observed to shift to lower frequencies 1577 and 1599 cm−1 in the complexes suggesting coordination of the Schiff base with the respective metal(II) ions. Molar conductance values 14.58 and 12.65 Ω−1∙cm2∙mol−1 show that the metal complexes were non-electrolyte in nature. The magnetic susceptibility of the complexes was determined and the gram magnetic susceptibility of the complexes was found to be positive, revealing that they are paramagnetic. The elemental analysis of the complexes for C, N and H determined suggested 1:1 metal to ligand ratio. The result of the antimicrobial studies showed that, the metal(II) complexes exhibited better antibacterial and antifungal activity than the Schiff base.

Comparative Studies of Some Novel Cu(II) Polymeric Complexes Derived from Cyanoacetylhydrazine (CAH;L). The Role of Solvents Used on the Structure and Geometry of the Isolated Cu²⁺Complexes

Novel polymeric Cu2+ complexes derived from the reaction of cyanoacetylhydrazine (CAH;L) with CuCl2•2H2O in different solvents were synthesized and characterized. The isolated solid polymeric complexes were investigated using modern conventional physicochemical and spectral (IR, 1H-NMR, UV-Vis. ESR, Raman), magnetic and thermal studies. The results revealed that CAH behaves in different ways towards the coordination of the Cu2+ ion. The promotion of solvents to the cyano group was discussed on the basis of the solvent and the Cu2+ ion used. Magnetic and spectral studies suggest octahedral geometry is proposed for the Cu2+ complexes. EPR studies indicate the existence of polymeric complexes depending on the results of g-values. The results suggest that the number of copper atoms ranges from three to twelve atoms. The molecular modeling is drawn and some chemical characteristics are calculated such as chemical reactivity and energy components are investigated between the different types of the ligands.

Synthesis of a New Type of Amphilic and Water - soluble Tertiary Phosphine Ligands Substituted by an Ethoxylated Phosphonic Acid Chain and Their Palladium Complexes

The highly water-soluble phosphine ligands Na2O3PCH2CH2NH(CH2CH2O)nCH2CH2N- (CH2PPh2)2 (n=1,2,3) were prepared by a new and simple route under mild conditions in good yield; the palladium (II) complexes of the ligands 3a~c with 2:1 or 4:1 -PPh2 to Pd2+ molar ratio were also prepared and characterized .

Synthesis and Characterization of Nickel(II) and Copper(II) Complexes with Schiff Base (1R,2R)-(-)-Diaminocyclohexane-N,N'-bis(3-tert-butyl-5-(4'-benzoic acid)-salicylidene)

Two homochiral metallosalen complexes, Ni（salen） （salen = （1R,2R）-（-）-diamino- cyclohexane-N,N′-bis（3-tert-butyl-5-（4′-benzoic acid）-salicylidene） 1 and Cu（salen） 2, have been synthesized and characterized by IR, microanalysis, TGA, powder and single-crystal X-ray crystallography. Both 1 and 2 crystallize in orthorhombic space group P21212 with Z = 4. For 1, a = 12.082（2）, b = 15.447（3）, c = 18.784（4）A^°, V= 3505.7（12）A^°3, Mr = 731.50, Dc = 1.386 g/cm^3, μ = 0.606 mm^-1, F（000） = 1544, the final GOOF = 1.043, R = 0.0496 and wR = 0.1248 for 4791 observed reflections with I 〉 2σ（I）. For 2, a = 12.181（2）, b = 15.501（3）, c = 18.877（4） A^°, V = 3564.3（12）A^°3, Mr = 736.33, Dc = 1.372 g/cm^3, μ = 0.665 mm^-1, F（000） = 1548, the final GOOF = 1.062, R = 0.0575 and wR = 0.1508 for 4562 observed reflections with I 〉 2σ（I）. The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. An infinite two-dimensional network is generated by hydrogen bonding interactions and intermolecular π…π interactions.

Synthesis and Crystal Structure of a Palladium(II) Coordination Polymer [Na_2Pd(2,6-pydc)_2(H_2O)_6]_n

A novel coordination polymer [Na2Pd（2,6-pydc）2（H2O）6]n （2,6-H2pydc = 2,6-pyridinedicarboxylic acid） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclirtic system, space group P21/c, with a = 11.962（2）, b = 6.5552（13）, c = 12.673（3） A, β = 91.72（3）^o, V = 993.3（3） A^3, Z = 2, Mr = 590.68, Dc = 1.975 g/cm^3,μ = 1.059 mm^-1, F（000） = 592, the final R = 0.0211 and wR = 0.0454. In the crystal the Pd（II） ion adopts a distorted four-coordinated square-planar geometry and bonds to two bidentate 2,6-pyridinedicarboxylate molecules through caronyl oxygen and pyridine nitrogen atoms. The title complex exhibits a novel three-dimensional network structure.

THE CHIRAL SELECTIVITY IN ACROSS－MEMBRANE TRANSPORT OF 1，2－DIAMINOCYCLOHEXANE PLATINUM（II）COMPLEXES AND THE CONTRIBUTION OF LEAVING GROUPS

The uptake kinetics of platinum(II)complexes of 1,2 -diaminocyclohexane(dach)isomers(1R,2R-dach, 1R,2S-dach. 1S,2S-dach) with various leaving groups, Chloride(CI), oxalate (OX),squaric acid(SA), and demethylcantharic acid (DA) was studied in the plasma isotonic buffer. The experimentalresults show that across-membrane transport of all the platinum complexes studied follows a firstorder Kinetic process and a passive diffustion mechanism. The uptake rate constants of these platinum(II)complexes decrease in the following sequence with the k value(h-1):CI>SA>OX>DA. It isnoteworthy that the k values of the platinum(II)complexes with same leaving group reduce as: 1R,2R-dach>1R,2S-dach>1S,2S-dach. Based on these results, it is firstly suggested that the erythocytemembrane recognizes the chirality of these platinum complexes.

Syntheses, Structures and Interactions with DNA of Two in situ Generated Palladium(Ⅱ) Complexes

Two new complexes [Pd（L-phe）2·2H2O] （1） and [Pd（4,4＇-dcbpy）（en）·H2O] （2） （L-phe = L-phenylalanine, 4,4＇-dcbpy = 2,2＇-bipyridyl-4,4＇-dicarboxylate, en = ethylenediamine） were synthesized and characterized. L-phenylalanine was in situ formed via the hydrolysis of N-（tert-butoxycarbonyl）-L-phenylalanine, and ethylenediamine came from the in situ reaction of piperazine （pip） under hydrothermal conditions. The single-crystal X-ray structure analyses reveal that the Pd（Ⅱ） ion constructs a square planer coordination geometry in complexes 1 and 2, respectively. Complex 1 extends into a 2D layered structure via H-bond interactions and complex 2 connects into a 3D network through hydrogen bonds and 7r-tr stacking interactions. The interactions of 1 and 2 with fish sperm DNA （FS-DNA） were examined via UV-Vis absorption spectra and fluorescence spectroscopy. The cleavage reaction for plasmid DNA has been assayed by agarose gel electrophoresis. The results indicate that two complexes interact with DNA and the insertion is the main binding mode.

Synthesis, Characterizations, Biological, and Molecular Docking Studies of Some Amino Acid Schiff Bases with Their Cobalt(II) Complexes

The synthesis and structural characterization of cobalt(II) complexes of amino acid Schiff bases was prepared from Salicylaldehyde and three amino acid (Valine, Leucine, and Isoleucine)?in basic medium. The metal complexes was synthesized by treating an ethanolic solution of the ligand with appropriate amount of metal salts [1:2] [M:L] ratio. The synthesized Schiff bases and their metal complexes have been investigated on the bases of elemental chemical analysis, FTIR, electronic spectral,?1HNMR,?13CNMR, MS, molar conductance and magnetic susceptibility measurements. The electronic spectra of the metal complexes and their magnetic susceptibility measurements suggest octahedral structures are the probable coordination geometries for the isolated complexes. The Schiff bases and their metal complexes were preliminary scanned against various strains of microbes to study their biological effect.

Some Hybrid Systems of Chiral Schiff Base Zn(II) Complexes and Photochromic Spiropyrans for Environmental Ion Sensing

This is a review article including our recent results and some previous photo functional hybrid system having potential applications for environmental ion sensing. We have prepared several new and known chiral Schiff base Zn(II) complexes and measured (and also calculated) absorption and fluorescence spectra for sole complexes. After assembling hybrid systems with 1,3,3-trime- thylindolino-6’-nitrobenzopyrylospiran (SP) in methanol solutions, we measured spectral changes before and after alternate irradiation of UV and visible light. Intensity of fluorescence spectra for pale yellow Zn(II) complexes (λem = 450 nm, λex = 270 and 360 nm) was quenched by colorless SP (λem = 533 nm, λex = 612 nm). After UV light irradiation to form purple merocyanine (MC), photoisomerization resulted in changes of the intensity of absorption spectra as well as fluorescence spectra. Thus the hybrid systems could successfully act as molecular logic circuit by input (excitation by light) and output (intensity of fluorescence peaks). Moreover, we investigated concentration dependence of doped Zn(II) and Cu(II) ions to confirm quenching of intensity of fluorescence peaks by Zn(II) and Cu(II) MC complexes for metal ion sensing in solutions.

Symmetrical Palladium (II) N,N,O,O-Schiff Base Complex: Efficient Catalyst for Heck and Suzuki Reactions

Palladium is arguably the most versatile and most widely applied catalytic metal in the field of fine chemicals due to its high selectivity and activity. Palladium catalyst offers an abundance of possibilities of carbon-carbon bond formation in organic synthesis. In this research, three different Schiff base ligands have been prepared by condensation reaction between appropriate aldehyde or ketone with amine namely 2,2-dimethyl-1,3-propanediamine in the molar ratio of 2:1. The corresponding palladium (II) Schiff base complexes were prepared through the reaction between the Schiff base ligand with palladium (II) acetate in a molar ratio 1:1. FTIR, 1H-NMR and 13C-NMR spectroscopic data revealed that the ligands are N,N,O,O-tetradentate coordinated to the Pd atom through both the azomethine N atoms and phenolic O atoms. From X-ray Crystallographic analysis, it showed that the complex exists as square planar geometry. The synthesized palladium (II) Schiff base complexes were then subjected in catalytic Heck and Suzuki reaction of iodobenzene.

Magnetic analyses of isosceles tricobalt(II) complexes containing two types of octahedral high-spin cobalt(II) ions

The observed magnetic data for two isosceles tricobalt(II) complexes have been successfully analyzed, considering the axial distortion around each cobalt(II) ion, the local spin-orbit coupling, the anisotropic exchange interactions, and the intermolecular exchange interactions. The complexes each contains two types of octahedral high-spin cobalt(II) ions (CoA and CoB) in the shape of an isosceles triangle (CoA1–CoB–CoA2), and the contribution of the orbital angular momentum is significant. The exchange interaction between the CoA and CoB ions is practically negligible (J = ~ 0), whereas the interaction between the CoA1 and CoA2 ions is ferromagnetic (J’ > 0) for both complexes.

Kinetic parameters and thermal decomposition for Novel 1,1-Malonyl-bis(4-p-Chlorophenylthiosemicarbazide) and Cu(II), Co(II), Zn(II) and Sn(II) complexes(H₄pClMaTS) synthesized by electrochemical method

Anodic oxidation of Co, Cu, Zn, and Sn metals in an acetone solution of 1,1-malonayl-bis(4-p- Chlorophenylthiosemicarbazide) yields complexes of composition with general formula [Co2(pClMaTS)(H2O)6]·2H2O, [Cu2(pClMaTS)(H2O)6], [Zn2(pClMaTS)(H2O)6] and [Sn2(pClMaTS)(H2O)6]·2H2O. Chelation was investigated based on elemental analysis, conductivity, magnetic moment, spectral (UV-Vis, IR, Raman, 1HNMR, mass), thermal, and ESR studies. The Raman and infrared spectral studies suggests the tridentate behavior of the ligand from each tail. Since the ligand has two thiose- micarbazide groups, it may acts in an SNO tridentate fashion from each side with one of the two metal ions forming a polynuclear complex coordinating through both of the lone pair of electrons the enolic oxygen of the carbonyl group (C=O), the azomethine nitrogen (C=N) and the thioenol form of the thiocarbonyl group (C=S). The differential thermogravimetric analysis (DTG) curves were used to study the decomposition steps of the isolated complexes using Horowitz-Metzger (HM) and Coats-Redfern (CR) methods. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS*and ΔG* are calculated from the DTG curves.