A Chiral Metal-Organic 1D-Coordination Polymer Upon Complexation of Phenylene-Bridged Bipyrrole and Palladium (II) Ion

Metal-organic 1D-coordination polymers, having unique electronic and optical properties, are expected to be a novel advanced functional material capable of fabricating smart plastics, films, and fibers. In this study, we have synthesized a novel metal-organic 1D-coordination polymer composed of a phenylene-bridged bipyrrole bearing N-alkylimino groups (BPI) and palladium(II) ion. The BPI and Pd(II) form square planar bis(bidentate) complex to form a metal coordinated π-conjugation polymer (Poly-BPI/Pd). It is stable in solutions at room temperature, and allowed measurement of its average molecular weight in SEC (Mw = 106,000 and Mn = 18,000, Mw/Mn = 5.88). It also provided a reversible multi redox profile in cyclic voltammetry, most likely originating from strong π-electronic interactions between the BPI components via Pd ion. A variety of substituent groups can be attached to the imino-nitrogens of BPI. A coordination polymer composed of a BPI derivative bearing chiral alkyl chains and Pd(II) showed strong circular dichroism (CD) in the solution due to the unidirectional chiral conformation of the BPI components in the polymer backbone.

Complexation of uranium(vi) with glutarimidoxioxime: thermodynamic and computational studies

Glutarimidoxioxime forms a bidentate complex with UO22+via the oxime and imino groups. Hydrogen bonding between water and the carbonyl group helps to stabilize the complex. The complex is much weaker than that of glutarimidedioxime previously studied.

Synthesis of palladium-bidentate complex and its application in Sonogashira and Suzuki coupling reactions

A new palladium-bidentate complex [m-C6H4(CH2ImMe)2(PdCl2)] (III) was prepared in two steps. In the first step, [m-C6H4(CH2ImMeAgCl)2] (II) (Im = imidazole moiety) was obtained by reacting imidazolium salt [m-C6H4(CH2ImMe)2]Cl2 (I) (prepared by quaternisation of Nmethylimidazole with 1,3-bis(chloromethyl)benzene) and Ag2O in CH2Cl2. In the next step, treatment of (II) with Pd(CH3CN)2Cl2 afforded complex III which was evaluated for its catalytic activity for C-C bond-formation reactions by examining the coupling reaction of 3-iodoanisole with phenylacetylene in the Sonogashira reaction. In addition, 3-methoxybiphenyls were obtained with good to excellent yields by Suzuki coupling reactions of 3-iodoanisole with phenylboronic acids or phenylborates salts in the presence of this complex.

Understanding the microcrystal tests of three related phenethylamines: theortho-metallated (±)-amphetamine formed with gold(III) chloride, and the tetrachloridoaurate(III) salts of (+)-methamphetamine and (±)-ephedrine

Theortho-metallation product of the reaction of (±)-amphetamine with gold(III) chloride, [D,L-2-(2-aminopropyl)phenyl-κ2N,C1]dichloridogold(III), [Au(C9H12N)Cl2], and the two salts resulting from crystallization of (+)-methamphetamine with gold(III) chloride, D-methyl(1-phenylpropan-2-yl)azanium tetrachloridoaurate(III), (C10H16N)[AuCl4], and of (±)-ephedrine with gold(III) chloride, D,L-(1-hydroxy-1-phenylpropan-2-yl)(methyl)azanium tetrachloridoaurate(III), (C10H16NO)[AuCl4], have different structures. The first makes a bidentate complex directly with a dichloridogold(III) group, forming a six-membered ring structure; the second and third each form a salt with [AuCl4]−(each has two formula units in the asymmetric unit). The organic components are all members of the same class of stimulants that are prevalent in illicit drug use. These structures are important contributions to the understanding of the microcrystal tests for these drugs that have been employed for well over 100 years.

Electrodeposition of Oriented Cerium Oxide Films

Cerium oxide films of preferred orientation are electrodeposited under anodic conditions. A complexing ligand, acetate, was used to stabilize the cerium (III) ion in solution for deposition of the thin films. Fourier transform infrared spectroscopy showed that the ligand and metal tended to bind as a weakly bidentate complex. The crystallite size of the films was in the nanometer range as shown by Raman spectroscopy and was calculated from X-ray diffraction data. Crystallite sizes from 6 to 20 nm were obtained under the anodic deposition conditions. Sintering of the (111) oriented films showed an increase in the (111) orientation with temperatures up to 900°C. Also, the crystallite size increased from 20 nm to 120 nm under sintering conditions. Addition of the deposited films to the substrate improved corrosion resistance for the substrate.

Modelling lead(II) sorption to ferrihydrite and soil organic matter

Environmental contextLead(II) is a toxic metal pollutant with many anthropogenic sources. We show that lead(II) is bound more strongly to soil surfaces than previously understood. This knowledge may lead to better models for lead(II) dissolution from the soils, which will improve risk assessments for this metal. AbstractLead(II) adsorption to soil organic matter and iron (hydr)oxides is strong, and may control the geochemical behaviour of this metal. Here, we report the adsorption of Pb2+ (i) to 2-line ferrihydrite, and (ii) to a mor layer. The results showed that ferrihydrite has heterogeneous Pb2+ binding. Use of a surface complexation model indicated that ~1 % of the surface sites adsorbed Pb2+ more strongly than the remaining 99 %. Although only one surface complexation reaction was used (a bidentate complex of the composition (≡FeOH)2Pb+), three classes of sites with different affinity for Pb2+ were needed to simulate Pb2+ binding correctly over all Pb/Fe ratios analysed. For the mor layer, Pb2+ sorption was much stronger than current models for organic complexation suggest. The results could be described by the Stockholm Humic Model when the binding heterogeneity was increased, and when it was assumed that 0.2 % of the binding sites were specific for Pb. Use of revised model parameters for nine Vietnamese soils suggest that lead(II) binding was more correctly simulated than before. Thus, underestimation of lead(II) sorption to both (hydr)oxide surfaces and organic matter may explain the failure of previous geochemical modelling attempts for lead(II).

Copper Fixation to Guaiacyl Lignin Units by Nitrogen Donor Ligands

Several new copper(II) complexes with guaiacyl lignin models vanillin (HL1) [Cu(L1)2(nia)2] (1) (nia = nicotinamide) or vanillic acid (HL2) [Cu(L2)2(nia)2] (2) [Cu2(μ-L2)4(nia)2] (3), and [Cu(L2)2(Hetam)2] (4) (Hetam = ethanolamine) were isolated and characterized. The molecular structure of complex 1 reveals bidentate vanillin (HL1) coordination via the methoxy and the deprotonated hydroxy groups. On the other hand, the vanillic acid (HL2) complexes 2 - 4 show a deprotonated carboxylate group with chelating coordination mode in 2, bridging in 3 and monodentate coordination in 4. The mononuclear complexes 1, 2 and 4 show a distorted trans octahedral coordination sphere with pairs of monodentate and chelating ligands. A replacement of the monodentate nicotinamide ligand in 2 with the bidentate ethanolamine ligand in 4 changes the coordination mode of the vanillic acid anion from bidentate (complex 2) to monodentate (complex 4). This shift inside the coordination sphere reveals different O-Cu-O Jahn-Teller axes by the vanillic acid anion in 2 and ethanolamine in 4. Empty channels are present in the crystal structure of the dinuclear complex 3, stabilized by hydrogen bonds and π-π stacking.

The Preparation and Crystal Structure of Ammonium Bismuth(III) Thiosalicylate Dihydrate

The bismuth(III) complex of thiosalicylic acid (2-mercaptobenzoic acid; H2L), ammonium tris(2-mercaptobenzoato-O,S) bismuth(III) dihydrate, {(NH4)3[Bi(L)3]·2 H2O}, has been prepared and its crystal structure determined. The distorted octahedral tris-bidentate complex unit has pseudo-C3 symmetry with the facially related thiolate sulfur donors providing a regular facial cap to the octahedron (Bi–S 2.595, 2.596, 2.596(5) Å) with the Bi–O(carboxylate) distances less regular (2.715, 2.741, 2.785(15) Å). The network polymeric structure is stabilized by hydrogen-bonding associations through both the ammonium counter ions and the lattice water molecules.