Effect of fulvic acid on neodymium uptake by goethite

Experimental studies of the interaction of aqueous neodymium (Nd), Suwannee River fulvic acid (FA), and solid phase goethite were conducted. Results from blank systems (individual Nd and FA), binary systems (Nd-goethite, FA-goethite, and Nd-FA), and ternary systems (Nd-FA-goethite) at 0.1 mol/kg and 25 °C are reported.In the binary Nd-goethite system a classic sorption edge is observed, whereby virtually all Nd is removed from solution above the goethite point of zero charge (PZC). Similarly, the binary FA-goethite system exhibits strong FA sorption; However in this system near complete removal of FA from solution is observed below the goethite PZC. In the binary Nd-FA system, both aqueous Nd and FA feature a sharp decrease in concentration at ca. pH 9.Various experiments in the ternary system were conducted. For all concentrations, FA enhanced Nd sorption below the goethite PZC, attributed to the formation of a Type B ternary surface complex (mineral-ligand-metal ion). Notably, the 100 ppm FA ternary system showed anomalously high dissolved Nd in solution above the PZC (i.e., Nd sorption suppression) and a concomitant increase in goethite dissolution (∼9 ppm total Fe³⁺ observed above circa pH 9.5).Our results suggest that Nd-FA complexation plays a key role in Nd uptake by goethite, and that this process is largely governed by pH: Whereas at pHs below the goethite PZC, Nd-FA complexation facilitates Nd sorption, above the PZC, and particularly at elevated FA concentrations, the formation of aqueous Nd-FA complexes suppresses Nd removal. Moreover, under these conditions, goethite dissolution may also play a role in mitigating Nd uptake by goethite.     

Dicopper complex of p-tert -butylcalix8arene bearing acylhydrazone pendant domains

A dicopper complex of p-tert-butylcalix8 Atwood, JL, Barbour, LJ, Hardie, MJ and Raston, CL. 2001. Coord. Chem. Rev., 222: 3[Crossref], [Web of Science ®] , [Google Scholar]arene bearing eight salicylaldehyde acylhydrazone domains was prepared and its single crystal structure determined, in which only four acylhydrazone domains act as monoanionic tridentate planar chelators to coordinate to two copper ions.     

Synthesis,spectral and antimicrobial studies of rare earth metal complexes with Schiff-base hydrazone containing quinoline moiety

The synthesis and characterization of lanthanide(III) complexes with the Schiff-base hydrazone, o-hydroxyacetophenone-7-chloro-4-quinoline, (HL) are reported. The complexes were characterized by different physicochemical methods: mass spectrometry, ¹H NMR, ¹³C NMR, and IR, UV-visible, molar conductance and magnetic studies. They have the stoichiometry [Ln(L)₂(NO₃)]·nH₂O where Ln = La(III), Pr(III), Nd(II), Sm(III), Eu(III) and n = 1–3. The spectra of the complexes were interpreted by comparison with the spectrum of the free ligand. The Schiff-base ligand and its metal complexes were tested against one stain Gram +ve bacteria (Staphylococcus aureus), Gram ?ve bacteria (Escherichia coli), and Fungi (Candida albicans). The tested compounds exhibited high antimicrobial activities     

Synthesis,DNA-binding,and photocleavage properties of Ru(II) complexes containing dppz-based ligand

A ligand ipdp (ipdp?=?indeno[1′,2′?:?5,6]pyrazino[2,3-i]dipyrido[3,2-a?:?2′,3′-c]phenazine-8-one) and its ruthenium complexes, [Ru(L)₂(ipdp)]²⁺ (L?=?bpy (2,2′-bipyridine), phen (1,10-phenanthroline)), have been synthesized and characterized by elemental analysis, electrospray mass spectra, and ¹H NMR. The interaction between the complexes and calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods and viscosity measurements. The results indicate that the complexes can bind to CT-DNA in an intercalative mode. In addition, both complexes promote the photocleavage of plasmid pBR322 DNA under irradiation. The mechanistic studies reveal that singlet oxygen ¹O₂ plays a significant role in DNA photocleavage.     

Synthesis and characterization of complexes of organotin(IV) with 2-thiazoline-2-thione

The reaction of 2-thiazoline-2-thione (TZDSH) with SnR₂Cl₂ (R=Ph 1, Me 2, Bu 3) in dry ethanol in the presence of sodium ethoxide leads to [SnR₂(C₃H₄NS₂)₂] (1, 2, and 3), respectively. Reaction between TZDSH and SnPh₂Cl₂ in dichloromethane and dry ethanol in an inert atmosphere produces [SnPh₂Cl₂(C₃H₅NS₂)₂] (4). The yields of the products were over 80%. These new complexes have been characterized by IR, UV-Vis, multinuclear (¹H, ¹³C, and ¹¹⁹Sn) NMR spectroscopy, and mass spectrometry, as well as elemental analysis.     

Synthesis and structures of three heterobimetallic compounds based on a new ferrocenyl pyridine ligand

The reactions of 2-PAMF with metal perchlorates [2-PAMF = (2-pyridylmethylamino)carbonylferrocene] yielded three coordination compounds, M(2-PAMF)₂(CH₃CH₂OH)₂(ClO₄)₂ (M = Co 1, Zn 2, and Cu 3), which were characterized by single crystal X-ray diffraction and IR spectroscopy. Compounds 1 and 2 have similar structures with six-coordinate metals in octahedral geometries. The CuII in 3 possesses a severely distorted octahedral geometry due to Jahn–Teller distortion. Adjacent molecules in the three compounds were linked by intermolecular hydrogen bonds to form a 1-D supramolecular chain.     

Diverse structures,magnetism and photoluminescence of four transition metal coordination compounds based on the semirigid 4-(pyridin-3-yloxy)-phthalic acid

Four transition metal coordination compounds, {[Co(PPDA)(H₂O)₂]}_n (1), {[Ni(HPPDA)₂]}_n (2), {[Cd(PPDA)(H₂O)]?H₂O}_n (3), and {Zn(HPPDA)₂(H₂O)₄}_n (4), were synthesized by assembling transition metal salts with a semirigid ligand 4-(pyridin-3-yloxy)-phthalic acid (H₂PPDA) under hydrothermal conditions. The compounds have been characterized by elemental analyses, IR spectra, TGA, powder X-ray diffraction, and single-crystal X-ray crystallography. Compound 1 exhibits a three-connected 2-D layered structure, 2 shows a (3,6)-connected 2-D layered structure, 3 displays a (3,6)-connected 2-D layered framework based on binuclear units, and 4 is a mononuclear structure, connected to generate a 3-D supramolecular architecture by hydrogen bonds. Compound 2 is thermally stable up to 300 °C. The magnetic properties of 1 and photoluminescent properties of 3 and 4 have been explored.