Search results for "Chelation"

Chelating behaviour of diacetylbisbenzoylhydrazone with SnIV, PbII and PbIV

1974

Metal complexes of sulfanilamide derivatives. Crystal structure of [Zn(sulfathiazole)2]·H2O

1993

Abstract The crystal structure of the Zn(sulfathiazole) 2 ·H 2 O complex is reported. The complex crystallizes in the monoclinic space group C 2/ c . The cell dimensions are a = 9.098(3) A, b = 17.871(5) A, c = 14.61(1) A, β = 99.44(6)°, V = 2343(2) A 3 , Z = 4, and D x = 1.68 g/cm 3 . The final conventional R-factor = 0.027 for 2669 “observed” reflections and 191 variables. The Zn ion is surrounded in a regular tetrahedral arrangement by two N amino and two N thiazole atoms pertaining to four sulfathiazole (Hstz) ligands. Each stz anion, acting as a bidentate ligand, chelates to two Zn ions as a bridge through the N thiazole and the N amino atoms. The IR, 13 C NMR in solid state, 1 H NMR, …

Suppression of pigment interference in the gas chromatographic analysis of proteinaceous binding media in paintings with EDTA.

2004

A method to suppress the interference of pigments in the analysis of proteinaceous media used in paintings is presented in this paper. This method is based on the formation of metallic ion-ethylenediaminetetraacetic acid (EDTA) complexes previous to the derivatisation process, using ethyl chloroformate (ECF), to transform the amino acids in N(O,S)-ethoxycarbonyl (EOC) ethyl esters. Test specimens, containing different proteinaceous media such as albumin, porcine gelatine and casein mixed with lead white, chalk, verdigris and raw Sienna have been prepared for carrying out this study. Different pH conditions have been probed for the different pigments studied. Values of peak area ratio of ami…

Determination of alternative and conventional chelating agents as copper(II) complexes by capillary zone electrophoresis—The first use of didecyldime…

2006

Abstract A capillary zone electrophoresis (CZE) method for analyzing 11 chelating agents [β-alaninediacetic acid (β-ADA), trans-1,2-diaminocyclohexane- N , N , N ′, N ′-tetraacetic acid (CDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), N -(2-hydroxyethyl)ethylenediamine- N , N ′, N ′-triacetic acid (HEDTA), N -(2-hydroxyethyl)iminodiacetic acid (HEIDA), iminodiacetic acid (IDA), methylglycinediacetic acid (MGDA), nitrilotriacetic acid (NTA), 1,3-diaminopropane- N , N , N ′, N ′-tetraacetic acid (PDTA) and triethylenetetraaminehexaacetic acid (TTHA)] as negatively charged copper(II) complexes has been established. Both conventional and alternative che…

Separation of U(VI) and Th(IV) from Some Rare Earths by Thin Layer Chromatography with Di‐(2‐Ethylhexyl)‐Dithiophosphoric Acid on Silica Gel

2005

Abstract Separation of U(VI) and Th(IV) from some rare earths by TLC has been studied using silica gel H and silica gel H impregnated with ammonium nitrate as the stationary phase. The solvent mixture ethyl‐methyl‐ketone–tetrahydrofuran (6∶3, v/v) containing di-(2‐ethylhexyl)-dithiophosphoric acid was used as the mobile phase. When silica gel H impregnated with 2.5 M NH4NO3 was used as stationary phase, the resolution was much improved and the separation of rare earths from each other was also achieved. The tetrad‐effect was observed in variation of R*m versus the atomic number of rare earths.

Tantalocene complexes as bidentate métalloligands: (C5Me5)(C5H4X)Ta(H2)(PPh2) (C5Me5) (C5H4X)Ta(CO) (PPh2) (X = PPh2, CH2CH2NMe2)

1999

Abstract The synthesis of new bidentate metalloligands derived from tantalocene (C5Me5)(C5H4X)Ta(H2)(PPh2) (X = PPh2, 2P; X = CH2CH2NMe22N) and (C5Me5)(C5H4X)Ta(CO)(PPh2) 4(P,N) is described. When opposed to chromium unsaturated fragments the phosphino functionalised complexes 2P and 4P act as chelating bidentate ligands affording Ta(V) (C5Me5)(C5H4PPh2)Ta(CH2) (μ-PPh2)Cr(CO)4 or Ta(III) (C5Me5)(C5H4PPh2)Ta(CO)(μ-PPh2)Cr(CO)4 bimetallic complexes. The same reaction carried out starting from 2N gives rise to a μ-phosphido, μ-hydrido dibridged complex Cp*(C5H4CH2CH2NMe2)TaH(μ-H)(μ-PPh2)Cr(CO)4.

The chemistry of Cr(VI) adsorption on to poly(p-phenylenediamine) adsorbent

2019

Abstract Water pollution due to industrial processes has necessitated and spurred robust research into the development of adsorbent materials for remediation. Polyphenylenediamines (PPD) have attracted significant attention because of their dual cationic and redox properties. They are able to reduce Cr(VI) to Cr(III) in solution. Interrogation of the chemical processes involved in the Cr(VI) adsorption on para-PPD was primarily by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) spectroscopy. It was confirmed that the underlying oxidation of the amino groups to imines during the reduction of Cr(VI) to Cr(III) was irreversible. This process occurred at both acidi…

(Dipyrido[3,2-a:2',3'-c]phenazine)(glycinato)copper(II) perchlorate: a novel DNA-intercalator with anti-proliferative activity against thyroid cancer…

2012

Abstract A novel copper(II) heteroleptic complex of dipyrido[3,2-a:2′,3′-c]phenazine (dppz) and glycinato (gly) as chelating ancillary ligand, [Cu(dppz)(gly)]ClO 4 ( 1 ), was synthesized and characterized. X-ray crystallography revealed that the coordination geometry of the cationic [Cu(dppz)(gly)] + unit is hexacoordinated and shows a distorted octahedral coordination geometry in the solid state, with the N,N and N,O chelating atoms of dppz and glycinato, respectively, in the square plane and in which the planar units are connected in a monodimensional polymeric array by the apical copper coordination of the second carboxylic oxygen atom. Biological assays showed that 1 exhibits a remarkab…

Cytotoxic hydrophilic iminophosphorane coordination compounds of d8 metals. Studies of their interactions with DNA and HSA

2012

The synthesis and characterization of a new water-soluble N,N-chelating iminophosphorane ligand TPAN-C(O)-2-NC(5)H(4) (N,N-IM) (1) and its d(8) (Au(III), Pd(II) and Pt(II)) coordination complexes are reported. The structures of cationic [AuCl(2)(N,N-IM)]ClO(4) (2) and neutral [MCl(2)(N,N-IM)] M=Pd (3), Pt(4) complexes were determined by X-ray diffraction studies or by means of density-functional calculations. While the Pd and Pt compounds are stable in mixtures of DMSO/H(2)O over 4 days, the gold derivative (2) decomposes quickly to TPAO and previously reported neutral gold(III) compound [AuCl(2)(N,N-H)] 5 (containing the chelating N,N-fragment HN-C(O)-2-NC(5)H(4)). The cytotoxicities of co…

Novel bifunctional DATA chelator for quick access to site-directed PET 68Ga-radiotracers: preclinical proof-of-principle with [Tyr3]octreotide

2017

Molecular imaging of tumors with the PET radionuclide 68Ga has gained momentum in clinical oncology due to the expanding availability of commercial 68Ge/68Ga-generators in combination with state-of-the-art PET/CT and PET/MRI hybrid imaging systems. Concurrently, interesting peptide-based or small-size vectors have been developed for theranostic use in cancer patients. Owing to the short half-life of 68Ga (t1/2 = 67.7 min) and the sensitivity of many targeting biomolecules, labeling and kit reconstitution in mild conditions allowing for quick access to ready-for-injection PET-tracers are highly desirable. The novel DATA ((6-pentanoic acid)-6-(amino)methy-1,4-diazepinetriacetate) chelator pre…