Search results for "Chela"

Lead Nanowires for Microaccumulators Obtained Through Indirect Electrochemical Template Deposition

2010

Metallic lead nanowires were deposited within pores of commercial anodic alumina membranes having an average pore diameter of 210 nm. "Direct" electrodeposition was attempted from 0.1 M Pb(NO 3 ) 2 aqueous solution with a variable concentration of H 3 BO 3 as a chelating agent, but it gave unsatisfactory results. An "indirect" two-step deposition procedure was then adopted, consisting of the anodic electrodeposition of α-PbO 2 nanowires, followed by their in situ reduction to metallic lead. Both these processes occurred at a high rate so that the indirect method led to a complete template pore filling with pure polycrystalline Pb in short times and with a high current efficiency.

Clinical and Biological Characterization of Patients with Low/Intermediate-1 Risk Myelodysplastic Syndrome and Iron Overload

2012

Abstract Abstract 4956 Introduction. Patients with Myelodysplastic Syndrome (MDS) are susceptible to developing iron overload as a response to the red blood cell (RBC) transfusions and ineffective hematopoiesis. This iron overload (IOL) is characterized by an increase in oxygen-reactive species accompanied by a decrease in antioxidants, and results in hepatic, cardiac and endocrine disorders, as well as an increased risk of infection. Ineffective hematopoiesis promotes iron absorption at intestinal level. This process is enhanced by the presence of mutations in the hereditary hemochromatosis gene (HFE). This study aims to define the features that accompany patients with iron overload, compa…

Complexes of organothallium(III) with Cis-1,2-dicyanoethylenedithiolate ion and a ‘tripod’ ligand. Synthesis, infrared and proton magnetic resonance …

1980

Abstract The reaction of cis-1,2-dicyanoethylenedithiolate ion (mnt2− with organothallium(III) derivatives has been examined. The complexes [(CH3)2Tl]2mnt and [(C4H9)4N] [(C6H5)2Tl mnt] have been synthesized. The results seem to indicate a trend in reactivity similar to that of arylmercury(II) derivatives towards chelating agents with nucleophilic character. In addition, the complex [(CH3)2Tl(tren)] [BPh4] has been obtained as a test of the complexing ability of 2,2′, 2″-triaminotriethylamine(tren) towards organometallic moieties. I.r. and 1H n.m.r. are presented and discussed.

6-Thiopurine complexes of organotin(IV) moieties. Synthesis and structural characterization by infrared and Mössbauer spectroscopy

1982

Abstract The novel complexes Me3Sn(6-TP−1) and Bun2Sn(6-TP−1)2, where 6-TP−1 is the mono-anion of 6-thiopurine, have been synthesized. The sites of stannylation of 6-TP have been inferred from the known directions of electrophilic substitution reactions of 6-TP itself. The compounds have been characterized by infrared and Mossbauer spectroscopy. A solid state polymeric structure has been proposed for Me3Sn(6-TP−1), where planar SnC3 skeletons are bridged by 6-TP−1 (thione tautomer) axially bound to Sn through N(3) and N(1) atoms. For Bun2Sn(6-TP−1)2, a molecular structure has been advanced, with the ‘aromatic’ ligand anions chelating Sn by S-N(7) atoms.

The Use of the Macrocyclic Chelator DOTA in Radiochemical Separations

2019

Deep-Red-Emitting Electrochemical Cells Based on Heteroleptic Bis-chelated Ruthenium(II) Complexes

2009

Two ruthenium(II)-based complexes were prepared that show intense deep-red light emission at room temperature. Solid-state electroluminescent devices were prepared using one of the ruthenium complexes as the only active component. These devices emit deep-red light at low voltages and exhibit extraordinary stabilities, demonstrating their potential for low-cost deep-red light sources.

Diastereospecific control in the synthesis of enantiomerically pure bis-equatorial rhodium(II) catalysts by chiral phosphanes

2000

The reaction of Rh2(O2CR)4 [R = CH3, CF3] with the chiral phosphane (1S,2S,5R)-(2-hydroxy-5-isopropenyl-2-methylcyclohexyl)(diphenyl)phosphane, (+)PPh2(CH−R*−OH) or its enantiomer (1R,2R,5S)-(2-hydroxy-5-isopropenyl-2-methylcyclohexyl)(diphenyl)phosphane, (−)-PPh2(CH−R*−OH), results in the specific formation of the products (P)-Rh2(μ-O2CR)2(η1-O2CR)2{η2-(+)PPh2(CH−R*−OH)}2 [P(+)1, R = CH3; P(+)2 R = CF3] and (M)-Rh2(μ-O2CR)2(η1-O2CR)2{η2-(−)-PPh2(CH−R*−OH)}2 [M(−)1, R = CH3; M(−)2, R = CF3] in a high yield. Their synthesis, characterisation and catalytic behaviour in metal−carbenoid reactions are reported. X-ray analysis of P(+)2 and M(−)2 shows, in each case, a Rh24+ unit supported by two …

Synthesis, Reactivity, and X-ray Crystallographic Characterization of Mono-, Di-, and Tetranuclear Palladium(II)-Metalated Species

2001

The reactivity of the tetranuclear metallated palladium compound (Pd[mu 2-(C6H4)PPh2]Br)4 (1) with different ligands has been investigated with the aim of evaluating the influence of the entering ligand on the nature of the reaction products. The results confirmed the ability of the ligand [(C6H4)PPh2]- to expand a bridging [mu 2-] or a chelating [eta 2-] coordination mode, depending on the auxiliary ligands present in the complex. Bulky phosphines stabilize mononuclear species of formula (Pd[eta 2-(C6H4)PPh2]Br[P]), with a four-atom metallocycle, while small phosphines give dinuclear compounds. The molecular structures of three different metalated palladium compounds have been determined b…

Low-Dimensional 3d–4f Complexes Assembled by Low-Spin [FeIII(phen)(CN)4]− Anions

2013

The synthesis, crystal structure, and magnetic properties of four new mixed 3d-4f complexes with formulas [{FeIII(phen)(CN)4} 4Gd2 III(bpym)(NO3) 2(H2O)4]·2CH3CN· 2H2O}n (1), [{FeIII(phen)(CN)4} 4Tb2 III(bpym)(H2O) 8]·(NO3)2·2CH3CN} n (2), [{FeIII(phen)(CN)4}4Sm III(bpym)(NO3)2(H2O) 5]·2CH3CN}n (3), and [{Fe III(phen)(CN)4}2Pr2 III(bpym)(NO3)4(H2O) 2]n (4) (phen = 1,10-phenanthroline and bpym = 2,2′-bipyrimidine) are discussed here. Compounds 1-3 are isomorphous and their structure consists of neutral ladder-like motifs where the rungs are made up by bpym-bridged dilanthanide(III) cations and the rods are defined by [Fe(phen)(CN)4]- units adopting a bis-monodentate coordination mode through…

Organometallic complexes with biological molecules: XII. Solid-state and solution studies on dialkyltin(IV)- and trialkyltin(IV)-thiaminepyrophosphat…

1999

Dialkyltin(IV) and trialkyltin(IV) derivatives of the coenzyme thiaminepyrophosphate (H2TPP) have been synthesized with general formula R2Sn(HTPP)2·nH2O (Alk = Me, n = 2; Alk = Bu, n = 4) and R3SnHTPP·nH2O (R=Me, n = 2; R = Bu, n = 1), respectively. The solid-state structure of the complexes has been investigated through infrared and Mossbauer spectroscopy. The infrared data suggest the involvement of only phosphate oxygen atoms in the coordination of both dialkyl- and trialkyl-tin(IV) moieties, with phosphate anions behaving as monoanionic bidentate bridging or chelating groups, with the tin(IV) involved in six- and five-fold coordination geometries, respectively, in R2Sn(HTPP)2·nH2O (R = …