NTA Ligand Research Articles

Macro‐ and nano‐oligomers ternary metal complexes preparation, structural elucidation: Antimicrobial, anticancer activities, and mechanistic study of Cu nanocomplexes on liver carcinoma

A new binuclear transition metal complexes of Co (II) and Cu (II) have been synthesized in both bulk and nanosized formations. The complexes were synthesized by the reaction between equimolar quantities of the metal sulfate with nitrilotriacetic acid and creatine. The nanosized forms are controlled by using (CTAB). Characterization of the nanocomplexes has been done using a transmission electron microscope (TEM) and X‐ray diffraction. This technique is considered a novel approach to the synthesis of the nanoternary complexes. The Co (II) and Cu (II) complexes displayed distorted dimeric octahedral and tetrahedral structures, respectively. The prepared metal complexes were investigated by electronic spectral analysis, magnetic susceptibility measurement, infrared spectra, thermal gravimetric analysis (TGA), UV–visible spectra, and mass spectra. The molecular weights of the dimer complexes are measured by GPC (Gel Permeation Chromatography). Characterization of the obtained complexes showed that the NTA ligand coordinates with metal ions in tridentate mode (one N and two COO−) after deprotonation, the creatine molecule coordinates through the carboxylate group, while the dimeric structure of these complexes formed with one of the sulfate groups which coordinates as a bridged bidentate ligand. Investigation of the biological activity of these complexes, as well as their hepatocellular carcinoma (HepG2) cell line inhibitory, has also been achieved.

Head to head comparison of [99mTc]Tc(CO)3(NTA) and [99mTc]Tc-MAG3 in patients with suspected obstruction

Purpose99mTc-tricarbonyl-nitrilotriacetic acid, [99mTc]Tc(CO)3(NTA), is a new 99mTc-renal radiopharmaceutical with a clearance equal to that of 131I-ortho-iodohippuran, [131I]I-OIH. Our purpose was to compare the performance of [99mTc]Tc(CO)3(NTA) and [99mTc]Tc-MAG3 in patients with suspected obstruction.Methods[99mTc]Tc(CO)3(NTA) was prepared with commercially available NTA ligand and CRS Isolink kit, and isolated by HPLC. Eighteen adult patients referred for diuretic renography received an intravenous injection of approximately 40 mg of furosemide 15 min prior to either [99mTc]Tc(CO)3(NTA) or [99mTc]Tc-MAG3 (mean activity of 47 ± 4.4 MBq). Data were acquired for 24 min followed by an anterior image of the liver and gall bladder and a measure of voided volume. Patients received a second furosemide injection equal to one third of the original dose followed fifteen minutes later by administration of the alternate tracer, mean activity of 320 ± 34 MBq. Clearances were measured using a camera-based technique.ResultsThe clearance of NTA was greater than that of MAG3, 331 ± 146 versus 271 ± 105 mL/min/1.73 m2, respectively, p < 0.0001. The kidney to background ratio for NTA was greater than that of MAG3 for both left and right kidneys, p < 0.001; the 20 min/maximum count ratio was significantly less, p < 0.0001. There was no significant difference in the voiding volumes following NTA and MAG3 administration, 598 ± 237 mL versus 498 ± 170 mL, respectively, p = 0.07. Gall bladder activity was not observed with NTA but was present in 6/17 MAG3 studies. Images and renogram curves were comparable except for two patients where the NTA study excluded obstruction but the MAG3 study suggested an indeterminate or obstructed kidney.ConclusionsUnlike MAG3, NTA is not eliminated via the hepatobiliary track. Moreover, NTA has a higher kidney to background ratio and more rapid clearance than MAG3. These advantages should allow more robust camera-based clearance measurements and may lead to better discrimination between obstructed and non-obstructed kidneys.

Enhanced luminescence of CaF2 :Er3+ /Nd3+ nanoparticles coated by fluorinated β-diketone.

In this study, several CaF2 nanoparticles doped with individual ions Nd3+ and Er3+ were synthesized with ligands pentafluorobenzoyl trifluoroacetone (PBTA) and 2-naphthoyltrifluoroacetone (NTA), which served as modifiers. Influence of the modifiers on the luminescence properties of the nanoparticles was investigated. The as-prepared nanoparticles had a similar size and dispersion with an irregular spherical shape, which reduced the influence of particle size on the luminescence of the nanoparticles. The luminescence spectra of these nanoparticles showed the characteristic luminescence of the central lanthanide ions under excitation of the maximum excitation wavelength. Compared with nanoparticles modified by the NTA ligand, nanoparticles modified by the PBTA ligand possessed stronger luminescence intensity for the doping Nd3+ or Er3+ ions.

Synthesis, Crystal Structure and Thermal Property of Two New Coordination Polymers with Ligands Containing Both N and O Donors

Two new metal–organic coordination polymer frameworks formulated as, {[Co(nta)]·H3O+}n (1), and {[Zn(ina)Cl2]·H3O+·H2O}n (2) (nta = nitriliotriacetic acid, ina = isonicotinate), have been synthesized under mild conditions and characterized by elemental analyses, IR spectrum, PXRD, thermal gravimetric analysis (TG) and single-crystal X-ray diffraction. Complex 1 crystallizes in the orthorhombic space group P2(1)2(1)2(1) with unit cell parameters a = 8.403(4) A, b = 10.165(5) A, c = 11.230 A, β = 90, V = 959.3(9) A3. Complex 2 crystallizes in the monoclinic space group P2(1)/c with unit cell parameters a = 7.1334(13) A, b = 22.369(4) A, c = 7.0089(13) A, β = 101.099(2), V = 1097.5(3) A3. In fact, 1 is a new 3D cobalt complex with the nta ligands acted as bridges to form network polymer. Each nta ligand bonds to three cobalt ions, and each cobalt ion coordinates with three nta ligands in different directions. 2 displays a new 1D zigzag chain linked by ina ligand and an interesting 1D hydrogen-bond infinite chain consists of seven-membered rings and four-membered rings. These chains are further linked to generate a new 3D framework. Two novel metal–organic coordination polymer frameworks have been synthesized under mild conditions and characterized by elemental analyses, IR spectrum, PXRD, thermal gravimetric analysis (TG) and single-crystal X-ray diffraction.

Structure and characterization of physicochemical and magnetic properties of new complex containing monobridged oxygen copper(II) dinuclear cation

The crystal and molecular structure of the new copper(II) complex with nitrilotriacetate (nta) and 1,10-phenanthroline (phen) ligands of the [Cu(phen)2Cu(nta)(phen)]2[Cu(Hnta)2]·20H2O molecular formula has been determined. The compound comprises the dianionic mononuclear entity, [Cu(Hnta)2]2−, and two monocationic dinuclear units, [Cu(phen)2Cu(nta)(phen)]+, in which the Cu(II) ions are bridged by one oxygen atom of the nta ligand in the rarely found μ1,1–O bridging mode. The complex was characterized by spectroscopic (IR, FIR and EPR) methods and magnetic measurements as well as thermogravimetry (TG). The magnetic measurements revealed an antiferromagnetic coupling between the Cu(II) ions in the dinuclear unit. Based on the experimental data supported by density functional theory (DFT) calculations the correlation between the coordination mode of the Cu(II) ions and magnetic properties of the compound studied has been discussed.

Structural and thermodynamic investigation of AnIVLI(O)HOPO

For the first time, capillary electrophoresis coupled with inductively coupled plasma mass spectrometry has been used to determine the stability constants of PuIV with the multidentate hydroxypyridinonate chelating agents LI(O)HOPO in 0.1 M NaNO3 solution, pcH = 1.395 at 25 °C through competition with the NTA ligand.

Red (Eu3+), Green (Tb3+) and Ultraviolet (Gd3+) Emitting Nitrilotriacetate Complexes Prepared by One-step Synthesis

The [RE(NTA)(H2O)2]⋅(H2O) rare-earth complexes (RE3+: Eu, Gd, Tb and NTA: nitrilotriacetate) were synthesized and characterized by elemental analysis, thermogravimetry, X-ray diffraction, and infrared spectroscopy. The complexes show high crystallinity and thermostability. The photoluminescence behavior was studied based on the excitation and emission spectra, and luminescence decay curves. The compounds exhibit red (Eu3+), green (Tb3+) and UV (Gd3+) monochromatic emissions under UV excitation. The NTA ligand acts as luminescence sensitizer in the ligand-to- RE3+ intramolecular energy transfer process, owing to the fact that the first excited triplet state (T1: 29 000 cm−1) is located above of the 5D0 (Eu3+) and 5D4 (Tb3+) emitting levels. The experimental intensity parameters Ωλ (λ: 2 and 4) for the Eu3+ NTA complex were calculated, and the results are discussed. The Gd3+-NTA complex exhibits a high-intensity emission band in the UV region (32 000 cm−1) assigned to the 6P7/2→8S7/2 intraconfigurational transition.

Construction, Characterization, and Photoluminescence of Mesoporous Hybrids Containing Europium(III) Complexes Covalently Bonded to SBA-15 Directly Functionalized by Modified β-Diketone

Novel organic−inorganic mesoporous luminescent hybrid materials were prepared by linking the binary and ternary Eu3+ complexes to the functionalized ordered mesoporous SBA-15 with the modified 1-(2-naphthoyl)-3,3,3-trifluoroacetonate (NTA) by co-condensation of tetraethoxysilane (TEOS) in the presence of Pluronic P123 surfactant as a template. 1-(2-Naphthoyl)-3,3,3-trifluoroacetonate (NTA) grafted to the coupling agent 3-(triethoxysilyl)propyl isocyanate (TEPIC) was used as the precursor for the preparation of mesoporous materials. SBA-15 consisting of the highly luminescent ternary complex Eu(NTA)3bpy covalently bonded to the silica-based network, which was designated as Eu(NTA−SBA-15)3bpy, was obtained by introducing EuCl3 and 2,2‘-bipyridine (bpy) complex into the hybrid material via a ligand-exchange reaction. In addition, for comparison, SBA-15 doped with Eu(NTA)3·2H2O and Eu(NTA)3bpy complexes and SBA-15 covalently bonded with the binary Eu3+ complex with NTA ligand were also synthesized, denoted as...

Synthesis and structure of a polymeric ten-coordinate rare earth metal complex with nta ligand: {[EuIII(C-nta)(T-nta)]·3H2O} n with a novel cage-like 3-D structure

The polymeric ten-coordinate rare earth metal (RE) complex with nta, {[EuIII(C-nta)(T-nta)] · 3H2O} n , has been synthesized in aqueous solution and characterized by FT-IR, elemental analyses, TG-DTA and single-crystal X-ray diffraction technique. The {[EuIII(C-nta)(T-nta)] · 3H2O} n crystallizes in the cubic system with P213 space group, a = b = c = 12.4153(3) Å, V = 1913.69(8) Å3, Z = 4, M = 582.24 g mol−1, D c = 2.021 Mg m−3, μ = 3.360 mm−1, F(000) = 1148, and its structure is refined to R 1(F) = 0.0204 for 1277 observed reflections [I ≥ 2.0σ(I)]. The coordination polyhedron adopts distorted C3v mono-top-capped & tri-lateral-capped trigonal prismatic conformation (MT&TL-TP); the three-dimensional geometry is a cage-like 3-D structure. According to thermal analyses, the collapsing temperature of the crystal structure is 173°C, indicating that its crystal structure is very stable.

Functional assays of membrane-bound proteins with SAMDI-TOF mass spectrometry.

Functional assays of membrane-bound proteins with SAMDI-TOF mass spectrometry.

Structural determinations, magnetic and EPR studies of complexes involving the Cr(OH) 2Cr unit

Five heterometallic compounds with formulae [Ba(H 2O) 4Cr 2(μ-OH) 2( nta) 2] · 3H 2O ( I), [M( bpy) 2(H 2O) 2] [Cr 2(OH) 2( nta) 2] · 7H 2O, where M 2+ = Zn, ( II); Ni, ( III); Co, ( IV) and [Mn(H 2O) 3( bpy)Cr 2(OH) 2( nta) 2] · ( bpy) · 5H 2O ( V); bpy = 2,2′-bipyridine, ( nta = nitrilotriacetate ion) have been prepared by reaction of I with the corresponding M II-sulfates in the presence of 2,2′-bipyridine. Substances I– V have been characterized by magnetic susceptibility measurements, EPR and X-ray determinations. I represents a 2D coordination polymer formed by coordination of centrosymmetrical dimeric chromium(III) units and Barium cations. The 10-coordinate Ba polyhedron is completed by four water molecules. Compounds II– IV are isostructural and consist of non-centrosymmetric dimeric anions [Cr 2(μ-OH) 2( nta) 2] 2−, complex cations [M II( bpy) 2(H 2O) 2] 2+ and solvate water molecules. The octahedral coordination of chromium atoms implies four donor atoms of the nta 3− ligands and two bridging OH groups. Multiple hydrogen bonds of coordinated and solvate water molecules link anions and cations in a 3D network. A similar [Cr 2(μ-OH) 2( nta) 2] 2− unit is found in V. The bridging function is performed by a carboxylate oxygen atom of the nta ligand that leads to the formation of a trinuclear complex [Mn( bpy)(H 2O) 2Cr 2(μ-OH) 2( nta) 2]. Experimental and calculated frequency and temperature dependences of EPR spectra of these compounds are presented. The fine structure appearing on the EPR spectra of compound V is analyzed in detail at different temperatures. It is established that the main part of the EPR signals is due to the transitions in the spin states of a spin multiplet with S = 2. Analyses of experimental and calculated spectra confirm the absence of interaction between metal ions (M II) and Cr-dimers in complexes III and IV and the presence of weak Mn–Cr interactions in V. The temperature dependence of magnetic susceptibilities for I– V was fitted on the basis of the expression derived from isotropic Hamiltonian including a bi-quadratic exchange term.

Lanthanide Complex Strategy for Detection and Separation of Histidine-tagged Proteins

Abstract A series of trivalent lanthanide complexes were immobilized on SPR sensory chips and protein separation membranes. They worked as alternatives to transition-metal complexes in detection and separation of histidine-tagged ubiquitin protein. Since the highly coordinated complex between NTA ligand, Eu3+ center, and hexahistidine moiety exhibited the enhanced luminescence, the present system provides a further possibility for use in in-situ optical protein imaging process.

Self-complementary self-assembly of 3D coordination framework involving d-block, s-block metal ions and flexible NTA 3− ligand

The reaction of the flexible ligand nitrilotriacetate with Cu(acac) 2 under hydrothermal condition gave a unique 3D coordination polymer, NaCuNTAH 2O (NTA 3− = the anion of nitrilotriacetate). Na + ion plays an important role in chargeable and structural complementarity in the construction of 3D coordination framework. The unusual coordination mode of NTA ligand has been found for the first time. The complex is an example of coordination polymer containing the d-block, s-block metal ions and NTA 3− ligand generated by an unusual self-complementary self-assembly process.

Syntheses and structural analyses of nine-coordinate protonated (Py)2[GdIII(HNta)(Nta)(H2O)] · 5H2O and eight-coordinate (NH4)3[HoIII(Nta)2] complexes

The syntheses and structural determination of Gd(III) and Ho(III) complexes with nitrilotriacetic acids (Nta) were reported in this paper. Their structures and compositions were determined and characterized by single-crystal X-ray structure analyses, elemental analyses, and IR spectra. The first protonated Nta complex was found. Structural analyses indicate that the structure greatly changes, while an alternative Nta ligand was protonated in the ((Py)2[GdIII(HNta)(Nta)(H2O)] · 5H2O complex and the(NH4)3[HoIII(Nta)2] complex crystallized as a centrosymmetric structure. By contrast, it is further confirmed that the coordination number and coordinate structure of all trivalent rare-earth metal complexes with aminopolycarboxylic acids mainly depend on the ionic radii and electronic configuration of the central metal ions and their countercations.

PbTe Nanorods by Sonoelectrochemistry.

AbstractFor Abstract see ChemInform Abstract in Full Text.

PbTe Nanorods by Sonoelectrochemistry

Size, shape, and compositional control are at the heart of nanochemistry. Herein, we present a novel method that allows control over all three variables in a simple one-step, wet-chemical procedure. One-dimensional (1D) nanomaterials are of great interest for the construction of highperformance thermoelectric (TE) devices. Theoretical calculations indicate that improvement in TE efficiency can be achieved as the diameter of the 1D structures approaches a few nanometers. To date, the most successful synthesis of 1D TE materials has been achieved by electrodeposition within alumina templates. A series of Bi2Te3, [4,5] Bi2 xSbxTe3, [6] Bi2Te3 ySey, [7] and Bi1 xSbx [8, 9] nanowires were prepared by using the template-based method. The advantages of the electrodeposition method include high efficiency, ease of control over composition, highly crystalline products, and room-temperature reaction conditions. However, the diameters of the nanowires synthesized by the template method are well above 10 nm. To get into the sub-10-nm regime, one needs to obtain templates with very narrow channel diameters, which is currently the limiting factor of this technique. However, advances in combining sonochemistry and electrochemistry have provided a new strategy for the synthesis of nanomaterials. The synthesis of quite sophisticated 1D nanomaterials has recently been demonstrated to be possible through careful control of the electrochemistry, sonochemistry, and initial composition of the precursor solutions. As observed, the advantage of the sonoelectrochemical method is that it achieves 1D control without any template, thereby practically overcoming the limitation of generating nanorods with diameters below 10 nm. This diameter is the size regime in which TE properties become enhanced and a controlled synthesis can produce technologically relevant nanomaterials. Herein, we report the first synthesis of monodispersed PbTe nanorods that are sub10 nm in diameter through a sonoelectrochemical technique. Furthermore, we present the effect of changing the concentration of the coordinating ligand on the resulting composition of the synthesized nanomaterials. Changing the metal/ ligand ratio enabled us to tune the composition of the product from pure Te to pure PbTe nanorods. Lead telluride is the material of choice because of its great potential in high-performance TE devices. Furthermore, it allows the mechanisms that lead to control over the resulting nanorod size and composition to be studied. Basically, the synthesis of PbTe nanorods consists of two steps: First, the electrodeposition of PbTe on the surface of the Ti sonication horn, and second, the dispersion of the PbTe nuclei into solution by pulsed sonication. Control over the electrodeposition process is crucial in obtaining pure and highly crystalline PbTe nanoparticles. Interestingly, we found that the Pb/nitrilotriacetic acid (NTA) ratio plays a key role in the synthesis of PbTe nanorods. In contrast to previous studies on the electrodeposition of bulk PbTe, we used a stoichiometric reactant ratio in the synthesis of the nanorods. The introduction of NTA helps to prevent the precipitation of Pb ions as Pb(OH)2. Furthermore, electrochemical studies show that NTA acts as more than a coordinating capping agent: it actually determines the final products of the process. The pH value of the solution was monitored during the electrodeposition, and TeO2 was shown to be sufficiently soluble at pH 7. However, the solubility of NTA was too poor at low pH values to keep the Pb ions coordinated and in solution. Therefore, the solution was kept at approximately pH 8 under our experimental conditions, as TeO2 is dissolved as TeO3 2 ions at this pH value. The overall PbTe reaction equation [Eq. (1)] is (the NTA ligand is omitted for clarity):

Structure–photoluminescence relationship in Eu(iii) β-diketonate-based organic–inorganic hybrids. Influence of the synthesis method: carboxylic acid solvolysis versus conventional hydrolysis

Organic–inorganic hybrids incorporating Eu(nta)3·bpy (where nta and bpy stand for 1-(2-naphthyl)-4,4,4-trifluoro-1,3-butanedionate and 2,2′-bipyridine, respectively) were prepared either by acetic acid solvolysis or a conventional hydrolysis sol–gel route. The host framework of these materials, classed as di-ureasil, consists of a siliceous network grafted, through urea cross-linkages, to both ends of poly(ethylene oxide) chains. The resulting Eu(III)-based di-ureasils were investigated by small angle X-ray scattering, X-ray diffraction, Fourier transform mid-infrared spectroscopy, 29Si and 13C nuclear magnetic resonance, and photoluminescence spectroscopy, with particular attention paid to the effect of the adopted synthesis strategy on the relationship between structure and emission properties. The dimensions and the degree of condensation of the siloxane nanodomains depend noticeably on the synthesis route and the overall emission quantum yield decreases from 15 (conventional hydrolysis) to 6% (solvolysis route). The broad white-light emission typical of the di-ureasil host was not detected here suggesting, therefore, the activation of energy transfer channels between the hybrid host's emitting centres and the Eu(III) ions. As the first coordination shell of Eu(III) is essentially independent of the synthesis method employed, the significant decrease in the emission quantum yield for the di-ureasil prepared by acetic acid solvolysis might be explained by the interaction between the hybrid emitting centres and the nta ligand levels, favouring a larger non-radiative transition probability.

Heterobimetallic gadolinium(III)–iron(III) complex of DTPA-bis(3-hydroxytyramide)

A derivative of diethylenetriamine- N, N, N′, N″, N″-pentaacetic acid (DTPA), carrying two catechol functional groups has been synthesised by the reaction between DTPA-bis(anhydride) and 3-hydroxytyramine (dopamine). The ligand DTPA-bis(3-hydroxytyramide), [DTPA(HTA) 2], is able to form stable heterobimetallic complexes with gadolinium(III) and iron(III) ions. The gadolinium(III) occupies the internal coordination cage of DTPA formed by three nitrogens, two carboxylate and two amide oxygens, while the [Fe(NTA)(H 2O) 2] (nitrilotriacetic acid, NTA) binds to catechol units by the substitution of two water ligands. The formation of polymeric species was avoided by using the tripodal NTA ligand. The heterobimetallic complex was characterised by means of visible absorption spectroscopy, electron spray ionisation–mass spectrometry (ESI–MS), and nuclear magnetic resonance (NMR) spectroscopy.

Coordinate Structures of PrIII, GdIII, TmIII, and YbIIIComplexes with Nitrilotriacetic Acids

The crystal and molecular structures of the [PrIII(nta)(H2O)2]·H2O (nta = nitrilotriacetic acids), K3[GdIII(nta)2(H2O)]·6H2O, and K3[YbIII(nta)2]·5H2O complexes have been determined by single-crystal X-ray structure analyses. In [PrIII(nta)(H2O)2]·H2O, the PrIIINO8 part forms a nine-coordinate pseudo-monocapped square antiprismatic structure in which one N and three O atoms are from one nta ligand in the same molecule, three O atoms from another nta ligand in the neighboring molecule and two O atoms from two coordinate water molecules. In K3[GdIII(nta)2(H2O)]·6H2O, the [GdIII(nta)2(H2O)3- complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which each nta acts as a tetradentate ligand with one N atom of the amino group and three O atoms of the carboxylic groups. In K3[YbIII(nta)2]·5H2O, each nta also acts as a tetradentate ligand with one N atom of amino group and three O atoms of the carboxylic groups, but the [YbIII(nta)2 3- complex anion has an eight-coordinate structure with a distorted square antiprismatic prism. All the results including those for [TmIII(nta)(H2O)2]·2H2O confirm the inferences on the coordinate structures and coordination numbers of rare earth metal complexes with the nta ligand.

Molecular Imprinting for the Recognition of N-Terminal Histidine Peptides in Aqueous Solution

A new procedure for creating macromolecular receptors for peptides using molecular imprinting has been developed. The polymeric receptor exhibits selective uptake of specific N-terminal histidine containing sequences of simple dipeptides. The polymerization and binding are carried out in water. The approach utilizes a strong Ni(II)−His binding to attract the N-terminus histidine of the dipeptide to the polymer surface and secondary interactions between peptide and polymer to discriminate between the peptide sequence. These developments are enabled by utilizing an aqueous based monomer formulation that includes N,N‘-ethylenebis(acrylamide) as a water-soluble cross-linking monomer and a polymerizable NTA ligand, which can be used to incorporate nickel and other metals into these polyacrylamides. The Ni−NTA complex provides a strong histidine binding site that draws the dipeptide to the polymer surface. Mild polymerization conditions that utilize low concentrations of water-soluble initiator and low-temperature result in quantitative polymer yields. Variation of monomer composition reveals an optimum cross-linking for achieving maximum selectivity for these polymers.