Gadolinium Acetate Research Articles

The first example of a polyhedral boron derivative of gadolinium(III) phthalocyaninate as a promising prototype of a theranostic agent

We report the first synthesis of a polyhedral boron derivative of gadolinium(III) phthalocyaninate. Initially, reaction of 4-nitrophthalonitrile with 4-formylphenol in the presence of base was carried out to give 4-(4-formylphenoxy)phthalonitrile. This compound was then converted to 4-(4-hydroxymethylphenoxy)phthalonitrile using sodium tris-acetoxy borohydride in THF. Sequential cyclotetramerisation of this semiproduct in the presence of magnesium acetate, treatment of the resulting complex with trifluoroacetic acid, and complexation with gadolinium(III) acetate afforded gadolinium(III) phthalocyanine containing four hydroxymethylphenoxy groups at the peripheral (β) positions. Then, a nucleophilic addition reaction of this complex with acetonitrilium derivative of [B10H10]2- anion afforded gadolinium(III) phthalocyaninate decorated with four closo-decaborate units in good/satisfactory yield. The new product was characterised by various techniques (CHN analysis, MALDI-TOF mass spectrometry and UV–Vis spectroscopy). The boron content in this product is 21.5 wt% (40 atoms), and the r1 relaxivity of the conjugate 6.1 ± 0.7 mM-1s−1 (at 3.0 T, 20 °C in water), which makes it a promising prototype for theranostic agents for MRI-guided BNC therapy in future investigations.

Gadolinyum(III) Asetat İçeren Yeni Tetrapirazinoporfirazinin Sentezi ve Spektroskopik Özellikleri

A new tetrakis-(2-methylpyrazino)porphyrazinato gadolinium(III) acetate complex was synthesized. Elemental analysis, Fourier-Transform Infrared, Ultraviolet-visible, and fluorescence spectroscopy techniques clarified its structure. It can dissolve very well without aggregation in both Dimethyl sulfoxide and N, N-Dimethylformamide, which have high dielectric constant and high dipole moment from polar aprotic solvent type. Its aggregation property was also investigated in dimethyl sulfoxide at different concentrations, and it was determined to contain monomeric species. In addition, its fluorescence properties were investigated in Dimethyl sulfoxide and the effect of gadolinium(III) acetate metal ion as a heavy rare earth element was determined. According to the findings in this study, it may be used as an electronic and optical material and in various technological applications such as photocatalytic applications. In addition, these findings may be useful for systems that include changes in pyrazinoporphyrazine-like forms.

ON THE POSSIBILITY TO RESOLVE GADOLINIUM- AND CERIUM-BASED CONTRAST AGENTS FROM THEIR CT NUMBERS IN DUAL-ENERGY COMPUTED TOMOGRAPHY.

Cerium oxide nanoparticles with integrated gadolinium have been proved to be useful as contrast agents in magnetic resonance imaging. Of question is their performance in dual-energy computed tomography. The aims of this work are to determine (1) the relation between the computed tomography number and the concentration of the I, Gd or Ce contrast agent and (2) under what conditions it is possible to resolve the type of contrast agent. Hounsfield values of iodoacetic acid, gadolinium acetate and cerium acetate dissolved in water at molar concentrations of 10, 50 and 100 mM were measured in a water phantom using the Siemens SOMATOM Definition Force scanner; gadolinium- and cerium acetate were used as substitutes for the gadolinium-integrated cerium oxide nanoparticles. The relation between the molar concentration of the I, Gd or Ce contrast agent and the Hounsfield value was linear. Concentrations had to be sufficiently high to resolve the contrast agents.

Sericin-based gadolinium nanoparticles as synergistically enhancing contrast agents for pH-responsive and tumor targeting magnetic resonance imaging

It is of great significance to develop gadolinium (Gd) contrast agents (CAs) for pH-responsive and tumor targeting magnetic resonance imaging (MRI). Silkworm sericin (SS) is a natural biomacromolecule from silkworm cocoon with good biocompatibility, biodegradability, and a variety of biological activities. Here, sericin was covalently cross-linked with gadolinium acetate (GAH) via Schiff's base reaction, and then blended with gadolinium chloride (GdCl3) through electrostatic adsorption to yield SS@GAH-GdCl3 nanoparticles. Zeta potential showed SS@GAH-GdCl3 could respond pH change naturally, and freely realize the transition from negative surface potential in pH 7.5 to positive surface potential in pH 5.8. The T1 weighted MR images in solution indicated that SS@GAH-GdCl3 has higher T1 relaxivity in pH 5.8 than that in pH 7.4, and magnevist under 3.0 T magnetic field. Further, the T1 weighted MR images in vivo suggested that SS@GAH-GdCl3 could target tumors and accumulate around tumor tissues to achieve MR imaging on the tumor up to 2 h. Moreover, SS@GAH-GdCl3 is stable without any leakage of gadolinium ions. SS@GAH-GdCl3 is cytocompatible and does not cause hemolysis, inflammation, tissue damage, and the change of serum biochemical indicators and body weight in vivo. SS@GAH-GdCl3 has exhibited great potentials as a high-performance GdCA for pH-responsive and tumor targeting MRI.

Nanosheets-nanorods transformation during the non-isothermal decomposition of gadolinium acetate

Gadolinium oxy-carbonate and oxide nanostructures have been successfully obtained via simple non-isothermal heat treatment of gadolinium acetate precursor. Nanosheets of (GdO)2CO3 were developed as a consequence of heating the acetate precursor over the 400–500 °C range and these were stripped into thin lamellar nanorods of cubic Gd2O3 when the heat treatment was applied at the 600–800 °C range. The analysis of N2 adsorption isotherms revealed the microporosity of both phases and the BET calculated surface areas showed a gradual decrease with the pretreatment temperature of Gd2O3. Surface inspection using XPS indicated the presence of Gd in 3+ valence states at the surfaces of (GdO)2CO3 and Gd2O3. H2-TPR results revealed the refractory nature of Gd2O3 nanoparticles against reduction. Moreover, a possible reaction of H2 and CO2 was suggested. The electrical conductivity has been measured during the decomposition of the gadolinium precursor and for the 500–800 °C pre-treated samples.

Novel d- and f-metal phthalocyaninates based on 4-(2,4,5-trichlorophenoxy)phthalonitrile. Synthesis, spectroscopic and fluorescent properties

The work reports synthesis and spectroscopic-luminescent properties of first obtained zinc, magnesium, erbium and gadolinium trichlorophenoxy-phthalocyanine complexes. The initial building unit being 4-(2,4,5-trichlorophenoxy)phthalonitrile is synthesized by nucleophilic substitution reaction. Zinc and magnesium complexes are obtained by template condensation of the phthalodinitrile and corresponding acetates. A demetallization of magnesium phthalocyaninate results in the formation of free tetra-4-(2,4,5-trichlorophenoxy)phthalocyanine ligand. Rare-earth element complexes are synthesized by two approaches: template condensation and metallization of free phthalocyanine ligand. The planar complex is found to be yielded higher in case of template fusion. Influence of lanthanide salts anion (acetate, chloride) on formation ability of sandwich-type complex is analyzed. A double-decker complex is testified to be formed only upon the template fusion of gadolinium acetate with 4-(2,4,5-trichlorophenoxy)phthalonitrile. The as-obtained compounds are studied in terms of spectral-luminescent characteristics. A bathochromic shift of absorption Q-band maximum is found to accompany d-to-f-metal transition. The zinc complex being associated in chloroform exhibits higher quantum yield of fluorescence than monomeric forms generated upon addition of organic ligand.

Investigation on nebulizer spray deposited Gd-doped PbS thin films for photo sensing applications

Nebulizer assisted spray technique has been implemented for the deposition of pure and gadolinium (Gd) doped PbS thin films at a substrate temperature of 210 °C onto glass substrate using lead nitrate and gadolinium (III) acetate as precursors. Doping percentage of Gd was varied from 0 to 5 wt% for the preparation of Gd doped films and to analyze the film property. A variety of techniques like X-ray diffraction, Raman spectrum, scanning electron microscopy, atomic force microscopy, energy dispersive X- ray, UV–Visible spectrometer, and keithley source meter were used to study the influence of Gd doping in PbS thin films X-ray diffraction revealed no change in preferential orientation of the crystal planes without any secondary phases formed for all the Gd-doped films. And also it confirmed that the nature of the films were polycrystalline with simple cubic structure. It also further confirmed polycrystalline simple cubic structure with decrease of crystallite size from 21 nm to 16 nm for the increase of gadolinium doping concentration from 0 to 5 wt%. Noticeable change in the grain size was observed for the 5 wt% of gadolinium doping with uniformly distributed spherical shaped nanosize grains fully covering the entire surface. The compositional analysis confirmed the presence of Pb, S and Gd in the films. The optical parameters of Gd doped PbS thin films such as band gap energy, refractive index; extinction co-efficient, and real and imaginary parts of dielectric constant were determined using transmission, absorption and reflectance spectra in the range of 300–2400 nm. A maximum value of photo current was observed for 5 wt% gadolinium doped film.

Abstract No. 616 Bismuth gadolinium oxide (BiGdO3) nanoparticles as biocompatible contrast agents for non-invasive in vivo imaging of biodegradable implants

Temporary biodegradable implants offer a favorable alternative for patients, as they provide short-term support and degrade at a rate matching tissue formation, and thus, eliminate the need for surgical removals. However, these biomaterials are radiolucent, making direct radiographic visualization a challenge. Here, we synthesized biocompatible BiGdO3 nanoparticles (BiGdNPs) with high X-ray attenuation that can be incorporated in biodegradable medical implants to provide radiopacity for image-guided delivery and allow non-invasive monitoring. BiGdNPs were synthesized by thermal decomposition of bismuth (III) acetate and gadolinium (III) acetate and characterized in terms of size, morphology, and radiopacity. BiGdNPs were incorporated into biodegradable polycaprolactone (PCL) nanocomposite scaffold by dispersing BiGdNPs in 12% (w/v) PCL in (4:1) toluene/MeOH solution and electrospun using a spraybase system. Quantification of the infused bismuth and gadolinium was done using elemental analysis, tensile strength measurement using Instron universal testing machine, and in vitro cytotoxicity against RF24 cells using a standard alamarBlue assay. Imaging was performed using X-ray, micro-, and dual energy computed tomography (CT). Synthesized BiGdNPs had an average size of 20 nm±4 nm and were successfully loaded uniformly in PCL scaffolds at 3% by weight. In vitro cytotoxicity showed no significant difference in cell viability between the treated and untreated PCL scaffolds (one-way ANOVA, p < 0.05). Improved structural integrity and increased radial stiffness were observed in the BiGdNPs-PCL scaffolds in comparison with the control (PCL only). Imaging studies showed higher attenuation with BiGdNP-treated PCL as compared to the control providing excellent contrast in X-ray and CT imaging. Controlled synthesis of radiopaque BiGdNPs was successfully achieved. These nanoparticles were then incorporated to the biodegradable PCL scaffolds without compromising its physical and mechanical properties. The high X-ray attenuation allows real time visualization, through fluoroscopy or CT, to monitor accurate placement of the device and its degradation over time.

Oxalic acid assisted synthesis of the gadolinium-doped ceria oxide-ion conductor as electrolyte for the solid oxide fuel cells

The aim of this paper is to investigate the thermal behavior of as-prepared Gd–Ce–O acetate–oxalate (GCO–AO) precursors and their affinity to the decomposition processes of the starting materials by means of thermogravimetric and differential scanning calorimetric analyses (TG/DTG/DTA). Moreover, the influence of the temperature, heating atmosphere, and heat treatment time on both the morphology and crystal structure of the Ce–Gd–O gel precursor were additionally investigated in detail using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT–IR). The obtained TG/DTG/DTA results revealed that the formation of the gadolinium-doped ceria (GDC) ceramic was closely related to the thermal decomposition processes of the initial compounds: gadolinium (III) acetate and cerium (IV) acetate. The powder XRD patterns of the heat-treated GCO–AO sample revealed that the crystallization process for the GDC ceramic starts at 1173 K, whereas the temperature and heat treatment time significantly affected on the surface morphology and the size of the obtained particles. Besides, the spectra of FT–IR analysis showed that the vibration modes of the oxygen–metal–oxygen (O–M–O) in GDC ceramic heat-treated at different temperatures were equivalent, although the sample heat-treated at 1273 K demonstrated a completely different optical behavior. In that case a strong absorption outspread in the region from 1000 to 500 cm−1 was observed, which could be attributed to the initial formation of the nano-sized spherical particles in size of about 50–100 nm.

Development of Room-Temperature Ferromagnetism in Nanocomposite CdO Codoped with Al and Gd: Treatment in Hydrogen Atmosphere

Cadmium oxide codoped with Al and Gd ion powders was synthesised by thermal codecomposition of a mixture of complexes of cadmium acetate dihydrate, gadolinium acetate hydrate, and aluminum nitrate nonahydrate. The mass ratio of Al/Cd was fixed while the mass ratio of Gd/Cd varied systematically. The purpose of the present study is to synthesise and study the transparent conducting oxide (TCO) CdO powder having room-temperature ferromagnetic (RT-FM) properties. To realize that purpose, the synthesised Al/Gd-codoped CdO powder was annealed under hydrogen gas with certain conditions. The X-ray diffraction (XRD) method confirmed the formation of a single nanocrystalline structure; thus, both Al/Gd ions were incorporated into CdO lattice forming solid solutions. Magnetic measurements revealed that some of the doped CdO powders gained paramagnetic (PM) properties where the susceptibility increases with increasing dopant Gd content; the measured effective magnetic moment of dopant Gd3+ was around 8 μB. Furthermore, the magnetic energy of the created RT-FM of the codoped CdO samples by hydrogenation was found to be dependent on the Gd% doping level. For hydrogenated CdO powder doped with 3% Gd, the coercivity (Hc) was 195.9 Oe, the remanence (Mr) was 0.77 memu/g, the saturation magnetisation (Ms) was 5.05 memu/g, and the energy product (Um) was 150.6 merg/g. Thus, the possibility of production of TCO CdO with RT-FM, where magnetic characteristics can be tailored by doping and post treatment under H2 gas, was proven. Thus, a new potential candidate to be used as a dilute magnetic semiconductor (DMS) was successfully synthesised.

Structural Properties and Magnetic Interactions in Al3+ and Co2+ Co-Incorporated CdO: Efficient Act of Hydrogenation on Ferromagnetic Order

Nano-powder samples of cadmium oxide doped with Al-Co ions were synthesized by the sol–gel technique using a mixture of complexes of cadmium acetate dihydrate, gadolinium acetate hydrate, and aluminum nitrate nonahydrate. The mass ratios of Al/Cd and Co/Cd in the investigated samples (CdO:Al, CdO:CO, and CdO:Al;Co) were 0.5% and 1%, respectively. X-ray diffraction studies confirmed the formation of a single-phase crystalline structure. Thus, both Al and Co ions were successfully incorporated into the CdO lattice. The present work aims to investigate the possible creation of room-temperature (RT) ferromagnetic properties in host CdO for the field of dilute magnetic semiconductorz (DMS). Annealing in H2 atmosphere under certain conditions was extensively utilized to enhance the Heisenberg interactions between the spins of the incorporated dopant ions which boosted the created FM behavior. Optical measurements revealed the redshift of the bandgap by doping and hydrogenation. RT magnetic measurements disclosed various magnetic properties [diamagnetic, paramagnetic (PM), and FM) at RT depending on the dopant type]. However, the hydrogenation converted all the investigated samples to FM. It was established that the hydrogenation could enhance the saturation magnetisation of CdO:Al:Co nano-powder by ∼ 400 times. Therefore, the system of Al/Co-doped CdO nano-powders, owning these amazingly tunable magnetic properties, can be considered as a potential candidate for many applications such as DMS in addition to its transparent conducting oxide properties.

One pot low temperature synthesis of graphene coupled Gd-doped ZnFe2O4 nanocomposite for effective removal of antibiotic levofloxacin drug

Nanocomposites of reduced graphene oxide (rGO) coupled gadolinium doped ZnFe2O4 (GZFG) have been successfully one pot in-situ synthesized adopting low temperature solution process from zinc nitrate, iron nitrate, gadolinium acetate and graphene oxide with varying concentrations of gadolinium (upto 10% Gd with respect to Zn) in the precursor medium. X-ray diffraction and transmission electron microscopy studies confirm the presence of single phase cubic spinel structure of ZnFe2O4 that uniformly distributed over the rGO layers. With increasing Gd doping concentration in precursor medium, the average crystallite size of ZnFe2O4 diminishes gradually from ~11 to ~5.5 nm. Raman and X-ray photoelectron spectral analyses confirm an existence of interaction between rGO and ZnFe2O4 in GZFG samples. Using antibiotic levofloxacin in water, the drug removal capacity (DRC) of GZFG has been performed by optimization of parameters such as gadolinium doping concentration in precursor medium, solution pH, etc. However, the gadolinium doping leads to an improvement in DRC of the nanocomposite and the 5% Gd doped sample shows about 86% DRC at the optimized condition. This simple strategy can be utilized in the synthesis of rGO coupled Gd doped other metal oxide nanocomposites for DRC application.

A Study and Comparison of the Preparation of Gadolinium Aluminate Nanoparticles Using γ‐Irradiated and Unirradiated Precursors

The effects of γ‐irradiation and the application of different precursors on the formation of gadolinium aluminate (GdAlO3) nanoparticles (NPs) have been studied in detail. GdAlO3 NPs were prepared by using different gadolinium‐based precursors including gadolinium acetate (Gd(CH3COO)3·4H2O) and gadolinium nitrate (Gd(NO3)3·6H2O), while Al2O3 and Al(NO3)3·9H2O were used as the source of Al3+. The preparation of GdAlO3 was carried out by two different methods, solid‐state reaction and sol‐gel process. To study the effect of γ‐irradiation, both irradiated and unirradiated Gd(CH3COO)3·4H2O have been tested for the preparation of gadolinium aluminate (GdAlO3). Notably, Gd(CH3COO)3·4H2O did not produce GdAlO3 in both solid‐state and sol‐gel processes even after optimizing various parameters, including the application of γ‐irradiation. However, single‐phase nanocrystalline GdAlO3 NPs were successfully obtained from the reaction of gadolinium nitrate Gd(NO3)3·6H2O and Al(NO3)3·9H2O by a sol‐gel process. The formation of NPs has been confirmed by X‐ray diffraction analysis (XRD) and Fourier‐transform infrared (FT‐IR) spectroscopy. The results indicate towards the formation of an orthorhombic perovskite structure of GdAO3 in the Pbnm space group. Transmission electron microscopy (TEM) has been employed for the particle‐size analysis, which revealed the formation of spherical‐shaped nanoparticles with the size range of 50–70 nm. Surface morphology of the sintered pellet was obtained from high‐resolution scanning electron microscopy (HR‐SEM). Besides, the effect of irradiation with γ‐rays on the quality of resultant NPs has also been studied.

A simple straightforward thermal decomposition synthesis of PEG-covered Gd2O3 (Gd2O3@PEG) nanoparticles

Paramagnetic polyethylene glycol (PEG) functionalized gadolinium oxide (Gd2O3@PEG) nanoparticles were synthesized by a facile thermal decomposition of gadolinium acetate hydrate (Gd(CH3CO2)3·XH2O) precursors in PEG-1000. PEG-1000 was used as a solvent, and as a size reducing and functionalizing agent. The advantages of the present method are that it is simple and relatively fast, and it only needs a small amount of reagents. The resulting nanoparticles were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDX). From the XRD data, the average crystallite size, t, of the Gd2O3@PEG nanoparticles was calculated to be about 5.4, 3.8, and 3.1nm at decomposition temperatures of 260°C, 280°C and 300°C respectively. The SEM images revealed that the synthesized nanoparticles had a homogenous spherical shape while the coated nanoparticle diameters were about 178nm at 260°C. Synthesis at higher temperatures tended to cause agglomeration. FTIR analysis showed that the oxidation of PEG is linked to the Gd2O3 surface. Magnetization was investigated using a Vibrating Sample Magnetometer (VSM). The magnetization vs. magnetic field (M–H) curve, measured at 300K, showed that the Gd2O3@PEG nanoparticles exhibit characteristic paramagnetic behavior. We confirmed that the dispersibility and functionalization behavior of the PEG was successfully transferred to the Gd2O3 nanoparticles.

Effects of Polyethyleneimine on the Sonochemical Synthesis of Gadolinium Ion-Modified ZnO Nanorods.

We prepared gadolinium (Gd) ion-modified ZnO nanorods by a sonochemical decomposition of zinc acetate dehydrate and gadolinium acetate hydrate precursor solutions with and without polyethyleneimine (PEI). We investigated the effects of PEI on the sonochemical synthesis of ZnO nanorods with and without Gd ion modifications. In the case of nascent ZnO nanorods, PEI in the precursor solutions can prohibit radial growth but allow axial growth, resulting in changes in the degree of preferred crystal orientations, and in the PL properties of the resulting nanorods. In the case of Gd ion-modified ZnO nanorods, we observed that the ZnO nanorods, fabricated sonochemically in the precursor solutions with PEI, exhibited a peak broadening of the ZnO(002) crystal plane and decreasing crystal orientation with respect to the c plane. We note that PEI can negatively affect the crystal orientation and crystallinity of Gd ion-modified ZnO nanorods, even though it cannot affect the lattice constant.

Specific lipase-responsive polymer-coated gadolinium nanoparticles for MR imaging of early acute pancreatitis

Currently, available methods for diagnosis of acute pancreatitis (AP) are mainly dependent on serum enzyme analysis and imaging techniques that are too low in sensitivity and specificity to accurately and promptly diagnose AP. The lack of early diagnostic tools highlights the need to search for a highly effective and specific diagnostic method. In this study, we synthesized a conditionally activated, gadolinium-containing, nanoparticle-based MRI nanoprobe as a diagnostic tool for the early identification of AP. Gadolinium diethylenetriaminepentaacetic fatty acid (Gd-DTPA-FA) nanoparticles were synthesized by conjugation of DTPA-FA ligand and gadolinium acetate. Gd-DTPA-FA exhibited low cytotoxicity and excellent biocompatibility when characterized in vitro and in vivo studies. L-arginine induced a gradual increase in the intensity of the T1-weighted MRI signal from 1 h to 36 h in AP rat models. The increase in signal intensity was most significant at 1 h, 6 h and 12 h. These results suggest that the Gd-DTPA-FA as an MRI contrast agent is highly efficient and specific to detect early AP.

Surface‐Confined Molecular Coolers for Cryogenics

An excellent molecule-based cryogenic magnetic refrigerant, gadolinium acetate tetrahydrate, is here used to decorate selected portions of silicon substrate. By quantitative magnetic force microscopy for a variable applied magnetic field near liquid-helium temperature, the molecules are demonstrated to hold their magnetic properties intact, and therefore their cooling functionality, after their deposition. These results represent a step forward towards the realization of a molecule-based micro-refrigerating device at very low temperatures.

Characterization of Gd&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Nano Clusters

Gadolinium (Gd) is a weak magnetic element at room temperature. Gadolinium oxide (Gd2O3) is a poor semiconductor with para-magnetism. In this work Gadolinium oxide is prepared from the thermal dissociation of Gadolinium acetate. The average cluster size is found to be dependent on the number of the sintering time. In this present work an attempt has been made to characterize the developed Gadolinium oxide. Experimental probes used to characterize it are optical absorbance (UV-VIS); Fourier transformed infra red (FTIR) spectroscopy, DC current voltage characteristics (CVC) and photo-sensitivity studies of the developed specimens. Gadolinium oxide exhibits a good optical sensing property.

Synthesis and characterization of Gd 0.1 Ce 0.9 O 1.95 nanopowder via an acetic–acrylicmethod

Abstract Nanocrystalline Ce0.9Gd0.1O1.95 (GDC) powders are successfully prepared by an acetic–acrylic method using acrylic acid, cerium acetate and gadolinium acetate as the starting materials. The polymeric precursors are characterized by means of TG/DTA, XRD and FT-IR, and the resultant powders are characterized by XRF, BET, SEM and particle size distribution (PSD) analysis. It is shown that the morphology of the oxide particles is dependent on the preparation conditions such as molar ratio of acrylic acid to metallic ions (L/M) and the sort of surfactant. High purity, single phase, homogeneous, nanocrystalline GDC powders with slight aggregation are obtained using ethylene glycol as surfactant, L/M=0.5 and heat treatment above 600 °C. The low application amount and high effect of acrylic acid is attributed to the co-operation of carboxyl group and ethylenic bond. The electrical conductivity of the sintered GDC pellet is 0.053 Scm−1 in air at 750 °C. The present work indicates that the acetic–acrylic method is a relatively green method without any NOx to synthesize high performance GDC powders.

Polynuclear and Polymeric Gadolinium Acetate Derivatives with Large Magnetocaloric Effect

Two ferromagnetic μ-oxo(acetate)-bridged gadolinium complexes [Gd(2)(OAc)(2)(Ph(2)acac)(4)(MeOH)(2)] (1) and [Gd(4)(OAc)(4)(acac)(8)(H(2)O)(4)] (2) and two polymeric Gd(III) chains [Gd(OAc)(3)(MeOH)](n) (3) and [Gd(OAc)(3)(H(2)O)(0.5)](n) (4) (Ph(2)acacH = dibenzoylmethane; acacH = acetylacetone) are reported. The magnetic studies reveal that the tiny difference in the Gd-O-Gd angles (Gd···Gd distances) in these complexes cause different magnetic coupling. There exist ferromagnetic interactions in 1-3 due to the presence of the larger Gd-O-Gd angles (Gd···Gd distances), and antiferromagnetic interaction in 4 when the Gd-O-Gd angle is smaller. Four gadolinium acetate derivatives display large magnetocaloric effect (MCE). The higher magnetic density or the lower M(W)/N(Gd) ratio they have, the larger MCE they display. Complex 4 has the highest magnetic density and exhibits the largest MCE (47.7 J K(-1) kg(-1)). In addition, complex 3 has wider temperature and/or field scope of application in refrigeration due to the dominant ferromagnetic coupling. Moreover, the statistical thermodynamics on entropy was successfully applied to simulate the MCE values. The results are quite in agreement with those obtained from experimental data.