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At least 19 recordsLinked to original sources
PubMed2006

Anodic electrodeposition of highly oriented zirconium phosphate and polyaniline-intercalated zirconium phosphate films.

Films of highly oriented alpha-zirconium phosphate and polyaniline-intercalated zirconium phosphate with controllable thickness in the micrometer range were grown anodically on Pt electrodes. To optimize the electrodeposition conditions, the exfoliation of alpha-zirconium phosphate by tetrabutylammonium (TBA) salts was investigated in several nonaqueous solvents. Acetonitrile was found to be the best solvent for making crack-free, oriented films because of its high vapor pressure, low viscosity, and relatively high permittivity. With TBA salts of neutral or weakly acidic anions (TBACl, TBABr, TBAI, TBA(HSO4), or TBA(H2PO4)), full exfoliation did not occur and alpha-zirconium phosphate and/or polyaniline were deposited as rough films. With basic anions (TBAF or TBAOH), dense, adherent films were obtained. X-ray diffraction patterns of the films showed that they were highly oriented along the stacking axis. The thickness could be controlled, up to about 40 microm, by limiting the time of the electrodeposition reaction. At monomer concentrations below 1.0 x 10(-2) mol/dm3, the emeraldine form of the intercalated polymer was obtained. Electrodeposition thus provides a thick film alternative to layer-by-layer assembly for intercalation compounds of alpha-zirconium phosphate with a conducting polymer.

Journal Article↗
PubMed2002

Highly anti-selective asymmetric aldol reactions using chiral zirconium catalysts. Improvement of activities, structure of the novel zirconium complexes, and effect of a small amount of water for the preparation of the catalysts.

Catalytic asymmetric aldol reactions of silyl enol ethers with aldehydes (Mukaiyama aldol reactions) have been performed using novel chiral zirconium catalysts. The reactions proceeded in high yields under mild conditions, and anti-adducts were obtained in high diastereo- and enantioselectivities. The catalysts were first prepared from zirconium(IV) tert-butoxide (Zr(O(t)Bu)(4)), (R)-3,3'-diiodo-1,1'-binaphthalene-2,2'-diol ((R)-3,3'-I(2)BINOL), a primary alcohol, and a small amount of water. It was revealed that the primary alcohol played an important role in completing the catalytic cycle and that a small amount of water was essential for obtaining high selectivities. Moreover, activities of the chiral zirconium catalysts were enhanced by using new ligands, (R)-3,3'-I(2)-6,6'-X(2)BINOL (X = Br, I, C(2)F(5)), and it has been shown that even aldol reactions of less reactive substrates proceeded smoothly using the novel zirconium catalysts. Finally, NMR studies of these catalysts were performed, which suggested that the catalyst would form a dimeric structure and that the water affected the catalyst formation.

Alcohols↗
PubMed2002

Preparation, characterization, and structure of zirconium fluoride alkylamino-N,N-bis methylphosphonates: a new design for layered zirconium diphosphonates with a poorly hindered interlayer region.

This paper reports the preparation and characterization of the homologous series of layered zirconium fluoride n-alkylamino-N,N-bis methylphosphonates, of general formula ZrF(O(3)PCH(2))(2)NHC(n)H(2n+1) (n = 1, 2, 3, 4, 5, 6, 8, 9, 10), in which the two phosphonic groups of each diphosphonate building block participate in the assembly of a single lamella, because they are joined to zirconium atoms belonging to the same layer. The crystal structure of one of the series of these zirconium diphosphonates, ZrF(O(3)PCH(2))(2)NHC(5)H(11), has been solved "ab initio" by X-ray powder diffraction data. The structure is monoclinic, space group P2(1)/c. The zwitterionic character of the diphosphonate moiety is a distinctive feature which acts as a structure-orienting factor, generating a layer framework which is different from the other structures known for zirconium phosphates and phosphonates. This compound undergoes a phase transition at 117 degrees C which involves a rearrangement of the interlayer alkyl chains. The structure of the high-temperature phase has been refined by the Rietveld method. Because only one organic residue is associated with two phosphonate tetrahedra, a poorly hindered interlayer region is formed, and alkyl chains bonded to adjacent layers are interdigitated. Preliminary experiments have shown that these compounds are able to intercalate organic molecules, such as n-alkanols, from very dilute water solutions.

Journal Article↗
PubMed1993

Zirconium granuloma resulting from an aluminum zirconium complex: a previously unrecognized agent in the development of hypersensitivity granulomas.

Zirconium compounds have been associated with the development of hypersensitivity granulomas. However, aluminum zirconium complexes have not previously been shown to induce sensitization. We present the clinical and histologic findings of a case in which a patient developed an acute hypersensitivity reaction to an aluminum zirconium complex.

Adult↗
PubMed2000

Ab initio structure determination and Rietveld refinement of a high-temperature phase of zirconium hydrogen phosphate and a new polymorph of zirconium pyrophosphate from in situ temperature-resolved powder diffraction data.

The collected in situ temperature-resolved synchrotron powder data revealed that the transformation of the recently reported three-dimensional tau-Zr(HPO4)2 to cubic ZrP2O7 goes through two intermediate phases. The first intermediate phase, rho-Zr(HPO4)2, is formed in a reversible phase transition at 598 K, which involves both rearrangement and disordering of the hydrogen phosphate groups of tau-Zr(HPO4)2. At 688 K condensation of the hydrogen phosphate groups leads to the formation of the second intermediate, a new polymorph of zirconium pyrophosphate (beta-ZrP2O7). Heating above 973 K results in the gradual transformation of beta-ZrP2O7 to cubic zirconium pyrophosphate (alpha-ZrP2O7). The crystal structures of the two intermediate phases were solved from the in situ powder diffraction data using direct methods and refined using the Rietveld method. Both phases are orthorhombic, space group Pnnm and Z = 2. The lattice parameters for the two phases are: p-Zr(HPO4)2: a = 8.1935 (2), b = 7.7090 (2), c = 5.4080 (1) A; beta-ZrP2O7: a = 8.3127 (5), b = 6.6389 (4), c = 5.3407 (3) A. The formation mechanism for the new zirconium pyrophosphate polymorph, beta-ZrP2O7, is discussed in relation to structurally restricted soft chemistry.

Diphosphates↗
PubMed2006

Adsorption of myoglobin onto porous zirconium phosphate and zirconium benzenephosphonate obtained with template synthesis.

Porous zirconium phosphate (P-ZrP) and zirconium benzenephosphonate (P-ZrBP) were prepared in the presence of an anionic surfactant acting as a template. Poorly crystalline materials with a P/Zr molar ratio equal to 2 and having a relatively high surface area and micro/mesoporosity have been obtained. The interaction of myoglobin with the two types of surfaces, the hydrophobic P-ZrBP and the hydrophilic P-ZrP, was investigated, and the adsorption isotherms were determined at different pH and temperature values. A model was proposed for the mechanism of the interaction of the protein with the surface based on the shape of the adsorption isotherm and the physical-chemical properties of myoglobin. The pH has been found to be an important parameter for determining the maximum adsorption capacity of P-ZrBP and P-ZrP for myoglobin molecules because of the changes that occur in the type and net charge of the protein surface as the pH of the medium changes. Protein binding affinity and capacity increase when the temperature is increased. This phenomenon occurs because myoglobin varies its conformation at high temperature with an increase in the exposed hydrophobic region. This process causes a stronger hydrophobic interaction between the protein and the adsorbent and reduces the repulsion between the adsorbed molecules. Studies on the activities of the obtained biocomposites are in progress.

Adsorption↗
PubMed2004

New complexes of zirconium(IV) and hafnium(IV) with heteroscorpionate ligands and the hydrolysis of such complexes to give a zirconium cluster.

A series of zirconium and hafnium heteroscorpionate complexes have been prepared by the reaction of MCl4 (M = Zr, Hf) with the compounds [[Li(bdmpza)(H2O)](4)] [bdmpza = bis(3,5-dimethylpyrazol-1-yl)acetate], [[Li(bdmpzdta)(H2O)](4)] [bdmpzdta = bis(3,5-dimethylpyrazol-1-yl)dithioacetate], and (Hbdmpze) [bdmpze = 2,2-bis(3,5-dimethylpyrazol-1-yl)ethoxide] (the latter with the prior addition of Bu(n)Li). Under the appropriate experimental conditions, mononuclear complexes, namely, [MCl3(kappa3-bdmpzx)] [x = a, M = Zr (1), Hf (2); x = dta, M = Zr (3), Hf (4); x = e, M = Zr (5), Hf (6)], and dinuclear complexes, namely, [[MCl2(mu-OH)(kappa3-bdmpzx)]2] [x = a, M = Zr (7), Hf (8); x = dta, M = Zr (9); x = e, M = Zr (10)], were isolated. A family of alkoxide-containing complexes of the general formula [ZrCl2(kappa3-bdmpzx)(OR)] [x = a, R = Me (11), Et (12), iPr (13), tBu (14); x = dta, R = Me (15), Et (16), iPr (17), tBu (18); x = e, R = Me (19), Et (20), (i)Pr (21), (t)Bu (22)] was also prepared. Complexes 11-14 underwent an interesting hydrolysis process to give the cluster complex [Zr6(mu3-OH)8(OH)8(kappa2-bdmpza)8] (23). The structures of these complexes have been determined by spectroscopic methods, and the X-ray crystal structures of 7, 8, and 23 were also established.

Journal Article↗
PubMed2003

A doubly bridged isodicyclopentadienyl zirconium complex: bis[N-(3,5-dimethylphenyl)-N-[(eta5-isodicyclopentadien-2-yl)dimethylsilyl]amido-kappaN]zirconium(II) diethyl ether solvate.

Transmetallation of the dilithium salt of (3,5-dimethyphenylamino)(isodicyclopentadienyl)dimethylsilane by treatment with zirconium tetrachloride in a 2:1 ratio leads to the substitution of all four chloride ligands. With the applied stoichiometry, the title complex, [Zr(C(20)H(25)NSi)(2)].C(4)H(10)O, was obtained and crystallized from diethyl ether. X-ray diffraction characterization showed that both isodicyclopentadienyl ligands (alternatively called 4,5,6,7-tetrahydro-4,7-methano-1H-indene) are complexed to the metal on their exo face in a completely stereoselective manner and that they are eta(5)-bonded to the Zr atom.

Journal Article↗
PubMed2002

A novel titanium-mu-O-zirconium complex: bis(mu-methyliminodiethanolato-1kappa(3)O,N,O';1:2kappa(2)O)(methyliminodiethanolato-2kappa(3)O,N,O')dipropanolato-1kappaO,2kappaO-titanium(IV)zirconium(IV).

The title compound, [TiZr(C(5)H(11)NO(2))(3)(C(3)H(7)O)(2)], contains three methyliminodiethanolate ligands, two in different mu-oxo bridging coordination modes and one bound only to the Ti atom. The Ti and Zr atoms have distorted octahedral and pentagonal-bipyramidal coordinations, respectively, which share edges. As well as some conformational disorder in the carbon chains, there is chemical disorder at one Ti site, with a mix of n- and isopropanolate ligands.

Journal Article↗
PubMedDate not supplied

[Toxicity and pharmacokinetics of zirconium oxychloride in mice and rats].

The experimental toxicity of zirconium compounds is examined in the Mouse (acute toxicity) and in the Rat (short time toxicity). The absorption, the distribution and the elimination of zirconium are evaluated by zirconium cation assay in some biological fluids and tissues. After a single oral dose, zirconium oxyd is not toxic, zirconium oxychlorure slightly toxic and zirconium chlorure moderately toxic. At certain concentrations, cerebral and pulmonary disorders are observed, particularly with zirconium chlorure. In considering molar toxicity, the studied zirconium compounds are more toxic than certain aluminium salts mentioned in the literature. The zirconium oxychlorure doesn't influence the growth curve after iterative administrations (0.23 g zirconium/kg/day). Only a weak fraction of administered zirconium is absorbed and is electively fixed in the ovaries, in a lesser degree in the lung and the bone. In the ovary the zirconium induces vascular variation (hypervascularization) which appear one month after the end of the treatment. The absorbed zirconium is eliminated by the urinary tract. The fecal elimination can be essentially explained by an important quantity of non absorbed zirconium.

Animals↗
PubMed2003

Effect of zirconium(IV) complexes on the thermal and enzymatic stability of type I collagen.

Understanding the mechanism of stabilization of collagen is an important area of research. Metal ions are known to interact with collagen and bring about the stability of the same. In the present investigation, the interaction of zirconium(IV) complexes with collagen was studied. The effect of zirconium(IV) complexes, namely zirconium oxychloride and zirconium oxalate on the enzymatic and thermal stability of collagen was investigated. Zirconium has been found to increase the hydrothermal stability of the rat tail tendon (RTT) collagen fibers to about 8-10 degrees C more than that of the native collagen. The order of stabilization of zirconium(IV) complexes is zirconium oxychloride>zirconium oxalate. This could be due to the differences in the type of interaction with collagen, which is also reflected in the differences in the conformational changes of collagen brought about by the two complexes. Zirconium oxychloride, which forms tetrameric species in solution, has been shown to have better crosslinking with collagen as seen from viscometry studies and hence provides better enzymatic stability to collagen than zirconium oxalate, which largely forms monomeric species in solution.

Animals↗
PubMed1993

[In vitro study on biocompatibility of zirconium and titanium].

The purpose of this study is to evaluate the biocompatibility of zirconium compared with titanium by the in vitro study using human osteosarcoma cell line (HOS). Various characteristics of the HOS cells cultured on zirconium (99.9%) and titanium (99.9%) discs were investigated. On the colony formation of the HOS cells, there were no differences between the zirconium and titanium in colony size and number. Good proliferation of the HOS cells was observed on the zirconium as well as on the titanium. Morphological observation of the HOS cells by SEM revealed that the cells on the zirconium as well as on the titanium were flat and polygonal in shape with radial pseudopods. Collagen fibers and calcified substances were observed in the matrix of the HOS cells by TEM on the zirconium as well as on the titanium. The calcium of the HOS cell layer was stained well by Dahl's method. Analysis of the HOS cell layer by the Fourier transform infrared spectroscopy indicated that the HOS cells formed the same matrices including the apatite on the zirconium as on the titanium. Measurements of the zirconium and titanium elution into the human saliva indicated that the elution of zirconium was less than that of titanium. These results suggest that zirconium possesses as excellent biocompatibility as titanium.

Biocompatible Materials↗
PubMed2001

[Leaching and vertical transport of Zirconium-95 in soils].

The leaching and vertical transport of Zirconium-95 in three representational soils (paddy soil, red-yellow earth and sea mud) in Zhejiang province and the influence of salinity on the activities of Zirconium-95 in sea mud were studied with soil-pole installation. The results show that: 1. The content of Zirconium-95 in collected leachate was low after passing through soil column with 250 ml, 500 ml, 750 ml leaching amount. The amount of Zirconium-95 in collected leachate of paddy soil, sea mud and red-yellow earth was about 5.33%-7.68%, 0.77%-1.32% and almost 0 of labelled amount respectively. And with increasing the total amount of leaching water, the content of Zirconium-95 in collected leachate varied indistinctively, which indicated that once Zirconium-95 was absorbed by soils, it was very difficult to desorb. 2. In paddy soil, red-yellow earth and sea mud, 45.99%-50.02%, 96.02%-97.16% and 95.94%-98.01% radioactivity of Zirconium-95 was concentrated in the 0.4 cm upper layer soils respectively, which illustrated that most of Zirconium-95 remained in the surface soils. 3. With the increase of salinity in leaching water, the amount of Zirconium-95 in surface soils (0-0.2 cm) presented obviously increased, which demonstrated that increasing salinity could raise the adsorption rate of Zirconium-95 in soils.

Kinetics↗
PubMed2006

MRI comparison of periprosthetic structures around zirconium knee prostheses and cobalt chrome prostheses.

OBJECTIVE: The purpose of our study was to compare reviewer confidence and interobserver agreement in the evaluation of MR images of periprosthetic structures around zirconium total knee prostheses and cobalt chrome prostheses. MATERIALS AND METHODS: Three board-certified radiologists blinded to prosthesis type used identical MRI protocols to independently evaluate 21 total knee prostheses: 14 zirconium prostheses and seven cobalt chrome prostheses. The radiologists evaluated the following eight parameters: integrity of the medial and lateral collateral ligaments, the quadriceps and the patellar tendons, presence of a joint effusion, and for evidence of periprosthetic osseous signal abnormality around each of the three components. The reviewers gave their degree of confidence in evaluating each of the findings on a five-point scale, 0 being no confidence and 4 being high confidence in the finding. The degree of confidence was used as the vehicle for comparing the two groups of patients. RESULTS: The confidence ratings for all MRI variables were significantly higher for the zirconium group than for the cobalt chrome group. The confidence ratings varied less for the zirconium group than for the cobalt chrome group with an SD of 0.45 versus 0.95, respectively. There was greater interobserver agreement in the zirconium group (coefficient of interobserver agreement, 0.82 vs 0.35). The reviewers had the highest degree of confidence when examining for joint effusion in both groups (3.9 for the zirconium group; 3.7 for the cobalt chrome group). The greatest discrepancies between the two groups were in evaluation of periprosthetic osseous signal changes with the greatest difference being between the femoral component of each group with an average confidence rating of 3.3 for the zirconium group and 0.8 for the cobalt chrome group. CONCLUSION: Reviewers had significantly more confidence, less variability, and greater interobserver agreement in MRI evaluation of periprosthetic structures around zirconium knee prostheses than those around cobalt chrome knee prostheses.

Adult↗
PubMed2004

[Experimental study on the antibacterial effects of zirconium phosphate gauze loaded with silver on the common bacteria on rat burn wound].

OBJECTIVE: To investigate the antibacterial effects of zirconium phosphate gauze loaded with silver on rat burn wounds seeded with commonly seen bacteria. METHODS: Wistar rats were employed in the study and were scalded and infected. The minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) of zirconium phosphate loaded with silver were determined by double dilution in tubes. The effect on wound healing and the subeschar bacterial count of the rat burn wounds were observed after the wounds had been covered by gauze loaded with zirconium phosphate and silver, and also with the gauze which has been rinsed for 20 times. RESULTS: The MIC of silver loaded zirconium phosphate on Staphylococcus aureus, Pseudomonas aeruginosa and E. coli were 8, 8 and 16 mg/L, respectively, while the MBC were 16, 8 and 32 mg/L, respectively. The subeschar bacterial count in the burn wounds with the gauze with silver loaded zirconium phosphate was ten times lower than that in those which were treated with gauze with SD-Ag and 100 times lower than that with ordinary gauze. But there was no difference in the bacterial count between the wounds which were treated with fresh gauze with silver loaded zirconium phosphate and that with the gauze which has been rinsed for 20 times (P > 0.05). Furthermore, wound healing seemed to be better with the gauze with silver loaded zirconium phosphate when compared with those by the other two kinds of gauze. CONCLUSION: The silver loaded zirconium phosphate was found to be bacteriocidal against bacteria commonly seen in the burn wounds.

Animals↗