Gd₂O(CO₃)₂ · H₂O Particles and the Corresponding Gd₂O₃: Synthesis and Applications of Magnetic Resonance Contrast Agents and Template Particles for Hollow Spheres and Hybrid Composites

Abstract

The solution approach was employed to yield multifunctional amorphous Gd2O(CO3)2 · H2O colloidal spheres by reflux of an aqueous solution containing GdCl3 · 6H2O and urea. By elongating the reaction time, crystalline rhombus‐ shaped Gd2O(CO3)2 · H2O with at least 87% yield could be formed and were also accompanied by some rectangular particles. High‐resolution synchrotron powder X‐ray diffraction provides crystal structure information, such as cell dimensions, and indexes the exact crystal packing with hexagonal symmetry, which is absent from the Joint Committee on Powder Diffraction Standards file, for the crystalline rhombus sample. Particle formation was studied based on the reaction time and the concentration ratio of [urea]/[GdCl3 · 6H2O]. After a calcination process, the amorphous spheres and crystalline rhombus Gd2O(CO3)2 · H2O particles convert into crystalline Gd2O3 at temperatures above 600 °C. For in vitro magnetic resonance imaging (MRI), both Gd2O(CO3)2 · H2O and Gd2O3 species show the promising T1‐ and T2‐weighted effects and could potentially serve as bimodal T1‐positive and T2‐negative contrast agents. The amorphous Gd2O(CO3)2 · H2O contrast agent further demonstrates enhanced contrast of the liver and kidney using a dynamic contrast‐enhanced MR imaging (DCE‐MRI) technique for in vivo investigation. The multifunctional capability of the amorphous Gd2O(CO3)2 · H2O spheres was also evidenced by the formation of nanoshells using these amorphous spheres as the template. Surface engineering of the amorphous Gd2O(CO3)2 · H2O spheres could be performed by covalent bonding to form hollow silica nanoshells and hollow silica@Fe3O4 hybrid particles.

Co-precipitation synthesis of Y 2 O 2 SO 4 :Eu 3+ nanophosphor and comparison of photoluminescence properties with Y 2 O 3 :Eu 3+ and Y 2 O 2 S:Eu 3+ nanophosphors

“…2e), and d-CO 3 2À (630 cm À1 in Fig. 2a) demonstrated the presence of the CO 3 2À groups [20], which was caused by absorbed H 2 O and CO 2 from ambient atmosphere on the surface of the precursor. When the molar ratio of Y 3þ :SO 4 2À is equal to 2:0, as shown in Fig.…”

A Hollow NaGdF4/AFn Nanosystem Based on “Relay Race” Release for Therapy

“…FTIR spectroscopy was performed for both the precursor and the final product to verify formation of the product and to characterize the surface structure ( Figure 1F). The FTIR spectrum of AFn is shown in Figure1Fa;a mide bonds are at 1405 and 1653 cm À1 .F igure 1Fbs hows the characteristica bsorption bands of u as OÀCÀO( 1524 and 1455 cm À1 ), p CO 3 2À (857 cm À1 ), and d CO 3 2À (726 and 696 cm À1 ), [16] demonstratingt he presence of the carbonate group. Figure 1Fcs hows that the compositiono fh ydrothermal products has changed.…”

Large-scale synthesis of Lu2O3:Ln3+ (Ln3+=Eu3+, Tb3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) microspheres and their photoluminescence properties

“…In Fig. 3B for the as-formed precursor sample, the FT-IR spectrum shows the characteristic absorption bands at 1531, 1399, 1084, 840 cm À1 which are assigned to the respective CO (n as ), CO (n as ), CO (n s ) and CO (d) (n s = symmetric stretch; n as = asymmetric stretch; and d = deformation) in the CO 3 2À groups, revealing the composition of the precursor (red line) [45]. After annealing the as-formed precursor sample at 800 8C (Fig.…”