Title: Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis
Na 2 B 12 I 12 has many of the properties desired by an X-ray contrast agent but is lethal at the concentrations needed for medical imaging. We demonstrate here that PBS solutions with >50 mM Na 2 B 12 I 12 induce hemolysis, consistent with the previously reported superchaotropic nature of the anion. The presence of <1 equiv. of 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis and suggests a strategy for exploiting B 12 I 12 2− as an X-ray contrast agent. more »« less
Two five-coordinate mononuclear Co( ii ) complexes [Co(12-TMC)X][B(C 6 H 5 ) 4 ] (L = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane (12-TMC), X = Cl − ( 1 ), Br − ( 2 )) have been studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes have a distorted square pyramidal geometry with the Co( ii ) ion lying above the basal plane constrained by the rigid tetradentate macrocyclic ligand. In contrast to the reported five-coordinate Co( ii ) complex [Co(12-TMC)(NCO)][B(C 6 H 5 ) 4 ] ( 3 ) exhibiting easy-axis anisotropy, an easy-plane magnetic anisotropy was found for 1 and 2 via the analyses of the direct-current magnetic data and HF-EPR spectroscopy. Frequency- and temperature-dependent alternating-current magnetic susceptibility measurements demonstrated that complexes 1 and 2 show slow magnetic relaxation at an applied dc field. Ab initio calculations were performed to reveal the impact of the terminal ligands on the nature of the magnetic anisotropies of this series of five-coordinate Co( ii ) complexes.
Lin, Yu-Ying; Gustafson, William J.; Murray, Shannon E.; Shoemaker, Daniel P.; Ertekin, Elif; Krogstad, Jessica A.; Perry, Nicola H.
(, Journal of Materials Chemistry A)
Na-ion conducting solid electrolytes can enable both the enhanced safety profile of all-solid-state-batteries and the transition to an earth-abundant charge-carrier for large-scale stationary storage. In this work, we developed new perovskite-structured Na-ion conductors from the analogous fast Li-ion conducting Li 3 x La 2/3− x TiO 3 (LLTO), testing strategies of chemo-mechanical and defect engineering. Na x La 2/3−1/3 x ZrO 3 (NLZ) and Na x La 1/3−1/3 x Ba 0.5 ZrO 3 (NLBZ) were prepared using a modified Pechini method with varying initial stoichiometries and sintering temperatures. With the substitution of larger framework cations Zr 4+ and Ba 2+ on B- and A-sites respectively, NLZ and NLBZ both had larger lattice parameters compared to LLTO, in order to accommodate and potentially enhance the transport of larger Na ions. Additionally, we sought to introduce Na vacancies through (a) sub-stoichiometric Na : La ratios, (b) Na loss during sintering, and (c) donor doping with Nb. AC impedance spectroscopy and DC polarization experiments were performed on both Na 0.5 La 0.5 ZrO 3 and Na 0.25 La 0.25 Ba 0.5 ZrO 3 in controlled gas environments (variable oxygen partial pressure, humidity) at elevated temperatures to quantify the contributions of various possible charge carriers (sodium ions, holes, electrons, oxygen ions, protons). Our results showed that the lattice-enlarged NLZ and NLBZ exhibited ∼19× (conventional sintering)/49× (spark plasma sintering) and ∼7× higher Na-ion conductivities, respectively, compared to unexpanded Na 0.42 La 0.525 TiO 3 . Moreover, the Na-ion conductivity of Na 0.5 La 0.5 ZrO 3 is comparable with that of NaNbO 3 , despite having half the carrier concentration. Additionally, more than 96% of the total conductivity in dry conditions was contributed by sodium ions for both compositions, with negligible electronic conductivity and little oxygen ion conductivity. We also identified factors that limited Na-ion transport: NLZ and NLBZ were both challenging to densify using conventional sintering without the loss of Na because of its volatility. With spark plasma sintering, higher density can be achieved. In addition, the NLZ perovskite phase appeared unable to accommodate significant Na deficiency, whereas NLBZ allowed some. Density functional theory calculations supported a thermodynamic limitation to creation of Na-deficient NLZ in favor of a pyrochlore-type phase. Humid environments generated different behavior: in Na 0.25 La 0.25 Ba 0.5 ZrO 3 , incorporated protons raised total conductivity, whereas in Na 0.5 La 0.5 ZrO 3 , they lowered total conductivity. Ultimately, this systematic approach revealed both effective approaches and limitations to achieving super-ionic Na-ion conductivity, which may eventually be overcome through alternative processing routes.
Hu, Zhaowei; Liu, Lili; Zhang, Ruixin; Jing, Qun; Wang, Huan; Tian, Jindan; Xu, Jiayue; Halasyamani, P. Shiv
(, Journal of Materials Chemistry C)
Planar MO 3 (M = B, C, N) units have frequently been considered important structural components of novel birefringent crystal materials. An efficient approach for constructing new functional crystals is to simultaneously assemble multiple structural motifs together. Two compounds, Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 X·6H 2 O (X = Br and Cl), were synthesized by the integration of three kinds of anionic groups. More interestingly, the [CO 3 ] 2− and [NO 3 ] − groups in Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 X·6H 2 O are all coplanar with the aid of [NaO 7 ] 13− polyhedra, which can enhance the anisotropic polarizability. Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 X·6H 2 O have a large theoretical birefringence of ∼0.165 at 1064 nm and possess a short UV cut-off edge of ∼230 nm. Additionally, the two compounds exhibit good crystal growth habits. These properties illustrate that Na 3 Rb 6 (CO 3 ) 3 (NO 3 ) 2 X·6H 2 O are promising UV birefringent crystals.
A series of Ag( i ) and Cu( i ) complexes [Ag 3 (L 1 ) 2 ][PF 6 ] 3 ( 8 ), [Ag 3 (L 2 ) 2 ][PF 6 ] 3 ( 9 ), [Cu(L 1 )][PF 6 ] ( 10 ) and [Cu(L 2 )][PF 6 ] ( 11 ) have been synthesized by reactions of the tridentate amine-bis(N-heterocyclic carbene) ligand precursors [H 2 L 1 ][PF 6 ] 2 ( 6 ) and [H 2 L 2 ][PF 6 ] 2 ( 7 ) with Ag 2 O and Cu 2 O, respectively. Complexes 10 and 11 can also be obtained by transmetalation of 8 and 9 , respectively, with 3.0 equiv. of CuCl. A heterometallic Cu/Ag–NHC complex [Cu 2 Ag(L 1 ) 2 (CH 3 CN) 2 ][PF 6 ] 3 ( 12 ) is formed by the reaction of 8 with 2.0 equiv. of CuCl. All complexes have been characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal X-ray diffraction studies. The luminescence properties of 10–12 in solution and the solid state have been studied. At room temperature, 10–12 exhibit evident luminescence in solution and the solid state. The emission wavelengths are found to be identical at 483 nm in CH 3 CN, but they are 484, 480 and 592 nm in the solid state for 10–12 , respectively. These results suggest that 12 dissociates into two molecules of 10 and Ag( i ) ions in solution. Complex 12 is the first luminescent heterometallic Cu/Ag–NHC complex.
Scheifers, Jan P.; Gibson, Kate A.; Fokwa, Boniface P.
(, Zeitschrift für Naturforschung B)
Abstract A new ternary phase, TiIrB, was synthesized by arc-melting of the elements and characterized by powder X-ray diffraction. The compound crystallizes in the orthorhombic Ti 1+ x Rh 2− x + y Ir 3− y B 3 structure type, space group Pbam (no. 55) with the lattice parameters a = 8.655(2), b = 15.020(2), and c = 3.2271(4) Å. Density Functional Theory (DFT) calculations were carried out to understand the electronic structure, including a Bader charge analysis. The charge distribution of TiIrB in the Ti 1+ x Rh 2− x + y Ir 3− y B 3 -type phase has been evaluated for the first time, and the results indicate that more electron density is transferred to the boron atoms in the zigzag B 4 units than to isolated boron atoms.
Hollow, Sophia E., and Johnstone, Timothy C. Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis. Retrieved from https://par.nsf.gov/biblio/10332153. Chemical Communications 58.14 Web. doi:10.1039/D1CC06348K.
Hollow, Sophia E., & Johnstone, Timothy C. Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis. Chemical Communications, 58 (14). Retrieved from https://par.nsf.gov/biblio/10332153. https://doi.org/10.1039/D1CC06348K
Hollow, Sophia E., and Johnstone, Timothy C.
"Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis". Chemical Communications 58 (14). Country unknown/Code not available. https://doi.org/10.1039/D1CC06348K.https://par.nsf.gov/biblio/10332153.
@article{osti_10332153,
place = {Country unknown/Code not available},
title = {Encapsulation of closo -dodecaiodododecaborate in 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis},
url = {https://par.nsf.gov/biblio/10332153},
DOI = {10.1039/D1CC06348K},
abstractNote = {Na 2 B 12 I 12 has many of the properties desired by an X-ray contrast agent but is lethal at the concentrations needed for medical imaging. We demonstrate here that PBS solutions with >50 mM Na 2 B 12 I 12 induce hemolysis, consistent with the previously reported superchaotropic nature of the anion. The presence of <1 equiv. of 2-hydroxypropyl-γ-cyclodextrin prevents hemolysis and suggests a strategy for exploiting B 12 I 12 2− as an X-ray contrast agent.},
journal = {Chemical Communications},
volume = {58},
number = {14},
author = {Hollow, Sophia E. and Johnstone, Timothy C.},
}
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