Characterization of Three 'Active' Rhodium(III) Hydroxides

1995 ◽  
Vol 48 (3) ◽  
pp. 557 ◽  
Author(s):  
SJ Crimp ◽  
L Spiccia
Keyword(s):  
Thermal Analysis ◽  
Thermal Decomposition ◽  
Infrared Spectroscopy ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
X Ray

Pure solutions of [ Rh (H2O)6]3+, dimer [Rh2(μ-OH)2(H2O)8]4+ and trimer [Rh3(μ-OH)4(H2O)10]5+ have been converted into their respective 'active' hydroxides by dropwise addition to an imidazole solution. These 'active' hydroxides have been analysed by a variety of techniques including rhodium determination, infrared spectroscopy, thermal analysis and powder X-ray diffraction. Purity determinations using ion-exchange chromatography showed that the three hydroxides consist primarily of the neutral forms of the starting aqua ion (>96%) with small amounts of species with higher nuclearity. Rhodium analysis and thermogravimetric measurements confirmed the composition of these hydroxides to be Rh (OH)3(H2O)3.H2O, Rh2(μ-OH)2(OH)4(H2O)4 and Rh3(μ-OH)4(OH)5(H2O)5.5H2O. A scheme for the thermal decomposition of each of the hydroxides has been proposed on the basis of the t.g . and d.t.a . data and the knowledge that the final product in each case is α-Rh2O3. Heating of the hydroxides in air resulted in oxidation of RhIII to RhIV (temperature 250-300°C) forming RhO2 which on further heating decomposed to α-Rh2O3 and dioxygen.

Darstellung von Mononitropentahydrohexaborat(2-) und Kristallstruktur von M2[B6H5(NO2)], M = K, Cs / Preparation of Mononitropentahydrohexaborate(2—) and Crystal Structure of M2[B6H5(NO2)], M = K, Cs

1993 ◽  
Vol 48 (12) ◽  
pp. 1727-1731 ◽  
Author(s):  
A. Franken ◽  
W. Preetz ◽  
M. Rath ◽  
K.-F. Hesse
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Dichloromethane Solution ◽  
Space Group ◽  
X Ray ◽  
Diethylaminoethyl Cellulose

By electrochemical oxidation of [B6H6]2- in the presence of nitrite ions and the base DBU in dichloromethane solution mononitropentahydrohexaborate [B6H5(NO2)]2- ions are formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of the K and Cs salt were determined from single crystal X-ray diffraction analyses. K2[B6H5(NO2)] is monoclinic, space group P21/m with a = 5.953(1), b = 8.059(4), c = 8.906(1) Å, β = 109.553(9)°; Cs2[B6H5(NO2)] is monoclinic, space group P21/a with a = 9.438(6), b = 9.644(7), c = 11.138(9) Å, β = 101.44(9)°. The B6 octahedron is compressed in the direction of the B—NO2 bond by about 5%, with bond lengths between 1.67 and 1.77 A.

scholarly journals Darstellung von μ-Nitroso-bis(pentahydro-closo-hexaborat)(3-) und Kristallstruktur von Cs3[B6H5(NO)B6H5] / Preparation of μ-nitroso-bis(pentahydro-closo-hexaborate)(3-) and crystal structure of Cs3[B6H5(NO)B6H5]

1994 ◽  
Vol 49 (9) ◽  
pp. 1263-1266 ◽  
Author(s):  
A. Franken ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Diethylaminoethyl Cellulose

By electrochemical oxidation of [B6H6]2- in the presence of nitrite ions and of the base DBU in dichlorom ethane solution the μ-nitroso-bis(pentahydrohexaborate) [B6H5(NO)B6H5]3- ion is formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of the Cs salt has been determined from single crystal X-ray diffraction analysis. Cs3[B6H5(NO)B6H5] is orthorhombic, space group Pnma with a = 16.2303(13), b = 12.245(6), c = 25.444(2) Å. The unit cell contains three crystallographically independent anions with nearly C2v symmetry but differently distorted B6 cages

Darstellung, 11 B-NMR- und Schwingungsspektren von cis-Dinitrotetrahydro-closo-hexaborat(2–), cis-[B6H4( NO2)2]2- sowie Kristallstruktur von cis-Cs2[B6H4(NO2)2] / Preparation, 11 B NMR and Vibrational Spectra of cis-Dinitrotetrahydro-closo-hexaborate(2–),cis-[B6H4(NO2)2]2-, and the Crystal Structure of cis-Cs2[B6H4(NO2)2]

1995 ◽  
Vol 50 (7) ◽  
pp. 1030-1034 ◽  
Author(s):  
A. Franken ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
Dichloromethane Solution ◽  
X Ray ◽  
Diethylaminoethyl Cellulose ◽  
Ir And Raman

By electrochemical oxidation of [B6H6,]2 in the presence of nitrite ions and of the base DBU in dichloromethane solution apart from [B6H5 (NO2)]2- and [B6H5(NO)B 6H5]3- the dinitro anion cis-[B6H4( NO2)2]2- is formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of the Cs salt has been determined from single crystal X-ray diffraction analyses. cis-Cs2[B6H4 ( NO2)2] is tetragonal, space group P4̄21 m with a = 10.0656(4), c = 11.0127(13) Å. The 11B NMR spectrum is consistent with a disubstituted octahedral B6 cage with local C2v symmetry. The IR and Raman spectra exhibit characteristic NO2, B - H and B6 vibrations.

scholarly journals Synthesis and characterization of a novel (glycinato-N,O) yttrium(III) complex

2001 ◽  
Vol 66 (5) ◽  
pp. 331-334 ◽  
Author(s):  
I.M. Hodzic ◽  
S.R. Niketic
Keyword(s):  
Infrared Spectroscopy ◽  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Synthesis And Characterization ◽  
Chelate Ligands

A novel yttrium(III) complex with glycine has been synthesized starting from tris(ethanedioato-O,O)yttrium(III) by the substitution of the acetylacetonato chelate ligands with glycine. The reaction product was purified by ion-exchange chromatography and characterized on the basis of infrared spectroscopy. The structure of the productwas tentatively established as tris(glycinato-N,O)yttrium(III) dihydrate.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF FEED GRADE MONOCALCIUM PHOSPHATE, Ca(H2PO4)2·H2O IN AQUEOUS MEDIUM

2018 ◽  
Vol 54 (4A) ◽  
pp. 7
Author(s):  
Nguyen Quang Bac
Keyword(s):  
Thermal Analysis ◽  
Aqueous Solution ◽  
Infrared Spectroscopy ◽  
Elevated Temperature ◽  
Calcium Content ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Monocalcium Phosphate ◽  
X Ray

The feed grade monocalcium phosphate monohydrate, Ca(H2PO4)2·H2O was prepared by the reaction of CaCO3 and H3PO4 at elevated temperature in aqueous solution. The obtained precipitates were characterized by powder X-ray diffraction, infrared spectroscopy (FTIR), and thermal analysis (TG, DTA) techniques. The chemical composition of final products was evaluated by analysing the phosphorus and calcium content in the samples.

Proteolysis in Heterocyst-Forming Cyanobacteria: Characterization of a Further Enzyme with Trypsin-Like Specificity, and of a Prolyl Endopeptidase from Anabaena variabilis

1994 ◽  
Vol 49 (1-2) ◽  
pp. 70-78 ◽  
Author(s):  
Ulrike Strohmeier ◽  
Christian Gerdes ◽  
Wolfgang Lockau
Keyword(s):  
Ion Exchange ◽  
Proteolytic Enzymes ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Anabaena Variabilis ◽  
Prolyl Endopeptidase ◽  
Cyanobacterium Anabaena

Soluble extracts of the cyanobacterium Anabaena variabilis ATCC 29413 and an engineered mutant that lacks an intracellular protease cleaving after Lys and Arg (Maldener, Lockau, Cai, and Wolk, Mol. Gen. Genet. 225, 113-120 (1991)) were separated by ion exchange chromatography, and protease profiles determined using azocasein, Nα-benzoyl-ᴅ,ʟ arginine- 4-nitroanilide and N-carbobenzoxy-glycyl-ʟ-proline-4-nitroanilide as substrates. A second enzyme cleaving at the carboxyl side of lysine and arginine, and a prolyl endopeptidase were detected, enriched and characterized. Both proteolytic enzymes appear to be located in the periplasm.

Stability of sodalite relative to nepheline in NaCl–H2O brines at 750 °C: Implications for hydrothermal formation of sodalite

2020 ◽  
Vol 58 (1) ◽  
pp. 3-18 ◽  
Author(s):  
Jonathan B. Schneider ◽  
David M. Jenkins
Keyword(s):  
Infrared Spectroscopy ◽  
Constant Temperature ◽  
Molar Ratio ◽  
Standard State ◽  
X Ray Diffraction ◽  
Cage Structure ◽  
X Ray ◽  
Brine Concentration

ABSTRACT Formation of the feldspathoid sodalite (Na6Al6Si6O24·2NaCl) by reaction of nepheline (NaAlSiO4) with NaCl-bearing brines was investigated at 3 and 6 kbar and at a constant temperature of 750 °C to determine the brine concentration at which sodalite forms with variation in pressure. The reaction boundary was located by reaction-reversal experiments in the system NaAlSiO4–NaCl–H2O at a brine concentration of 0.16 ± 0.08 XNaCl [= molar ratio NaCl/(NaCl + H2O)] at 3 kbar and at a brine concentration of 0.35 ± 0.03 XNaCl at 6 kbar. Characterization of the sodalite using both X-ray diffraction and infrared spectroscopy after treatment in these brines indicated no obvious evidence of water or hydroxyl incorporation into the cage structure of sodalite. The data from this study were combined with earlier results by Wellman (1970) and Sharp et al. (1989) at lower (1–1.5 kbar) and higher (7–8 kbar) pressures, respectively, on sodalite formation from nepheline and NaCl which models as a concave-down curve in XNaCl – P space. In general, sodalite buffers the concentration of neutral aqueous NaCl° in the brine to relatively low values at P < 4 kbar, but NaCl° increases rapidly at higher pressures. Thermochemical modeling of these data was done to determine the activity of the aqueous NaCl° relative to a 1 molal (m) standard state, demonstrating very low activities (<0.2 m, or 1.2 wt.%) of NaCl° at 3 kbar and lower, but rising to relatively high activities (>20 m, or 54 wt.%) of NaCl° at 6 kbar or higher. The results from this study place constraints on the concentration of NaCl° in brines coexisting with nepheline and sodalite and, because of the relative insensitivity of this reaction to temperature, can provide a convenient geobarometer for those localities where the fluid compositions that formed nepheline and sodalite can be determined independently.

Co-crystal formation between 2-amino-4,6-dimethylpyrimidine and new p-xylylene-bis(thioacetic) acid

CrystEngComm ◽  
2014 ◽  
Vol 16 (44) ◽  
pp. 10262-10272 ◽  
Author(s):  
A. Ostasz ◽  
R. Łyszczek ◽  
L. Mazur ◽  
B. Tarasiuk
Keyword(s):  
Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Single Crystal ◽  
Crystal Formation ◽  
Thioacetic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Analysis Methods

Novelp-xylylene-bis(thioacetic) acid (p-XBTA) and its co-crystals with 2-amino-4,6-dimethylpyrimidine (DMP) have been synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis methods (TG/DSC).

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