The Synthesis, Stereochemistry and Properties of Linear and Branched Chain Tetraethylenepentaamine Cobalt(III) Complexes

1999 ◽  
Vol 52 (3) ◽  
pp. 185 ◽  
Author(s):  
David A. Buckingham ◽  
W. Gregory Jackson ◽  
Patricia A. Marzilli ◽  
Alan M. Sargeson
Keyword(s):  
Ion Exchange ◽  
Fractional Crystallization ◽  
Ion Exchange Chromatography ◽  
Crystallographic Analysis ◽  
Exchange Chromatography ◽  
X Ray ◽  
Commercial Grade ◽  
Branched Chain ◽  
The Many ◽  
Original Crude

Described are the syntheses, isolation and resolution of many diastereoisomers of pentaaminecobalt(III) complexes obtained from commercial-grade tetraethylenepentaamine. They contain both linear (tetraen; 3,6,9-triazaundecane-1,11-diamine) and branched chain (trenen; 3-(2-aminoethyl)-3,6-diazaoctane-1,8- diamine) isomers of C8H23N5 and are free of the many other amines present in the original (crude) pentaamine mixture. A dimeric bridging peroxocobalt(III) complex [Co2(C8H23N5)2O2] (ClO4)4 has been isolated and converted into a mixture of s-[Co(trenen)X]n+ and α-anti β-, α-syn β- and α-α-[Co(tetraen)X]2+ complexes (X = Cl¯, Br¯, N3¯), and the various isomers have been separated by a combination of fractional crystallization and ion-exchange chromatography. In addition, some X = NO3¯ and OH2 derivatives have been made by a kinetic route, including the unstable α-syn β isomers. Many of the complexes have been resolved into their enantiomers, and visible, o.r.d. and c.d. spectra are reported. An X-ray crystallographic analysis of a prototype of each of the four isomeric complexes (X = Cl¯ or N3¯) has been determined previously, thereby establishing the identity of many related complexes. Stereoretentive reactions are used to correlate these related isomers, and 13 C and 1 H n.m.r. spectra are reported. The pure trenen and tetraen ligands have been recovered from the CoIII complexes and can be distinguished by 13 C n.m.r. spectroscopy

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

Kristallstruktur von Cs2[B6H5(SCN)]/ Crystal Structure of Cs2[B6H5(SCN)]

1998 ◽  
Vol 53 (8) ◽  
pp. 816-818 ◽  
Author(s):  
W. Preetz ◽  
S. Zander ◽  
C. Bruhn
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Structure Determination ◽  
Deae Cellulose ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray

Abstract By reaction of [B6H6]2-with (SCN)2 in dichloromethane at -80 C° the thiocyanatohexaborate anion is formed and can be isolated by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The X-ray structure determination of Cs2[B6H5(SCN)] (orthorhombic, space group Pbca with a = 9.506(5), b = 10.644(5), c = 21.857(5) Å, Z = 8) reveals that the SCN substituent is bonded via the S atom with the B-S distance of 1.885(9) Å and the B-S-C angle of 99.8(5)°. The SCN group is nearly linear (179.9(9)°).

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, 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 Darstellung und Kristallstruktur von [P(C6H5)4]2[2-SnCl(C6H5)2B10H9] / Preparation and Crystal Structure of [P(C6H5)4]2[2-SnCl(C6H5)2B10H9]

1996 ◽  
Vol 51 (8) ◽  
pp. 1061-1063 ◽  
Author(s):  
C. Nachtigal ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Deae Cellulose ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Starting Compound

By reaction of [N(C4H9)4]2[B10H10] with chlorotriphenyltin in acetonitrile at 70°C the 2- (chlorodiphenyltin)-decaborate anion [2-SnCl(C6H5)2B10H9]2- is formed and can be separated from the starting compound by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The X-ray structure of [P(C6H5)4]2[2-SnCl(C6H5)2B10H9] (monoclinic space group P 21/c with a=17.263(2), b = 13 .045(3), c=26.171(2) Å, β = 102.882(7)°) reveals that the SnCl(C6H5)2 substituent is bonded with a B2-Sn distance of 2.168(4) Å.

The Synthesis, Separation and Structures of Three [Co(cyclen)((S)-AlaO)]2+ Isomers. The Alkaline Hydrolysis of [Co(cyclen)((S)-AlaO)]2+

1998 ◽  
Vol 51 (6) ◽  
pp. 461 ◽  
Author(s):  
David A. Buckingham ◽  
David A. Buckingham ◽  
Charles R. Clark ◽  
Charles R. Clark ◽  
Andrew J. Rogers ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Alkaline Solution ◽  
Spectroscopic Observation ◽  
Reversed Phase ◽  
Ion Exchange Chromatography ◽  
Ion Pair ◽  
Exchange Chromatography ◽  
X Ray ◽  
Ion Pair Chromatography ◽  
Hydrolysis Of

The reaction of [Co(cyclen)(OH2)OH]2+ (cyclen = 1,4,7,10-tetraazacyclododecane) with (S)-alanine at pH 7·2 gives a mixture of three [Co(cyclen)((S)-AlaO)]2+ isomers (1)–(3). These have been isolated by using both cation ion-exchange chromatography (Dowex 50 W×2, HCl eluent) and reversed phase ion-pair chromatography (C18, p-toluenephosphate in MeOH/H2O eluent). By using a combination of 1H n.m.r. techniques (n.O.e. and COSY) for solutions in (CD3)2SO the syn(N),anti(O) (1), syn(O), anti(N) (2) and syn(N), syn(O) (3) configurations have been assigned to these isomers. These have been confirmed by single-crystal X-ray analysis: [Co(cyclen)((S)-AlaO)] I2.H2O, isomer (1), P43212, a = b = 8·55150(10), c 51·8693(11) Å, Z 8, R 0·0343; [Co(cyclen)((S)-AlaO)] (ClO4)2.H2O, isomer (2), P212121, a 8·499(3), b 14·538(5), c 16·592(4) Å, Z 4, R 0·0388; [Co(cyclen)((S/R)-AlaO)] ZnBr4, a 1 : 1 mixture containing both (S)-alanine (isomer (3)) and (R)-alanine, P21/c, a 7·618(2), b 13·806(4), c 19·094(7) Å, Z 4, R 0·0726. In alkaline solution (0·1–1·0 M NaOH, 25·0°C, I = 1·0 M (NaClO4)), equilibration between (1), (2) and (3) is faster than hydrolysis to give cis-[Co(cyclen)(OH)2]++(S)-AlaO-. Time zero spectroscopic observation (300 nm) allowed the equilibrium constant, K, for the reaction [Co(cyclen)((S)-AlaO)]2+ + OH- ↔ [Co(cyclen – H)((S)-AlaO)]+ +H2O to be determined as 1·05 M-1 at 25·0°C and I = 1·0 M. The hydrolysis reaction follows the rate law kobs = kKK1K2[OH-]2/(1+K[OH-]+KK1K2[OH-]2) with k = 1·0 s-1 corresponding to rate-determining loss of (S)-AlaO- from the ring-opened complex, [Co(cyclen – H)((S)-AlaO)OH].

scholarly journals Online ion-exchange chromatography for small-angle X-ray scattering

2016 ◽  
Vol 72 (10) ◽  
pp. 1090-1099 ◽  
Author(s):  
Stephanie Hutin ◽  
Martha Brennich ◽  
Benoit Maillot ◽  
Adam Round
Keyword(s):  
Ion Exchange ◽  
Small Angle ◽  
Solution Structure ◽  
Volume Ratio ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Size Exclusion ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Biological small-angle X-ray scattering (BioSAXS) is a powerful technique to determine the solution structure, particle size, shape and surface-to-volume ratio of macromolecules. However, a drawback is that the sample needs to be monodisperse. To ensure this, size-exclusion chromatography (SEC) has been implemented on many BioSAXS beamlines. Here, the integration of ion-exchange chromatography (IEC) using both continuous linear and step gradients on a beamline is described. Background subtraction for continuous gradients by shifting a reference measurement and two different approaches for step gradients, which are based on interpolating between two background measurements, are discussed. The results presented here serve as a proof of principle for online IEC and subsequent data treatment.

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