Darstellung, 19F- und 195Pt-NMR-Spektren, Schwingungsspektren und Normalkoordinatenanalyse von Fluoro-Chloro-Bromo-Platinaten(IV) / Preparation, 19F and 195Pt NMR Spectra, Vibrational Spectra and Normal Coordinate Analysis of Fluoro-Chloro-Bromo-Platinates(IV)

1996 ◽  
Vol 51 (11) ◽  
pp. 1563-1570 ◽  
Author(s):  
H.-H. Drews ◽  
W. Preetz
Keyword(s):  
Deae Cellulose ◽  
Exchange Chromatography ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Exchange Reactions ◽  
Normal Coordinate ◽  
Vibrational Coupling ◽  
Trans Influence ◽  
The Mean

By stereoselective ligand exchange reactions of [PtF5Cl]2− and cis-[PtF4Cl2]2− with Br− mixtures containing seven different fluoro-chloro-bromo- and two fluoro-bromo-platinates(IV) are formed, from which trans-Cs2[PtF4ClBr] 4t 11 and mer-Cs2[PtF3Clc 2Br] 3m2c 1 have been isolated by ion exchange chromatography on DEAE cellulose. All threefold mixed complexes could be detected by in situ 19F and 195 Pt NMR measurements. Due to the stronger trans influence of Cl in comparison with F on asymmetric F′-Pt-Cl′ axes the F atoms are deshielded and their signals δ(19F) are shifted on the average by 106 ppm to lower field as compared with δ(19F) of symmetric F-Pt-F axes. For the same reason the mean coupling constant 1J(FPt) of 1857 Hz is 44 % higher than 1J( FPt) of 1288 Hz. The substitution of a cis positioned Cl against Br causes shifts of -7,6 ppm for δ(19F) and of -8,4 ppm for δ(19F ). The cis influence on the coupling constants 1J(F P t) and 1J( FPt), on the average 4 Hz, is more than two orders of magnitude smaller than the trans influence. The coupling constants between inequivalent F atoms 2J(FF) amounts to 44 Hz. The mean highfield shift of the l95Pt signals on exchange of one F for Cl is 1177, of one Cl for Br 210 ppm. Due to the increasing trans influence F < Cl < Br on the stretching vibrations of asymmetrically coordinated axes characteristic frequency shifts of up to 15 % are observed. The normal coordinate analyses performed on 4t11 and 3m2c 1 reveal that the force constant fd(PtF) is by 15 % higher than fd(PtF), and that fd(PtCl′) is by 31 % higher than fd(PtCl). Very intense Raman bands at 277 and 267 cm −1 are explained by strong vibrational coupling of the π-deformation with a symmetric valence mode of the Cl -Pt-Br′axis.

Schwingungsspektren und Normalkoordinatenanalyse der 35Cl/37Cl-isotopierten Chloro-Iodo-Osmate(IV), [OsClnI6-n]2-, n = 0-6 / Vibrational Spectra and Normal Coordinate Analysis of the 35Cl/37Cl Labelled Chloro-Iodo-Osmates(IV), [OsClnI6-n]2-, n = 0-6

1993 ◽  
Vol 48 (6) ◽  
pp. 747-753 ◽  
Author(s):  
M. Manthey ◽  
W. Preetz
Keyword(s):  
Deae Cellulose ◽  
Exchange Chromatography ◽  
Vibrational Modes ◽  
Geometric Isomers ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Trans Influence ◽  
Isotopic Shifts ◽  
Ir And Raman

All components of the two series [Os35ClnI6-n]2- and [Os37ClnI6-n]2-, n = 0-6, including the pairs of geometric isomers for n = 2, 3, 4, have been prepared and isolated by ion exchange chromatography on DEAE cellulose. The highly resolved low temperature (80 K) IR and Raman spectra of the pure isotopomers show distinct isotopic shifts for different vibrational modes up to 10 cm-1. Normal coordinate analyses have been performed, based on a general valence force field. Due to the stronger trans influence of I as compared to Cl in all asymmetric Cl˙—Os—I′ axes the Os—I′ bonds are strengthened and the Os—Cl˙ bonds are weakened, as indicated by valence force constants for Os—I′ approximately 9% higher, for Os—Cl˙ 7% lower, as compared with the values calculated for symmetric axes.

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse von Chloro-Bromo-Rhodaten(III) / Preparation, Vibration Spectra and Normal Coordinate Analysis of Chloro-Bromo-Rhodates(III)

1989 ◽  
Vol 44 (10) ◽  
pp. 1221-1227 ◽  
Author(s):  
W. Preetz ◽  
W. Kuhr
Keyword(s):  
Exchange Chromatography ◽  
Trans Isomers ◽  
Normal Coordinate ◽  
Valence Force ◽  
Trans Influence ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups ◽  
First Time ◽  
Ir And Raman ◽  
Good Agreement

The mixed chloro-bromo-rhodates(III) [RhClnBr6-n]3-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethyl-cellulose. Due to the stronger trans-effect of Br, as compared with Cl, on treatment of [RhBr6]3- with conc. HCl nearly pure cis/fac-isomers for n = 2, 3, 4 are formed. The reaction of [RhCl6]3- with conc. HBr yields mixtures of the cis/trans-isomers for n = 2, 4, which cannot be separated, but mer-[RhCl3Br3]3 is formed stereospecifically. The IR and Raman spectra of all isolated mixed ligand complexes are completely assigned according to point groups Oh, D3d, C4v, C3v and C2v, supported by normal coordinate analyses based on a general valence force field. The good agreement of calculated and observed frequencies confirms the assignments. Due to the stronger trans-influence of Br as compared to Cl, in all asymmetric Cl—Rh—Br axes the Rh—Br bonds are strengthened and the Rh—Cl bonds are weakened, indicated by valence force constants for Rh—Br approximately 14% higher, for Rh—Cl 10% lower, as compared with the values calculated for symmetric Br—Rh—Br and Cl—Rh—Cl axes, respectively.

Berechnung der 19F- und 195 Pt-NMR-Verschiebungen von FIuoro-Chloro-Bromo-Platinaten(IV) / Calculation of 19F and 195Pt NMR Shifts of Fluoro-Chloro-Brom o-Platinates(IV )

1997 ◽  
Vol 52 (4) ◽  
pp. 435-442 ◽  
Author(s):  
H.-H. Drews ◽  
W. Preetz
Keyword(s):  
Experimental Data ◽  
Chemical Shifts ◽  
Coupling Constant ◽  
Lower Field ◽  
Trans Influence ◽  
Nmr Signals ◽  
Increments Of Chemical Shifts ◽  
Good Agreement

By reaction of [PtBr4]2- with XeF2 in dichloromethane product mixtures containing nine fluoro-chloro-, four fluoro-bromo- and 15 fluoro-chloro-bromo-platinates(IV) are formed. All complexes are detectable by in situ l9F NMR measurements. Due to the increasing trans influence F < Cl < Br, the signals <5(19F) of symmetric F-Pt-F axes observed at highest field are shifted downfield on the average by 93 ppm as compared with δ(19F•) of F••Pt-Cl′ axes, and further to lower field by 40 ppm for <5(F••) of F••-Pt-Br″ axes. For the same reason the coupling constant 1J(F••Pt) ≈ 1099 Hz is by 13.3 % smaller than 1J(F•Pt) ≈ 1268 Hz, which is by 32.3 % smaller than δ(FPt) ≈ 1873 Hz. Based on the axis method, and taking into account characteristic increments of chemical shifts depending on cis influences, the calculation of the 195Pt NMR signals of 27 observed species of the system [PtFnCl6-n-mBrm]2- n, m = 0 - 6, has been successful. The 195Pt NMR shifts of further 29 so far not detected complexes are predicted. Using parameters depending on the geometry of the complex, the 19F NMR shifts of 28 F-containing platinates(IV) have been calculated in good agreement with the experimental data. 19F resonances are predicted for 19 so far missing complexes.

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse der Chloro-Bromo-Technetate(IV), [TcCl„Br6_n]2-, n = 0-6 / Preparation, Vibrational Spectra and Normal Coordinate Analysis of Chloro-Bromo-Technetates(IV), [TcCln Br6-n]2-, n = 0-6

1991 ◽  
Vol 46 (11) ◽  
pp. 1496-1502 ◽  
Author(s):  
W. Preetz ◽  
A. Wendt
Keyword(s):  
Exchange Chromatography ◽  
Normal Coordinate Analysis ◽  
Exchange Reactions ◽  
Normal Coordinate ◽  
Geometrical Isomers ◽  
Valence Force ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups ◽  
First Time ◽  
Ir And Raman

The mixed chloro-bromo-technetates(IV), [TcClnBr6-n2-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethyl-cellulose. Due to the stronger trans-effect of Br as compared to Cl, the ligand exchange reactions of [TcBr62- with HCl and of [TcCl6]2- with HBr proceed stereospecifically, to form either cis/fac- or trans/merspecies for n = 2, 3, 4, respectively. To avoid photoisomerization the compounds have to be handled in the absence of light. The IR and Raman spectra of the ten chloro-bromo-techne-tates(IV), including the pure geometrical isomers, have been recorded at low temperature (80 K) and completely assigned to structures of point groups Oh, D4h, C4v, C3v, and C2v, supported by normal coordinate analysis based on a general valence force field. Due to the different trans-influences Cl &lt; Br in asymmetric Cl′—Tc— Br′ axes, the Tc— Br′ bonds are strengthened and the Tc—Cl′ bonds are weakened, as indicated by valence force constants, for Tc—Br′ on average 6% higher and for Tc—Cl′ 10% lower, as compared with the values calculated for symmetric Br—Tc—Br and CI—Tc—Cl axes, respectively.

A comparison of two procedures used for complexing Fe(III) with human apotransferrin: I. physicochemical properties of the Fe(III) transferrin products

1986 ◽  
Vol 64 (9) ◽  
pp. 936-945
Author(s):  
Leslie R. Berry ◽  
Mark W. C. Hatton
Keyword(s):  
Hyperfine Coupling ◽  
Deae Cellulose ◽  
Trisodium Citrate ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Coupling Constants ◽  
Excitation Wavelength ◽  
Protein Conformations ◽  
Spin Resonance ◽  
Single Batch

Samples of human Fe∙transferrin (Fe∙HTr) were prepared from a single batch of apotransferrin (apo∙HTr) by either the Fe(III)–citrate or the Fe(II)–ceruloplasmin (ferroxidase) method. By using 55Fe, 55Fe∙HTr prepared by the citrate method and 55Fe∙HTr prepared by the ceruloplasmin method contained 2.2–2.3 and 2.0 Fe/mol, respectively. For both 55Fe∙HTr preparations, the isotope was shown to be associated with the protein from the measurement of absorbance at 465 nm and dialysis studies. However, passage of the 55Fe∙HTr (ceruloplasmin) reaction mixture through DEAE-cellulose caused 55–60% of 55Fe to be lost from the protein, although no decrease in absorbance at 465 nm was observed. Ion-exchange chromatography of 55Fe∙HTr (citrate) did not induce loss of 55Fe. Absorbance measurements showed significant differences between the two Fe∙HTr preparations with respect to the ratios A212/A278 and A463/A278. Using an excitation wavelength of 275 nm, the fluorescence intensity ratios relative to apo∙HTr were 0.275 and 0.309 for Fe∙HTr (citrate) and Fe∙HTr (ceruloplasmin), respectively. Electron spin resonance (ESR) measurements confirmed that Fe∙HTr (citrate) and Fe∙HTr (ceruloplasmin) were saturated with Fe. Hyperfine coupling constants and other features of the resonance profile revealed distinct differences between the two Fe∙HTr preparations. Dialysis against H2O caused Fe∙HTr (citrate), but not Fe∙HTr (ceruloplasmin), to lose absorbance at 465 nm. The ESR profile of Fe∙HTr (citrate), after dialysis against H2O, was reduced to multiple splittings and a lack of resolution of the central hyperfine structure. Addition of Na2CO3 restored the absorbance (465 nm) and the ESR pattern of Fe∙HTr (citrate). In contrast, these properties of Fe∙HTr (ceruloplasmin) were little affected by dialysis against H2O. However, the addition of trisodium citrate to Fe∙HTr (ceruloplasmin) caused a reduction in absorbance at 465 nm and a change in ESR profile to resemble that of Fe∙HTr (citrate) after dialysis in H2O; these changes, caused by citrate binding to Fe∙HTr (ceruloplasmin), were restored to normal by the addition of Na2CO3. The data indicate that different protein conformations result from complexing Fe(III) with apo∙HTr by these two different procedures. The two Fe∙HTr products may differ, conceivably, in their abilities to transfer Fe to cells.

Schwingungsberechnungen der käfigstrukturierten Molekülionen P73-, AS73- und Sb73-

1986 ◽  
Vol 41 (3) ◽  
pp. 549-552 ◽  
Author(s):  
B. N. Cyvin ◽  
S. J. Cyvin ◽  
M. Somer ◽  
W. Brockner
Keyword(s):  
Force Field ◽  
Coupling Constants ◽  
Potential Energy Distribution ◽  
Coriolis Coupling ◽  
Normal Coordinate ◽  
Mean Amplitudes Of Vibration ◽  
First Order ◽  
The Mean ◽  
Title Molecule ◽  
Initial Force

Normal coordinate analyses for the cage-like molecule ions P73-, As73- and Sb73- with C3 symmetry were performed, based on a very simple initial force field with three numerical parameters transferred from P4S3. FIR frequencies of Sb73- have been recorded. The force field was refined by adjusting the symmetry force constants to fit the observed frequencies. The final force fields were used to calculate the potential energy distribution terms (PED), the mean amplitudes of vibration and the first-order Coriolis coupling constants for the title molecule ions.

Schwingungsberechnungen der käfigstrukturierten Moleküle P4Se3 , AS4S3, As4Se3 und PAs3S3 / Molecular Vibration Analysis of the cage-like Molecules P4Pe3, As4S3, As4Se3 and PAs3S3

1981 ◽  
Vol 36 (8) ◽  
pp. 846-849 ◽  
Author(s):  
W. Brockner ◽  
M. Somer ◽  
B. N. Cyvin ◽  
S. J. Cyvin
Keyword(s):  
Force Field ◽  
Coupling Constants ◽  
Molecular Vibration ◽  
Coriolis Coupling ◽  
Normal Coordinate ◽  
Cage Structure ◽  
Mean Amplitudes Of Vibration ◽  
The Mean ◽  
Initial Force ◽  
Thermodynamical Functions

AbstractnThe P4Se3, As4S3, As4Se3 and PAs3S3 molecules are supposed to have a cage-structure of the C3V symmetry. Normal coordinate analyses for these molecules were performed, based on a very simple initial force field transferred from P4S3. The force field was refined by adjusting the symmetry force constants to fit exactly observed frequencies. The force fields were used to calculate the mean amplitudes of vibration and Coriolis coupling constants. The standard thermodynamical functions from spectroscopic data are also given.

Darstellung, 11B-NMR-Spektren, Schwingungsspektren und Normalkoordinatenanalyse von conjuncto-Bis-hexahydro-closo-hexaborat, [B6H6-B6H6]2-, sowie Kristallstruktur von [P(C6H5)4]2-conjuncto-[B6H6-B6H6] / Preparation, 11B NMR Spectra, Vibrational Spectra and Normal Coordinate Analysis of conjuncto-Bis-hexahydro-closo-hexaborate, [B6H6-B6H6]2-, and the Crystal Structure of [ P(C6H5)4]2-conjuncto-[B6H6-B6H6]

1996 ◽  
Vol 51 (5) ◽  
pp. 609-618 ◽  
Author(s):  
D. Bublitz ◽  
A. Franken ◽  
W. Preetz ◽  
H. Thomsen
Keyword(s):  
Crystal Structure ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Normal Coordinate ◽  
Vibrational Coupling ◽  
Nmr Spectrum ◽  
Triclinic Space Group ◽  
Diethylaminoethyl Cellulose ◽  
11B Nmr ◽  
Ir And Raman

By reaction of [B6H6]2- with dibenzoylperoxide in dichloromethane conjuncto-[B6H6- B6H6]2- is formed. The product could be separated from excess [B6H6]2- by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of [P(C6H5)4]2 -conjuncto- [B6H6-B6H6] has been determined by single crystal X-ray diffraction analysis; triclinic, space group P1̄ with a = 10.8315(10), b = 11,2422( 12), c = 20.340(2) Å, α = 91.278° (9), β = 90.178° (9), γ = 105.662°(9). The 11B NMR spectrum reveals three signals with the intensity ratio 1:1:4, for two equivalent moieties of the conjuncto molecule ion with local C4v symmetry. The IR and Raman spectra of the deprotonated Cs salts of the 10B, 11B and their respective D isotopomers of conjuncto-[B6H5-B6H5]4- exhibit characteristic shifts. Using averaged crystallographic data and assuming idealized D4h symmetry, normal coordinate analyses have been performed based on a modified valence force field. With a set of eleven force constants (e.g. fd(BB)conjuncto = 2.9, fd(BB)cage = 1.6 mdyn/Å) very good agreement between observed and calculated frequencies has been achieved. From strong vibrational coupling with the B6 clusters two vibrations result for the conjuncto B-B bond at 1142/1198 and 292/304cm-1 for 11B/10B species, respectively. They can be assigned as anti-phase and in-phase motions of the conjuncto B atoms related to the equatorial B4 planes.

Separation of Heparin into Subtractions by DEAE-Cellulose Chromatography

1979 ◽  
Vol 42 (05) ◽  
pp. 1452-1459 ◽  
Author(s):  
Robert H Yue ◽  
Toby Starr ◽  
Menard M Gertler
Keyword(s):  
High Activity ◽  
Uronic Acid ◽  
Deae Cellulose ◽  
Exchange Chromatography ◽  
Net Charge ◽  
Uronic Acid Content ◽  
Successful Separation ◽  
Salt Gradient ◽  
Structure And Activity ◽  
Low Activity

SummaryCommercial porcine heparin can be separated into three distinct subtractions by using DEAE-cellulose chromatography and a stepped salt gradient. Gram quantities of heparin can be fractionated by this technique. All three heparin subtractions can accelerate the inhibition of thrombin by antithrombin III with different efficiency. The specific activities of the high activity heparin, intermediate activity heparin and low activity heparin are 228 units/mg, 142 units/mg and 95 units/mg, respectively. Both the uronic acid content and the quantity of N-SO4 for all three heparin subfractions have been evaluated. The high activity heparin has the lowest uronic acid and N-SO4 content. The successful separation of commercial heparin into three distinct subfractions by means of ion-exchange chromatography suggests that the net charge on these three heparin components will serve as a model system in the elucidation of the structure and activity relationship to the biological function of heparin.

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Drug Loading ◽  
In Vitro Release ◽  
Formulation Development ◽  
Ciprofloxacin Hydrochloride ◽  
Potential Value ◽  
The Mean ◽  
In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

Sign in / Sign up

Export Citation Format

Share Document