Darstellung und Schwingungsspektren von Chloro-Bromo-Ruthenaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Chloro-Bromo-Ruthenates(IV) Including Stereoisomers

1987 ◽  
Vol 42 (4) ◽  
pp. 381-386 ◽  
Author(s):  
W. Preetz ◽  
H. N. v. Allwörden
Keyword(s):  
Ion Exchange ◽  
Force Field ◽  
Vibrational Spectra ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Trans Effect ◽  
Point Groups ◽  
First Time

Abstract The mixed chloro-bromo complexes [RuClnBr6-n]2-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethylcellulose. Due to the stronger trans-effect of Br compared with Cl, on treatment of [RuBr6]2- with Cl- in the presence of Br2 nearly pure cis/fac-isomers,and by reaction of [RuCl6]2- withBr-/Br2 nearly purer tranS/mer-isomersforn = 2,3,4 are formed. The vibrational spectra of the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v and C2v, respectively. The bands are observed in the characteristic regions: ν(RuCl): 340-270 > ν(RuBr): 245-190 > δ(ClRuCl) ≥ δ(ClRubr) ≥ δ(BrRuBr): 125-90 > νʟ: < 100 cm-1. The lower stability of the hexahalogeno complexes of Ru(IV), 4d, compared with the homologous complexes of Os(IV), 5d, is confirmed by a decrease of the force field constants by approximately 15%.

Darstellung und Schwingungsspektren von Fluoro-Chloro-Iridaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Fluoro-Chloro-Iridates(IV) Including Stereoisomers

1984 ◽  
Vol 39 (9) ◽  
pp. 1185-1192 ◽  
Author(s):  
D. Tensfeldt ◽  
W. Preetz
Keyword(s):  
Ion Exchange ◽  
Vibrational Spectra ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Trans Isomers ◽  
Trans Effect ◽  
Diethylaminoethyl Cellulose ◽  
Stretching Vibration ◽  
Point Groups

The reaction of [IrCl6]2- with BrF3 generates the mixed complexes [IrFnCl6-n]2-, n = 1-5, of which the species with n = 2, 3, 4 are ds-configurated. Due to the stronger trans-effect of Cl as compared to F on treatment of [IrF5Cl]2- and cis-[IrF4Cl2]2- with SOCl2 the trans-isomers are formed stereospecifically. The pure fluoro-chloro-iridates(IV) are separated by ion exchange chromatography on diethylaminoethyl-cellulose. The vibrational spectra of the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v, and C2v. The IrCl stretching vibration of [IrF5Cl]2- is split by the isotopes 35C1 and 37Cl, showing two well resolved sharp Raman lines at 361 and 355 cm-1.

Darstellung und Schwingungsspektren von Fluoro-Chloro-Osmaten(IV) einschließlich der Stereoisomeren/ Preparation and Vibrational Spectra of Fluoro-Chloro-Osmates(IV) Including Stereoisomers

1984 ◽  
Vol 39 (8) ◽  
pp. 1100-1109 ◽  
Author(s):  
W. Preetz ◽  
D. Ruf ◽  
D. Tensfeldt
Keyword(s):  
Ion Exchange ◽  
Electric Field ◽  
Vibrational Spectra ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Deformation Bands ◽  
Trans Isomers ◽  
Trans Effect ◽  
Point Groups

AbstractThe stepwise replacement of ligands in [OsCl6]2- by oxidation with BrF3 generates the mixed complexes [OsFnCl6-n]2-, n = 1 - 5, of which the species with n = 2,3,4 are cw-configurated. Due to the stronger trans-effect of Cl compared to F on treatment of [OsF5Cl]2- and cis-[OsF4Cl2]2- with Cl- the trans-isomers are formed stereospecifically. The pure fluoro-chloro-osmates(IV) are separated by ion exchange chromatography on diethylaminoethylcellulose. From the pairs of stereoisomers the cis-compounds are always first eluted, whereas the trans-complexes are moving faster in an electric field by 3 to 5% . The vibrational spectra of octahedral mixed ligand complexes are generally discussed according to point groups Oh, D4h, C4v, C3v and C2v. For the fluoro-chloroosmates(IV) all stretching and deformation bands are assigned. They are observed in the characteristic regions; ν(OsF): 625-490 > ν(OsCl): 360-300 > δ (FOsF): 275-210 > δ (FOsCl) > δ (ClOsCl): 190-150 > νL: < 100 cm -1.

Darstellung und Schwingungsspektren von Fluoro-Chloro- Platinaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Fluoro-Chloro-Platinates(IV) Including Stereoisomers

1989 ◽  
Vol 44 (4) ◽  
pp. 412-418 ◽  
Author(s):  
W. Preetz ◽  
P. Erlhöfer
Keyword(s):  
Ion Exchange ◽  
Vibrational Spectra ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Trans Isomers ◽  
Trans Effect ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups ◽  
Stretching Vibrations

The reaction of [PtCI6]2- with BrF3 generates the mixed complexes [PtFnC6-n]2- , n = 1- 5, of which the species with n = 2. 3, 4 are cis-configurated. Due to the stronger trans-effect of Cl compared to F, on treatment of [PtF5Cl]2- and cis-[PtF4Cl2]2- with Cl- the trans-isomers are formed stereospecifically. The pure fluoro-chloro-platinates(IV) are separated by ion exchange chromatography on diethylaminoethyl-cellulose. The vibrational spectra o f the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v and C2v. The Pt-Cl stretching vibrations of [PtF5Cl]2-, trans-[PtF4Cl2]2-, mer-[PtF3Cl3]2- and [PtFCl5]2- are split by the isotopes 35Cl and 37Cl, showing well resolved sharp Raman lines in the expected ratio of intensities.

Darstellung und Schwingungsspektren von Chloro-Bromo-Platinaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Chloro-Bromo-Platinates(IV) Including Stereoisomers

1982 ◽  
Vol 37 (5) ◽  
pp. 579-586 ◽  
Author(s):  
W. Preetz ◽  
G. Rimkus
Keyword(s):  
Vibrational Spectra ◽  
Ligand Exchange ◽  
Critical Discussion ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Exchange Reactions ◽  
Separation Processes ◽  
Point Groups ◽  
Better Than

The mixed chloro-bromo complexes [PtClnBr6-n]2-, n = 1-5, are separated by ion exchange chromatography on diethylaminoethylcellulose. The separation of corresponding stereoisomers for n = 2, 3, 4 is not possible. Due to the stronger trans-effect of Br compared with Cl, on treatment of [PtBrß]2- with Cl- in the presence of Br2 nearly pure cis-isomers, and by reaction of [PtClsBr]2- and cis-fPtC^Bro]2- with Br~/Br2 completely pure transisomers are formed. The stereoselectivity of the successive ligand exchange reactions is better than in corresponding series of Re, Os and Ir. The highly resolved vibrational spectra allow the distinction of the mixed ligand complexes as well as the estimation of purity of the isomers. All allowed stretching frequencies are observed and assigned according to point groups D4h, C4V, C3V and C2V. Especially in the ν(Pt-Br) region it is possible to distinguish bands arising either from symmetric Br-Pt-Br or asymmetric Cl-Pt-Br axes. The UV/VIS spectra exhibit systematic hypsochromic shifts on the successive exchange of Br-ligands by Cl. A critical discussion of the literature concerning chloro-bromo-platinates- (IV) shows the importance of effective separation processes for the isolation of pure mixed ligand complexes

scholarly journals Darstellung von trans-[PtCl4Br2] 2 -und [PtCl5Br] 2- durch oxidative Addition an [PtCl4]2-/Preparation of trans-[PtCl4Br2] 2--and [PtCl5Br] 2 -by Oxidative Addition to [PtCl4]2-

1983 ◽  
Vol 38 (4) ◽  
pp. 442-445 ◽  
Author(s):  
W. Preetz ◽  
G. Rimkus
Keyword(s):  
Ion Exchange ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Oxidative Addition ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Diethylaminoethyl Cellulose ◽  
Ir And Raman ◽  
Stereospecific Reaction

Abstract The oxidative addition of Br2 to [PtCl4]2-in HBr yields almost pure trans-[PtCl4Br2]2-, in HCl nearly pure [PtCl5Br]2-, and in CH2Cl2 by a quantitative and stereospecific reaction completely pure trans-[PtCl4Br2]2-. This is confirmed by ion exchange chromatography on diethylaminoethyl cellulose and by analysis of the vibrational spectra in comparison with the IR and Raman spectra of the well-known species of the series [PtClnBr6-n]2- , n = 0-6. The literature concerning trans-[PtCl4Br2]2- and other mixed ligand complexes is critically discussed.

Darstellung und Schwingungsspektren von Fluoro-Chloro-Osmaten(V)/ Preparation and Vibrational Spectra of Fluoro-Chloro-Osm ates(V)

1986 ◽  
Vol 41 (7) ◽  
pp. 885-889 ◽  
Author(s):  
W. Preetz ◽  
Th. Groth
Keyword(s):  
Bond Strength ◽  
Vibrational Spectra ◽  
Trifluoroacetic Acid ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Significant Shift ◽  
Stretching Vibration ◽  
Point Groups

AbstractBy oxidation of the pure fluoro-chloro-osmates(IV ) with BrF3 in dichlorom ethane the mixed pentavalent complexes [OsF5Cl]-, cis-[OsF4Cl2]-, fac-[OsF3Cl3]- and cis-[OsF2Cl4]- are formed without replacement of ligands. Trans-[OsF4Cl2]- and trans-[OsF2Cl4]- are generated from the corresponding osmates(IV) by oxidation with PbO2 in dichloromethane under addition of trifluoroacetic acid. The vibrational spectra o f the mixed ligand complexes are assigned according to point groups D4h, C4v, C3v and C2v. The increased bond strength com pared with the corresponding Os(IV ) complexes is indicated by a significant shift to higher energy by about 5 -15% . The Os -Cl stretching vibration of [OsF5Cl]- and also the symmetric ClOsCl of trans-[OsF4Cl2]- is split by the isotopes 35Cl and 37Cl, showing two and three well resolved sharp Raman lines in the expected ratio of intensities, respectively.

Darstellung und Charakterisierung der Chloro-Bromo-Iridate(III) und -(IV) einschließlich der Stereoisomeren / Preparation and Characterisation of Chloro-Bromo-Iridates(III) and -(IV) Including Stereoisomers

1985 ◽  
Vol 40 (6) ◽  
pp. 745-754 ◽  
Author(s):  
W. Preetz ◽  
H.-J. Steinebach
Keyword(s):  
Ligand Exchange ◽  
Redox Reactions ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Mixed Ligand ◽  
Redox Potentials ◽  
Exchange Reactions ◽  
Cyclic Voltammetric ◽  
Point Groups ◽  
Voltammetric Measurements

AbstractThe mixed chloro-bromo complexes [IrClnBr6-n]2- and [IrClnBr6-n]3-, n = 1 - 5. were separated by ion exchange chromatography on diethylaminoethylcellulose. Due to the stronger trans-effect of Br compared with Cl, on treatment of [IrBr6]2- 3- with Cl- nearly pure cis/fac-isomers and by reaction of [IrCl6]2,3- with Br- trans/mer-isomers for n = 2,3,4 were formed. The stereoselectivi­ty of successive ligand exchange reactions is better for the Ir(III) than for the Ir(IV) system. The diamagnetic Ir(III) and the paramagnetic Ir(IV) complexes can be interconverted reversibly by redox reactions at low temperature. As shown by cyclic voltammetric measurements, the redox potentials within the series [IrClnBr6-n]2- 3- are linearly dependent on n. In aqueous solution the normal potentials are in the range of Eo = 0.838 V ([IrBr6]2-,3-) to Eo = 0.908 V ([IrCl6]2-,3-). The vibrational spectra of the mixed ligand complexes are assigned according to point groups D4h, C4v, C3v and C2v. They are similar for corresponding chloro-bromo-iridates, but distinguished by a shift of 10-25 cm-1 to higher wave numbers for most of the stretching vibrations going from Ir(III) to Ir(IV).

Darstellung und spektroskopische Charakterisierung von Tetrakis (chloro -iodo ) oxalato -osmaten (IV )/Preparation and Spectroscopical Characterisation of Tetrakis(chloro-iodo)oxalato-osmates(IV)

1981 ◽  
Vol 36 (1) ◽  
pp. 62-69 ◽  
Author(s):  
W. Preetz ◽  
H. Schulz
Keyword(s):  
Mutual Influence ◽  
Complete Separation ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Vibrational Modes ◽  
Spin Orbit ◽  
Geometric Isomers ◽  
Trans Effect ◽  
Diethylaminoethyl Cellulose ◽  
Point Groups

Abstract On treatment of [OsI4ox]2- with Cl- the mixed complexes [OsClnI4-nox]2-, n = 1, 2, 3, are formed. The isolation and complete separation of the differently coloured geometric isomers is achieved by ion exchange chromatography on diethylaminoethyl cellulose. The IR and Ra spectra are assigned according to point groups C2v, Cs, C1. The mutual influence of ligands, especially by the high trans effect of I, is indicated by shifts of the distinct vibrational and electronic bands. The observed splittings of I→Os transitions are attributed to the different groupings I-Os-I, I-Os-Cl, and I-Os-O, important for the distinction of stereoisomers. The CT-bands as well as the d-d-transitions show batho-chromic shifts with increasing number of I-ligands. Up to five spin-orbit components in the NIR region are well resolved. The assignment is improved by the electronic Ra spectra. The fine structure of some d-d-bands originates from coupling with symmetric vibrational modes.

Darstellung, 11B-, 13C-, 1H-NMR - und Schwingungsspektren von μ-Pentamethylen-bis-hexahydro-closo-hexaborat, [B6H6(CH2)5B6H6]2-, und μ-Hexamethylen-bis-hexahydro-closo-hexaborat, [B6H6(CH2)6B6H6]2/Preparation, 11B, 13C, 1H NMR and Vibrational Spectra of μ-Pentamethylene-bis-hexahydro-closo-hexaborate, [B6H6(CH2)5 B6H6 ]2-, and μ-Hexamethylene-bis-hexahydro-closo-hexaborate, [B6H6(CH2)6B6H6]2-

1996 ◽  
Vol 51 (3) ◽  
pp. 359-362 ◽  
Author(s):  
W. Lübbe ◽  
W. Preetz
Keyword(s):  
Ion Exchange ◽  
Vibrational Spectroscopy ◽  
1H Nmr ◽  
Vibrational Spectra ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
H Nmr ◽  
Diethylaminoethyl Cellulose

Abstract In the reaction of [B6H6]2- with diiodopentane or diiodohexane in dichloromethane μ-pentamethylene-bis-hexahydro-closo-hexaborate, [B6H6(CH2)5B6H6]2- (I), and μ-hexamethylene-bishexahydro-closo-hexaborate, [B6H6(CH2)6B6H6]2- (II), are formed, respectively. The products were separated from excess [B6H6]2- by ion exchange chromatography on diethylaminoethyl cellulose and have been identified and characterized by 11B, 13C, 1H NMR and vibrational spectroscopy.

Isolation of Peptides with Anti-Urokinase Activity from the Human Placenta

1979 ◽  
Vol 42 (05) ◽  
pp. 1411-1416
Author(s):  
Mieczyslaw Uszynski
Keyword(s):  
Ion Exchange ◽  
Human Placenta ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Plasminogen Activation ◽  
Urokinase Inhibitor ◽  
Step Procedure ◽  
Homogenate Extraction ◽  
First Time

SummaryIt is known that the fibrinolysis inhibitors in the human placenta are proteins which, in vitro, block urokinase plasminogen activation and are for this reason called urokinase inhibitors. In the present study it was found, for the first time, that a low-molecular urokinase inhibitor also occurs in the human placenta. It is a peptide which can be isolated through a three-step procedure: dialysis of human placenta homogenate, extraction of peptides from a filtrable fraction, and ion exchange chromatography of peptides on a Dowex-50 column.

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