Ludwig Rodehüser

Solvation of copper(I) perchlorate in mixed solvent systems containing acetonitrile. A63Cu,65Cu and31P nuclear magnetic resonance study

Copper(I) solvation in mixed solvent systems containing acetonitrile (AN) and co-solvents water (W), methanol (ME), dimethylformamide (DMF), trimethyl phosphate (TMPA), trimethyl phosphite (TMP) or pyridine (PY) have been studied using 63Cu, 65Cu and 31P NMR. Evidence for preferential solvation by AN is given for the first four systems whereas the latter two are characterized by strong preferential solvation of the copper(I) ion by the co-solvent. From the linewidths of the 63Cu and 65Cu signals the rotational correlation times τR of the solvates Cu(AN)+4 and Cu(PY)+4 have been determined.

63 Cu and 109Ag NMR studies of copper(I) and silver(I) salts in mixed solvents containing nitriles

The solvation of copper(I) in mixed solvent systems containing acetonitrile or benzonitrile and the co-solvents propionitrile, butyronitrile, valeronitrile, as well as trimethyl-, triethyl- and tributyl-phosphite has been examined by 63Cu NMR and also, in the case of the phosphites, by 31P NMR. The concentration dependence and the variation of the chemical shift of the silver-109 signal with solvent composition have been studied in solutions of silver trifluoroacetate (AgO2CCF3).

Amphiphilic and cation-complexing compounds based on peptidoamines

The synthesis of different types of amphiphilic compounds containing peptidoamine groups leads to surfactants with original properties such as the ability to coordinate metal ions. Water soluble acylcarcinine and alkylamidocarnosine surfactants are compared and the preparation of a silyloxyalkylamidocarnosine is described. The latter can be copolymerised with tetraalkoxysilanes to yield amphipathic organo-mineral solids that are also good ligands for metal cations.

Interactions of surfactants with living cells.

Summary. The toxicity of new surfactants containing a β-lactam ring has been established by studying their interaction with a hybridoma cell line. An hour of contact is sufficient to generate an apoptotic signal after two days of culture. Under the experimental conditions chosen for the experiments, surfactants have been divided into three categories: i) biocompatible and non-apogenic; ii) surfactants triggering an apoptotic signal without inducing cell necrosis; iii) surfactants triggering an apoptotic signal at low concentrations and destroying the cells by necrosis at higher concentrations. The necrosis inducing surfactants also had haemolytic properties. These properties were related to the values of the hydrophilic-lipophilic balance of the molecules.

Synthesis of perfluoroalkylatedβ-alanine and some peptide derivatives: An access to original surfactants

SummaryThe reaction of amines or sodium azide with 3-perfluoroalkyl-3-fluoroprop-2-enoate, followed by hydrogenation, affords perfluoroalkylatedβ-alanine analogues in very good yields. These compounds can be linked via an amide bond to produce peptide analogues such as carnosine or carcinine derivatives, which could have surfactive and complexing properties.

An NMR study of the complexes of Zn(II) and Cd(II) ions with tris(dimethylamino)phosphine sulphide: Ligand exchange kinetics

Abstract The preparation of the complex species [Cd(TDPS)4](ClO4)2 and [Zn(TDPS)4](ClO4)2 (TDPS = tris(dimethylamino)phosphine sulphide)

Interactions of colloidal grafted silica with transition-metal cations

Synthetic silica-bearing organic groups derived from amino acids at their surface have been prepared via the sol—gel technique. The particle size of the colloidal silica obtained in this way has been assessed by different methods. The complexation of divalent metal cations, such as Cu2+, Cd2+, and Pb2+, has been studied in aqueous media by using ion-selective electrodes.

Mixed ligand complexes containing β-diphosphoramides. I. Substitution of DMSO by NIPA in solvates of Cd(II). A cadmium-113 NMR study

Abstract The stepwise substitution of DMSO in the complex [Cd(DMSO) 6 ] 2+ , 2ClO 4 − on addition of nonamethylimidodiphosphoramide (NIPA) has been monitored by 113 Cd NMR at −22 °C in nitromethane solution. All the species [Cd(DMSO) 6−2 i (NIPA) i ] 2+ ( i = 0–3) can be observed as separate signals under these conditions and identified on the basis of signal multiplicity, due to 31 P 113 Cd coupling. The integration of the signals yields the relative concentrations of the different complexes and allows the determination of the stability constant β i corresponding to the equilibria [Cd(DMSO) 6 - 2 i (NIPA) i ] 2+ + 2 i DMSO for the different ratios of R = [NIPA]o/[Cd 2+ ] o . The values obtained are log β 1 = 3.58, log β 2 = 6.58, and log β 3 = 8.13. The distribution of the complex species has been calculated for a range of 0 R The 113Cd shielding found for the compound Cd(NIPA) 3 2+ is one of the strongest reported to date for an ionic cadmium complex containing small neutral ligands.

A comparative study of the structures, NMR properties and magnetic behaviour of complexes of cobalt(II) with octamethylpyrophosphoramide and nonamethylimidodiphosphoramide

Abstract The structure of the complex Co(NIPA)3(ClO4)2 has been determined by X-ray diffraction analysis and found to be very close to that of the corresponding OMPA complex. The magnetic susceptibilities of the OMPA and NIPA complexes have been measured by a thermomagnetic method and have allowed the calculation of χ| and χ⊥, the susceptibilities along the principal axes of the complex. The magnetic properties of the isomorphous nickel compounds have been studied for comparison. Results give evidence for the greater magnetic anisotropy of the NIPA complexes.

LIQUID-LIQUID EXTRACTION OF METAL IONS BY NEUTRAL PHOSPHOR- AMIDES. PART I, EXTRACTION OF URANYL IONS FROM NITRATE AND SULPHATE MEDIA. EXAMINATION OF EXTRACTED SPECIES BY UV/V1S AND sip NMR SPECTROSCOPY.

ABSTRACT The extraction of uranyl nitrate and uranyl sulphate from aqueous media by the neutral chelating diphosphoramides CH3-N[P(OKNMe2)2] (NIPA) and its less hydrophilic homologues R-N[P(O)(NMe2)2]2 (R = -C12H25 (OD1PA) or -C16H33 (OHDIPA)), diluted in CH3NO2 or toluene, has been studied. In the presei ce of HNO3, NaNO3, NaCl, and Na2SO4 as salting-out agents, extraction is generally excellent. Some of the extracted complex species have been identified by comparing their 31P NMR and UV/vis spectra with those of pure complexes of known structure. The results are compared with extractions using tri-n-butyl phosphate (TBP) as complexing agent.