B. J. Van Brecht

POLYNITROGEN REAGENTS IN METAL SEPARATION. PART 1. DITERTIARY AND DIQUATERNARY AMMONIUM EXTRACTANTS FOR COBALT(II) AND COPPER(II) IN HCl MEDIUM.

Abstract A variety of alkyldiammonium extractants (tertiary and quaternary)were prepared, characterised and used to extract cobalt(II) and copper(II) from HCl medium. These extractants were compared with Aliquat-336 and Alamine-336. The diammonium derivatives of ethylene diamine proved to be superior to their mono analogues.

Syntheses and Structures of Tris-(1,2-Benzosemiquinone DIimine) Complexes of Rhenium(IV)

Reactions of trans-[ReO2(py)4Cl] and cis-[ReO2I(PPh3)2] with 2,3-diaminophenol (H2dab-OH) and 1,2-diaminobenzene (H2dab), respectively, in ethanol under aerobic conditions led to the corresponding isolation of [Re(sbqdi-OH)3]Cl (1) and [Re(sbqdi)3]I (2). Crystallographic data show that the ligand sbqdi represents the monoanionic N,N-coordinated π-radical form of the 1,2-benzosemiquinone diimine of H2dab. The ligands in Complex 1 clearly show semiquinoid character; e.g., the two C-N and two Re-N bondlengths differ considerably. In 2, the phenyl rings display typical quinoid distortions with two localized double bonds, and the C-N bondlengths are short, approaching double bonds. Rhenium is formally in the +IV oxidation state.

NITROGEN REAGENTS IN METAL ION SEPARATION. PART 6 2-(r-OCTYLTHIOMETHYL)PYRIDINE AS EXTRACTANT FOR LATER 3d TRANSITION METAL IONS.

ABSTRACT The new extractant 2-(r-octylthiomethyl)pyridine was synthesized and applied in dilute acid medium in the presence of chloride and thiocyanate ions, for the separation of later 3d transition metal ions. Good Cu(II) specificity was revealed in dilute chloride medium as well as very promising nickel(II) preference to iron(III). The extractant behaviour of the ligand was explained in terms of its coordination behaviour.

SECONDARY EFFECTS ASSOCIATED WITH THE FUNCTIONING OF BULKY SUBSTITUTED AMMONIUM CATIONS — REVISED INTERPRETATIONS.

ABSTRACT The behaviour of mono and diquaternary ammonium cations during extraction and precipitation of CoCI4 2 ions is used to clarify some aspects of the secondary effects present during their operation. A quantitative treatment of the “HCI effect” is offered. It is illustrated that this effect must be ascribed to a lowering of the activity of the cation rather than formation of undissociated acid species like H2CoCI4

DERIVATIVES OF IMIDOPYROPHOSPHORIC ACIDS AS EXTRACTANTS.PART I. THE PREPARATION AND FUHDAHEHTAL CONSTANTS OF TETRAALKYLIMIDOPYROPHOSPHORIC ACIDS.

ABSTRACT Improved methods for the preparation of imidotetraalkyl-pyrophosphates are reported. The dissociation constant of the water soluble tetraethyl analogue was determined by potentiometric titration. The values for the partition constant and aggregation constant of the tetradodecyl analogue were determined by two phase EMF potentiometric titration of which the data were processed through a sophisticated general optimization technique.The application of this method also made it possible to obtain a species distribution curve of the organic phase in terms of variation of pH in the aqueous phase.

Synthesis of oxorhenium(V) complexes of heterocyclic-N,O and -N,S ligands

Abstract The complex trans-ReOCl3(PPh3)2 reacts with potentially bidentate N,O- and N,S-donor benzimidazolylalcohols and benzimidazolylthiols (HL) in ethanol to produce the compounds ReOGl2(L)(PPh3) or ReOCl(OEt)(L)(PPh3), depending on the reaction conditions. The complexes were characterized by elemental analysis, NMR, vibrational and optical spectroscopy. Mechanisms for the formation reactions and probable configurations of the products are proposed, and these are supported by qualitative studies and spectroscopy.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF THE MIXED TER- AND BIDENTATE SCHIFF BASE TECHNETIUM(V) COMPLEX TcO{(o[sbnd]O[sbnd]C6H4) (CH3) C[dbnd]NN[dbnd]C(S) (SCH3)} {(CH3)2C[dbnd]NN[dbnd]C(S) (SCH3)}

Abstract The complex TcO{(o[sbnd]O[sbnd]C6H4)(CH3) C[dbnd]NN[dbnd]C(S)(SCH3)}{(CH3)2C[dbnd]NN[dbnd]C(S) (SCH3)} was prepared by the reaction of (n-Bu4N) [TcOCl4] in methanol with the Schiff base S-methyl-β-N-(2-hydroxyphenylethylidene)dithiocarbazate in acetone. The compound was characterized by elemental analysis, vibrational and optical spectroscopy, and X-ray crystallography. Crystal data: C15H19N4O2S4Tc, monoclinic, space group P21/c, a = 14.799(5), b = 7.470(2), c = 19.272(5)A, U = 2064.4(1.8)A3, Z = 4, D calc = 1.65 g cm−3. The structure was refined by least-squares methods to R = 0.102. The complex has a Tc=O bond distance of 1.633(8)A, and the deprotonated phenolic oxygen of the terdentate ONS-donor ligand is coordinated trans to the oxo oxygen.

The coordination chemistry of divalent cobalt, nickel and copper—IX: The crystal structure and characterisation of a cationic 5-coordinate Cu(II) complex

Abstract The preparation, properties and X-ray crystal structure of [Cu(ttda)(tmen)](ClO4)2, a complex of divalent copper perchlorate with the ligands N,N,N′,N′-tetramethyl-1,2-diaminoethane (tmen) and bis-(N,N′-dimethyl-acetamido)thioether(ttda) are reported. The crystals are monoclinic with a = 15.35(1), b = 15.04(1), c = 10.91(1) A, β = 98.74(2)°, four formula units per unit cell and space group P21/n. The complex cation is shown to be penta-coordinate with a distorted square pyramidal geometry. Comparison is made with the properties and structure of the previously reported CuCl2·ttda.