Bromo-, Chloro-, Rhodano- und Azidokomplexe des Vanadyl(IV)ions in Nitromethan

Zusammenfassung Die Bildung von Bromo-, Chloro-, Rhodano- und Azidokomplexen von VO²⁺ wurde in Nitromethan auf spektrophotometrischem, potentiometrischem und konduktometrischem Wege untersucht. Die Regel, daß ein Lösungsmittel geringer Donorzahl auch die Bildung schwacher Komplexe gestattet, wird bestätigt.

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The formation of bromo-, chloro-, thiocyanato- and azidocomplexes of VO²⁺ has been investigated in nitromethane by spectrophotometric, potentiometric and conductometric methods. The rule is confirmed that solvents of low donor number will allow also the formation of weak complexes.

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Mit 6 Abbildungen     

Chloro-, Bromo- und Jodokomplexe von Nickel(II) in einigen nichtwäßrigen Lösungsmitteln

The formation of chloro-, bromo- and iodocomplexes of nickel(II) is investigated by spectrophotometric, potentiometric and conductometric methods in acetonitrile (AN), propanediol-1,2-carbonate (PDC), trimethylphosphate (TMP), N,N-dimethylacetamide (DMA) and dimethylsulfoxide (DMSO) as far as data were not available. The results are discussed mainly with respect to the donor properties of solvent molecules and halide ions.     

Darstellung und Charakterisierung von bindungsisomeren Hexakis(thiocyanato-isothiocyanato)-iridaten(III) und einiger Chloro-, Cyano-pentarhodanoiridate(III)

Preparation and Characterization of Bond-Isomeric Hexakis(thiocyanato-isothiocyanato)-iridates(III) and Some Chloro-, Cyano-pentarhodanoiridates(III) The evaporated ethanolic extract of the reaction product of K₃[IrCl₆] and HNO₃, refluxed with an aqueous KSCN solution yields a mixture of the bond isomers [Ir(NCS)_n(SCN)_6?n]^3?, n = 0–2 and small amounts of bond isomeric chloropentrahodanoiridates(III). By heating the tetrabutylammonium salts, N coordination of the ambident SCN^? is favoured forming compounds with n = 2–5 beside chloro- and cyanopentarhodanoiridates(III). With n = 2, 3 pairs of geometric isomers can be detected. The pure compounds are separated by ion exchange chromatography on diethylaminoethylcellulose. The trans/mer-complexes migrate 1.9 times faster than the cis/fac-isomers. Depending on S- or N-bonding the IR and Raman spectra show typical vibrations: ν_CN(N) and ν_CN(S): 2100–2175, ν_CS(N): 810–855, ν_CS(S): 690–710, δ_NCS: 470–480, δ_SCN: 420–470, ν_IrN: 300–325, ν_IrS: 255–313 cm^?1. Except the inner ligand vibrations the Rh? N and Rh? S valence frequencies are assigned according to the supposed point symmetries. By interaction of the trans-positioned ligands characteristic shifts are caused.     

New Fluorescent 2- Ortho -( Meta - and Para -) Chloro-(and Bromo-) Benzylthio- N -Phenylcytosines and 6-Methylcytosines

Twelve new fluorescent ortho -, meta -, and para -, chloro-(bromo-) substituted derivatives of 2-benzylthio- N -phenylcytosines and 6-methylcytosines have been prepared. EI induced mass spectral fragmentation of these compounds was investigated. Fragmentation pathways are proposed on the basis of accurate mass and metastable transitions measurements. Correlation between the intensities of the M +. and the selected fragment ions of these compounds is discussed. The data obtained permit a distinction of the isomers. The 1 H and 13 C NMR spectra of these compounds were assigned unambiguously using a combination of heternuclear (HETCOR) spectra and the chemical shifts. The data derived from these spectra can be used to differentiate the isomers.     

Bromo- and chloro-selenate(II) compounds

Addition of R₄NX (R = Et, n-Pr, n-Bu) to solutions of SeX₂ (X = Cl, Br) in acetonitrile results in the formation of tri- and tetra-haloselenate(II) complexes (SeX₃⁻ and SeX₄²⁻). Raman spectroscopic characterization of these solutions and solids, R₄NSeX₃ and (R₄N)₂SeX₄, which may be crystallized from them, are reported. R₄NSeCl₃ compounds are shown to be relatively unstable; they are readily destroyed by laser light, 2R₄NSeCl₃ = (R₄N)₂SeCl₆+Se(O) and especially sensitive to hydrolysis, 2SeCl₃⁻+H₂O = SeOCl₃⁻+2HCl+Cl⁻+ Se(O). The Raman spectra of solutions of SeX₃⁻ and SeX₄²⁻ are consistent with T-shaped and square planar structures, respectively.     

Partial Molar Volumes and Refractions of Cobalt(III) Complexes, Part 2: Homologous Series of Nitrilopentaamminecobalt(III) Complexes

Both the partial molar volumes (V° _2m refractions (R° _2m ) of the solutes at infinite dilution have been determined at 20 °C for a series of six octahedral N₆-coordinated cobalt(III) species featuring five coordinated ammonia ligands along with a sixth N-coordinated organonitrile of increasing ligand size (from acetonitrile to sebaconitrile). The experimental values for V° _2m are consistent with the relative sizes of the ligands but show larger values than those generated by computer modeling as the size of the cation increases, presumably due to the void space of the cation which increases with the size of the nitrile ligand.     

Partial Molar Volumes and Refractions of Cobalt(III) Complexes, Part 1: Homologous Series of Hexaaminecobalt(III) Complexes

Both the partial molar volumes (V∘_solute) and refractions (R∘_solute) of the solute at infinite dilution have been determined for a series of four octahedral N₆-coordinated cobalt(III) species with increasing ligand size (ammonia, ethylenediamine, sepulchrate, and 1,2-diaminocyclohexane). The experimental values for V∘ _solute are consistent with the relative sizes of the ligands but show larger values than those generated by computer modeling as the size of the cation increases. This suggests that the void space of the cation increases with the size of the cation. It is proposed that increasing hydrophobicity of the alkane ligand frameworks contributes to larger volumes.     

三价金配合物抗肿瘤活性研究*

三价金配合物具有潜在的抗肿瘤活性,是目前金属药物领域的研究热点。本文按配位原子的不同总结了稳定三价金配合物的结构特征,按其生物活性的构效关系、生物靶点和作用机制综述了三价金配合物抗肿瘤活性研究的最新成果：配体的结构特点以及离去基团对三价金配合物的体外细胞毒性影响较大;介绍了用于检测三价金配合物与可能的生物靶分子之间的相互作用的多种物理和生物学方法,重点关注了相互作用的模式,如嵌入/静电吸引/共价结合等,并解释了三价金配合物抗肿瘤活性的原因。最后提出了一些研究新思路,以期有助于设计得到靶标明确的具有良好药理活性的抗肿瘤药物。     

Complexes of oxamic acid with Au(III) and Rh(III)

The preparation and some properties of the deprotonated complexes of oxamic acid with Au(III) and Rh(III) are reported. On the basis of analytical results, conductometric measurements, magnetic moments and spectral data (IR and UV-visible), a square planar structure is proposed for K[AuL(OH)₂] and octahedral for K₃[RhL ₃] 3H₂O (whereLH₂=oxamic acid).L ^2– acts as a bidentate, non-bridging ligand.

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Komplexe der Oxamidsäure mit Au(III) und Rh(III)

Zusammenfassung Es wird über die Darstellung und einige Eigenschaften von deprotonierten Komplexen der Oxamidsäure mit Au(III) und Rh(III) berichtet. Auf der Grundlage von analytischen Ergebnissen, Leitfähigkeitsmessungen, magnetischen Momenten und IR- und UV(vis)-spektroskopischen Daten wird für K[AuL(OH)₂] eine quadratisch planare und für K₃[RhL ₃] 3 H₂O eine oktaedrische Struktur vorgeschlagen (LH₂=Oxamidsäure).L ^2– reagiert als zweizähniger, nicht überbrückender Ligand.

     

Isosaccharinate Complexes of Fe(III)

Prior to this study there were no thermodynamic data for isosaccharinate (ISA) complexes of Fe(III) in the environmental range of pH (>~4.5). This study was undertaken to obtain such data in order to predict Fe(III) behavior in the presence of ISA. The solubility of Fe(OH)₃(2-line ferrihydrite), referred to as Fe(OH)₃(s), was studied at 22?±?2?°C in: (1) very acidic (0.01?mol·dm^?3 H⁺) to highly alkaline conditions (3?mol·dm^?3 NaOH) as a function of time (11?C421?days), and fixed concentrations of 0.01 or 0.001?mol·dm^?3 NaISA; and (2) as a function of NaISA concentrations ranging from approximately 0.0001 to 0.256?mol·dm^?3 and at fixed pH values of approximately 4.5 and 11.6 to determine the ISA complexes of Fe(III). The data were interpreted using the SIT model that included previously reported stability constants for $ {{\text{Fe(ISA}})_{n}}^{3 - n} $ (with n varying from 1 to 4) and Fe(III)?COH complexes, and the solubility product for Fe(OH)₃(s) along with the values for two additional complexes (Fe(OH)₂(ISA)(aq) and $ {\text{Fe(OH)}}_{ 3} ( {{\text{ISA}})_{2}}^{2 - } $ ) determined in this study. These extensive data provided a log₁₀ K ⁰ value of 1.55?±?0.38 for the reaction $ ({\text{Fe}}^{ 3+ } + {\text{ISA}}^{-} + 2 {\text{H}}_{ 2} {\text{O}} \rightleftarrows {\text{Fe(OH}})_{ 2} {\text{ISA(aq}}) + 2 {\text{H}}^{ + } ) $ and a value of ?3.27?±?0.32 for the reaction $ ({\text{Fe}}^{ 3+ } + 2 {\text{ISA}}^{-} + 3 {\text{H}}_{ 2} {\text{O}} \rightleftarrows {\text{Fe(OH)}}_{ 3} ( {\text{ISA}})_{2}^{2 - } + 3 {\text{H}}^{ + } ) $ and show that ISA forms strong complexes with Fe(III) which significantly increase the Fe(OH)₃(s) solubility at pH?<~12. Thermodynamic calculations show that competition of Fe(III) with tetravalent ions for ISA does not significantly affect the solubilities of tetravalent hydrous oxides (e.g., Th and Np(IV)) in ISA solutions.     

Sulfitoamine Complexes of Cobalt(III)

Abstract

Monosulfito and bis(hydrogensulfito) cobalt(III) complexes were prepared using sodium sulfite and sodium metabisulfite salts respectively. The two types of products showed different and characterizing patterns of IR and UV-visible spectra. They both contain Co-SO₃ linkages and the sulfite groups have similar or different site symmetries in the same compound.     

Binuclear Homoleptic Manganese(III,III) and Manganese(IV,III) Complexes with Deprotonated D-Mannose from Aqueous Solution

Just a “reducing” sugar —namely, D -mannose—is a starting material in the synthesis of a mixed-valence complex of manganese in the oxidation states +III and +IV . Ba₂[Mn^IIIMn^IV(β-D -ManfH₋₅)₂]Cl⋅14 H₂O (Manf=mannofuranose; the structure of the anion is shown on the right) is prepared in aqueous solution by oxidation of an analogous Mn₂^III complex with oxygen. In neutral solutions the Mn^IIIMn^IV binuclear complex is formed by disproportionation of the Mn₂^III precursor.     

Dihaloperhaloaryl(triphenylarsine)gold(III) Complexes

When C₆Cl₅AuAsPh₃ reacts with halogens, oxidation of the gold(I) complex and formation of X₂Au(C₆Cl₅)AsPh₃ (X = Cl, Br, I) take place. However, when C₆F₅AuAsPh₃ reacts with halogens, oxidation is only observed in the case of Cl₂, whilst I₂ (totally) and Br₂ (partially) split the AuC bond. This behaviour is contrary to that observed with C₆F₅AuPPh₃ and halogens, where the tendency to split the AuC bond decreases in the sequence Cl>B>I.     

Chromium(III) and Chromium(IV) Tetraphenylporphine Complexes

Stable chromium complex (AcO)CrTPP was synthesized through the reaction of meso-tetraphenylporphine with chromium(III) acetate in boiling phenol. Coordination properties of chromium porphyrin in reaction with imidazole and pyridine in o-xylene were studied by electronic absorption spectroscopy and computer modeling. A single-electron oxidation of chromium(III) complex was found to be affected by peroxide compounds. The stability of an extra complex depends on the basic properties of the extra ligand and oxidation number of the central metal atom. The complex stability correlates with the calculated energy of formation of the metal–extra ligand bond. The geometrical structure and energy parameters of hexacoordinated chromium porphyrins were calculated using the quantum-chemical method. The effect of the cis and trans position of ligands in the composition of a macrocyclic compound was established to be significant only in the extra complexes (AcO)CrTPP.     

Five-Coordinated Iron(III) Monohalobisdithiocarbamate Complexes

Fünffach koordinierte Eisen(III)- monohalogen-bis-dithiocarbamat-Komplexe Eine neue Reihe von fünffach koordinierten Komplexen der allgemeinen Formel [Fe(Rdtc)₂X], X = Halogen, Rdtc = Piperidindithiocarbamat (Pipdtc), Thiomorpholindithiocarbamat (Timdtc), Morpholindithiocarbamat (Morphdtc), wurden dargestellt und durch magnetische und spektroskopische Messungen charakterisiert. Die magnetischen Momente dieser Verbindungen liegen nahe den Werten für Komplexe von Metallionen in dsp³ Hybridisierung, d. h. drei ungepaarte Elektronen und kein Orbitalbeitrag. Die Komplexe sind in Nitrobenzol monomer. Die Eisen–Halogen- und Eisen–Schwefel-Schwingungen wurden bestimmt.     

Dithiocarbamate Iridium(III) Hydride Complexes

Complexes of IrH₃(PPh₃)₂ and IrH₃(AsPh₃)₂ with piperidinedithiocarbamate (Pipdtc), piperazinedithiocarbamate (Pzdtc), N-methylpiperazinedithiocarbamate (CH₃—Pzdtc), morpholinedithiocarbamate (Morphdtc) and thiomorpholinedithiocarbamate (Timdtc) have been prepared and characterized by infrared and nuclear magnetic resonance techniques and vapor phase osmometric molecular weight determinations. The possible stereochemistry of the complexes is discussed based upon the obtained results.     

Formation and transformation of Amminecarbonatocobalt(III) Complexes

The preparation is described of [CoCO₃(NH₃)₅]ClO₄ · H₂O, trans-[CoCO₃(NH₃)₄(¹⁵NH₃)]ClO₄, and trans-[CoCO₃(NH₃)₄(NH₂CH₃)]ClO₄. The transformation reactions of these complexes, in which a chelate carbonate ligand is formed and one NH₃ is eliminated, were studied in solution and in the solid state. ¹H NMR spectroscopy is used for the identification of the products. It is shown that the transformation reactions are not stereospecific.     

Complexes of silver(III) with oxoanions

Silver(III) has a half-life at pH 11 of several hundred seconds in aqueous solutions in the presence of 0.1–1.0 M concentrations of certain basic oxoanions (Oxo) (phosphate, carbonate, borate, pyrophosphate, and arsenate). This compares with a lifetime of a few seconds at pH 11 in the absence of these oxoanions. UV-visible spectra and kinetic data for these solutions are interpreted as evidence for the following equilibria in the pH range 9–13.Ag(OH)₄^?1 + H₂O ? Ag(OH)₃H₂O + OH^? (1)Ag(OH)₄^?1 + Oxo ? Ag(OH)₃Oxo + OH^? (2)Ag(OH)₃Oxo + H₂O ? Ag(OH)₂(Oxo)H₂O + OH^? (3) Values of K₃ lie in the range 10^?3 < K₃ <10⁴ M for the systems studied. K₂ is estimated to be ～10² for phosphate and slightly smaller for the other systems. Ag(OH)₄^? undergoes an unusual reaction with pyrophosphate at pH ～ 8 to form a novel silver(II) complex, [Ag(P₂O₇)₂]^6?, for which EPR and electronic absorption spectral parameters are reported.