Piatzwechselvorgänge der Liganden in festen Komplexsalzen. I. Intramolekulare Isomerisierung an Gemischten Hexahalogenokomplexen von Osmium(IV)

Ligand Exchange in Solid Complex Salts. I. Intramolecular Isomerization of Mixed Hexahalo-complexes of Osmium(IV) The isomerization of pure solid complex salts of the type cis- or trans-K₂[OsCl_nY_6?n], Y = Br, I; n = 2, 3, 4, is measured spectrophotometrically at 115, 125 and 135°C. By intramolecular rearrangement of the ligands statistical relations of the isomers are adjusted. For the solid-state exchange reactions a dissociative bond-breaking-and a twist-mechanism are discussed.     

Platzwechselvorgänge der Liganden in festen Komplexsalzen. V. Photochemische cis/trans-Umlagerung in festen Chloro-Jodo-Osmaten(IV)

Ligand Exchange in Solid Complex Salts. V. Photochemical Cis/Trans-Rearrangement in Solid Chloro-Iodo Osmates(IV) The photochemical isomerization of solid chloroiodo osmates(IV) is observed at ?50°C spectrophotometrically as an uniform reaction until equilibrium, reached within some hours. The quantum yields are 10^?1–10^?2. The temperature dependence is low and the rearrangement takes place, even at the temperature of liquid nitrogen, with nearly the same rate. An intramolecular exchange mechanism is discussed.     

Der Einfluß von cis- und trans-Effekten auf den Ligandenaustausch an gemischten Hexahalogenoosmaten(IV)

Influence of Cis and Trans Effects on the Ligand Exchange of Mixed Hexahalo Osmates(IV) The 24 possible ligand exchange reactions in the system of chloro-bromo osmates(IV) are investigated by kinetic measurements. The rate constants k_HBr (trans-series) or k_HCl (cis-series) determined in 5N HBr or 5N HCl at 80°C are summarized in the following equations The influence of relative cis and trans effects of ligands and of the geometry of complexes on the rates of ligand exchange is completely described by the three parameters s, y, z. This is supported by the close agreement between calculated and experimental concentration-time diagrams. The equations characterize both consecutive and parallel reactions and permit the calculation of ratios of isomers a t any time. The relative cis-effects forC1:Br:I are about 1:1.8:7, while the trans-effects are 1:6:1000. With the set of kinetic data an equilibrium diagram is derived from which the individual stability constants of the stepwise-formed mised-ligand complexes are deduced. There is good agreement between experimental and calculated values.     

Bestimmung der Stabilitätskonstanten gemischter Hexahalogenokomplexe von Osmium(IV)

Determination of the Stability Constants of Mixed Hexahalogeno Complexes of Osmium(IV) The individual and total stability constants of the complex series [OsX_xY_6?x]^2?; X ≠ Y = Cl, Br, I; x = 0–6 are determined by radiometric measurements of the equilibrium concentrations of all compounds. The thermodynamical stability increases from the hexabromo- over the hexachloro- to the hexaiodo-complex. The total stability constants are in ratio of 1:5,2:1225. With the individual constants the equilibrium diagrams are calculated. The photometric determination of the cis/trans ratio in complexes with x = 2, 3, 4 gives the statistical distribution of the ligands in the octahedrons. The relationship between thermodynamical and kinetical data is discussed.     

Komplexierung von Be(II) mit gemischten Liganden

The complexation of Be(II) with mixed ligands viz. 3,5-dinitrosalicylic acid (3,5-DNS) and -resorcylic acid (-RSA) in aqueous 0.1M-KNO₃ medium has been investigated potentiometrically, which evince the formation of 111 complex.

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Gemischte Halogeno-Äthylendiamin-Komplexe von Osmium(III) und (IV)

Mixed Halogeno-Ethylendiamine Complexes of Osmium (III) and (IV) [OsCl₄en] or [OsBr₄en] and [OsCl₄en]- or [OsBr₄en]- are prepared by reaction of [Os(en-H)₂en]Br₂ with HCl or HBr. Whereas the chelate group behaves inert, the halogeno ligands become substituted easily, alltogether or partly. This enables the preparation of [OsI₄en], of complexes of the type [OsCl_nBr_4?en]-, n = 1–3, and of other compounds. The chemical properties and infrared spectra of the new complexes are discussed.     

Potentiometrische Untersuchung von Lanthan(III)-Komplexen mit gemischten Liganden

Potentiometric studies of the 1∶1∶1, ternary systems, La(III)-aminopolycarboxylates-hydroxy acids [where amino-polycarboxylates=dipotassium nitrilotriacetate (NTA), N-hydroxyethylethylenediamine-N,N′,N′-dipotassiumtriacetate (HEDTA) and ethylenediamine-N,N,N′,N′-tripotassiumtetra-acetate (EDTA); hydroxy acids-5-sulfosalicylic acid (SSA) and dipotassium salt of 1.2-dihydroxybenzene-3.5-disulfonic acid (Tiron)], indicate the formation of 1∶1∶1, mixed ligand complexes.     

Optimale Bedingungen zur Darstellung von gemischten Chloro-Jodo-Osmaten (IV)

Optimum Conditions for Preparation of Mixed Chloro-Iodo Osmates(IV) Using the rate constants of the substitution reactions in the system [OsCl_nI_6-n]^2-, n = 0–6, the formation of the different mixed-ligand complexes by consecutive reactions can be described quantitatively. From calculated concentration-time diagrams one can take the best conditions for the preparation of the single species. The stereospecific run of the substitution reactions and the formation of pure cis- and trans-complexes are discussed.     

Photochemischer Ligandenaustausch an Hexahalogenoosmaten(IV)

Photochemical Ligand Exchange of Hexahalo Osmates(IV) Irradiation of hexahaloosmates(IV) in various polar solvents (H₂O, CH₃CN, C₅H₅N) gives preferable monosubstituted products. First time [OsCl₅(NC? CH₃)]^?, [OsBr₅(NC? CH₃)]^? and [OsCl₅py]^? are prepared photochemically in larger amounts. The quantum yields in the region 313–436 nm are 10^?2–10^?3. The photochemical stability of the mono-substituted products is discussed. By photolysis of [OsBr₆]^2? in CH₂Cl₂ and 1,2-C₂H₄Cl₂ the mixed-ligand complexes [OsCl_nBr_6–n]^2? are formed. After ionophoretic separation for the species with n = 2, 3, 4 a statistical ratio of the stereoisomers is observed. Slow photosubstitution takes place too in alkali halide pellets of the complex salts at room temperature.     

Titan(IV)-Komplexe mit dreizähnigen diaciden Liganden. Kristallstruktur von Bis[2,6-diphenacylpyridinato(2 –)]titan(IV)

Titanium(IV) Complexes with Tridentate Diacidic Ligands. Crystal Structure of Bis[2,6-diphenacylpyridinato(2–)]titanium(IV) The titanium(IV) chelates with 2,2′-dihydroxy-azobenzene, salicylaldehyde-2-hydroxyanil, 2-(2′-hydroxyphenyl)-8-quinolinol, 2,6-diphenacylpyridine as well as with aroylhydrazones of salicylaldehyde, benzoylacetone and thenoyltrifluoroacetone were synthesized by ligand exchange reactions of titanium(IV)-isopropoxide. The compounds are red or black in colour and were identified by distinct molecular peaks in the mass spectra. The crystal and molecular structure was determined for bis[2,6-diphenacylpyridinato(2–)] titanium(IV). Crystallographic data see “Inhaltsübersicht”.     

Mangan(IV)-Komplexe mit dreizähnigen diaciden Liganden. Kristallstruktur von Acetylacetonato-salicylaldehydbenzoylhydrazonato(2−)-methanol-mangan(III)

Manganese(IV) Complexes with Tridentate Diacidic Ligands. Crystal Structure of Acetyl-acetonato-salicylaldehydebenzoylhydrazonato(2?)-methanol-manganese(III) The manganese(IV) chelates of salicylaldehyde benzoylhydrazone and salicylaldehyde salicylhydrazone were synthesized by ligand exchange reactions using bis(acetylacetonato)manganese(II), tris(acetylacetonato)manganese(III) as well as manganese(III) acetate. The brown complexes show the expected molecular ions in the APCI mass spectra. As an intermediate compound acetyacetonato-salicylaldehydebenzoylhydrazonato(2?)-methanol-manganese(III) was isolated and characterized by X-ray structural analysis. Crystallographic data see “Inhaltsübersicht”.     

Zinn(IV)-Komplexe mit dreizähnigen diaciden Liganden

Tin(IV) Complexes with Tridentate Diacidic Ligands By template reactions including bis(acetylacetonato)-dichloro-tin(IV) and O-aminophenol as well as o-aminothiophenol, benzoylhydrazine, and thiobenzoylhydrazine the tin chelates of tridentate diacidic ligands containing ligator atoms were prepared. To characterize the compound, IR, UV-VIS and Mössbauer spectroscopy were used. Crystal structure analyses demonstrate the existence of disturbed octahedral structures. Bis[acetylacetonbenzoylhydrazonato(2-)]tin(IV): space group P2₁/c, Z = 4, 2501 observed unique reflections, R = 0.045. Lattice dimensions at 20°C: a = 992.3, b = 2405.5, c = 1071.8pm, β = 116.94°. Bis[acetylacetonthiobenzoylhydrazonato(2-)] tin(IV): space group P2₁/c, Z = 4, 3603 observed unique reflections, R= 0.029. Lattice dimensions at 20°C: a = 1581.5, b = 947.8, c = 1644.9pm, β = 90.32°.     

Solvatochromie von Metall(0)-Komplexen der 6. Nebengruppe mit zweizähligen Azomethinen als Liganden

Solvatochromism of Subgroup VI Metal(0) Complexes with Bidentate Azomethine Ligands Some mononuclear and binuclear chelat compounds of azomethines, derived from the carbonyls of molybdenum and chromium are described. The spectrophotometrical behaviour of the compounds is compared with the behaviour of the diazabutadiene and dipyridyl metalcarbonyls. The complexes show strong negative solvatochromic effects in organic solutions and in polymers.     

Schwefel(IV)-Verbindungen als Liganden XVII. Übergangsmetall-vermittelte Insertion von Schwefeldioxid in die C---O-Einfachbindung

Methoxyethyliron complexes [Cp(CO)(L)Fe(CH₂CHROMe)] (L = CO, P(OPh)₃; R = H, Me) insert SO₂ into the C---O single bond wih formation of metalated sulphonic acid esters [Cp(CO)(L)Fe(CH₂-CHRSO₂OMe)]. the insertion is stereospecific wih retention of configuration at carbon. The complexes [Cp(CO)₃M(CH₂CHRSO₂OMe)] (M = Mo, W; R = H, Me) are obtained analogously. Oxidation of [Cp(CO)₃W(CH₂CH₂SO₂OMe)] wih iodine gives the ionic tungsten(IV) alkyl complex [Cp(CO)₃(I)W(CH₂CH₂SO ₂OMe)]⁺. Triphenylphosphine converts [Cp(CO)₃Mo(CH₂CHRSO₂OMe)] into acyl complexes [Cp(CO)₂(Ph₃P)Mo(C(O)CH₂CHRSO ₂OMe)] (R = H, Me), which upon oxidation with Ce^IV in MeOH yield the diesters MeOC(O)CH₂CHRSO₂OMe.     

Auftrennung von gemischten Hexa(bromochloro)-rhenaten(IV) und -osmaten(IV) auf Dünnschichtcelluloseplatten

The ions ReBr_nCl _6?n ^2? (0?n?6) and OsBr_nCl _6?n ^2? , respectively, ReO₄ ^? and Br^? have been separated on cellulose using the thin-layer chromatographic technique with 3.2 M sulphuric acid as the mobile phase.     

Oxofreie Vanadium(IV)-Komplexe mit dreizähnigen diaciden Liganden. Struktur von Bis[2,2′-dihydroxy-azobenzenato(2−)]vanadium(IV)

Non-oxo Vanadium(IV) Complexes with Tridentate Diacidic Ligands. Molecular Structure of Bis[2.2′-dihydroxy-azobenzenato(2?)]vanadium(IV) By the reaction of tris(acetylacetonato)vanadium(III) with tridentate diacidic ligands non-oxo vanadium(IV) complexes of these ligands were synthesized. The complexes were characterized by mass spectrometry. Electrochemical studies show that the complexes are reversibly oxidized or reduced. Bis[2,2′-dihydroxy-azobenzenato(2?)]vanadium(IV) has a distorted trigonal-prismatic structure. Crystallographic data see ?Inhaltsübersicht”?.