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°.     

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”?.     

Struktur-Reaktivitäts-Beziehungen bei koordinativ ungesättigten Chelatkomplexen. III. Vergleich des Akzeptorverhaltens der Nickel- und Cobalt(II)-Chelate von dreizähnigen,dianionischen Schiffschen Basen

Structure Reactivity Relations of Coordinatively Unsaturated Chelate Complexes. III. Acceptor Tendency of Nickel and Cobalt Chelates with Tridentate Di-anionic Schiff Base Ligands The reactivity of nickel and cobalt chelate complexes of the type 3 with several donors is compared by isolation of stable adducts. In the case of nickel the reactivity is vigorously influenced by the substituents R¹ and R². The equatorial and the axial unoccupied coordination centers of the nickel chelates exhibit a markedly different behaviour. The cobalt(II) chelates – all of them are high spin complexes – favour O-donors. The complicate composition of the adducts point to a polynuclear structure. With pyridine, high spin diadducts have been isolated probably with coordination number 5 for the metal.     

Zu einigen Besonderheiten des thermischen Zerfalls von Ni(II)-Komplexen mit dreizähnigen Schiffschen Basen

Zusammenfassung Es wurde eine Reihe von Komplexen des zweiwertigen Nickels mit den Schiffbasen H₂L,H₂L der Zusammensetzung NiL·ROH(R=Me, Et, Pr, i-Pr)und NiL ·ROH (R=Me, Et, Pr, i-Pr, Bu) hergestellt und deren thermischer Zerfall untersucht. Es wurde festgestellt, dass bei den Addukten NiL·ROH der Zerfall unter Abspaltung des Alkohols (Zwischenprodukt NiL) verläuft, während bei NiL·ROH sofort nach der Abspaltung des Alkohols zur Massenzunahme auf TG-Kurve durch Oxidation des Stoffes kommt. Das Plateau, das dem Zwischenprodukt NiL entspricht, ist hier nur in der Ineratmosphäre erhaltbar. Es wurden auch die Aktivierungsenergien für die Abspaltung des Alkohols berechnet.

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Ni(II) Schiff base complexes of compositions NiL ROH (R=Me, Et, Pr, i-Pr) and NiL·ROH (R=Me, Et, Pr, i-Pr, Bu) were prepared and investigated by methods of thermal analysis. The thermal decomposition of NiL·ROH led to NiL (plateau in TG curve), whereas NiL·ROH underwent a similar decomposition only in an inert atmosphere (N₂); thermal decomposition in air involved alcohol fragmentation, followed by a mass increase due to oxidation by atmospheric oxygen. The activation energy of alcohol fragmentation was calculated.

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NiL · ROH (R=-, -, - ) NiL-ROH (R=-, -, -, -, ). , NiL ] NiL — . , . .

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Wir möchten uns sehr herzlich bei Doz. RNDr. E. Jóna, CSc. und RNDr. I. Horváth, CSc. für die Messungen in der Stickstoffatmosphäre in SAV Bratislava bedanken.     

Struktur-Reaktivitäts-Beziehungen bei koordinativ ungesättigten Chelatkomplexen. VIII Neue Eisen(II)-Komplexe von dreizähnigen,dianionischen Schiffschen Basen mit [NO2]-Donorsatz

Structure Reactivity Correlations in Coordinatively Unsaturated Chelate Complexes. VIII. New Iron(II) Complexes of Tridentate Di-anionic Schiff Base Ligands with [NO₂]-Donor Set The synthesis of new iron(II) complexes of the type 3 is described. The complexes have been isolated as red or reddish brown adducts with the solvent (MeOH) and with additional bases (NH₃, pyridine), respectively. The compounds are extremely sensitive to air. All of them are high spin complexes. In absence of oxygen, the adducts cannot be converted into the solvent-free complexes by thermal treatment without decomposition of the chelate ligand. In the presence of moist air, however, the solvent molecules are removed quickly at room temperature. The oxidation results in black products which seem to be hydroxo ( 3a , 3b ) or dinuclear μ-oxo ( 3c , 3d , 3f ) iron(III) derivatives. Their reduced magnetic moments (3,2 … 4,5 μ_b) point to antiferromagnetic interactions. The iron(II) complexes react with iodine to form black 1:1 derivatives which exhibit a slightly reduced paramagnetism.     

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”.     

Diorganozinn(IV)-Komplexe dreizähniger Carbazone – Strukturuntersuchungen im festen Zustand und in Lösung

Diorganotin(IV) Complexes of Tridentate Carbazones – Structural Investigations in Solid State and in Solution The structures of the products from the reaction of diphenyltin oxide with O-methyl-β-N-(salicylmethyliden)-carbazone H₂I , di-n-butyltin oxide, respectively, and neophyl-phenyl-tin oxide with 2[(2-methoxycarbonyl)-hydrazono]-propionic acid H₂II were solved with X-ray crystal-structure analyse and multinuclear NMR spectroscopy in solution. IR investigations support the statements. While Ph₂Sn-I is found as a trigonal bipyramidal coordination polyhedron we demonstrated an increased coordination number for the tin atom in n-Bu₂Sn-II and NeoPhSn-II by formation of dimers. The coordinated carboxylate oxygen atom acts as bridging donor atom with bond lengths of Sn1–O3 2,353(2) Å, Sn1–O3 a 2,579(2) Å ( n-Bu₂Sn-II ) and Sn1–O3 2,369(2) Å, Sn1–O3 a 2,721(3) Å ( NeoPhSn-II ). In addition the dimers are stabilized by intermolecular hydrogen bonds.     

The Hexacyanodiborane(6) Dianion [B2(CN)6]2−

Diborane(6) dianions with substituents that are bonded to boron via carbon are very reactive and therefore only a few examples are known. Diborane(6) derivatives are the simplest catenated boron compounds with an electron‐precise B–B σ‐bond that are of fundamental interest and of relevance for material applications. The homoleptic hexacyanodiborane(6) dianion [B₂(CN)₆]²⁻ that is chemically very robust is reported. The dianion is air‐stable and resistant against boiling water and anhydrous hydrogen fluoride. Its salts are thermally highly stable, for example, decomposition of (H₃O)₂[B₂(CN)₆] starts at 200 °C. The [B₂(CN)₆]²⁻ dianion is readily accessible starting from 1) B(CN)₃²⁻ and an oxidant, 2) [BF(CN)₃]⁻ and a reductant, or 3) by the reaction of B(CN)₃²⁻ with [BHal(CN)₃]⁻ (Hal=F, Br). The latter reaction was found to proceed via a triply negatively charged transition state according to an S_N2 mechanism.     

Zinn(IV)-Komplexe mit dreizähnigen diaciden Liganden — 119Sn-NMR und 119mSn-Mössbauer-spektroskopische Untersuchungen

Tin(IV) Complexes with Tridentate Diacidic Ligands — ¹¹⁹Sn NMR and ^119mSn Mössbauer Studies The tin(IV) chelates of tridentate diacidic azomethines of acetylacetone resp. salicylaldehyde with benzoylhydrazine, thiobenzoylhydrazine, 2-hydroxyaniline and 2-mercaptoaniline as well as with the ligands 2-(2′-hydroxy-4-methylphenyl)-6-(2″-hydroxyphenyl)pyridine, 2-(2′-hydroxyphenyl)-8-quinolinol and 2.6-diphenacylpyridine were synthesized. The compounds were characterized by IR-, UV/VIS-, MS-, ¹¹⁹Sn NMR and ^119mSn Mössbauer spectroscopy. They exist as a mixture of geometrical isomers.     

Zum Ligandenaustausch an TcNX4−-Komplexen (X = Cl,Br)

Ligand-Exchange Reactions on TcNX₄^? Complexes (X = Cl, Br) Ligand exchange reactions on the nitridotechnetium(VI) compounds (Bu₄N)TcNCl₄ and (Bu₄N)TcNBr₄ are reported. The use of various organic ligands having different donor atom sets produces Tc^V nitrido complexes. The reaction of (Bu₄N)TcNCl₄ with (Bu₄N)TcNBr₄ is characterized by the formation of Tc^VI complex species with mixed Cl/Br coordination spheres. EPR detection of the mixed-ligand complexes results in a well-defined dependence of the EPR parameters on the composition of the first coordination sphere of the complexes.     

Elektronenstruktur von strukturell offenen Derivaten des [Mo6X14]2−-Clusters: [Mo5Cl13]2− und [Mo4I11]2−

Electronic Structure of Structural Open Derivatives of the [Mo₆X₁₄]^2?-Cluster: [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? The electronic structure of structural open derivatives of the [Mo₆X₁₄]^2?-cluster [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? has been studied by the EHMO method. In [Mo₅Cl₁₃]^2? 9 occupied MO's with dominant Mo4d character are responsible for the formation of the 8 metal-metal bonds. In [Mo₄I₁₁]^2? the stronger covalent character of the Mo? I bonds affects the localization and the energy of molecular orbitals and also the charge distribution. The metal-metal bonds are formed by 8 MO's containing considerable participation of halogen AO's contrary to the chloride cluster. There is no bonding between the Mo atoms at the wing tips of the Mo₄ butterfly and the reason for decreasing the dihedral angle between the Mo₃ planes in [Mo₄I₁₁]^2? compared with the octahedral angle is apparently the stabilization of the whole system (Mo? Mo and Mo? I bonds). The unpaired electron occupies in both clusters a slightly antibonding (with regard to the Mo? Mo bonds) orbital.