Darstellung und Kristallstruktur der Kupfer(I)-chalkogenolat-2,2′-Bipyridin-Komplexe [CuS(2,4,6-iPr3C6H2)]4(Bipy)2 und [CuSe(2,4,6-iPr3C6H2)]2(Bipy)2

Synthesis and Structure of Copper(I)Chalcogenolate-2,2′-Bipyridine Complexes [CuS(2,4,6-iPr₃C₆H₂)]₄(Bipy)₂ and [CuSe(2,4,6-iPr₃C₆H₂)]₂(Bipy)₂ The oligomeric homoleptical copper(I) chalcogenolate compounds [CuS(2,4,6-iPr₃C₆H₂)]_x=4,8 and [CuSe(2,4,6-iPr₃C₆H₂)]₆ react with 2,2′-bipyridine (Bipy) to yield the tetranuclear complex [CuS(2,4,6-iPr₃C₆H₂)]₄(Bipy)₂ ( 4 ) and the dinuclear complex [CuSe(2,4,6-iPr₃C₆H₂)]₂(Bipy)₂ ( 5 ). The structures of 4 and 5 were determined by X-ray analysis. In the eight-membered Cu₄S₄ core of 4 with chair conformation the copper atoms are linked by μ₂-bridging selenolate ligands. Only two copper atoms are coordinated by 2,2′bipyridine. The corresponding copper(I) selenolate complex ( 5 ) forms a folded four-membered Cu₂Se₂ ring with μ₂-bridging selenolate ligands. The Cu? Cu distance of 2.52 Å is relatively short. In contrast to the reaction performed with 2,2′-bipyridine, addition of phenantroline to 1 respectively 2 yields a dinuclear complex [CuS(2,4,6-iPr₃C₆H₂)]₂(Phen)₂ ( 10 ). NMR spectroskopic and cryoscopic measurement of 4 show that this complex dissociates into smaller fragments in solution which undergo rapid exchange reactions. However, corresponding investigations performed on 5 indicate that the solid state structure is maintained in solution. The electrochemical behaviour of 4, 5 and 10 was studied in CH₂Cl₂ and in any case no reversible redox processes could be observed.     

Untersuchungen zu Synthese und Reaktionen von Fluorphenylquecksilber-Derivaten mit den Liganden 2-FC6H4, 2,6-F2C6H3 und 2,4,6-F3C6H2

Investigations on Syntheses and Reactions of Fluorophenylmercury Compounds with the Ligands 2-FC₆H₄, 2,6-F₂C₆H₃, and 2,4,6-F₃C₆H₂ 2,6-F₂C₆H₃HgCl and 2,4,6-F₃C₆H₂HgCl are synthesized via the reactions of the corresponding phenylmagnesium compounds and HgCl₂. 2-FC₆H₄HgCl is selectively obtained only in a reaction involving intermediately formed Cd(2-FC₆H₄)₂. The diphenylmercury derivative Hg(2,4,6-F₃C₆H₂)₂ is obtained while stirring a dichloromethane solution of 2,4,6-F₃C₆H₂HgCl for several days. The direct mercuration of 1,3,5-trifluorobenzene with Hg(OCOCF₃)₂ yields, depending on the stoichiometry, 2,4,6-trifluorophenylmercury trifluoroacetate and 1,3-bis(trifluoroacetatomercuri)-2,4,6-trifluorobenzene which is converted into the corresponding chloromercuri derivative by treatment with hydrochloric acid in CH₃CN. As a product of the reaction of 1,3,5-trifluorobenzene and HgO in CH₃COOH only 2,4,6-trifluorophenylmercury acetate is isolated although spectroscopic evidence has been found for double and triple mercurated derivatives. All compounds are characterized by elemental analyses, nmr and mass spectra. The reaction of Hg(2,4,6-F₃C₆H₂)Cl and Cd(CF₃)₂ · 2 CH₃CN gives Hg(2,4,6-F₃C₆H₂)CF₃ which slowly dismutates in CH₂Cl₂ solution into Hg(2,4,6-F₃C₆H₂)₂ and Hg(CF₃)₂. The ligand exchange of Hg(2,4,6-F₃C₆H₂)₂ and TeCl₄ selectively gives Te(2,4,6-F₃C₆H₂)₂Cl₂ and Hg(2,4,6-F₃C₆H₂)Cl. Transmetalations of Hg(2,4,6-F₃C₆H₂)₂ and gallium or tin give NMR spectroscopic evidence for the new derivates Ga(2,4,6-F₃C₆H₂)₃ and Sn(2,4,6-F₃C₆H₂)₄.     

Synthese und Charakterisierung von Aquapentachloroplatinaten(IV) – Struktur von [K(18-Krone-6)][PtCl5(H2O)]

Synthesis and Characterization of Aquapentachloroplatinates(IV) – Structure of [K(18-crown-6)][PtCl₅(H₂O)] The crown ether complex of the aquapentachloroplatinic acid of the composition [H₁₃O₆][PtCl₅(H₄O₂)] · 2(18-cr-6) ( 2 ) reacts with K₂CO₃ and [NⁿBu₄]OH in aqueous solution to give [K(18-cr-6)][PtCl₅(H₂O)] ( 5 a ) and [NⁿBu₄][PtCl₅(H₂O)] · ¹/₂ (18-cr-6) · H₂O ( 5 b ), respectively. Both compounds were characterized by microanalysis, vibrational (IR, Raman) and NMR (¹H, ¹³C, ¹⁹⁵Pt) spectroscopy. The X-ray structure analysis of 5 a (orthorhombic, pnma; a = 16,550(4), b = 18,044(3), c = 7,415(1) Å; Z = 4; R1 = 0,0183; wR2 = 0,0414) reveals that the crystal is threaded by chains built up of [PtCl₅(H₂O)]^? and [K(18-cr-6)]⁺ units. There are tight K …? Cl contacts (d(K? Cl1)) = 3,0881(9) Å and O_W? H? O_cr hydrogen bridges (d(O1 …? O2) = 2,806(3) Å) between these units. The coordination polyhedron [PtCl₅O] has approximately C_4v symmetry.     

Synthese,Struktur und magnetische Eigenschaften von [CrCl(μ-Cl)(TMEDA)]2

Synthesis, Structure, and Magnetic Properties of [CrCl(-μCl)(TMEDA)]₂ The title complex [CrCl(μ-Cl)(TMEDA)]₂ ( 1 ) is obtained in an equimolar reaction of CrCl₂(THF) with TMEDA in high yield. 1 crystallises in the monoclinic space group P2₁/c with a = 843.2(2), b = 1 109.(2), c = 1 147.4(3) pm, β = 102.99(2)° and Z = 2. The molecular structure of 1 contains two, slightly distorted quadratic pyramidal CrL₅-subunits, which are linked via two unsymmetrical Cl-bridges. The μ-Cl-functions take the apical position of one and a basal position of the second CrL₅-unit, wherein the apical Cr–Cl bond (277.6(1) pm) is destinctly longer than the basal Cr–Cl bond (240.6(1) pm). The terminal Cr–Cl bond is still shorter (237.5(1) pm). The Cr…Cr distance is far beyond any bonding interaction. This is confirmed by means of magnetic susceptibility measurements, which show four unpaired electrons per Cr centre; however, a small antiferromagnetic coupling of J/k = ?7.3 K can be calculated. This coupling is suggested to be originated by a 90°-σ-superexchange via the asymmetric μ-Cl functions.