Synthesen und Kristallstrukturen von Cu‐ und Ag‐Komplexen mit Dithiophosphinat‐ und Trithiophosphonat‐Liganden

Syntheses and Crystal Structures of Copper and Silver Complexes containing Dithiophosphinato and Trithiophosphonato Ligands The reactions of Cu^I and Ag^I salts with diphenyldithiophosphinic acid trimethylsilylester in the presence of tertiary phosphines yield the complexes [Cu(μ‐S)SPPh₂(PR₃)]₂ (R = Me 1a , ⁱPr 1b ), [Ag(μ‐S)SPPh₂(PⁿPr₃)]₂ ( 2 ), [Ag(S₂PPh₂)(PEt₃)]₂ ( 3 ), and [Cu₈(μ₈‐S)(S₂PPh₂)₆] ( 4 ). The cage complex [(PhPS₃)₂Cu₄(PMe₃)₅] ( 5 ) is obtained by the reaction of phenyltrithiophosphonic acid trimethylester. All compounds were structurally characterised by X‐ray crystallography.     

Neue Sr‐Verbindungen mit planaren Al‐Si/Ge‐Anionen und eine Korrektur zu SrSi‐II und SrGe0.76

New Sr Compounds with Planar Al‐Si/Ge Anions and a Correction of SrSi‐II and SrGe_0.76 Planar anions with considerable p_π‐p_π interactions between heavier group 13 and 14 elements are observed in several alkaline earth trielides and tetrelides. In the intermetallics of the series SrAlxGe_2?x (border phases: x = 1: , a = 429.4(3), c = 474.4(3) pm, Z = 1, R1 = 0.0305, SrPtSb type and x = 1.6: P6/mmm, a = 440.4(2), c = 478.2(2) pm, Z = 1, R1 = 0.0125, AlB₂ type) graphite analogue planar Al/Ge nets with short Al‐Ge bonds are stacked in identical orientation, showing inter‐layer distances of approx. 475 pm. Starting from the related planar ribbons of condensed six‐membered rings in the known intermetallics (M^IV = Si, Ge) a series of new metal‐rich oxides with chain pieces consisting of three, two and finally only one six‐membered ring have been prepared and characterized on the basis of single crystal X‐ray data. The formal fragmentation of the ribbons is achieved by the incorporation of [OSr₆] octahedra, chains of which (connected via common corners) exactly fit the distance between the planar anions. The structures of the two compounds (M^IV = Si, Ge; formerly erroneously reported as SrSi and SrGe_0.76, space group Immm, a = 482.48(5)/484.55(8), b = 1306.5(2)/1342.2(2), c = 1814.0(2)/1857.4(3) pm, Z = 2, R1 = 0.0369/0.0316) contain isolated planar anions [M₂Al₂M₂Al₂M₂]^18? with only one six‐membered ring. In the monoclinic structures of the silicide Sr₁₃[Al₆Si₈][O] (C2/m, a = 2245.1(4), b = 482.76(5), c = 1720.6(5) pm, β=125.21(2)°, Z = 2, R1 = 0.0579) and the germanide Sr₁₆[Al₈Ge₁₀][O] (C2/m, a = 2287.23(14), b = 484.94(3), c = 2065.70(13) pm, β=120.150(4)°, Z = 2, R1 = 0.0730) anions [Si₂Al₂Si₂Al₂Si₂Al₂Si₂] and [Ge₂M₂Ge₂M₂Ge₂M₂Ge₂M₂Ge₂] with two and three six‐membered rings are left as fragments of the ribbons in Sr₃Al₂M₂. The puzzling bonding situation in these type of polar intermetallics at the Zintl border is calculated (using the DFT FP‐LAPW approach) for the structures with manageably small unit cells and discussed for the series SrAlM – Sr₃Al₂M₂ – Sr₁₆[Al₈M₁₀][O] – Sr₁₃[Al₆M₈][O] – Sr₁₀[Al₄M₆][O].     

Ligandstabilisierte cyclische und polycyclische Aluminium‐Phosphor‐ und Aluminium‐Arsen‐Verbindungen

Ligand Stabilized Cyclic and Polycyclic Aluminium Phosphorus and Aluminium Arsenic Compounds The reaction of AlCl₃ with Li₂AsSiRMe₂ (R = CMe₂iPr) in a mixture of ether and heptane yields the ether stabilized polycyclic compound [(AlCl)₄(AsSiRMe₂)₄(Et₂O)₂] ( 4 ) with a ladder shaped Al₄As₄ core structure. The shape of 4 is mostly similar to the aluminium phosphorus compound [(AlCl)₄(PSiiPr₃)₄(Et₂O)₂] ( 1 ) described recently [1]. These two compounds 1 and 4 can be cleaved into the cyclic compounds [{AlCl(C₅H₅N)}₂(PSiiPr₃)₂] ( 3 ) and [{AlCl(NEt₃)}₂(AsSiRMe₂)₂] ( 5 ) by reaction with pyridine and NEt₃, respectively. The compounds 3 , 4 , and 5 have been characterized by single crystal X‐ray diffraction.     

Synthese und Charakterisierung neuer cyclischer und käfigartiger Indium‐Phosphor‐ und Indium‐Arsen‐Verbindungen

Synthesis and Characterization of New Cyclic and Cage‐like Indium — Phosphorus and Indium — Arsenic Compounds The reaction of InEt₃ with H₂ESiiPr₃ initially yields the cyclic compound [Et₂InP(H)SiiPr₃]₂ ( 2 ). 2 appears as a mixture of cis and trans isomers and has been characterized by ³¹P‐NMR spectroscopy, IR spectroscopy, and mass spectrometry. 2 decomposes in solution under elimination of ethane during a few days to form [EtInPSiiPr₃]₄ ( 3 ) with a cage‐like structure. The analogous arsenic compound [EtInAsSiiPr₃]₄ ( 4 ) can be prepared by reaction of InEt₃ with H₂AsSiiPr₃. Central structural motif of 3 and 4 is an In₄E₄ heterocubane like structure (E = P, As), whereas the reaction of InEt₃ with H₂PSiMe₂Thex (Thex = CMe₂iPr) yields [EtInPSiMe₂Thex]₆ ( 5 ) with a hexagonal prismatic structure.     

HMBC‐ und NOESY‐NMR‐Spektroskopie

In this article we first discuss the NMR pulse sequence HMBC (heteronuclear multiple bond correlation) and demonstrate its importance for the final structure verification of the natural product cytisine. The ¹H‐, ¹³C‐, COSY‐ und HSQC‐spectra of this compound have been shown in the first two articles of this series. After this we explain the physics of the NOESY‐experiment (nuclear Overhauser effect spectroscopy) and apply this for the stereochemical assignment of the proton signals. A correlation diagram between NOE integrals and hydrogen atom distances proofs the correct analysis.