Structures and isomerizations of carbenoids H2CCCLiX (X  F,Cl)

Novel structures of H₂C?C?CLiX (X ? F, Cl) were determined using HF/STO-3G gradient method. Both of the carbenoids have two equilibrium structures, askew and linear forms, at the level of calculation. In the case X?F, the former is more stable, but in the case X=Cl, the latter is more stable. The frontier MOs are given and analyzed.     

Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Kristallstrukturuntersuchungen an Verbindungen des Typs A3(M,Nb)8O21 (A  Tl,Ba; M  Fe,Ni)

Crystal Structure Investigations of Compounds with the A₃(M, Nb)₈O₂₁-Type (A ? Tl, Ba; M ? Fe, Ni) Tl₃Fe_0,5Nb_7,5O₂₁ (A), a hitherto unknown phase of the A₃(M, Nb)₈O₂₁-type, and Ba₃Fe₂Nb₆O₂₁ (B), Ba₃Ni_1.33Nb_6,66O₂₁ (C) were prepared and investigated by single crystal X-ray technique. ((A): a = 9.145(1), c = 11.942(1) Å; (B): a = 9.118(2), c = 11.870(1) Å; (C) a = 9.173(3), c = 11.923(1) Å, space group D? P6₃/mcm, Z = 2). There is a statistic occupation of the M-positions by Nb⁵⁺ and Fe³⁺ or Nb⁵⁺ and Ni²⁺, respectively. An other compound Ba₃Fe₂Ta₆O₂₁ is partially ordered in respect to Ta⁵⁺ and Fe³⁺. Calculations of the Coulomb-part of lattice energy are discussed.     

Alternativ-Liganden. III. Koordinatives verhalten von chelatliganden des typs me2XSi(Me2)CH2XMe2 (X  N und/oder P: Me  CH3)

Co-ordinative Properties of Chelating Ligands of the Type Me₂XSi(Me₂)CH₂XMe₂ (X ? N and/or P; Me ? CH₃) The reactions of the ligands L ? Me₂XSi(Me₂)CH₂XMe₂ (X ? N and/or P; Me ? CH₃) with M(CO)₆ and M(CO)₄norbor (norbor ? norbornadiene) (M ? Cr, Mo), respectively, yield derivatives of the types M(CO)₅L, M(CO)₄L, and M(CO)₄L₂, respectively. M(CO)₅L compounds are formed from the hexacarbonyls with Me₂NSiMe₂CH₂PMe₂, whereas the ligand Me₂NSiMe₂CH₂NMe₂ does not afford analogous derivatives under the same conditions. Even on substitution of the diene-ligand in M(CO)₄norbor by Me₂NSiMe₂CH₂PMe₂ the chelate complexes M(CO)₄NMe₂SiMe₂CH₂PMe₂ are not obtained, but the cis-disubstituted products M(CO)₄[PMe₂CH₂SiMe₂NMe₂]₂ with phosphorus acting as donor atom are produced. The ligands Me₂PSiMe₂CH₂XMe₂(X ? N, P) give the chelate complexes M(CO)₄PMe₂SiMe₂CH₂XMe₂ in high yields. The new compounds were identified by analytical and spectroscopic (PMR, IR, mass spectra) methods.     

The distonic ions HO+CHCH2C˙H2 and CH3C(O+H)CH2C˙H2

The distonic ions HO⁺?CHCH₂C^˙H₂ (1) and CH₃C(?O⁺H)CH₂C^˙H₂ (2) were directly generated, their decompositions characterized and their appearance energies determined by photoionization. Heats of formation derived from the appearance energies were 757 kJ mol^?1 for 1 and 692 kJ mol^?1 for 2. Deuterium labeling demonstrates that both ions decompose at low energies in the same ways as their isomers with the same skeletal structures, consistent with proposals that 1 and 2 are intermediates in the decompositions of those systems. Surprisingly, the values of the translational energy releases accompanying the formation of CH₃CO⁺ and C₂H₅CO⁺ from 2 appear to be inversely proportional to the available excess energy. The 1,2-H-shift RC(?O⁺H)CH₂C˙H₂ → RC(?O₊H)C˙HCH₃ is compared to the corresponding, non-occurring 1,2-H-shift in alkyl free radicals.     

Zur Kenntnis des RbNiCrF6-Typs: über CsCuMF6 (M  NiIII,TiIII), CsMgMF6 (M  Co,Fe, Ga) und CsZnMF6 (M  NiIII,CoIII, FeIII)

On the RbNiCrF₆ Type(¹): On CsCuMF₆ (M?Ni^III, Ti^III), CsMgMF₆ (M ?Co, Fe, Ga), and CsZnMF₆ (M?Ni^III, Co^III, Fe^III) New prepared are the cubic compounds CsCuNi^IIIF₆ (dark brown, a = 10.14 Å); CsZnNi^IIIF₆ (dark brown, a = 10.17 Å); CsCuTi^IIIF₆ (light grey, a = 10.39 Å); CsMgGaF₆ (colourless, a = 10.23 Å); CsMgFeF₆ (colourless, a = 10.53 Å); CsZnFeF₆ (colourless, a = 10.42 Å); CsMgCo^IIIF₅ (light blue, a = 10.27 Å) and CsZnCo^IIIF₆ (light blue, a = 10.34 Å), all RbNiCrF₆-type of structure. The Madelung part of lattice energy, MAPLE, is calculated and discussed.     

Über die Existenz von Verbindungen des Typs Hg2XA (X  Halogen,A  Anion ≠ Halogen) und Hg2XY (X und Y Halogen)

Existence of Hg₂XA (X ? Halide, A ? Anion ≠ Halide) and Hg₂XY Compounds (X and Y Halide) Investigations in molten mercuric bromide HgBr₂ [1, 2] and comparing considerations between mercuric and mercurous chemistry lead to the till now unknown or less investigated compounds Hg₂XA and Hg₂XY (X, Y halide; A anion ≠ halide). Using TGA and DTA measurements in order to improve the reaction conditions Hg₂XClO₄ salts could be synthesized, whereas the hydrogene sulfates Hg₂XHSO₄ are formed in concentrated sulfuric acid (crystalline, instable by solvent removing). Powder diagrams and spectrochemical investigations point our that the lattices of the isolated mixed halides Hg₂BrCl, Hg₂BrI, and Hg₂ClI contain not only the pure molecules Hg₂X₂ and Hg₂Y₂ but also the mixed molecules Hg₂XY. Final statements need X-ray investigations.     

From Disilene (SiSi) to Phosphasilene (SiP) and Phosphacumulene (PCN)

The generation of heavier double‐bond systems without by‐ or side‐product formation is of considerable importance for their application in synthesis. Peripheral functional groups in such alkene homologues are promising in this regard owing to their inherent mobility. Depending on the steric demand of the N‐alkyl substituent R, the reaction of disilenide Ar₂Si?Si(Ar)Li (Ar=2,4,6‐iPr₃C₆H₂) with ClP(NR₂)₂ either affords the phosphinodisilene Ar₂Si?Si(Ar)P(NR₂)₂ (for R=iPr) or P‐amino functionalized phosphasilenes Ar₂(R₂N)Si? Si(Ar)?P(NR₂) (for R=Et, Me) by 1,3‐migration of one of the amino groups. In case of R=Me, upon addition of one equivalent of tert‐butylisonitrile a second amino group shift occurs to yield the 1‐aza‐3‐phosphaallene Ar₂(R₂N)Si? Si(NR₂)(Ar)? P?C?NtBu with pronounced ylidic character. All new compounds were fully characterized by multinuclear NMR spectroscopy as well as single‐crystal X‐ray diffraction and DFT calculations in selected cases.