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.     

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.     

Synthese und Struktur von MII[AuF4]2 (MII  Cd,Hg)

Synthesis and Structure of M^II[AuF₄]₂ (M^II ? Cd, Hg) Cd[AuF₄]₂ and the isotypic compound Hg[AuF₄]₂, both are yellow, crystallize tetragonal in the space-group P4/mcc-D (No. 124) with a = 575.0/575.6 pm, c = 1034.8/1042.3 pm and Z = 2. The single-crystals were obtained by solid-state reactions in goldtubes.     

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.     

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.     

Atran-analoge Verbindungen III. Atran-analoge Verbindungen des Typs Me2DCH2CH2OSi(Me) (OCH2CH2)2D′ Me (I) und Me2DCH2CH2OSi(Me) (OCH2CH2D′Me2)OCH2CH2D″ Me2 (II) (MeCH3; D,D′, D‴N,P, As)

Atrane-analogous Compounds. III. Atrane-analogous Compounds of the Type Me₂DCH₂CH₂OSi(Me)(OCH₂ CH₂)₂ D′Me (I) and Type Me₂DCH₂CH₂OSi(Me) OCH₂CH₂₂D″Me₂ (II) (Me?CH₃; D, D′, D″?N, P, As) Atrane analogous compounds I and II (Abb. 1) have been prepared by condensation reactions of trifunctional silanes RSiX₃ (X?Cl, OEt, NMe₂) with N-methyldiethanolamine, ß-chloroethanol, ß-dimethylaminoethanol, and ß-dimethylarsanoethanol according to eqn. (1) to (3) and reaction schemes of Figs. 2 and 3, respectively. For compounds of type I weak N→Si adduct bonding is indicated for the MeN-donor of the eight-membered ring by significant shifts of the MeNCH₂ and OCH₂ proton n.m.r. signals. For compounds of type II there is no n.m.r. evidence for D→Si interactions. In spite of equal Lewis acidity of the Si atoms differences in adduct formation are observed for cage, ring, and acyclic podand systems, which can be explained mainly by entropy effects connected to the formation of five-membered rings.     

Silaethene. III. Versuche zur Darstellung und spektroskopischen Charakterisierung von H2SiCH2, D2SiCH2 und Me(H)SiCH2

Silaethenes. III. Preparation and Spectroscopic Characterization of H₂Si?CH₂, D₂Si?CH₂, and Me(H)Si?CH₂ H₂Si?CH₂ and D₂Si?CH₂ are formed together with ethene and propene by gas phase pyrolysis at low pressure (10^?2–10^?3 mbar) from the corresponding mono- or 1,3-disilacyclobutanes in good yield and are characterized by i.r. and mass spectroscopic methods. Formation of propene can be explained by following reactions of the silaethene intermediate using a “head-to-head” mechanism. H₂Si?CH₂ can be stored at ?196°C for several months and can be transferred by trap-to-trap distillation in a vacuum system. Similar results are obtained for .     

Zur Strukturchemie der Verbindungsreihe BaMg2X2 (X  Si,Ge, Sn,Pb)

On the Structural Chemistry of BaMg₂X₂ (X ? Si, Ge, sn, Pb) The new compounds BaMg₂X₂ (X ? Si, Ge, Sn, Pb) have been prepared and their structures have been determined. BaMg₂Si₂ and BaMg₂Ge₂ crystallize in the ThCr₂Si₂-type, BaMg₂Sn₂ and BaMg₂Pb₂ show two new atomic arrangements, which are layer variants of the former type.     

Zur Bildung und Struktur der Phosphinophosphiniden-phosphorane tBu2P?PP(Me)tBu2 1, tBu(Me3Si)P?PP(Me)tBu2 2 und tBu2P?PP(Br)tBu2 3

Synthesis and Structure of Phosphinophosphinidene-phosphoranes tBu₂P? P?P(Me)tBu₂ 1, tBu(Me₃Si)P? P?P(Me)tBu₂ 2, and tBu₂P? P?P(Br)tBu₂ 3 A new method for the synthesis of 1 and 2 (Formulae see ?Inhaltsübersicht”?) is reported based on the reaction of 5 with substitution reagents (Me₂SO₄ or CH₃Cl). The results of the X-ray structure determination of 1 and 2 are given and compared with those of 3 . While in 3 one P? P distance corresponds to a double bond and the other P? P distance to a single bond (difference 12.5 pm) the differences of the P? P distances in 1 and 2 are much smaller: 5.28 pm in 1 , 4.68 pm in 2 . Both 1 and 2 crystallize monoclinic in the space group P2₁/n (Z = 4). 2 additionally contains two disordered molecules of the solvent pentane in the unit cell. Parameters of 1 : a = 884.32(8) pm, b = 1 924.67(25) pm, c = 1 277.07(13) pm, β = 100.816(8)°, and of 2 : a = 1 101.93(12) pm, b = 1 712.46(18) pm, c = 1 395.81(12) pm, β = 111.159(7)°, all data collected at 143 K. The skeleton of the three P atoms is bent (PPP angle 100.95° for 1 , 100.29° for 2 and 105.77° for 3 ). Ab initio SCF calculations are used to discuss the bonding situation in the molecular skeleton of the three P atoms of 1 and 3 . The results show a significant contribution of the ionic structure R₂P? P(^?)? P(⁺)(X)R₂. The structure with (partially) charged P atoms is stabilized by bulky polarizable groups R (as tBu) as compared to the fully covalent structure R₂P? P(X)? PR₂.     

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.     

Perfluormethyl-Element-Liganden. XXXV. Reaktivität metallierter Phosphane und Arsane des Typs π-C5H5(CO)3MER2 (M  Cr,Mo, W; E  P,As; R  CF3, CN)

Perfluoromethyl-Element-Ligands. XXXV. Reactivity of Metallated Phosphanes and Arsanes of the Type π-C₅H₅(CO)₃MER₂ (M ? Cr, Mo, W; E ? P, As; R ? CF₃, CN) The influence of the complex fragments π-C₅H₅(CO)₃M (M ? Cr, Mo, W) on the basicity of the metallated phosphanes or arsanes π-C₅H₅(CO)₃MER₂ (E ? P, As; R ? CF₃, CN) has been investigated by reactions with sulfur, methyliodide, fluorotrichloromethane, and W(CO)₅THF, respectively. π-C₅H₅(CO)₃ME(CF₃)₂ (E ? P: 1a–c ; E ? As: 2a–c ) react with sulfur only for E ? P to give the complexes π-C₅H₅(CO)₃P(S)(CF₃)₂ ( 5a–c ) in good yield. The attempted thermal transformation of the phosphane sulfides to η² coordinated (CF₃)₂P?S complexes proves unsuccessful. The reactions of 1a–c, 2a–c and π-C₅H₅(CO)₃MP(CN)₂ ( 3a–c ) with CH₃I or CCl₃F do not lead to onium salts, but to cleavage of the M–E bonds forming π-C₅H₅(CO)₃MX (X ? I, Cl) and CH₃ER₂ and R₂ECCl₂F, respectively. The reactivity depends on ER₂ and M: P(CF₃)₂ > P(CN)₂ > As(CF₃)₂; Cr > Mo > W. Due to the low donor ability of the complexes 1a–c, 2a–c and 3a–c binuclear compounds π-C₅H₅(CO)₃MER₂W(CO)₅ (E ? As, R ? CF₃: 11a–c ; E ? P, R ? CN: 12a–c ; ER₂?P(CN)Ph: 13a, b ) are obtained only with the highly reactive W(CO)₅THF. In case of the (CF₃)₂P bridged derivatives spontaneous CO-elimination leads to the threemembered ring systems ( 10a–c ).