Monomere und dimere Oxovanadium(IV)-phenolate: Synthese,Struktur und Reaktionen mit reduzierenden und arylierenden Reagenzien

Monomeric and Dimeric Oxovanadium(IV)-phenolate Complexes: Synthesis, Structure, and Reaction with a Reducing and Arylation Agent Reaction of [OVCl₂(THF)₂] with LiOMes yields dimeric [Li(Et₂O)₂OVCl₂(μ-OMes)]₂ ( 1 ) which can be converted with excess LiOMes to the substitution product [Li(THF)₂OV(OMes)₃(THF)] ( 2 ). Treatment of ( 1 ) with LiMes results in the formation of complexes [Li(THF)₃OVMes₃] ( 3 ) and [Li(THF)₃OVMes₂(OMes)] ( 4 ). Complex [{Li(THF)₂OV(OMes)₂(μ-OH)}₂ · 2 THF] ( 6 ) has been isolated as a by-product of an unknown reaction of [OV(OMes)₃] and Li. The structures of 1 , 2 , 3 , and 6 have been determined by X-ray analysis. In 1 (monoclinic, P2₁/c, a = 9.522(1) Å, b = 19.777(2) Å, c = 12.311(1) Å, β = 104.45(1)°, Z = 2) the vanadium atoms which are bridged by the phenolate ligands show a square-pyramidal coordination sphere. The central atom in 2 (monoclinic, P2₁/c, a = 17.755(2) Å, b = 11.629(1) Å, c = 20.956(3) Å, β = 113.98(1)°, Z = 4) has a bipyramidal environment which is realized by coordination of a THF donor molecule. The (THF)₂Li fragment is bound via bridging phenolate ligands. The structure of 3 (orthorhombic, P2₁2₁2₁, a = 15.465(2) Å, b = 15.456(2) Å, c = 15.469(2) Å, Z = 4) is built up by two tetrahedrons linked by the oxo atom. Dimeric 6 (triclinic, P1, a = 10.780(4) Å, b = 11.428(2) Å, c = 13.734(3) Å, α = 77.24(2)°, β = 84.79(2)°, γ = 74.35(2)°, Z = 1) has a structure similar to 1 . The vanadium atoms are bridged by two OH groups while phenolate ligands link the lithium cations with the vanadium atoms.     

Struktur von S-9,10-Dimethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantan und 9,10-Diethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantan

Structure of S-9,10-Dimethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantane and 9,10-Diethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantane S-9,10-Dimethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantane ( 1 ) and 9,10-diethyl-1,3,5,7-tetraarsa-2,4,6,8-tetraoxaadamantane ( 2 ) have been prepared by the reaction of propionic acid, propionic anhydride and butyric acid, butyric anhydride, respectively, with arsenic(III)-oxide. The crystals of 1 are rhombic, a = 6.902(4), b = 11.121(5), c = 13.988(8), space group P2₁2₁2₁. The crystals of 2 are monoclinic, a = 11.757(10), b = 11.255(10), c = 18.631 (18), β = 91.78(7), space group P2₁/n. The mean bond lengths and angles in 1 are AsO = 1.790 Å, AsC = 1.959 Å, OAsO = 100.60°, CAsO = 99.65°, AsOAs = 128.77°, AsCAs = 118.73°, and in 2 they are AsO = 1.780 Å, AsC = 1.978 Å, OAsO = 101.45°, CAsO = 99.55°, AsOAs = 129.64°, AsCAs = 117.72°.     

Struktur und ausgewählte Reaktionen von ReCl4(PPh3)2

ReCl₄(PPh₃)₂ – Reactions and Structure The compounds ReCl₄(PPh₃)₂ and Re₂OCl₃(C₂H₅COO)₂(PPh₃)₂ resulting from the reaction of ReOCl₃(PPh₃)₂ with PPh₃ in boiling propionic acid and HCl atmosphere were characterized by their VIS-spectra and structural data. Ligand exchange reactions with acetylacetone gave ReCl₂(acac)₂ as well as ReCl₂(acac)(PPh₃)₂. Crystallographic data see “Inhaltsübersicht”.     

Bildung Siliciumorganischer Verbindungen. LV. Die Konformeren des 1,3,5,7-Tetrasila-bicyclo[3,3,1]nonans und 2,4,6,8,9-Pentasila-bicyclo[3,3,1]nonans

Formation of Organosilicon Compounds. LV. Conformeres of the 1,3,5,7-Tetrasilabicyclo [3,3,1] nonane and 2,4,6,8,9-Pentasila-bicyclo [3,3,1] nonane Two types of carbosilanes with a bicyclo [3,3,1] nonane structure are reported, derivatives of 1,3,5,7-Tetrasila-bicyclo-[3,3,1] nonane (a) and of 2,4,6,8,9-Pentasila-bicyclo [3,3,1] nonane (b) with an inverse structure in respect to the Si- and C-atoms. By means of NMR-investigations the structure can be determined. Derivatives of (a) are present in the Si₄C₁₁H₂₈ with fully methylated Si-atoms, the 1,5 dichloro-1,3,5,7-tetrasila-bicyclo [3,3,1] nonane and Si₄Cl₆C₅H₁₀ with fully chlorinated Si-atoms with twofold boat conformation. In the derivatives of type (b) as Si₅H₁₀C₄H₆ with hydrogenated Si-atoms as well as in 9,9-dichloro-2,4,6,8,9-pentasila-bicyclo [3,3,1] nonane a change in conformation is observed, whereas a rigid chair conformation is found for both rings in the Si-chlorimated derivative Si₅Cl₁₀C₄H₁₀. A comparison of atom-resp. H? H distances in cyclohexane and 1,3,5-Trisilacyclohexane gives evidence that the boat conformation is more preferable for the 1,3,5-Trisilacyclohexane than for cyclohexane due to larger H? H-distances (caused by Si? C-distances).     

Darstellung,Struktur und Reaktionen von N,N-Difluorsulfonyl-fluoridamid

Preparation, Structure, and Reactions of N,N-Difluorosulfonylfluoridamide FSO₂NF₂ is obtained in high yield by fluorination of FSO₂NH₂ at room temperature. The reaction of FSO₂NF₂ with Et₂NH yields FSO₂NEt₂ and HNF₂. The structure of FSO₂NF₂ was determined by electron diffraction analysis.     

Spezifische und selektive Reaktionen (Reagenzien)

Ohne Zusammenfassung     

Bildung siliciumorganischer Verbindungen. 83. Bildung,Reaktionen und Struktur von Yliden aus perchlorierten Carbosilanen

Formation of Organosilicon Compounds. 83. Formation, Reactions, and Structure of Ylides Generated from Perchlorinated Carbosilanes The CCl-moiety in perchlorinated carbosilanes as (Cl₃Si)₂ a, Cl₃Si? CH₂? SiCl₂? CCl₂? SiCl₃ b, (Cl₃Si? CCl₂)₂SiCl₂ c or (Cl₂Si? CCl₂)₃ d, e.g., cleaves the Si? P bond of me₃Si? Pme₂ e (me = CH₃); and by subsequent rearrangement ylides are formed. Such, treating e with a yields (Cl₃Si)₂CPme₂Cl 1, which also results from the reaction of me₂P? Pme₂ with a. The ylides also can be obtained by means of treating the carbosilanes a, b, c or d with LiPme₂. Thus, c with one mole of LiPme₂ yields Cl₃Si? CCl₂? SiCl₂? C(Pme₂Cl)? SiCl₃ or Cl₃Si? C(Pme₂Cl)? SiCl₂? C(Pme₂Cl)? SiCl₃, resp., with two moles of LiPme₂. The corresponding Si-methylated derivates do not form ylides; (me₃Si)₂CCl₂, e.g., with e in benzene yields me₃Si? CH(Pme₂)? Sime₃. One mole of Lime methylates 1 to yield (Cl₃Si)₂CPme₃ 11. With either LiPme₂, me₃Si? Pme₂ or Me₂P? Pme₂ 1 forms (Cl₃Si)₂CPme₂-Pme₂. Reacting 1 with CH₃OH/(C₂H₅)₂NH, (Cl₃Si)[SiCl₂(OCH₃)]CPme₂(OCH₃) is formed. Ylides also result from the reactions of partially C-chlorinated 1,1,3,3,5,5-hexachloro-1,3,5-trisilacyclohexanes with me₃Si? Pme₂, (Cl₂Si? CCl₂)₃ with three moles of me₃Si? Pme₂ or LiPme₂, resp., yields (Cl₂Si? CPme₂Cl)₃ 16, the 1,1,3,3,5,5-Hexachlor-2,4,6-tris(chlordimethylphosphoranyliden)-1,3,5-trisilacyclohexan, which crystallizes with one mole of monoglyme. X-ray structure determinations revealed that 1, 11 and 16 are planar. As well the (P? C) as the (Si? C) bond lengths are remarkably shortened; in 1 (P? C) to 173.3 pm, (Si? C) to 173.3 pm, (Si? C) to 179.5 pm, in 16 (P? C) to 168.7 pm, (Si? C) to 180 pm. The (Si? C) and (P? C) bond orders amount to about 1.33, and are relatively equally distributed. Therefore, the charge of the formal carbanion is equally distributed, which shall be expressed by means of the following kind of writing for 1 and 16 see “Inhaltsübersicht”.     

Offenkettige und cyclische As‐funktionalisierte Stannylarsine: Darstellung,Reaktionen und Struktur

Open‐Chain and Cyclic As‐functionalized Stannylarsines: Synthesis, Reactions, and Structure ^tBu₃SnAsH₂ ( 1 ) reacts with MeLi to form the lithium compound ^tBu₃SnAsHLi which reacts with ^tBu₂SnCl₂ to give the AsH‐functionalized bis(arsino)stannane ^tBu₂Sn(AsHSn^tBu₃)₂ ( 2 ). Metallation of diarsadistannetane (^tBu₂SnAsH)₂ ( 3 ) with two equivalents of ^tBuLi yields the dilithio compound (^tBu₂SnAsLi)₂ which reacts with Me₃SiCl or Me₃SnCl to give the corresponding As,As′‐bis‐substituted diarsadistannetanes (^tBu₂SnAsSiMe₃)₂ ( 4 ) and (^tBu₂SnAsSnMe₃)₂ ( 5 ), respectively. The novel compounds are characterized by NMR (¹H, ¹¹⁹Sn) and mass spectroscopy, ring compounds 4 and 5 further by X‐ray structure analysis. In the solid state both ring compounds contain molecules with planar tin‐arsenic rings and two trans‐configurated Me₃Si‐ or Me₃Sn‐ring substituents (space group P2₁/n (No. 14), Z = 2).     

γ-anti-Effekt an 1-Phosphabicyclo[3.3.1]nonan-Derivaten mit Substituenten am Phosphor. Synthese und Struktur von Pentacarbonyl(1-phosphabicyclo[3.3.1]nonan)chrom

γ-Anti Effect in 1-Phosphabicyclo[3.3.1]nonane Derivatives with Substituents at Phosphorus. Synthesis and Structure of Pentacarbonyl(1-phosphabicyclo[3.3.1]nonane) Chromium In 1-phosphabicyclo[3.3.1]nonane derivatives of the composition C₈H₁₅P(X) the CC-conformation always dominates. Changes in the chemical shifts of the bridge-head carbon atom C(5) in the ¹³C-NMR spectrum are only originated by the electronic influence of the substituent X at the phosphorus centre. Based on a homogeneous interpretation of the electronic interactions and with regard to Pearsons's definition of electronegativity the electronegativities of substituents at the phosphorus atom X = Cr(CO)₅, Fe(CO)₄, and Ni(CO)₃ are estimated. These groups are placed in antiperiplanar orientation to the carbon atom C(5). The molecular structure of (1-phosphabicyclo[3.3.1]-nonane) Cr(CO)₅ 3 was elucidated by X-ray diffraction analysis. The molecule features the 1-phosphabicyclononane ligand in the CC-conformation, which has a nearly undistorted Cr(CO)₅ unit coordinated to the phosphorus atom (d Cr P = 2.368(1) Å).     

Reaktionen von (η2-Ethen)bis(triphenylphosphan)-platin(0) mit dimerem Hexafluorthioaceton Darstellung und Struktur von Platinacyclopentan- und -cyclopropanderivaten

Reactions of (η²-Ethene)bis(triphenylphosphane)platinum(0) with Dimeric Hexafluorothioacetone. Preparation and Structure of Platina Cyclopentane and Cyclopropane Derivatives The five-membered (CS)₂Pt ring 1 was obtained by the reaction of 2, 2, 4, 4-tetrakis(trifluoromethyl)-1,3-dithietane and (η²-ethene)bis(triphenylphosphane)platinum(0) at low temperatures. 1 is converted at its melting point to the three-membered CSPt ring derivative 2 , with elimination of one molecule of hexafluorothioacetone. 2 is also formed directly when the reaction is conducted at temperatures above +30°C. 2 was characterized by an X-ray Structural analysis.     

Bildung siliciumorganischer Verbindungen. 87. Das 2,8,9-Trioxa-1,3,5,7-tetrasilaadamantan

Formation of Organosilicon Compounds. 87. 2,8,9-Trioxa-1,3,5,7-Tetrasilaadamantane Hydrolysis of cis-cis-1,3,5-tribromo-1,3,5-tri-t-butyl-1,3,5-trisilacyclohexane yields the trisilanole 2 (mp. 205°C) which forms the tetrasilaadamantane 3 with SiCl₄/et₂NH. Hydrolysis of 3 yields 4 (Formulae see “Inhaltsübersicht”).