Johann Weidlein

Präparative, spektroskopische und röntgenographische studien an bis(dimethylmetall)di(μ-1-propinylen) des aluminiums, galliums und indiums

Abstract Dimethylpropynylmetal compounds of Al, Ga and In are formed in 40–60% yield by the reaction of NaCCCH3 with (CH3)2MIIIHal (MIII  Al, Ga, In; Hal  Cl, Br). The IR, Raman, 1H and 13C NMR spectra of these, in solution dimeric, compounds are discussed. The indium derivative crystallizes in the orthorhombic space group Pnma with 4 formula units per unit cell. The lattice parameters are a  926.9; b  578.7 and c  1216.6 pm.

Das unterschiedliche Reaktionsverhalten von basefreiem Tris(trimethylsilyl)methyl‐Lithium gegenüber den Trihalogeniden der Erdmetalle und des Eisens

Basefreies Tris(trimethylsilyl)methyl-Lithium, Tsi–Li, reagiert mit den Trihalogeniden der Erdmetalle (MHal3 mit M = Al, Ga, In und Hal = Cl, Br, I) primar unter Bildung der Metallate [Tsi–MHal3]Li. Vor allem mit den schwereren Halogeniden von Ga und In findet aber mit uberschussigem Tsi–Li zusatzlich zur simplen Metathese gleichzeitig auch eine Methylierung statt, die in unterschiedlichem Mase die Mono- und Dimethylverbindungen Tsi–M(Me)Hal (M = Ga, In; Hal = I), Tsi–MMe2 (M = Ga) bzw. das Bis-(trisyl)derivat (Tsi)2InMe sowie stets als Nebenprodukt noch 1,3-Disilacyclobutan ergibt. Durch mehrmalige, fraktionierende Kristallisationen oder Sublimationen konnten Vertreter dieser Verbindungstypen aus den Reaktionsmischungen isoliert und mit spektroskopischen Methoden (1H, 13C, 29Si-NMR; IR, Raman) sowie zum Teil rontgenographisch charakterisiert werden. FeCl3 reagiert mit Tsi–Li (Verhaltnis 1 : 3) in Toluol bei 55–60 °C unter Reduktion, wobei rotviolettes Fe(Tsi)2, 1,1,1-Tris(trimethylsilyl)-2-phenylethan und geringe Mengen an Tsi–Cl gebildet werden. Fe(Tsi)2 ist monomer, kristallisiert in der monoklinen Raumgruppe C2/c und hat ein lineares C–Fe–C-Skelett mit Fe–C-Bindungsabstanden von 204,5(4) pm. The Variable Reaction Behaviour of Base-free Tris(trimethylsilyl)methyl Lithium with Trihalogenides of Earth-Metals and Iron Base-free tris(trimethylsilyl)methyl Lithium, Tsi–Li, reacts with the earth-metal trihalogenides (MHal3 with M = Al, Ga, In and Hal = Cl, Br, I) primarily to give the metallates [Tsi–MHal3]Li. Simultaneous to this simple metathesis a methylation also takes place, mainly with heavier halogenides of Ga and In with excess Tsi–Li, forming the mono and dimethyl compounds Tsi–M(Me)Hal (M = Ga, In; Hal = I), Tsi–MMe2 (M = Ga), and the bis(trisyl)derivative (Tsi)2InMe, respectively and the main by-product 1,3-disilacyclobutane. Representatives of each type of compound have been isolated by fractionating crystallizations or sublimations and characterized by spectroscopic methods (1H, 13C, 29Si NMR, IR, Raman) and X-ray elucidations. Reduction takes place, when FeCl3 reacts with Tsi–Li (1 : 3 ratio) in toluene at 55–60 °C, yielding red-violet Fe(Tsi)2, 1,1,1-tris(trimethylsilyl)-2-phenyl ethane and low amounts of Tsi–Cl. Fe(Tsi)2 is monomeric, crystallizes in the monoclinic space group C2/c and consists of a linear C–Fe–C skeleton with d(Fe–C) of 204,5(4) pm.

13 C Chemical shifts and CH Coupling constants of main group element cyclopentadienyl de rivatives; a critical survey

Abstract For a series of cyclopentadienyl derivatives of Group IA, IIA and IIIB elements, δc, 1J(CH) and 2,3J(CH) values are reported. The results indicate that neither the 13C chemical shift nor the primary CH coupling constant may be used as a criterion for assigning a π- or σ- bonded structure to a given cyclopentadienyl compound. The ”high resolution“ 13C spectrum of lithium cyclopentadienide is fully analyzed; for (C5H5)BeBr, a 13C9Be coupling has been observed.

Schwingungsspektroskopische studien an alkylaluminium- und -gallium-dihalogeniden

Abstract Infrared and Raman spectra of alkylaluminium dichlorides, alkylaluminium dibromides as well as of alkylgallium dichlorides (alkyl = CH 3 and C 2 H 5 ) are measured and assigned. From the rule of mutual exclusion it follows that the skeleton (α-CMHal 2 ) 2 of these compounds is centrosymmetric and belongs to the point group C 2 h .

Heteroleptische diorganylzink-verbindungen des typs (Me3Si)3CZnR

Abstract The equimolar reaction of lithium tris(trimethylsilyl)methanide with zinc(II) chloride in a solvent mixture of THF and diethylether yields Lithium-trichloro-bis[tris(trimethylsilyl)methyl] zincate·2THF·Et 2 O. The addition of organyl lithium leads to the formation of heteroleptic organyl-[tris(trimethylsilyl)methyl]zinc. No ligand exchange reactions can be observed for these compounds. Due to the steric demand of the tris(trimethylsilyl)methyl substituent these derivatives are monomeric in solution as well as in the solid state. Bis(trimethylsilyl)methyl-[tris(trimethylsilyl) methyl]zinc crystallizes in the monoclinic space group P 2 1 / n ( a = 910.7(2), b = 1633.0(4) c = 1863.9(4) pm, β = 94.18(2)° and Z = 4). The ZnC-distances are elongated to a value of 197 pm due to the steric demand of both the substituents. The zinc atom is with an CZnC angle of 176° nearly linear coordinated. Phenyl-[tris(trimethylsilyl)methyl]zinc with a melting point of about 24°C crystallizes upon cooling in a nitrogen stream ( P 2 1 , a = 908.4(3), b = 1489.0(4), c = 1594.5(3) pm, β = 94.68(2)° and Z = 4). Due to the small size of the phenyl group rather short ZnC-bond lengths of about 193.5 pm are formed.

Bis(dimethylmetall)-N,N′,N″,N‴-tetramethyloxamidine des aluminiums, galliums und indiums; synthese, spektren und röntgenstrukturen

N , N′ , N″ , N‴ -Tetramethyloxamidine, (HNMe) 2 C 2 (NMe) 2 , reacts with the trimethyl derivatives of Al, Ga and In, respectively, in a molar ratio. Monomeric bis(dimethylmetal)oxamidines, [Me 2 M] 2 C 2 (NMe) 4 with M = Al, Ga, In, and methane are formed. According to the vibrational spectra (IR and Raman) and the X-ray structure determinations of all three compounds these molecules consist of two fused five-membered rings, with an essentially planar structure. The results in the homologous series [Me 2 M] 2 C 2 O 4− x (NMe) x ( x = 0, 2 and 4 and M = Ga) are compared.

SO3-einschiebungsreaktionen bei aluminium-, gallium-, indium- und thalliumtrialkylen

Only one metalC-bond in trialkyl-aluminium, -gallium, -indium and -thallium can be cleaved by SO3 in a 1/1 molar ratio reaction. The so formed dialkylmetal alkylenesulfonates can also be obtained by treatment of the trialkyl compounds with alkylenesulfonic acids. The aluminium and gallium derivatves are dimeric or trimeric in benzene solution. The metal atoms are bridged by R(O=)SO2 -groups. In the corresponding indium and thallium compounds the good solubility in water and the dissociation in R2M+ and RSO3− -ions is remarkable. The vibrational spectra of the dialkylmetal alkylsulfonates are discussed.

Dimethylthallium-methyl-xanthogenat (CH3)2TlS2COCH3, darstellung, eigenschaften und struktur

Abstract The vibrational spectra (IR and Raman) of dimethylthallium methylxanthogenate were investigated. The crystal and molecular structure has been determined. The compound crystallizes in the orthorhombic space group Pca21. The unit cell with lattice constants a = 10.990, b = 6.819 and c = 11.245 A contains 4 molecules. Thallium is seven-coordinated in the crystal lattice. The two thalliumsulfur distances in the nearly planar four-membered ring are almost equal. The distances from thallium to the next nearest oxygen and suflur atoms are slightly longer; the distance to the next again nearest sulphur atom is markedly longer.

SO2-einschiebungsreaktionen bei aluminium-, gallium- und indiumalkylverbindungen☆

Sulfur dioxide can be inserted into bonds between carbon and the elements aluminium, gallium and indium. Organometallic aluminium compounds such as R3Al (R = CH3C2H5), R2AlX (R = CH3, C2H5 and X = F, Cl, Br, SCN) and RAlX2 (R = CH3, C2H5 and X = Cl, Br) react with three, two or one mole SO2 according to the number of AlC bonds present. The properties of these insertion compounds and their IR spectra are discussed. Trimethylgallium and trimethylindium react with SO2 with the cleavage of only one metal-C bond. The solid dimethylmetal sulfinates are dimeric and soluble in nonpolar solvents. The vibrational spectra (IR, Raman) point to 8-membered ring skeletons, M2O4S2, (M = Ga, In).

Über dialkylaluminium-, -gallium- und -indium- thiocarboxylate

Abstract Gaseous COS cleave one metal-carbon bond in Al, Ga and In trialkyls, leading to dialkylmetal thiocarboxylates, which can be identified by the IR spectra but cannot be isolated as pure products. They are obtained more easily by the reaction of the trialkyls (or their addition compounds with ether) with equivalent amounts of thiocarboxylic acid. While Al forms dimeric thiocarboxylates, the corresponding Ga and In derivatives are monomeric. IR and Raman spectra show the dimeric Al compounds to consist of puckered eight-membered Al 2 O 2 S 2 C 2 ring skeletons, while the Ga and In compounds presumabl have planar four-membered MOSC rings ( C s ).