Strontium- und Barium-bis[N,N′ -bis(trimethylsilyl)benzamidinate] aus der Additionsreaktion der Erdalkalimetall-bis[bis(trimethylsilyl)amide] mit Benzonitril

Strontium and Barium Bis[N,N′-bis(trimethylsilyl)benzamidinates] from the Addition Reaction of the Alkaline Earth Metal Bis[bis(trimethylsilyl)amides] and Benzonitrile The reaction of strontium bis[bis trimethylsilyl)amide] with benzonitrile yields strontium bis[N,N′- bis(trimethylsilyl)benzamidinate] · 2THF, which crystallizes in the orthorhombic space group Pbcn (a = 1845.4(3); b = 131 1,3(2); c = 1838,(3) pm; Z = 4). During the similar reaction of barium bis[bis(trimethylsilyl)amide] with benzonitrile the benzonitrile adduct barium bis[N,N′-bis(trimethylsilyl)benzamidinate] · 2 THF · benzonitrile is formed. After the addition of diphenylacetylene to the strontium di(benzamidinate) in diglyme a clathrate of the composition strontium bis[N,N′-bis(trimethylsilyl)benzamidinate] · diglyme · diphenylacetylene could be isolated; the spectroscopic data as well as the X-ray structure (monoclinic, C2/c, a = 1492.2(2); b = 1539.1(2); c = 2337.8(3)pm; Z = 4) confirm the isolated appearance of the acetylene molecule without interaction to the metal center in solution and in the solid state, respectively.     

Synthese und Molekülstruktur von Barium-bis[N,N′-bis(trimethylsilyl)benzamidinat] · DME · THF

Synthesis and Molecular Structure of Barium Bis[N,N′-bis(trimethylsilyl)benzamidinate] ° DME ° THF Barium bis[N,N′-bis(trimethylsilyl)benzamidinate] · thf · dme crystallizes in the monoclinic space group P2₁/n with a = 1 122.0(2), b = 2 190.7(4), c = 1 840.2(3) pm, β = 98.04(1)° and Z = 4 containing a metal center in a distorted monocapped trigonal prismatic surrounding. The barium dibenzamidinate moiety is sent with an angle of 120°, although this leads to different Ba? N distances of 273 and 282 pm originating from the interligand repulsion of the trimethylsilyl groups and the dme substituent. The 1,3-diazaallyl fragment with C? N bond lengths of 132 pm shows a delocalisation of the anionic charge.     

Bis(trimethylsilyl)amide und -methanide des Yttriums — Molekülstrukturen von Tris(diethylether-O)lithium-(μ-chloro)-tris[bis(trimethylsilyl) methyl]yttriat,solvensfreiem Yttrium-tris[bis(trimethylsilyl)amid] sowie dem Bis(benzonitril)-Komplex

Bis(trimethylsilyl)amides and -methanides of Yttrium — Molecular Structures of Tris(diethylether-O)lithium-(μ-chloro)-tris[bis(trimethylsilyl)methyl]yttriate, solvent-free Yttrium Tris[bis(trimethylsilyl)amide] as well as the Bis(benzonitrile) Complex The reaction of yttrium(III) chloride with the three-fold molar amount of LiE(SiMe₃)₂ (E = N, CH) yields the corresponding yttrium derivatives. Yttrium tris-[bis(trimethylsilyl)amide] crystallizes in the space group P3 1c with a = 1 636,3(2), c = 849,3(2) pm, Z = 2. The yttrium atom is surrounded trigonal pyramidal by three nitrogen atoms with Y? N-bond lengths of 222 pm. Benzene molecules are incorporated parallel to the c-axes. The compound with E = CH crystallizes as a (Et₂O)₃LiCl-adduct in the monoclinic space group P2₁/n with a = 1 111,8(2), b = 1 865,2(6), c = 2 598,3(9) pm, β = 97,41(3)° and Z = 4. The reaction of yttrium tris[bis(trimethylsilyl)amide] with benzonitrile yields the bis(benzonitrile) complex, which crystallizes in the triclinic space group P1 with a = 1 173,7(2), b = 1 210,3(2), c = 1 912,4(3) pm, α = 94,37(1), β = 103,39(1), γ = 117,24(1)° and Z = 2. The amido ligands are in equatorial, the benzonitrile molecules in axial positions.     

Molekül- und Kristallstruktur von Magnesium-bis[bis(trimethylsilyl)phosphanid] · DME

Molecular and Crystal Structure of Magnesium Bis[bis(trimethylsilyl)phosphide] · DME Magnesium bis[bis(trimethylsilyl)phosphide] crystallizes in the tetragonal space group I4 c2 with a = 1652.9(2); c = 2282.6(5) pm and Z = 8. The magnesium atom is distorted tetrahedrally surrounded by two oxygen and two phosphorus atoms with Mg? P- and Mg? O-bond lengths of 248.7(2) and 204.7(5) pm, respectively. The phosphorus atom displays a trigonal pyramidal coordination.     

Synthese,NMR-spektroskopische Charakterisierung und Struktur von Bis(1,2-dimethoxyethan-O,O′)barium-bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenid]

Synthesis, NMR Spectroscopic Characterization and Structure of Bis(1,2-dimethoxyethane-O,O′)barium Bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide] Barium-bis[bis(trimethylsilyl)phosphanide] 1 reacts with two equivalents of benzonitrile to give barium bis[1,3-bis(trimethylsilyl)-2-phenyl-1-aza-3-phosphapropenide]; the choice of the solvent determines whether a tris-(tetrahydrofuran)- or a bis(1,2-dimethoxyethane)-complex 2 can be isolated. 2 crystallizes from DME as red cuboids (monoclinic, C2/c, a = 1627.0(3), b = 1836.6(3), c = 1602.5(2) pm; β = 96.071(12)°; V = 4761.7(12); Z = 4; wR₂ = 0.0851). The phosphorus atom displays a pyramidal surrounding in contrast to the planar coordination sphere of the nitrogen atom. In addition a twist within the P? C? N skeleton of the heteroallyl anion is observed.     

Beiträge zur Chemie der Alkylverbindungen von Übergangsmetallen. 64. Darstellung und Kristallstruktur von Bis[N,N′-bis(trimethylsilyl)benzamidinato]dimethyltitan

Contributions to the Chemistry of Transition Metal Alkyl Compounds. 64 [1] Preparation and Crystal Structure of Bis[N,N′ -bis(trimethylsilyl)-benzamidinato]dimethyltitanium Tetramethyltitanium reacts with excess N,N′-bis(trimethylsilyl)-benzamidine ( 1 ) to give bis[N,N′-bis(trimethylsilyl)benzamidinato]dimethyl-titanium ( 2 ) via protolysis. This compound was isolated and characterized by X-ray crystal structure analysis. In the crystal, 2 adopts an octahedral coordination with the methyl groups in cis-positions. The monomethyl complexes [PhC(NSiMe₃)₂]₂M(Me)Cl ( 3 : M = Ti, 4 : M = Zr) have been prepared by treatment of the dichloro precursors with one equivalent of methyllithium.     

Synthese,Eigenschaften und Struktur von Amin-Addukten der Lithium-tris[bis(trimethylsilyl)methyl]zinkate

Synthesis, Properties, and Structure of the Amine Adducts of Lithium Tris[bis(trimethylsilyl)methyl]zincates . Bis[bis(trimethylsilyl)methyl]zinc and the aliphatic amine 1,3,5-trimethyl-1,3,5-triazinane (tmta) yield in n-pentane the 1:1 adduct, the tmta molecule bonds as an unidentate ligand to the zinc atom. Bis[bis(trimethylsilyl)methyl]zinc · tmta crystallizes in the triclinic space group P1 with {a = 897.7(3); b = 1 114.4(4); c = 1 627.6(6) pm; α = 90.52(1); β = 103.26(1); γ = 102.09(1)°; Z = 2}. The central C₂ZnN moiety displays a nearly T-shaped configuration with a CZnC angle of 157° and Zn? C bond lengths of 199 pm. The Zn? N distances of 239 pm are remarkably long and resemble the loose coordination of this amine; a nearly complete dissociation of this complex is also observed in benzene. The addition of aliphatic amines such as tmta or tmeda to an equimolar etheral solution of lithium bis(trimethylsilyl)methanide and bis[bis(trimethylsilyl)methyl]zinc leads to the formation of the amine adducts of lithium tris[bis(trimethylsilyl)methyl]zincate. Lithium tris[bis(trimethylsilyl)methyl]zincate · tmeda · 2 Et₂O crystallizes in the orthorhombic space group Pbca with {a = 1 920.2(4); b = 2 243.7(5); c = 2 390.9(5) pm; Z = 8}. In the solid state solvent separated ions are observed; the lithium cation is distorted tetrahedrally surrounded by the two nitrogen atoms of the tmeda ligand and the oxygen atoms of both the diethylether molecules. The zinc atom is trigonal planar coordinated; the long Zn? C bonds with a value of 209 pm can be attributed to the steric and electrostatic repulsion of the three carbanionic bis(trimethylsilyl)methyl substituents.     

Molekül- und Kristallstruktur des Dimeren Magnesium-bis[bis(trimethylsilyl)amids]

Molecular and Crystal Structure of the dimeric Magnesium bis[bis(trimethylsilyl)-amide] The magnesium bis[bis(trimethylsilyl)amide] crystallizes as a dimeric molecule in the space group C2/c with {a = 1821.0(4); b = 1494.4(4); c = 1859.6(6) pm; β = 121.10(2)°; Z = 4 dimers}. The cyclic planar Mg₂N₂ moiety shows endocyclic NMgN angles of 95.8°. The bond lengths within this ring system to the four-coordinate, bridging nitrogen atoms N^b are 215 pm, whereas the distances between the magnesium atom and the terminal, three-coordinate nitrogen atom N^t display values of approximately 198 pm. These different coordination numbers of the nitrogen atoms affect the NSi bond length (N^tSi 171, N^bSi 177 pm).     

Bis(1,2-dimethoxyethan-O,O′)lithium-phosphanid, -arsanid und -chlorid – drei neue Vertreter des Bis(1,2-dimethoxyethan-O,O′)lithium-bromid-Typs

Metal Derivatives of Molecular Compounds. IX. Bis(1,2-dimethoxyethane- O,O′ )lithium Phosphanide, Arsanide, and Chloride – Three New Representatives of the Bis(1,2-dimethoxyethane- O,O′ )lithium Bromide Type Experiments to obtain thermally unstable lithium silylphosphanide at –60 °C from a 1,2-dimethoxyethane solution resulted in the isolation of its dismutation product bis(1,2-dimethoxyethane-O,O′)lithium phosphanide ( 1 ). The homologous arsanide 2 precipitated after a frozen solution of arsane in the same solvent had been treated with lithium n-butanide at –78 °C. Unexpectedly, too, the analogous chloride 3 and bromide 4 were formed in reactions of 1-chloro-2,2-bis(trimethylsilyl)-1λ³-phosphaethene with (1,2-dimethoxyethane-O,O′)lithium bis(trimethylsilyl)stibanide and of lithium 1,2,3,4,5-pentaphenyl-2,3-dihydro-1λ³-phosphol-3-ide with ω-bromostyrene, respectively. The monomeric complexes 1 {–100 ± 3 °C; a = 1391.1(4); b = 809.8(2); c = 1249.1(3) pm; β = 102.84(2)°}, 2 {–100 ± 3 °C; a = 1398.3(4); b = 819.8(3); c = 1258.5(4) pm; β = 103.35(2)°} and 3 {–100 ± 3 °C; a = 1308.4(2); b = 788.2(1); c = 1195.6(1) pm; β = 95.35(1)°} crystallize in the monoclinic space group C2/c with four solvated ion pairs in the unit cell; they are isotypic with bis(1,2-dimethoxyethane-O,O′)lithium bromide ( 4 ) {–73 ± 2 °C; a = 1319.0(2); b = 794.1(1); c = 1214.3(2) pm; β = 96.22(1)°}, already studied by Rogers et al. [13] at room temperature. The neutral complexes show a trigonal bipyramidal configuration of symmetry C₂, pnicogenanide or halide anions occupying equatorial sites {Li–P 260.4(4); Li–As 269.8(6); Li–Cl 238.6(7); Li–Br 256.3(10) pm} and the chelate ligands spanning equatorial and axial positions {Li–O_eq 205.4(4) to 207.4(4); Li–O_ax 208.9(3) to 215.5(2) pm}. The coordination within the (dme)₂Li fragment, the Li–X distances (X = P, As, Cl, Br), the structure of the chelate rings, and the packing of the neutral complexes are discussed in detail.     

Synthese und Charakterisierung heterobimetallischer Bis(trimethylsilyl)phosphanide von Barium und Zinn

Synthesis and Characterization of Hetero-bimetallic Bis(trimethylsilyl)phosphanides of Barium and Tin The reaction of barium bis[bis(trimethylsilyl)amide] with one equivalent of bis(trimethylsilyl)phosphane in 1,2-dimethoxyethane (dme) yields the heteroleptic dimeric (dme)barium bis(trimethylsilyl)amide bis(trimethylsilyl)phosphanide. This colorless compound crystallizes in the monoclinic space group P2₁/n with a = 1 259.1(3), b = 1 822.7(4), c = 1 516.1(3) pm, β = 110.54(3)° and Z = 4. The central moiety of the centrosymmetric molecule is the planar Ba₂P₂-cycle with Ba? P-bond lengths of 329 and 334 pm. In the presence of bis[bis(trimethylsilyl)amino]stannylene hetero-bimetallic bis(trimethylsilyl)phosphanides of tin(II) and barium are isolated. If the reaction of Ba[N(SiMe₃)₂]₂ and Sn[N(SiMe₃)₂]₂ in the molar ratio of 1:2 with six equivalents of HP(SiMe₃)₂ is performed in toluene, barium bis{tin(II)-tris[bis(trimethylsilyl)phosphanide]} can be isolated. This compound crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 1 265.1(1), b = 2 290.1(3), c = 2 731.9(3) pm and Z = 4. The anions {Sn[P(SiMe₃)₂]₃}^? bind as two-dentate ligands to the barium atom which shows the extraordinary low coordination number of four. The addition of tetrahydrofuran (thf) to the above mentioned reaction solution leads to the elimination of tris(trimethylsilyl)phosphane and the formation of thf complexes of barium bis{tin(II)-bis(trimethylsilyl)phosphanide-trimethylsilylphosphandiide}. The derivative crystallizes from toluene in the monoclinic space group P2₁/c with a = 1 301.9(2), b = 2 316.3(3), c = 3 968.7(5) pm, β = 99.29(1)° and Z = 8.     

Metallderivate von Molekülverbindungen. VII. Bis[1,2-bis(dimethylamino)ethan-N,N′]lithium-disilylphosphanid — Synthese und Struktur

Metal Derivatives of Molecular Compounds. VII. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium Disilylphosphanide — Synthesis and Structure Crystalline lithium phosphanides studied so far show a remarkably high diversity of structure types dependent on the ligands at lithium and the substituents at phosphorus. Bis[1,2-bis(dimethylamino)ethane-N,N′]lithium disilylphosphanide ( 1 ) discussed here, belongs to the up to now small group of compounds which are ionic in the solid state. It is best prepared from silylphosphane by twofold lithiation with lithium dimethylphosphanide first and subsequent monosilylation with silyl trifluoromethanesulfonate, followed by complexation. As found by X-ray structure determination (wR = 0.038) on crystals obtained from diethyl ether {monoclinic; space group P2₁/c; a = 897.8(1); b = 1 673.6(2); c = 1 466.8(1) pm; β = 90.73(1)° at ?100 ± 3°C; Z = 4 formula units}, the lithium cation is tetrahedrally coordinated by four nitrogen atoms of two 1,2-bis(dimethylamino)ethane molecules. Characteristic parameters of the disilylphosphanide anion are a shortened average P? Si bond length of 217 pm (standard value 225 pm) and a Si? P? Si angle of 92.3°.     

Bis[N-(trimethylsilyl)iminobenzoyl]phosphanide des Lithiums und Zinks – Synthese sowie NMR-spektroskopische,strukturelle und quantenchemische Untersuchungen

Acyl- and Alkylidenephosphanes. XXXV. Bis[ N -(trimethylsilyl)iminobenzoyl]phosphanides of Lithium and Zinc – Syntheses as well as NMR Spectroscopic, Structural, and Quantumchemical Studies From the reaction of bis(tetrahydrofuran)lithium bis(trimethylsilyl)phosphanide with two equivalents of benzonitrile in 1,2-dimethoxyethane, the yellow dme complex ( 2 a ) of lithium bis[N-(trimethylsilyl)iminobenzoyl]phosphanide ( 2 ) was obtained in 69% yield. However, the intermediate {1-[N-lithium-N-(trimethylsilyl)amido]benzylidene}trimethylsilylphosphane ( 1 ), formed by an analogous 1 : 1 addition in diethyl ether, turned out to be unstable and as a consequence could be characterized by nmr spectroscopic methods only; attempts to isolate the compound failed, but small amounts of the neutral complex 2 b , with the ligands benzonitrile and tetrahydrofuran coordinated to lithium, precipitated. The reaction of compound 2 with zinc(II) chloride in diethyl ether gives the orange-red spiro-complex zinc bis{bis[N-(trimethylsilyl)iminobenzoyl]phosphanide} ( 3 ); this complex is also formed from bis[N-(trimethylsilyl)iminobenzoyl]phosphane ( 4 ), easily amenable by a lithium hydrogen exchange of 2 a with trifluoroacetic acid [18], and zinc bis[bis(trimethylsilyl)amide]. As derived from nmr spectroscopic studies and x-ray structure determinations, compounds 2 a {δ³¹P +63.3 ppm; P2₁/n; Z = 4; R₁ = 0.067}, 2 b {δ³¹P +63.3 ppm; P2₁/c; Z = 4; R₁ = 0.063}, 3 {δ³¹P +58.2 ppm; C2/c; Z = 4; R₁ = 0.037} and 4 {δ³¹P +58.1 ppm [18]} exist as cyclic 3-imino-2λ³σ²-phosphapropenylamides and -propenylamine, respectively, in solution as well as in the solid state. Unlike hydrogen derivative 4 the bis[N-(trimethylsilyl)iminobenzoyl]phosphanide fragments N,N′-coordinating either a lithium or a zinc cation are characterized by almost completely equalized bond lengths; typical mean distances and angles are: PC 180.3 and 178.7; CN 130.5 and 131.8; N–Si 175.3 and 179.3; N–Li 202.3; N–Zn 203.5 pm; CPC 108.8° and 110.5°; PCN 130.9° and 132.9°; CN–Li 113.0°, CN–Zn 117.4°; N–Li–N 104.6°; N–Zn–N 108.8°. Alterations in the shape of the six membered chelate rings, caused by an exchange of the 3-imino-2λ³σ²-phosphapropenylamide or related 2λ³σ²-phospha-1,3-dionate units for the corresponding phosphorus free ligands, are discussed in detail. The results of quantumchemical DFT-B3LYP calculations coincide very well with the experimentally obtained findings.     

Synthese von substituierten Calcium-bis(disilylamiden) mittels der Transmetallierung von Zinn(II)- und Zinn(IV)-amiden

Synthesis of Substituted Calcium-bis(disilylamides) by Transmetalation of Tin(II) and Tin(IV) Amides Stannylenes as well as stannanes with substituted disilylamino groups are valuable synthons for the synthesis of alkaline earth metal bis(disilylamides) via the transmetallation reaction. Whereas bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentyl]stannylene 1 is a suitable reagent for this type of reaction, bis[trimethylsilyl-tris(trimethylsilyl)silylamino]stannylene 2 (monoclinic, P2₁/c, a = 1492.6(2), b = 1705.2(2), c = 1865.3(3) pm, β = 109.03(2)º, Z = 4) is not only attacked at the Sn? N-bond but also the N? Si-bond is cleaved by calcium metal. Similar light sensitivity as for 2 is observed for the mercury bis[trimethylsilyl-tris(trimethylsilyl)silylamide] 3 , the homolytic M? N-bond cleavage leads to the formation of the trimethylsilyl-tris(trimethylsilyl)silylamino radical (g = 2.00485; a(N) = 16.2 G). The calcium tin exchange reaction of 1 in THF yields tris(tetrahydrofuran-O)calcium-bis[2,2,5,5-tetramethyl-2,5-disilaaza-cyclo-pentanide] 4 (monoclinic, P2₁/n, a = 1060.9(2), b = 1919.3(5), c = 1686.0(3) pm, β = 90.30(2)º, Z = 4). The stannanes Me_n-4Sn[N(SiMe₃)₂]_n with n = 1 or 2 are also valuable materials for the synthesis of bis(tetrahydrofuran-O)calcium-bis[bis(trimethylsilyl)amide].     

Verbrückende und terminale Koordination von Ga–Ga-Bindungen durch die Chelatliganden Imidotetraphenyldiphosphinat bzw. -dithiodiphosphinat

Bridging and Terminal Coordination of Ga–Ga Bonds by the Chelating Ligands Imidotetraphenyldiphosphinate and -dithiodiphosphinate Tetrakis[bis(trimethylsilyl)methyl]digallane(4) ( 1 ) reacted with imidotetraphenyldiphosphinic acid to yield two products, which were separated by recrystallization: The first one, bis[bis(trimethylsilyl)methyl]-imidotetraphenyldiphosphinato-O,O′-gallium ( 2 ), resulted from the cleavage of the Ga–Ga bond and contained a dialkylgallium unit, which was coordinated by a chelating imidodiphosphinato ligand. The digallium compound 1,2-bis[bis(trimethylsilyl)methyl]-bis(μ-tetraphenyldiphosphinato-O,O′)digallium ( 3 ) was formed as the second product by a substituent exchange reaction and the release of bis(trimethylsilyl)methane. Its Ga–Ga bond (245.7 pm) was bridged by two imidodiphosphinato ligands. In contrast, the reaction of digallane(4) 1 with the sulfur derivative imidotetraphenyldithiodiphosphinic acid afforded a complicated mixture of unknown products. A compound analogous to 3 containing two imidodithiodiphosphinato ligands ( 5 ) was, however, obtained in a moderate yield by the precipitation of lithium acetate, when we treated dialkyldi(μ-acetato)digallium ( 4 ) with lithium imidotetraphenyldithiodiphosphinate. Remarkably, the chelating ligands did not adopt a bridging position across the Ga–Ga bond (249.9 pm) similar to 3 , but each one was terminally coordinated to one Ga atom.     

Die Kristall- und MolekülStruktur von N,N′-Bis-(trimethylsilyl)-oximidsäure-bis(trimethylsilyl)-ester

The Crystal and Molecular Structure of N,N′-Bis(trimethylsilyl) Oximidic Acid Bis (trimethylsilyl) Ester The X-ray structure analysis of the reaction product of oxalyl chloride with sodium bis(trimethylsilyl) amide formulated by PUMP and ROCHOW as N,N′-bis(trimethylsilyl) oximidic Acid bis (trimethylsilyl) ester shows that the suggested structure is correct for the solid state. The compound crystallizes in the space group P1 with a = 9.948(4), b = 6.612(3), c = 10.370(4) Å, α = 88.87(6), β = 116.95(4), γ = 98.23(6)°, and Z = 1. The molecule manifests symmetry 1 .     

O-Halogensilyl-N,N-bis(trimethylsilyl)hydroxylamine – Synthese,Kristallstruktur und Reaktionen

O-Halogenosilyl-N,N-bis(trimethylsilyl)hydroxylamines – Synthesis, Crystal Structure, and Reactions The substitution of halogenosilanes on lithiated N,O-bis(trimethylsilyl)-hydroxylamine in the molar ratio of 1 : 1 occurs on the oxygen atom. The O-halogenosilyl-N,N-bis(trimethylsilyl)hydroxylamines were prepared: RSiF₂ON · (SiMe₃)₂ (R = CMe₃ 1 , CHMe₂ 2 , CH₂C₆H₅ 3 , C₆H₂(CMe₃)₃ 4 ), RR′SiFON(SiMe₃)₂ (R = CMe₃, R′ = C₆H₅ 5 ; R = Me, R′ = C₆H₅ 6 ; R = C₆H₂Me₃, R′ = C₆H₂Me₃ 7 ; R = CH₂C₆H₅, R′ = CH₂C₆H₅ 8 ; R = CHMe₂, R′ = CHMe₂ 9 ; R = CMe₃, R′ = CMe₃ 10 ), RSiCl₂ON(SiMe₃)₂ (R = CMe₃ 11 ; R = Cl 12 ). The reaction of fluorosilanes with lithiated N,O-bis(trimethylsilyl)hydroxylamine in the molar ratio of 1 : 2 leads to the formation of O,O′-fluorosilyl-bis[N,N-bis(trimethylsilyl)hydroxylamines]: RSiF[ON(SiMe₃)₂]₂ (R = CMe₃ 13 ; R = C₆H₅ 14 ). 13 could be prepared in the reaction of 1 with LiON(SiMe₃)₂. Lithiated dimethylketonoxime reacts with 1 to Me₂C=NOSiRF–ON(SiMe₃)₂ [R = CMe₃ ( 15 )]. The first crystal structure of a tris(silyl)hydroxylamine ( 4 ) is shown. The angle at the nitrogen prove a pyramidal geometry.     

Tris[bis(trimethysilyl)amido]zinkate von Lithium und Calcium

Tris[bis(trimethylsilyl)amido]zincates of Lithium and Calcium Calcium-bis[bis(trimethylsilyl)amide] and Bis[bis(trimethylsilyl)amido]zinc yield in 1,2-dimethoxyethane quantitatively Calcium-bis{tris[bis(trimethylsilyl)- amido]zincate} · 3DME. When THF is chosen as a solvent, the two reactants and the zincate form a temperature-independent equilibrium, whereas in benzene no reaction occurs. The tris[bis(trimethylsilyl)amido]zincate anion displays characteristic ¹³C{¹H) and ²⁹Si{¹H] chemical shifts of 7 and ?8 ppm, respectively; the nature of the solvent, the cation and the complexating ligands don't influence the IR nor NMR data of the zincate anion and thus verify that [Ca(DME)₃]²⁺ and {Zn[N(SiMe_{3 2}]₃}^? appear as solvent separated ions, which is also confirmed by their insolubility in hydrocarbons.     

Convenient Synthesis of N-Trimethylsilylaminotitanium Trichlorides

Bis(N-trimethylsilylamino)plumbylenes 1 {[Me₃Si(R)N]₂Pb with R = ^tBu ( a ), Me₃Si ( b ), 9-(9-borabicyclo[3.3.1]nonyl) ( c )} react smoothly with an excess of TiCl₄ to give PbCl₂ and N-trimethylsilylaminotitanium trichlorides 3 a – c . In contrast, the analoguous reaction of the corresponding stannylenes 2 a – c leads to mixtures containing unidentified Ti^III compounds, the amides 3 a or 3 b , bis[bis(trimethylsilyl)amino]titanium dichloride 4 b and bis(amino)tin dichlorides 5 a – c . The crystal structure of 3 a was determined by X-ray structural analysis. Compound 3 a is a dimer in the solid state with distorted trigonal pyramidal surroundings of the titanium atoms. Each titanium atom bears two μ²-Cl ligands which are in axial (d_Ti–Cl = 250.7(1) pm) and equatorial positions (d_Ti–Cl = 247.0(1) pm) and two terminal chloro ligands, one in axial (d_Ti–Cl = 228.0(1) pm) and one in equatorial position (d_Ti–Cl = 221.1(1) pm). The equatorial Ti–N bonds are short (183.8(2) pm).     

Crystal structure of (N,N,N′,N′-tetramethyl-1,2-diaminoethane)(1,1,1-trifluoro-6-methyl-2,4-heptanedionato)copper(II) perchlorate

The solvatochromic compound [Cu(tfmh)Me₄en]ClO₄ (tfmh^? denotes the anion of 1,1,1-trifluoro-6-methyl-2,4-heptanedione) was prepared and its structure has been determined from three-dimensional X-ray diffraction data. The structure consists of discrete [Cu(tfmh)Me₄en]⁺ monomeric units and perchlorate ions. The copper(II) ion is surrounded by the two nitrogen atoms of the diamine molecule and the two oxygen atoms of the β-dionato anion. The N,N,N′,N′-tetramethyl-1,2-diaminoethane, Me₄en, coordinates as bidentate ligand through the nitrogen atoms and adopts the gauche conformation and λ configuration. The CuN₂O₂ chromophore is virtually planar. The compound crystallizes in the monoclinic system (space group P2₁/c) with a = 11.9520(2), b = 14.6600(2), c = 17.2240(4) Å, β = 135.72(2)°, Z = 4 and V = 2107.01(7) ų.     

Die Kristallstruktur von Bis(N,N-diethyl-N′ -benzoylselenoureato)nickel(II)

The Crystal Structure of Bis(N,N-diethyl-N′ -benzoylselenoureato)nickel(II) Ni(C₁₂H₁₅N₂OSe)₂ crystallizes in the monoclinic space group P2₁/c. The cell parameters are a = 11.399(3), b = 16.016(4), c = 14.910(6) Å, β = 104.64(3)° and Z = 4. The structure was solved with Patterson and direct methods and was refined to a final R-value of 5.43%. Nickel is coordinated to two N,N-diethyl-N′ -benzoylselenourea molecules to form a bidentally coordinated chelate complex with cis arrangement of the donor atoms. Coordinaton around the nickel atom is planar while the chelate rings diverge from planarity. The ethyl groups of one diethylamino group are disordered. The Ni? Se bond lengths are 2.244(1) and 2.264(1) Å, the Ni? O bond lengths are 1.871(4) and 1.883(4) Å, respectively.