[Yb3OBr4{N(SiMe3)2}3 (THF)3], ein Amido-Komplex des Ytterbiums mit clusterähnlichem Aufbau

[Yb₃OBr₄{N(SiMe₃)₂}₃(THF)₃], an Amido Complex of Ytterbium with a Clusterlike Structure The title compound has been prepared from YbBr₃ and NaN(SiMe₃)₂ in THF suspension, forming yellow single crystals from hexane solutions which were characterized by a crystal structure determination. Space group P1 , Z = 2, lattice dimensions at ?100°C: a = 1085.4(1), b = 1410.2(1), c = 1912.0(1) pm; α = 78.62(1)°, β = 80.61(1)°, γ = 73.45(1)°, R = 0.025. In the molecular structure of [Yb₃OBr₄{N(SiMe₃)₂}₃(THF)₃] the three ytterbium atoms together with the μ₃-oxygen atom and a μ₃-bromine atom form a distorted trigonal bipyramid. In addition, three μ₂-Br atoms coordinate the Yb atoms in the equatorial plane, whereas the THF molecules and the N(SiMe₃)₂^? ligands are terminally coordinated, thus forming a distorted octahedrally surrounding of the Yb atoms.     

Die Deprotonierung silylierter Amido-Komplexe von Seltenerdelementen

Deprotonation Reactions of Silylated Amido Complexes of Rare Earth Elements The deprotonation of the rare earth element-tris(bistrimethylsilyl)amides Ln[N(SiMe₃)₂]₃ of scandium, ytterbium, and lutetium with sodium-bis(trimethylsilyl)amide in THF leads to the complexes [Na(THF)₃LnCH₂SiMe₂NSiMe₃{N(SiMe₃)₂}₂] [Ln = Sc ( 1 ), Yb ( 2 ), and Lu ( 3 )]. According to crystal structure analyses of 1 and 2 the metal atoms Sc and Yb are constituents of planar LnCSiN four-membered rings. At the same time, the C atom of the CH₂ group is coordinated with the sodium ion in a linear axis Ln–C–Na; the sodium ion obtains a distorted tetrahedral arrangement by three THF molecules. The equatorial positions of the methylene-C atom, which is coordinated in a trigonal bipyramidal fashion, are occupied by the two H atoms and the Si atom of the four-membered ring. 2.6-dimethylbenzoisonitrile can be inserted into the Yb–CH₂ bond of 2 and the new five-membered heterocylce YbNCSiN originates, the exocyclic CH₂ group of which enters into a C–C coupling with the centrosymmetric dimer 4 while the ytterbium undergoes reduction. At the same time, sodium-7-methyl indolate is formed, which together with [NaN(SiMe₃)₂(THF)₂] forms the centrosymmetric dimeric molecular aggregate [NaN(SiMe₃)₂(THF)₂Na(C₉H₁₆N)]₂ ( 5 ). 1 : Space group P2₁/n, Z = 8, lattice dimensions at –80 °C: a = 2941.4(2), b = 1205.5(1), c = 2952.4(3) pm; β = 113.455(8)°; R₁ = 0.0625. 2 : Space group P2₁/n, Z = 8, lattice dimensions at –80 °C: a = 2943.9(1), b = 1219.5(1), c = 2944.3(1) pm; β = 113.372(4)°; R₁ = 0.0361. 4 : Space group P 1, Z = 4, lattice dimensions at –80 °C: a = 1117.0(1), b = 1207.5(1), c = 1614.3(2) pm; α = 73.634(10)°, β = 82.091(10)°, γ = 74.391(10)°; R₁ = 0.0525. 5 : Space group P2₁/n, Z = 2, lattice dimensions at –80 °C: a = 1126.7(1), b = 1459.3(1), c = 1741.1(1) pm; β = 96.461(8)°; R₁ = 0.0458. Quantum chemical DFT calculations of the scandium model compound [Na(Me₂O)₃ScCH₂SiMe₂NSiH₃{N(SiH₃)₂}₂] ( 1 M ) give a very large negative charge at the pentacoordinated carbon atom of the four-membered ring that is concentrated in a lone-pair orbital which has mainly p character. The carbon atom interacts with the positively charged scandium atom mainly by Coulombic interactions.     

Amidometallate von Seltenerdelementen. Synthese und Kristallstrukturen von [Na(12-Krone-4)2][M{N(SiMe3)2}3(OSiMe3)] (M = Sm,Yb), [Na(THF)3Sm{N(SiMe3)2}3(C≡C–Ph)], [Na(THF)6][Lu2(μ-NH2)(μ-NSiMe3){N(SiMe3)2}4] sowie von [NaN(SiMe3)2(THF)]2. Anwendungen der Seltenerdkomplexe als Polymerisationskatalysatoren

Amido Metalates of Rare Earth Elements. Syntheses and Crystal Structures of [Na(12-crown-4)₂][M{N(SiMe₃)₂}₃(OSiMe₃)] (M = Sm, Yb), [Na(THF)₃Sm{N(SiMe₃)₂}₃(C≡C–Ph)], [Na(THF)₆][Lu₂(μ-NH₂)(μ-NSiMe₃){N(SiMe₃)₂}₄], and of [NaN(SiMe₃)₂(THF)]₂. Applications of Rare Earth Metal Complexes as Polymerization Catalysts The amido silyloxy complexes [Na(12-crown-4)₂][M{N(SiMe₃)₂}₃(OSiMe₃)] with M = Sm ( 1 a ), Eu ( 1 b ), Yb ( 1 c ), and Lu ( 1 d ) were obtained from the trisamides M[N(SiMe₃)₃]₃ and NaOSiMe₃ in n-hexane in the presence of 12-crown-4; they form yellow to orange-red crystals, of which 1 a and 1 c were characterized crystallographically. The complexes crystallize isotypically with one another in the monoclinic space group I2/a with eight formula units per unit cell. The metal atoms of the complex anions are tetrahedrally coordinated by the three nitrogen atoms of the N(SiMe₃)₂^– ligands and by the oxygen atom of the OSiMe₃^– ligand. With 172.4° for 1 a and 179.3° for 1 c the bond angles M–O–Si are practically linear. With ethynylbenzene in the presence of NaN(SiMe₃)₂ in tetrahydrofuran the trisamides M[N(SiMe₃)₂]₃ react under formation of the complexes [Na(THF)₃M{N(SiMe₃)₂}₃ · (C≡C–Ph)] with M = Ce ( 2 a ), Sm ( 2 b ), and Eu ( 2 c ), of which 2 b was characterized crystallographically (monoclinic, space group P2₁/n, Z = 4). 2 b forms an ion pair in which the terminal carbon atom of the C≡C–Ph^– ligand is connected with the samarium atom of the Sm[N(SiMe₃)₂]₃ group and the sodium ion is side-on connected with the acetylido group. According to the crystal structure determination (space group P2₁2₁2₁, Z = 4) [Na(THF)₆][Lu₂(μ-NH₂)(μ-NSiMe₃) · {N(SiMe₃)₂}₄] ( 3 ), which is formed as a by-product, consists of [Na(THF)₆]⁺ ions and dimeric anions, in which the lutetium atoms are connected to form a planar Lu₂N₂ four-membered ring via a μ-NH₂ bridge with average Lu–N distances of 227.2 pm and via a μ-NSiMe₃ bridge of average Lu–N distances of 218.5 pm. According to the crystal structure determination (space group P 1, Z = 1) [NaN(SiMe₃)₂(THF)]₂ ( 4 ) forms centrosymmetric dimeric molecules with Na–N distances of the Na₂N₂ four-membered ring of 239.9 pm and distances Na–O of the terminally bonded THF molecules which are 226.7 pm. The vinylic polymerization of methylmethacrylate (MMA) catalyzed by 1 c resulted in high molecular weight polymethylmethacrylate (PMMA) with moderate yields. The reaction of 1 a or 2 b with MMA did not give PMMA. Insoluble polynorbornene was obtained in low yields by reaction of norbornene/methylaluminoxane (MAO) with 1 a , 1 c , or 2 b . The ring opening polymerization of ϵ-caprolacton or δ-valerolacton catalyzed by 2 b resulted in corresponding polylactones in quantitative yields.     

Untersuchungen zu Reaktionen des Diphosphanylsilans iPr2Si(PH2)2 mit Erdalkalimetallsilazaniden

The reaction of iPr₂Si(PH₂)₂ ( 1 ) with [Ca{N(SiMe₃)₂}₂(THF)₂] at 25 °C in molar ratio 1:1 yields the compound [Ca₃{iPr₂Si(PH)₂}₃(THF)₆] ( 2 ). Compound 2 consists of two Ca₂P₃ trigonal bipyramids with one conjoint calcium corner and SiiPr₂ bridged phosphorus atoms. In contrast, the same reaction at 60 °C yield the complex [Ca({P(SiiPr₂)₂PH}₂(THF)₄] ( 3 ). The isotype strontium compound [Sr({P(SiiPr₂)₂PH}₂(THF)₄] ( 4 ) was obtained from the reaction of iPr₂Si(PH₂)₂ with [Sr{N(SiMe₃)₂}₂(DME)₂]. The Compounds 2 – 4 were characterised by single crystal X‐ray diffraction, elemental analysis as well as IR and NMR spectroscopic techniques.     

Kristallstrukturen der Samarium-Amido-Komplexe [Sm(l-X){N(SiMe3)2}2(THF)]2 mit X = Cl,Br

Crystal Structures of the Samarium Amido Complexes [Sm(l-X){N(SiMe₃)₂}₂(THF)]₂ with X = Cl, Br The crystal structures of the title compounds have been determined by X-ray methods. [Sm(μ-Cl) · {N(SiMe₃)₂}₂(THF)]₂ ( 1 ): Space group P2₁/n, Z = 2, lattice dimensions at 223 K: a = 1429.5(2), b = 1302.3(3), c = 1658.6(3) pm, β = 114.212(10)°, R = 0.0561. [Sm(μ-Br) · {N(SiMe₃)₂}₂(THF)]₂ ( 2 ): Space group Pbca, Z = 4, lattice dimensions at 223 K: a = 1850.0(7), b = 1611.0(9), c = 1888.1(6) pm, R = 0.0497. 1 and 2 form centrosymmetric dimeric complexes via μ-X-halogeno bridges. The samarium atoms are coordinated in a distorted trigonal-bipyramidal surrounding, the THF molecule and one of the bridging halogen atoms being in axial positions.     

f‐Element Half‐Sandwich Complexes: A Tetrasilylcyclobutadienyl–Uranium(IV)–Tris(tetrahydroborate) Anion Pianostool Complex

Despite there being numerous examples of f‐element compounds supported by cyclopentadienyl, arene, cycloheptatrienyl, and cyclooctatetraenyl ligands (C_5–8), cyclobutadienyl (C₄) complexes remain exceedingly rare. Here, we report that reaction of [Li₂{C₄(SiMe₃)₄}(THF)₂] ( 1 ) with [U(BH₄)₃(THF)₂] ( 2 ) gives the pianostool complex [U{C₄(SiMe₃)₄}(BH₄)₃][Li(THF)₄] ( 3 ), where use of a borohydride and preformed C₄‐unit circumvents difficulties in product isolation and closing a C₄‐ring at uranium. Complex 3 is an unprecedented example of an f‐element half‐sandwich cyclobutadienyl complex, and it is only the second example of an actinide‐cyclobutadienyl complex, the other being an inverse‐sandwich. The U?C distances are short (av. 2.513 Å), reflecting the formal 2? charge of the C₄‐unit, and the SiMe₃ groups are displaced from the C₄‐plane, which we propose maximises U?C₄ orbital overlap. DFT calculations identify two quasi‐degenerate U?C₄ π‐bonds utilising the ψ₂ and ψ₃ molecular orbitals of the C₄‐unit, but the potential δ‐bond using the ψ₄ orbital is vacant.     

PPh4{MoNCI3[N(SiMe3)2]}, ein Nitrido-Amido-Komplex von MoIybdän(VI)

Inhaltsübersicht. PPh₄{MoNCl₃[N(SiMe₃)₂]} entsteht aus PPh₄[MoNCl₄] und N,N,N′-Tris-(trimethylsilyl)benzamidin in siedendem Dichlormethan in Form bernsteinfarbener Kristalle, die wir IR-spektroskopisch und durch eine röntgenographische Strukturanalyse charakterisiert haben. Raumgruppe P2₁/n, Z = 4, R = 4,3% für 5168 unabhängige beobachtete Reflexe. Die Gitterkonstanten betragen für ?65°C: A = 918,9; b = 2850,5; c = 1353,9 pm; β = 107,51°. Die Verbindung besteht aus PPh₄⁺-Ionen und Anionen [MoNCl₃[N(SiMe₃)₂]}^–, in denen das Molybdänatom verzerrt tetragonal-pyramidal von dem Nitridoliganden in Apical-Position (r MoN = 165 pm), von drei Chloratomen und von dem N-Atom des Bis(trimethylsilyl)amido-Liganden (r MoN = 194 pm) umgeben ist. Das N-Atom des Amido-Liganden besitzt eine planare Umgebung. PPh₄{MoNCl₃[N(SiMe₃)₂]}, a Nitrido Amido Complex of Molybdenum (VI) PPh₄{MoNCl₃[N(SiMe₃)₂}] has been prepared by the reaction of PPh₄[MoNCl₄] with N,N,N′-Tris(trimethylsilyl)benzamidine in boiling dichloromethane, forming amber coloured crystals, which were characterized by their IR spectrum as well as by an X-ray structure determination. Space group P2₁/n, Z = 4, R = 0.043 for 5168 observed independent reflexions. The lattice dimensions are at ?65°C: A = 918.9; b = 2850.5; c = 1353.9 pm; β = 107.51°. The compound consists of PPh₄⁺ ions and anions {MoNCl₃[N(SiMe₃)₂]}^– in which the complex molybdenum anion forms a distorted tetragonal pyramid with the nitrido ligand (r MoN 165 pm) in the apical position and the chlorine atoms along with the nitrogen atom of the amido ligand (r MoN 194 pm) in the basical positions. The N atom of the amido ligand has a planar geometry.     

Die Reaktion von Ytterbium mit N‐Iod‐triphenylphosphanimin. Kristallstrukturen von [Yb2I(THF)2(NPPh3)4] · 2 THF, [YbI2(HNPPh3)(DME)2] und [{YbI2(DME)2}2(μ‐DME)]

The Reaction of Ytterbium with N‐iodo‐triphenylphosphaneimine. Crystal Structures of [Yb₂I(THF)₂(NPPh₃)₄] · 2 THF, [YbI₂(HNPPh₃)(DME)₂], and [{YbI₂(DME)₂}₂(μ‐DME)] When treated with ultrasound, the reaction of ytterbium powder with INPPh₃ in tetrahydrofuran leads to [YbI₂(THF)₄] and to the mixed‐valence phosphoraneiminato complex [Yb₂I(THF)₂(NPPh₃)₄] · 2 THF ( 1 ), which forms red single‐crystals. In the analogous reaction in 1,2‐dimethoxyethane (DME) only the ytterbium(II) iodide solvates [YbI₂(HNPPh₃)(DME)₂] ( 2 ) and [{YbI₂(DME)₂}₂ · (μ‐DME)] ( 3 ) can be isolated, which form yellow single crystals. All compounds were characterized by crystal structure analyses. 1 : Space group P1, Z = 2, lattice dimensions at –80 °C: a = 1337.6(5), b = 1389.6(5), c = 2244.2(17) pm; α = 86.11(7)°, β = 88.06(7)°, γ = 88.63(4)°; R = 0.0759. In 1 the two ytterbium atoms are connected via the N atoms of two phosphoraneiminato groups (NPPh₃^–) to form a planar Yb₂N₂ four‐membered ring. The structure can also be described as an ion pair consisting of [YbI(THF)₂]⁺ and [Yb(NPPh₃)₄]^–. 2 : Space group P2₁, Z = 2, lattice dimensions at –80 °C: a = 811.9(1), b = 1114.0(1), c = 1741.3(1) pm; β = 95.458(5)°; R = 0.0246. 2 forms molecules in which the ytterbium atom is coordinated in a pentagonal‐bipyramidal fashion with the iodine atoms in the axial positions. The O atoms of the two DME‐chelates and the N atom of the phosphaneimine ligand HNPPh₃ are in the equatorial positions. 3 : Space group P1, Z = 2, lattice dimensions at –70 °C: a = 817.5(1), b = 1047.7(1), c = 1115.5(2) pm; α = 90.179(10)°, β = 97.543(15)°, γ = 91.087(12)°; R = 0.0317. 3 has a dimeric molecular structure, in which the two fragments {YbI₂(DME)₂} are connected centrosymmetrically via a μ‐DME bridge. As in 2 , the ytterbium atoms are coordinated in a pentagonal‐bipyramidal fashion with the iodine atoms in the axial positions, as well as with the two DME chelates and with one O atom each of the μ‐DME ligand in the equatorial positions.     

Reaction of aryl azides with tris(trimethylsilyl)silyllithium: Synthesis of tmeda or thf adducts of [Li{N(Ar)Si(SiMe3)3}] and 1,4-trimethylsilyl migration from oxygen to nitrogen

Reaction of ArN₃ (Ar = Ph, p-MeC₆H₄, 1-naphthyl) with [Li{Si(SiMe₃)₃}(thf)₃] yielded lithium amides [Li{N(Ar)Si(SiMe₃)₃}L] (L = tmeda or (thf)₂). Similar treatment of o-phenylene diazide with 2 equiv. of [Li{Si(SiMe₃)₃}(thf)₃] formed dilithium diamide complex 4. Reaction between o-Me₃SiOC₆H₄N₃ and [Li{Si(SiMe₃)₃}(thf)₃] afforded, via 1,4-trimethylsilyl migration from oxygen to nitrogen, [Li{OC₆H₄{N(SiMe₃)Si(SiMe₃)₃}-2}]₂ (5). The structures of complexes 3 and 5 have been determined by single crystal X-ray diffraction techniques.     

Die Kristallstrukturen einer Serie von Verbindungen mit Kationen des Typs [R3PNH2]+, [R3PN(H)SiMe3]+ und [R3PN(SiMe3)2]+

Crystal Structures of a Series of Compounds with Cations of the Type [R₃PNH₂]⁺, [R₃PN(H)SiMe₃]⁺, and [R₃PN(SiMe₃)₂]⁺ The crystal structures of a series of compounds with cations of the type [R₃PNH₂]⁺, [R₃PN(H)SiMe₃]⁺, and [R₃PN(SiMe₃)₂]⁺, in which R represents various organic residues, are determined by means of X‐ray structure analyses at single crystals. The disilylated compounds [Me₃PN(SiMe₃)₂]⁺I^–, [Et₃PN(SiMe₃)₂]⁺I^–, and [Ph₃PN(SiMe₃)₂]⁺I₃^– are prepared from the corresponding silylated phosphaneimines R₃PNSiMe₃ with Me₃SiI. [Me₃PNH₂]Cl (1): Space group P2₁/n, Z = 4, lattice dimensions at –71 °C: a = 686.6(1), b = 938.8(1), c = 1124.3(1) pm; β = 103.31(1)°; R = 0.0239. [Et₃PNH₂]Cl (2): Space group Pbca, Z = 8, lattice dimensions at –50 °C: a = 1272.0(2), b = 1147.2(2), c = 1302.0(3) pm; R = 0.0419. [Et₃PNH₂]I (3): Space group P2₁2₁2₁, Z = 4, lattice dimensions at –50 °C: a = 712.1(1), b = 1233.3(2), c = 1257.1(2) pm; R = 0.0576. [Et₃PNH₂]₂[B₁₀H₁₀] (4): Space group P2₁/n, Z = 4, lattice dimensions at –50 °C: a = 809.3(1), b = 1703.6(1), c = 1800.1(1) pm; β = 96.34(1)°; R = 0.0533. [Ph₃PNH₂]ICl₂ (5): Space group P1, Z = 2, lattice dimensions at –60 °C: a = 825.3(3), b = 1086.4(3), c = 1241.2(4) pm; α = 114.12(2)°, β = 104.50(2)°, γ = 93.21(2)°; R = 0.0644. In the compounds 1–5 the cations are connected with their anions via hydrogen bonds of the NH₂ groups with 1–3 forming zigzag chains. [Me₃PN(H)SiMe₃][O₃S–CF₃] (6): Space group P2₁/c, Z = 8, lattice dimensions at –83 °C: a = 1777.1(1), b = 1173.6(1), c = 1611.4(1) pm; β = 115.389(6)°; R = 0.0332. [Et₃PN(H)SiMe₃]I (7): Space group P2₁/n, Z = 4, lattice dimensions at –70 °C: a = 1360.2(1), b = 874.2(1), c = 1462.1(1) pm; β = 115.19(1)°; R = 0.066. In 6 and 7 the cations form ion pairs with their anions via NH … X hydrogen bonds. [Me₃PN(SiMe₃)₂]I (8): Space group P2₁/c, Z = 8, lattice dimensions at –60 °C: a = 1925.4(9), b = 1269.1(1), c = 1507.3(4); β = 111.79(3)°; R = 0.0581. [Et₃PN(SiMe₃)₂]I (9): Space group Pbcn, Z = 8, lattice dimensions at –50 °C: a = 2554.0(2), b = 1322.3(1), c = 1165.3(2) pm; R = 0.037. [Ph₃PN(SiMe₃)₂]I₃ (10): Space group P2₁, Z = 2, lattice dimensions at –50 °C: a = 947.7(1), b = 1047.6(1), c = 1601.6(4) pm; β = 105.96(1)°; R = 0.0334. 8 to 10 are built up from separated ions.     

f-Element Half-Sandwich Complexes: A Tetrasilylcyclobutadienyl–Uranium(IV)–Tris(tetrahydroborate) Anion Pianostool Complex

Despite there being numerous examples of f-element compounds supported by cyclopentadienyl, arene, cycloheptatrienyl, and cyclooctatetraenyl ligands (C_5–8), cyclobutadienyl (C₄) complexes remain exceedingly rare. Here, we report that reaction of [Li₂{C₄(SiMe₃)₄}(THF)₂] ( 1 ) with [U(BH₄)₃(THF)₂] ( 2 ) gives the pianostool complex [U{C₄(SiMe₃)₄}(BH₄)₃][Li(THF)₄] ( 3 ), where use of a borohydride and preformed C₄-unit circumvents difficulties in product isolation and closing a C₄-ring at uranium. Complex 3 is an unprecedented example of an f-element half-sandwich cyclobutadienyl complex, and it is only the second example of an actinide-cyclobutadienyl complex, the other being an inverse-sandwich. The U−C distances are short (av. 2.513 Å), reflecting the formal 2− charge of the C₄-unit, and the SiMe₃ groups are displaced from the C₄-plane, which we propose maximises U−C₄ orbital overlap. DFT calculations identify two quasi-degenerate U−C₄ π-bonds utilising the ψ₂ and ψ₃ molecular orbitals of the C₄-unit, but the potential δ-bond using the ψ₄ orbital is vacant.     

Sc3+ Chloro and Alkyl Complexes Coordinated by Pincer NHC-Tethered Bis(phenolate) Ligands

Bis(phenolate) ligands with benzimidazole-2-ylidene ( L¹) and tetrahydropyrimidine-2-ylidene ( L² ) linkers proved to be suitable coordination environments for the synthesis of isolable Sc³⁺ chloro and alkyl complexes. The treatment of Sc(CH₂SiMe₃)₃(THF)₂ with equimolar amounts of [ L^1,2H₃ ] Cl afforded chloro complexes L^1,2ScCl ( solv ) ₂ (solv=THF, Py) in 76–85 % yields. L^1,2ScCl ( THF ) ₂ were also prepared by the salt metathesis reactions of ScCl₃ with [ L^1,2 ] Na₂ generated from [ L^1,2H₃ ] Cl and 3 equiv. of NaN(SiMe₃)₂ (−40 °C, THF) and isolated in somewhat lower yields (68–73 %). L²ScCl ( THF ) ₂ was subjected to the alkylation reaction with LiCH₂SiMe₃ affording alkyl derivative [ L²Sc ( CH₂SiMe₃ )] ₂ . This compound can be alternatively prepared by the subsequent reactions of [ L²H₃ ] Cl with equimolar amount of NaN(SiMe₃)₂ and Sc(CH₂SiMe₃)₃(THF)₂. In the dimeric alkyl compound [ L²Sc ( CH₂SiMe₃ )] ₂ , one of the phenoxide groups of the dianionic ligand is coordinated to one scandium center, while the second one features μ-bridging coordination with two metal centers.     

Bis(arylimido) Molybdenum(VI) Amidinate and Guanidinate Complexes; Molecular Structures of [(ArN)2MoMe{N(Cy)C[N(i‐Pr)2]N(Cy)}] (Ar = 2,6‐i‐Pr2C6H3; Cy = Cyclohexyl) and [(2,6‐i‐Pr2C6H3N)2MoCl2] · [NH=C(C6H5)CH(SiMe3)2]

The reaction of [(ArN)₂MoCl₂] · DME (Ar = 2,6‐i‐Pr₂C₆H₃) ( 1 ) with lithium amidinates or guanidinates resulted in molybdenum(VI) complexes [(ArN)₂MoCl{N(R¹)C(R²)N(R¹)}] (R¹ = Cy (cyclohexyl), R² = Me ( 2 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 3 ); R¹ = Cy, R² = N(SiMe₃)₂ ( 4 ); R¹ = SiMe₃, R² = C₆H₅ ( 5 )) with five coordinated molybdenum atoms. Methylation of these compounds was exemplified by the reactions of 2 and 3 with MeLi affording the corresponding methylates [(ArN)₂MoMe{N(R¹)C(R²)N(R¹)}] (R¹ = Cy, R² = Me ( 6 ); R¹ = Cy, R² = N(i‐Pr)₂ ( 7 )). The analogous reaction of 1 with bulky [N(SiMe₃)C(C₆H₅)C(SiMe₃)₂]Li · THF did not give the corresponding metathesis product, but a Schiff base adduct [(ArN)₂MoCl₂] · [NH=C(C₆H₅)CH(SiMe₃)₂] ( 8 ) in low yield. The molecular structures of 7 and 8 are established by the X‐ray single crystal structural analysis.     

Synthese und Struktur gemischt‐substituierter Dialane Al2X2{Si(SiMe3)3}2 · 2 THF (X = Cl,Br)

Synthesis and Structure of two Mixed Substituted Dialanes Al₂X₂{Si(SiMe₃)₃}₂ · 2 THF (X = Cl, Br) The syntheses of tris(trimethylsilyl)silyl (hypersilyl) and halide substituted dialanes Al₂X₂{Si(SiMe₃)₃}₂ · 2 THF (X = Cl, Br) are presented. The results of the X‐ray diffraction experiments are presented and discussed in comparison to the Al^III compounds AlBr₂Si(SiMe₃)₃ · THF and AlBr₃ · OPh₂.     

[Cs(Toluol)3(FIn{N(SiMe3)2}3)], ein Fluoroindat mit gestreckter Cs–F–In-Achse

[Cs(toluene)₃(FIn{N(SiMe₃)₂}₃)], a Fluoroindate with Rectified Cs–F–In Axis The metalate [Cs(FIn{N(SiMe₃)₂}₃)] has been prepared by the reaction of In[N(SiMe₃)₂]₃ with CsF in THF: The title compound 1 can be obtained by recrystallization from toluene as colorless airsensitive needles. 1 has been characterized by NMR-, IR-, and MS-techniques as well as by an X-ray structure determination. The result of the structure analysis shows an prolated molecule with an almost linear Cs–F–In axis [174.7(1)°]. The Cs⁺ center is surrounded by the indate ion and three toluene molecules in a distorted tetrahedral fashion.     

Dinuclear Dysprosium and Ytterbium Complexes Incorporating N,N‐Bis(pyrrolyl‐α‐methyl)‐N‐methylamine Ligand: Syntheses and Structures

Reaction of DyCl₃ with two equivalents of NaN(SiMe₃)₂ in THF yielded {Dy(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 1 ). X‐ray crystal structure analysis revealed that 1 is a centrosymmetric dimer with asymmetrically bridging chloride ligands. The metal coordination arrangement can be best described as distorted trigonal bipyramid. The bond lengths of Ln–Cl and Ln–N showed a decreasing trend with the contraction of the size of Ln³⁺. Treatment of N,N‐bis(pyrrolyl‐α‐methyl)‐N‐methylamine (H₂dpma) with 1 and known compound {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂, respectively, led to the formations of [Dy(μ‐Cl)(dpma)(THF)₂]₂ ( 2 ) and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ ( 3 ). Compounds 2 and 3 were fully characterized by single‐crystal X‐ray crystallography, elemental analysis, and ¹H NMR spectroscopy. Structure determination indicated that 2 and 3 exhibit as centrosymmetric dimers with asymmetrically bridging chloride ligands. One pot reactions involving LnCl₃ (Ln = Dy and Yb), LiN(SiMe₃)₂, and H₂dpma were explored and desired products 2 and 3 were not yielded, which indicated that 1 and {Yb(μ‐Cl)[N(SiMe₃)₂]₂(THF)}₂ are the demanding precursors to synthesize Dysprosium and Ytterbium complexes supported by dpma^2– ligand. Compounds 2 and 3 are the first reported lanthanide complexes chelated by dpma^2– ligand.     

Synthese und Kristallstrukturen der Seltenerd-Komplexe [LaI2(THF)5]+I3−, [SmCl3(THF)4], [ErCl2(THF)5]+ [ErCl4(THF)2]−, [ErCl3(DME)2] und [Na(18-Krone-6)(THF)2]+ [YbBr4(THF)2]−

Syntheses and Crystal Structures of the Rare-Earth Complexes [LaI₂(THF)₅]⁺I₃^?, [SmCl₃(THF)₄], [ErCl₂(THF)₅]⁺ [ErCl₄(THF)₂]^?, [ErCl₃(DME)₂], and [Na(18-Crown-6)(THF)₂]⁺[YbBr₄(THF)₂]^? [LaI₂(THF)₅]⁺I₃^? ( 1 ) is obtained as red crystals from lanthanum powder and 1,2-diiodoethane in THF on exposure to light. Space group Pbcn, Z = 4, lattice dimensions at ?83°C: a = 1264.9, b = 2218.9, c = 1199.1 pm, R = 0.031. The lanthanum atom of the cation of 1 is coordinated with iodine atoms in the axial positions in a pentagonal-bipyramidal way. [SmCl₃(THF)₄] ( 2 ) originates as colourless crystals on heating SmCl₃ with excess THF in the presence of Me₃SiNPEt₃. Space group P2₁/c, Z = 8, lattice dimensions at ?50°C: a = 3092.7, b = 826.2, c = 1758.3 pm, β = 93.85°, R = 0.054. Just like the known sample that crystallizes within the space group F2dd, 2 forms monomeric molecules in which the samarium atom is coordinated with two chlorine atoms in the axial positions in a distorted pentagonal-bipyramidal way. [ErCl₂(THF)₅]⁺[ErCl₄(THF)₂]^? ( 3 ). Pale pink single crystals of 3 were prepared according to the described method by reaction of erbium powder with trimethylchlorosilane and methanol in THF. Space group C2/c, Z = 4, lattice dimensions at ?50°C: a = 1246.3, b = 1145.7, c = 2726.0 pm, β = 91.293°, R = 0.036. The erbium atom of the cation of 3 has a pentagonal-bipyramidal coordination with the chlorine atoms in the axial positions. Within the anion the THF molecules are in trans-arrangement of the octahedrally coordinated erbium atom. [ErC1₃(DME)₂] ( 4 ) originates as pink single crystals from ₃ with excess boiling 1,2-dimethoxyethane. Space group P2₁/c, Z = 4, lattice dimensions at ?50°C: a = 1137.2, b = 886.5, c = 1561.1 pm, β = 104.746°, R = 0.032. 4 forms monomeric molecules in which the erbium atom has a pentagonal-bipyramidal surrounding with two chlorine atoms in the axial positions. [Na(18-Krone-6)(THF)₂]⁺ [YbBr₄(THF)₂]^? ( 5 ) is formed as by-product by the reaction of YbBr₃ with NaN(SiMe₃)₂ in THF in the presence-of 18-crown-6 forming colourless crystals. Space group P1 , Z = 1, lattice dimensions at ?70°C: a = 934.6, b = 988.9, c = 1208.0 pm, α = 73.82°, β = 72.98°, γ = 76.89°, R = 0.029. 5 contains isolated [YbBr₄(THF)₂]^?ions, in which the THF molecules are arranged in trans-position.     

Amido-Komplexe von Mangan(II). Synthese und Kristallstrukturen von [Mn(NPh2)2(THF)]2 und Na2[Mn(NPh2)4] · 2 C7H8

Amido Complexes of Manganese(II). Syntheses and Crystal Structures of [Mn(NPh₂)₂(THF)]₂ and Na₂[Mn(NPh₂)₄] · 2 C₇H₈ The silylated amido complex [Mn{N(SiMe₃)₂}₂ · (THF)] reacts in toluene solution with diphenylamine under ligand exchange to form the diphenylamido complex [Mn(NPh₂)₂(THF)]₂ ( 1 ), which forms orange-red columnar crystals. 1 reacts in THF solution with NaN(SiMe₃)₂ and after crystallization from toluene yellow-orange Na₂[Mn(NPh₂)₄] · 2 C₇H₈ ( 2 ) is obtained. According to the crystal structure analyses the manganese atoms in 1 (space group P2₁/c, Z = 2) are linked via the N atoms of two of the NPh₂^– groups to form centrosymmetric Mn₂N₂ four-membered rings with Mn–N bonds of almost the same length. 2 (space group I4₁/a, Z = 4) forms a three-dimensional space-lattice structure, which arises from ”︁inner solvation”︁”︁ of the sodium atoms with the phenyl rings of the NPh₂^– group.     

Kristallstruktur des Zinkamids Zn[N(SiMe3)2]2

Crystal Structure of the Zinc Amide Zn[N(SiMe₃)₂]₂ X‐ray quality crystals of Zn[N(SiMe₃)₂]₂ (monoclinic, P2₁/c) are obtained by sublimation of the zinc amide Zn[N(SiMe₃)₂]₂ at —30 °C in vacuo (300 torr). According to the result of the X‐ray structural analysis, Zn[N(SiMe₃)₂]₂ contains an almost linear N‐Zn‐N unit with two short N‐Zn bonds.     

Synthese und Kristallstrukturen der Nitrido‐Chloro‐Molybdate [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 und [Li(12‐Krone‐4)(NMoCl4)]2 · 2 CH2Cl2

Syntheses and Crystal Structures of the Nitrido‐chloro‐molybdates [Mg(THF)₄{NMoCl₄(THF)}₂] · 4 CH₂Cl₂ and [Li(12‐Crown‐4)(NMoCl₄)]₂ · 2 CH₂Cl₂ Both the title compounds as well as [Li(12‐crown‐4)₂]⁺MoNCl₄^– were made from MoNCl₃ and the chlorides MgCl₂ and LiCl, respectively, in dichloromethane suspensions in the presence of tetrahydrofuran and 12‐crown‐4, respectively. They form orange‐red moisture‐sensitive crystals, which were characterized by their IR spectra and partly by crystal structure analyses. [Mg(THF)₄{NMoCl₄(THF)}₂] · 4 CH₂Cl₂ ( 1 ): space group C2/m, Z = 2, lattice dimensions at –50 °C: a = 1736.6(1), b = 1194.8(1), c = 1293.5(2) pm; β = 90.87(1)°; R₁ = 0.037. In 1 the magnesium ion is coordinated octahedrally by the oxygen atoms of the four THF molecules and in trans‐position by the nitrogen atoms of the two [N≡MoCl₄(THF)]^– ions. [Li(12‐crown‐4)(NMoCl₄)]₂ · 2 CH₂Cl₂ ( 2 ): space group P 1, Z = 1, lattice dimensions at –70 °C: a = 930.4(1), b = 957.9(1), c = 1264.6(1) pm; α = 68.91(1)°, β = 81.38(1)°, γ = 63.84(1)°; R₁ = 0.0643. 2 forms a centrosymmetric ion ensemble in the dimeric cation of which, i. e. [Li(12‐crown‐4)]₂²⁺, the lithium ions on the one hand are connected to the four oxygen atoms each of the crown ether molecules in a way not yet known; and in addition, each of the lithium ions enters into a intermolecular Li–O bond with neighboring crown ether molecules under formation of a Li₂O₂ four‐membered ring. The two N≡MoCl₄^– counterions are loosely coordinated to one oxygen atom each of the crown ether molecules with Mo–O distances of 320.2 pm.