bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dilithium Derivatives of Bis(tert‐butyldimethylsilylamino)silanes as Building Units for Inorganic Ring Compounds
Authors: Hemme Ina , Tecklenburg Brigitte , Noltemeyer Mathias , Klingebiel Uwe 
Published: July 2007

AbstractThe bis[(tert‐butyldimethylsilyl)amino]silanes 1–3 are converted into their lithium derivatives 4–7 with BuLi. Depending on the bulkiness of the substituents, the dilithium derivatives 4 and 5 crystallize in cis or trans conformation. Monolithiated 3 (6) forms a four‐membered (SiFLiN) ring system, while its dilithium salt is characterized as a lithium silyldiamide (7), Although 4, 5, and 7 have different structures, they react with PF3 (8, 9), SiF4 (10, 11), and CMe3SiF3 (12) as diamides to give the corresponding four‐membered ring systems 8–12. The crystal structures of 4 and 5 are reported.
Ionenpaarbildung und Cyclisierungsreaktionen an koordinierten Oxalamidinen
Authors: Fehling Peer , Döring Manfred , Knoch Falk , Beckert Rainer , Görls Helmar 
Published: July 2007

Ion Pairing and Cyclization on Coordinatively Bound OxalamidinesThe tetraphenyloxalamidine ligand of complex 8a reacts easily in the presence of bases with elementorganic dichlorides (R2MCl2) to form coordinated metalacycles. The cyclization with phosgene gives the (CO)4Mo‐coordinated 1,3‐diphenyl‐4,5‐bis(phenylimino)‐2‐imidazolidinones 10. In contrast to the reaction forming the piperazine derivative 2, the reaction of 8a with oxalyl chloride also proceeds to 10 by decarbonylation. The product of this cyclization, (CO)4Mo(OCTPOA) (10), and two possible intermediates, the dinuclear sodium salts Na2(THF)8[(CO)4Mo(HTPOA)]2 (11a) and Na(THF)4[(CO)4Mo(EtO2COCTTOA)]2 (15) have been characterized by X‐ray analyses. 11a contains the coordinated oxalaminate anion. The structure of the ionic complex 15 shows the simultaneous attack at both sp3‐hybridized nitrogen atoms and the selective formation of the five‐membered 2‐imidazolidinone heterocycle by coordination of the oxalamidine. Both sodium complexes 11a and 15 are dimeric and centrosymmetric ion pairs. Complex 11a contains two CONaOC bridges while compound 15 has a central [Na2O2] four‐membered ring consisting of sodium alcoholate bridges.
Synthese und Charakterisierung neuer Hemiporphyrazinato‐Nickelkomplexe
Authors: Haberroth Klaus , Rack Michael , Ruff Detlef , Hanack Michael 
Published: July 2007

Synthesis and Characterization of New Hemiporphyrazinato Nickel ComplexesThe new substituted (hemiporphyrazinato)nickel complexes [HpNi] 3–9 and 11–14, the (heminaphthoporphyrazinato)‐nickel complexes 15–19 [HnpNi], and the hemianthraceno‐phorphyrazine complex [HapNi] 20 are prepared from isoin‐dolenines 1a–e and 10a–d, diaminopyridines 2a–e and nickel acetate. The compounds were characterized by 1H‐ and 13C‐NMR spectroscopy. The 1H‐NMR spectrum of the mixture of the 3,18/3,19‐substituted (C2v/C2h) complexes is discussed.
Syntheses and Properties of X6Te2N2Se (XCl, Br): Stable Heterocycles with an NSeN Moiety
Authors: Haas Alois , Schäfers Mike 
Published: July 2007

AbstractTreatment of Se[N(SiMe3)2]2 with TeX4 (XCl, Br) yields new bicyclic tellura heterocycles X6Te2N2Se (XCl, 1a; XBr, 1b). Similarly, these compounds are obtained with elimination of elemental selenium by reaction of Se2‐[N(SiMe3)2]2 with TeX4 (XCl, Br). They are characterized by IR and mass spectroscopy as well as elemental analyses. 125Te‐ and 77Se‐NMR data are given for Cl6Te2N2Se (1a), and spectra are compared with those of the corresponding sulfur analogs.
Synthesis and Structure of the First Dimetalated Diphosphane Disulfide [(η5‐C5Me5)(CO)2FeP(H)(S)]2
Authors: Weber Lothar , Misiak Hanns , Stammler Hans‐Georg , Neumann Beate 
Published: July 2007

AbstractThe first transition metal derivative meso‐[(η5‐C5Me5)(CO)2FeP(H)(S)]2 (2) of the unknown diphosphane disulfide [PH2(S)]2 results from treatment of (η5‐C5Me5)(CO)2FePH2 (1) with 1.5 equivalents of elemental sulfur. Compound 2 was characterized by means of spectroscopy (IR, 31P, 31P{1H}, 13C{1H}, 1H NMR) as well as X‐ray diffraction analysis.
Chiral Organometallic Reagents, XIII. Structural Aspects of Differentially Solvated Benzyllithium Contact Ion Pairs
Authors: Ruhland Thomas , Hoffmann Reinhard W. , Schade Steffen , Boche Gernot 
Published: July 2007

AbstractThe solvation and ion pair nature of α‐(phenylthio)benzyllithium (2d) in THF solution were investigated by NMR‐spectroscopic methods. The effect of additives such as diethylene‐glycol dimethyl ether or of 12‐crown‐4 was studied. The results were compared to those of benzyllithium compounds 4 and 6, containing a pentaoxapentadecane ansa chain. These compounds exist as contact ion pairs in which lithium is held at the anionic carbon. This is reflected in the 6Li,13C coupling and 1H,6Li‐HOESY contacts in the NMR spectra.
Tin for Organic Synthesis, 12. Synthesis of Aromatic and Olefinic Sodium Sulfonates by Electrophilic Destannylation with Trimethylsilyl Chlorosulfonate
Authors: Niestroj Michael , Lube Andreas , Neumann Wilhelm P. 
Published: July 2007

AbstractA mild and effective method for the preparation of a variety of aromatic, olefinic, and acetylenic sodium sulfonates is described. The reaction of trialkylaryl‐ (2a‐k) and ‐heteroarylstannanes (4a‐d), bis‐(1‐alkenyl)dibutylstannanes (6a‐f), or trialkylalkynylsta manes with trimethylsilyl chlorosulfonate (1) followed by hydrolysis with aqueous NaHCO3 provides the sodium sulfonates in an ipso‐specific and in the case of vinylic stannanes stereospecific manner. A comparison of the reactivity of stannylated and silylated olefinic compounds 13 and 14 underlines the greater leaving ability of the stannyl moiety. The in situ preparation of the stannanes makes it possible to apply the synthetic method to natural products such as N‐substituted apocodeine (17).
Contributions to the Chemistry of Boron, 230. Electrophilic Borylation of Metallocenes: Synthesis and Molecular Structures of 1,1′,3,3′‐Tetrakis(dibromoboryl)metallocenes of the Iron Triad
Authors: Appel Andrea , Nöth Heinrich , Schmidt Martin 
Published: July 2007

AbstractReactions of metallocenes MCp2 (M = Fe, Ru, Os) with an excess of BBr3 at reflux temperature lead specifically to 1,1′,3,3′‐tetrakis(dibromoboryl)metallocenes 3, 7, and 8 in high yield. MeBBr2 and PhBBr2 are less effective borylating agents. X‐ray structural analyses of 3, 7, and 8 reveal an increasing tilt of the Br2B groups towards the metal center while retaining the trigonal‐planar environment at the boron atoms. This indicates a weak metal‐boron interaction of the kind found for carbon‐metal interactions in ferrocenyl carbocations.
Synthesis of 2‐ and 3‐Stannolenes via Addition of Trimethyltin Alkoxides to 3‐Diethylboryl‐4‐ethyl‐1,1‐dimethylstannole
Authors: Wrackmeyer Bernd , Klaus Uwe , Milius Wolfgang 
Published: July 2007

AbstractTrimethyltin alkoxides (2) react stereoselectively with 3‐diethylboryl‐4‐ethyl‐1,1‐dimethylstannole (1) via addition of the Me3Sn group to C(2) to the C(2) = C(3) bond and a 1,2 shift of an ethyl group from boron to C(3) to give the 2‐stannolenes 3. The molecular structure of 3f' [R = (S)‐2‐Bu] was determined by single‐crystal X‐ray analysis, confirming the cis positions of the Et(RO)B and the Me3Sn group. These 2‐stannolenes 3 undergo, upon heating to ca. 80°C, facile rearrangement by irreversible allylic migration of the Et(RO)B group to the 3‐stannolenes 4 in which the cis positions of the boryl and the stannyl group are retained. All 2‐stannolenes (in contrast to the 3‐stannolenes) are readily deprotoborylated to give the 3‐stannolene 5. The structures of 3, 4, and 5 follow conclusively from 1H‐, 11B‐, 13C‐, and 119Sn‐NMR spectra. The negative sign of the geminal coupling constants 2J(SnSn) was determined in the case of 3, 4, and 5 by 2D 119Sn/1H heteronuclear shift correlations.
A New Synthesis of P‐Substituted 2,3‐Dihydro‐1,3‐dimethyl‐1,3,2δ3‐benzodiazaphosphorin‐4(1H)‐ones and Alkylaminodifluorophosphanes with Chlorodifluorophosphane. — Synthesis and Structure of {cis‐Bis[bis(2‐chloroethyl)aminodifluorophosphane]dichloro}platinum(II)
Authors: Plinta Hans‐Jürgen , Neda Ion , Fischer Axel , Jones Peter G. , Schmutzler Reinhard 
Published: July 2007

Abstract2,3‐Dihydro‐1,3‐dimethyl‐2‐oxo‐1,3,2δ4‐benzodiazaphosphorin‐4(1H)‐one 1 reacted with diethylaminotrimethylsilane to give solely the 2‐trimethylsiloxy‐δ3‐diazaphosphorinone 2. The reaction of 2 with the 2‐chloro‐δ3‐diazaphosphorinone 3 yielded the P—O—P‐bridged compound 4 in an equilibrium reaction with elimination of trimethylchlorosilane. The synthesis of the P‐difluorophosphite‐substituted δ3‐benzodiaza‐phosphorinone 6 was effected by the reaction of chlorodifluorophosphane (5) with 1 in the presence of triethylamine in a 1:1 molar ratio, or in the reaction of 5 with 2 or 4. The reaction of 5 with 6 led, with elimination of μ‐oxo‐bis(difluoro‐phosphane), to the P(III)Cl species 3, 5 reacted with N,N'‐dimethylanthranilamide in the presence of triethylamine in a 2:1:2 molar ratio to give the N,N'‐bis(difluorophosphane) derivative 9, as evidenced by low temperature (‐30°C) 19F‐and 31P‐NMR data. At room temperature the 2‐fluoro‐δ3‐diazaphosphorinone 10 was formed from 9 with intramolecular elimination of phosphorus trifluoride. 2‐Chloroethyl‐ or bis(2‐chloroethyl)aminodifluorophosphane 11 and 12 were obtained in the reaction of 5 with 2‐chloroethyl‐ or bis(2‐chloroethyl)amine hydrochloride in the presence of triethylamine in a 1:1:2 molar ratio. 12 reacted with (COD)PtCl2 (COD = 1,5‐cyclooctadiene) in a 2:1 molar ratio to give the {cis‐bis[bis(2‐chloroethyl)aminodifluorophosphane]dichloro}platinum(II) complex 13. The characterization of 2, 4, 6, and 11–13 is based on their NMR and mass spectra. The structures of 10 and 13 were established by single‐crystal X‐ray analysis. 10 crystallizes with two independent molecules. Both six‐membered heterocycles display an envelope conformation with the phosphorus atoms 36.9 and 50.4 pm, respectively, out of the plane. The phosphorus atoms have pyramidal coordination geometry. The cis‐configuration at platinum(II) in the complex 13 was confirmed; two ligands (12) are coordinated to PtII via phosphorus. The platinum atom has a distorted square‐planar coordination geometry.
Novel Aromatic Azopolymers with Regularly Interposed Tellurium Atoms in the Backbone
Authors: Suzuki Hitomi , Nakamura Tohru , Seki Kenji 
Published: July 2007

AbstractPreviously unknown alt‐copoly(telluro‐1,4‐phenylene/azo‐1,4‐phenylene) and related polymers were synthesized by several different approaches, which include a) reductive polymerization of bis(4‐nitrophenyl) tellurides with zinc; b) oxidative polymerization of bis(4‐aminophenyl) telluride using a CuI/CuII redox system as catalyst under oxygen; c) electrochemical polymerization of bis(4‐amino‐3,5‐dimethylphenyl) telluride; d) condensation polymerization of 1,4‐dinitrosobenzene with bis(4‐aminophenyl) telluride Te, Te‐dichloride, and e) condensation polymerization of bis(4‐nitrophenyl) telluride with bis(4‐aminophenyl) telluride in the presence of sodium hydroxide. The polymers obtained were characterized by elemental analysis, 13C‐CPMAS NMR, IR and UV‐vis spectroscopy, GPC, and inherent viscosity measurements, and their properties were examined, particularly their electrical conductivity. The electrical conductivities of the new polymers 9b c, and 10 were shown to increase from below 10−7 up to 10−5 ∽ 10−2 S cm−1 upon bromine doping in spite of their formally interrupted conjugation structure.
Mo(CO)2(PPh3)2(O3SCF3)2: Ein neuer Vorläufer einer dikationischen, metallorganischen Lewis‐Säure mit drei freien Koordinationsstellen
Authors: Rosendorfer Philipp , Beck Wolfgang 
Published: July 2007

AbstractOrganometallic Lewis Acids, LIV. — Mo(CO)2(PPh3)2(O3SCF3)2: A New Precursor for an Organometallic Dicationic Lewis Acid with Three Accessible Coordination SitesThe reaction of Mo(CO)2(PPh3)2Br2 (1) with AgO3SCF3 gives the bis(triflate) complex Mo(CO)2(PPh3)2(O3SCF3)2 (3) which can be considered as a precursor for the 12‐e− system “Mo‐(CO)2(PPh3)2+2”. According to the spectroscopic data one of the two coordinated CF3SO−3 anions is acting as a chelate ligand. Treatment of 3 and of the in situ generated W(CO)2(PPh3)2(O3SCF3)2 (4) with H2O affords the dinuclear hydroxo‐bridged complexes [M2(μ‐OH)3(CO)4(PPh3)4][CF3SO3] (5: M = Mo; 6: M = W). Acetonitrile replaces the CF3SO−3 ligands in 3 and 4 to afford the cationic complexes [M(CO)2(PPh3)2(NCMe)3][CF3SO3]2 (7: M = Mo; 8: M = W). The reaction of 3 with an excess of 2‐butyne and 1‐phenyl‐1‐propyne leads to the monoalkyne complexes Mo(CO)(MeCCR)(PPh3)2(O3SCF3)2 (9: R = Me; 10: R = Ph) in moderate yield. In contrast, the bisalkyne complexes [M(CO)(MeCCMe)2(PPh3)2(O3SCF3)][CF3SO3] (11: M = Mo; 12: M = W) are formed in high yield when a CH2Cl2 solution of 2‐butyne is added to 1 and 2 in the presence of AgO3SCF3. At room temperature, 11 and 12 are highly fluxional in solution, while 9 and 10 are stereochemically rigid. Treatment of 11 with acetonitrile yields [Mo(CO)(MeCCMe)2(PPh3)2(NCMe)][CF3SO3]2 (13). Compounds 3–13 (except 4) are characterized by IR, 1H‐, 13C‐, 19F‐, and 31P‐NMR spectrescopy.
The Gas‐Phase Structure of 1‐Trifluoromethylthio‐1,2,2‐trifluoroethene, CF3SC(F)=CF2
Authors: Olleta Adriana , Haas Alois , Oberhammer Heinz 
Published: July 2007

AbstractThe molecular structure of 1‐trifluoromethylthio‐1,2,2‐trifluoroethene, CF3SC(F) = CF2, was determined by gas electron diffraction (GED) and ab initio calculations (HF/3–21G*). The S—CF3 bond is oriented nearly perpendicular to the ethene plane with Φ(C = C‐S‐C) = 96.9(12)°. This orientation implies that the p‐shaped sulfur lone pair is perpendicular to the ethene π orbitals. The following skeletal bond lengths (ra in Å) and angles (χ α in °) were obtained (error limits are 30 values): C = C = 1.302(19) Å, C(sp2)—S = 1.719(9) Å, SC(sp3) = 1.820(10) Å, C  CS = 120.0(9)°, and CSC  101.7(7)°. The experimental geometric parameters were reproduced reasonably well by the ab initio method.
The Molecular Structures and Conformations of Bis(dichlorosilyl)amine and Bis(dichlorosilyl)methylamine in the Gas Phase: Determination by Electron Diffraction and by ab Initio Calculations
Authors: Fleischer Holger , Hnyka Drahomir , Rankin David W. H. , Robertson Heather E. , Bühl Michael , Thiel Walter 
Published: July 2007

AbstractThe gas‐phase molecular structures of bis(dichlorosilyl)‐amine, (HSiCl22NH, and bis(dichlorosilyl)methylamine, (SiHCl2)2NMe, have been investigated by electron diffraction and ab initio calculations on a MP2/6–31G* level. Because the latter suggest the presence of a mixture of two conformers for each molecule, attempts were made to fit the electron diffraction data in each case by two different models, one assuming the presence of only one conformation, and another allowing for two different conformers. The principal parameters (ra) from electron diffraction for (HSiCl2)2NH are (the appropriate ab initio calculated values are given in brackets []): r(Si‐N) 171.9(2) [172.7], r(Si‐Cl) 204.1(1)[204.5] pm; Si‐N‐Si 126.5(8) [127.4] N‐Si‐Cl 107.3(5) [110.8] and Cl‐Si‐Cl 106.5(3) [107.5]°. For (SiHCl2)2NMe: r(Si‐N) 171.1(3) [171.5], r(Si‐Cl) 204.0(9) [205.2], r(N‐C) 149.7(10) [148.3] pm; Si‐N‐Si 124.9(13) [123.4], N‐Si‐Cl 109.7(5) [110.7] and Cl‐Si‐Cl 107.1(3) [107.2]° [110.8] and Cl‐Si‐Cl 106.5(3) [107.5]°. For (SiHCl2)2NMe: r(Si‐N) 171.1(3) [171.5], r(Si‐Cl) 204.0(9) [205.2], r(N‐C) 149.7(10) [148.3] pm; Si‐N‐Si 124.9(13) [123.4], N‐Si‐Cl 109.7(5) [110.7] and Cl‐Si‐Cl 107.1(3) [107.2]°. For (HSiCl2)2NH three different conformers were found to fit the experimental data with the single‐conformation model. In two of the conformers, the dichlorosilyl groups are twisted by Θ1 = 146.0(10)/Θ2 = 155.2(20)° and Θ1= 101.1(49)/Θ2 = 196.8(12)°; respectively counterclockwise from the positions in which the Si‐H bonds eclipse the N‐H bond. Both of these lead to nearly ideally staggered conformations of the two SiHCl2 groups when viewed along the Si–Si axis. In contrast, the third conformation is nearly eclipsed, with torsion angles Θ1 = 131.4(15)/Θ2 = 80.4(26)°. Planarity of the Si2NH group was assumed as suggested by ab initio calculation. For (HSiCl2)2NMe the experimental data could be suitably fitted by two conformers, in which the dichlorosilyl groups are twisted by Θ1= 161.8(13)/Θ2 = 63.1(23)° and Θ1 = 156.1(9)/ Θ2 = 177.1(15)° from the positions in which the Si‐H bonls eclipse the N‐C bond. The first of these structures has an eclipsed Si(NSi)Cl conformation and an Si…Cl nonbonded distance close to distance clse to the sum of the appropriate van der waals radii. MP2/6–31G* calculations support the GED bond lengths and bond angles of both molecules, but indicate different conformations for the most stable equilibrium geometries: the computed twists are Θ1 = 180/Θ2 = 180° and Θ1 = 177.0/ Θ2 = 183.0° for (HSiCl2)2NH and (HSiCl2)2NMe, respectively. Rotation about the Si—N bonds is a very facile process, cf. the computed [MP2/6–31G*//MP2/6–31G* + ZPE(SCF/6–31G*)] rotational barrier of 2.9 kJ. mol‐1 for (HSiCl2)2NH.
Auriophilicity in Polynuclear (Phosphane)gold(I) Thiolates {Me3CS[Au(PPh3)]2}+ BF‐4 and {(CH2S)2[Au(PPh3)]3}+ BF‐4
Authors: Sladek Alexander , Schmidbaur Hubert 
Published: July 2007

AbstractThe reaction of tert‐butanethiol with tris[(triphenylphosphane)gold(I)]oxonium tetrafluoroborate in dichloromethane in the presence of sodium tetrafluoroborate gave quantitative yields of a product {Me3CS[Au(PPh3)]2}+ BF‐4 (1). In the crystal lattice of this salt, the sulfonium cations are associated into dimers through close Au…Au contacts. The centrosym‐metrical tetranuclear unit has Au…Au distances of 3.292(1) and 3.206(1) Å, and the Au‐S‐Au angles are exactly 90.0(1)°. Both data are indicative of significant intra‐ and intercationic Au…Au attractions. The analogous reaction of ethane‐1, 2–dithiol afforded high yields of a product {(CH2S)2[Au(PPh3)]3}+ BF‐4 (2). The compound is fluxional in CD2Cl2 solution and shows only one 31P‐NMR signal at ‐60°C. In the crystal, the quasi C2‐symmetrical trinuclear cations feature the sulfur atoms in bridging positions between two gold atoms. The central gold atom is thus three‐coordinate; the peripheral gold atoms are two‐coordinate with Au…Au contacts at 3.284(1) and 3.129(1) Å and Au‐S‐Au angles as small as 86.5(1) and 81.0(1)°. This provides clear evidence for “auriophilic” bonding.
Metallatomsynthese, Eigenschaften und Struktur von μ2‐(η3,η3‐Toluol)bis[(η6‐toluol)eisen](Fe‐Fe)
Authors: Schneider Jöurg J. , Specht Ullrich , Goddard Richard , Krüger Carl , Ensling Jürgen , Gütlich Philipp 
Published: July 2007

Metal Atom Synthesis, Properties, and Structure of μ2(η3,η3‐Toluene)bis[(η6‐toluene)iron](Fe‐Fe)Metal atom cocondensation of iron atoms and toluene produces the mononuclear iron sandwich compound [(η6‐toluene)(η4‐toluene)Fe] 1. Complex 1 reacts with a palette of N‐containing ligands such as primary, secondary, and tertiary amines as well as pyridine, pyrrolidine, and tmeda to form highly reactive instable intermediates. In the temperature range from ‐80 to ‐30°C, the proposed intermediates react with toluene to form the first homoleptic Fe/toluene complex μ2‐(η3η3‐toluene)‐bis[(η6‐toluene)iron](Fe‐Fe) (3) regardless which N‐containing ligand is used. Additionally, 3 is also formed when ethanol is used instead of N‐containing base ligands. Black thermolabile 3 was characterized by low‐temperature 1H‐, 13C‐, and Möβbauer spectroscopy as well as by an X‐ray structure analysis (‐173°C). The X‐ray structure determination reveals a μ‐η3η3‐briding toluene ligand capping two {(η6‐toluene)Fe} units which are connected by an Fe‐Fe bond [2.746(1) Å]. However, in solution up to ‐30°C all three toluene ligands are fluxional according to 1H‐ and 13C‐NMR data. At ‐10°C 3 reacts with CO with decomposition to form Fe metal. With 2,2‐bipyridine and ethene no reaction is observed up to room temperature.
Compounds of Germanium and Tin, 16. A Tetraaryldistannene with a Long Tin—Tin Multiple Bond and Differing Environments at the Tin Atoms
Authors: Weidenbruch Manfred , Kilian Hartmut , Peters Karl , Schnering Hans Georg Von , Marsmann Heinrich 
Published: July 2007

AbstractAlthough tetrakis(2‐tert‐butyl‐4,5,6‐trimethylphenyl)distannene (9), the first tetraaryl‐distannene to be reported on, is stable in the solid state, only the monomeric stannylene 8 can be detected in solution. An X‐ray crystal structure analysis of 9 reveals a long tin‐tin bond length of 291.0(1) pm and a trans‐bent Sn2C4 framework with different fold angles of 21.4° and 64.4°.
Synthesis and Structures of Magnesium Tetrahydridoaluminates
Authors: Nöth Heinrich , Schmidt Martin , Treit Andreas 
Published: July 2007

AbstractThe molecular structures of XMg(A1H4) · 4 THF (1a, 2, 3a) (X = A1H4, Cl, Br) have been determined by X‐ray structural analysis. Each compound possesses a hexacoordinated Mg center and AlH4− groups bound to this center via a single hydride bridge bond. Attempts to prepare ROMg(AlH4) compounds were successful only for sterically demanding groups R (R = CMe3, CPh3, naph, mes, smes). The 2‐naphthoxy derivative 7, a compound with the composition (naphO)Mg‐(AlH4) · 2.5 THF, is a dimer with a central Mg2O2 ring. One of its two AlH4− groups is terminally bound to one Mg atom, the other bridges the two Mg centers. This structure indicates how AlH4− transfer may occur from ROMg(AlH4) compounds to form Mg(OR)2 and Mg(AlH4)2.
Formation of a [μ‐(η1‐N:η2‐C,N)‐Aryl cyanide]biszirconocene Cation by Ligand Exchange Reaction
Authors: Röttger Dirk , Erker Gerhard , Fröhlich Roland 
Published: July 2007

AbstractThe planar‐tetracoordinate carbon compound 4 exchanges the bridging μ‐(η1‐C:η2‐C,C)‐2‐butyne ligand for p‐tolunitrile in dichloromethane at 90°C to yield the [μ‐(η1‐N:η2‐C,N)‐aryl cyanide]dizirconium cation complex 2a. X‐ray diffraction revealed an aza‐allenyl‐type character of the RCNZr moiety in this thermodynamically favored (μ‐nitrile)zirconium cation complex.
Chiral Carbanions, 1. Configurational Stability and Reactions of α‐Acyloxy‐Substituted α‐Methylbenzyllithium Compounds
Authors: Hammerschmidt Friedrich , Hanninger Achim 
Published: July 2007

AbstractRacemic and optically active 1‐phenylethyl esters of pivalic, (—)‐camphanic and 2,4,6‐triisopropylbenzoic acid were prepared. The esters 7a of pivalic acid were deprotonated with lithium 2,2,6,6‐tetramethylpiperidide (Li‐TMP) to form α‐oxy‐α‐methylbenzyllithium compounds which are partly con‐figurationally stable prior to acylation with starting material. Camphanic ester (–)‐7b cannot be deprotonated by Li‐TMP and tBuLi is added to the ester function to afford ketone (–)‐12a. 1‐Phenylethyl 2,4,6‐triisopropylbenzoates 16 were transformed within minutes to carbanions 19 by using sBuLi/TMEDA in THF, hexane, toluene and sBuLi without TMEDA in toluene/20% diethyl ether at –78°C. The carbanions are configurationally stable only in toluene/20% diethyl ether and racemise partly in the other solvents. They react with a variety of electrophiles with either retention [MeOD, AcOD, (MeO)2CO, CICO2Me] or inversion (Me3SnCl) of configuration. Carbanions 19 rearrange on warming to –20°C to hydroxy ketone 24 with racemisation.