bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metal Complexes with Tetrapyrrole Ligands, LXV[1]. Generation and ESR Spectra of the Cation Radicals of Bis(octaethylporphyrinato)zirconium(IV) and Bis(chelate)(octaethylporphyrinato)zirconium(IV) Complexes
Authors: Buchler Johann W. , Eberle Mike , Hammerschmitt Peter , Hüttermann Jürgen , Kappl Reinhard 
Published: July 2007

AbstractElectron spin resonance spectra of the cation radicals A+ and B+ generated from a zirconium(IV) monoporphyrin, bis(acetato)(octaethylporphyrinato)zirconium(IV), Zr(OEP)(OAc)2 (A), and bis(octaethylporphyrinato)zirconium(IV), Zr(OEP)2 (B), respectively, have been measured at 293 and 77 K. [Zr(OEP*)(OAc)2]Br (A+ Br–) has been prepared in situ by oxidation of A with bromine, [Zr(OEP√/2)2]PF6 (B+ PF6–) by electrochemical oxidation of B. ESR parameters at 293 K are as follows: A+ Br–: g = 2.0025, ΔHpp = 0.57 mT; B+ PF6–: g = 2.0024, ΔHpp = 0.39 mT. The ratio of the line widths ΔHpp(A+) and ΔHpp(B+) of the ESR signals of A+ and B+ is 1.46 at room temperature, i. e. very close to the value of √2 expected for a defect electron completely delocalized between the two porphyrin π electron systems in [Zr(OEP*/2)2]+. The ESR signal of A+Br– persists on cooling to 77 K excluding any kind of π‐π dimer formation. Treatment of (octaethylporphyrinato)bis(2,4‐pentanedionato)zirconium(IV), Zr(OEP)(acac)2, with bromine yields bis(3‐bromo‐2,4‐pentanedionato)(octaethylporphyrinato)zirconium(IV), Zr(OEP)(Bracac)2.
Ephedrine‐Derived Imidazolidin‐2‐ones. Broad Utility Chiral Auxiliaries in Asymmetric Synthesis
Authors: Drewes Siegfried E. , Malissar Dean G. S. , Roos Gregory H. P. 
Published: July 2007

AbstractThe scope of the readily available (4R,5S)‐1,5‐dimethyl‐4‐phenylimidazolidin‐2‐one (4) and its 4‐cyclohexyl analogue 6 as practical, efficient chiral auxiliaries has been demonstrated. The enolate chemistry of their N‐acyl derivatives exhibits features which recommend their use in asymmetric synthesis. The stereoselective boron‐mediated aldol as well as alkylation and acylation results are presented. The steric control benefit derived by conversion of phenyl to cyclohexyl is highlighted.
Nb4Te17I4, a New Pseudo One‐Dimensional Solid‐State Polytelluride
Authors: Tremel Wolfgang 
Published: July 2007

AbstractThe new ternary compound Nb4Te17I4 has been prepared and structurally characterized. It crystallizes in the monoclinic system, space group C2/c with unit‐cell parameters a = 16.199(4), b = 8.128(2), c = 27.355(6) Å, β = 110.84(2)°, Z = 4. The structure consists of infinite one‐dimensional niobium/tellurium chains running parallel to the crystallographic c direction. The chains are separated by iodine atoms. Short and long metal–metal distances alternate in the sequence of three consecutive short bonds ([d ≈ 3.1 – 3.2 Å) and one long (d = 4.268 Å) metal–metal separation. Each Nb atom is eight‐coordinate. The composition of the chain is ∞11[(Nb5+)2(Nb4+)2(Te22−)4(Te32−)3(I−)4].
Zur Bildung eines Fe2(CO)6‐Komplexes mit (Boryloxy)allyl‐Brücke
Authors: Braunschweig Holger , Spaniol Thomas P. , Paetzold Peter 
Published: July 2007

On the Formation of a Fe2(CO)6 Complex with a (Boryloxy)allyl BridgeThe amino(imino)borane Me3Si(tBu)NBNtBu (1) reacts with (benzylideneacetone)tricarbonyliron (2) in 1:2 molar ratio to give a 50% yield of the hexacarbonyldiiron complex 3 with a fly‐over (boryloxy)allyl bridge, which crystallizes in the space group P21/c. The structure of 3 can be described as a pyramid with Fe(CO)3 at the apex and a non‐planar pentagon [‐Fe(CO)3‐O(BXX′)‐C(Me)‐CH‐C(Ph)‐] [X = NHtBu, X′ = N(SiMe3)tBu] as the basis, but there is no bond between the apex and the O atom.
Reaktion von Decaboran mit dem Phosphaalkin PCtBu
Authors: Meyer Franc , Pactzold Peter , Englert Ulli 
Published: July 2007

Reaction of Decaborane with the Phosphaalkyne PC tBuThe borane B10H12(SMe2)2 (1) reacts with the phosphaalkyne P°CtBu to form the product [B10H11(SMe2)][C(tBu)‐PH](B10H12) (2), in which two B10 units are linked by a HP‐CtBu bridge. The B10 unit B is simply bound to the bridge C atom, whereas the B10 unit A is bound to both bridging atoms, P and C, by atom B6 and, moreover, to the P atom by atom B5. The solvate complex 2 · CH2Cl2 crystallizes in the space group P¯.
Darstellung geeigneter Vorstufen zur Synthese von 16,16,16,17,17,17‐Hexafluorretinalen
Authors: Abele Herbert , Haas Alois , Lieb Max , Zwingenberger Jorg 
Published: July 2007

Preparation of Suitable Precursors for the Synthesis of 16,16,16,17,17,17‐HexafluororetinalsCycloaddition reactions of (CF3)2C = CHCHO with butadiene or 1,3‐pentadiene provide the corresponding cyclohexane derivatives 2, 3 and 4. Condensation of 3 with (C2H5O)2P‐(O)CH2C(O)CH3 or of 2 with acetone in the presence of bases yields 5 and 7. While 5 reacts with CH2 = CHMgBr to give 6, treatment of 7 with diluted HCI provides 8. Compounds 7 and 8 proved to be not suitable as starting materials for the preparation of 16,16,16,17,17,17‐hexafluororetinals. A better synthon is the diene 11. This is obtained in a threestep reaction starting from hexafluoroacetone and (C6H5)3PCHC(O)CH3 to give 9 which on treatment with CH3MgI provides 10. Dehydration of 10 with 50% H2SO4 forms 11. In this reaction sequence byproduct 12 is formed presumably by addition of CF3C(O)CF3 to 9. At elevated temperatures under pressure 11 adds ethylene to form 13. Functionalization of 13 in 2‐position is achieved by hydroboration/oxidation yielding 14 which is oxidized with pyridinium dichromate to 15. Oxidation and bromination reaction of 13 are described.
Stereoselektive Protonierung von Carbanionen, 2. Diastereoselektive Protonierung von Schöllkopf‐Bislactimether‐Anionen
Authors: Hünig Siegfried , Klaunzer Norman , Wenner Hermann 
Published: July 2007

Stereoselective Protonation of Carbanions, 2[1]. — Diastereoselective Protonation of Schöllkopf's Bislactim Ether AnionsThe anions of the bis‐lactim ethers 5–7 serve as models for a systematic investigation of diastereoselective protonation. From 5Li, 6Li, and 7Li in THF at −78°C 30 proton sources (OH, NH, SH, CH) of different acidity and bulkiness produce the following cis/trans ratios: 5 8:92 → 37:63; 6 15:85 → 48:52; 7 25:75 → 59:41 (equilibria ≈ 50:50). Substitution of R1 = iPr in 5 by Me (→ 6) decreases the stereoselectivity slightly, but substitution of OMe in 6 by OEt (7) much stronger (Table 1). Most of the added Lewis acids show week or even leveling effects, whereas with 5K a dramatic change is observed with cis/trans‐5 = 27:73 → 89:11 (Table 2). By variation of solvent and several additives only minor effects on the cis/trans ratio are observed (Table 3). Backed by 13CNMR spectra of the ion pairs and literature data protonation of 5Li‐7Li is supposed to occur on a dimer, which will mainly react to give trans‐5–7. The prevailing formation of cis‐5 from 5K is explained by the reaction of the monomeric ion aggregat.
Relative Reactivities of Acetals and Ethers under Friedel‐Crafts Conditions
Authors: Mayr Herbert , Dau‐Schmidt Jan‐Peter 
Published: July 2007

AbstractCompetition experiments have been performed to determine the relative reactivities of acetals and ethers toward allyltrimethylsilane in the presence of catalytic amounts of BF3 OEt2. It is found that acetals R‐CH(OMe)2 and their phenylogous p‐anisyl ethers R‐CH(p‐MeOC6H4)(OMe) show very little differences in reactivity. The reactivity scales are employed to rationalize the results of Lewis acid‐catalyzed additions of acetals and ethers to CC double bonds.
Radikalische Cyclisierung von Dienen, VIII. Über die regioselektive Herstellung von ungesättigten Cyclopenta[b]furan‐2‐onen aus (S)‐(+)‐Carvon — Bausteine zur Synthese von enantiomerenreinen Triquinanen
Authors: Weinges Klaus , Reichert Hans , Braun Ralf 
Published: July 2007

Radical‐Type Cyclization of Dienes, VIII[1]. — On the Regioselective Synthesis of Unsaturated Cyclopenta[b]furan‐2‐ones from (S)‐(+)‐Carvone — Building Blocks for the Synthesis of Enantiomerically Pure TriquinanesThe diastereomeric products 2a and 2b, which were synthesized from (S)‐(+)‐carvone (1), are converted to (3aS,5S,6aS)‐(‐)‐5‐acetoxyhexahydro‐6a‐methyl‐2H‐cyclopenta[b]furan‐2‐one (4) in ca. 50% yield. 4 is regioselectively converted to (3aR,6aS)‐(‐)‐3,3a,6,6a‐tetrahydro‐6a‐methyl‐ (8a) and (3aS,6aR)‐(+)‐3,3a,4,6a‐tetrahydro‐6a‐methyl‐2H‐cyclopenta[b]‐furan‐2‐one (8b). These are used at the 10‐g scale for the synthesis of enantiomerically pure triquinanes.
Bimolecular Formation of Radicals by H‐Transfer, 6. Uncatalyzed Transfer Hydrogenation of a Benzhydryl Fluoride by 9,10‐Dihydroanthracene
Authors: Schaffer Frank , Beckhaus Hans‐Dieter , Rieger Hans‐Jürgen , Rüchard Christoph 
Published: July 2007

Abstract1‐Adamantylfluorodiphenylmethane (2) was reduced to 1‐adamantyldiphenylmethane (3) when heated with 9,10‐dihydroanthracene to 330°C. From the second‐order kinetics, the activation parameters (ΔH‡ = 37.2 ± 0.5 kcal mol−1, ΔS‡ = −18.8 ± 0.8 cal mol−1 K−1), the kinetic isotope effect kH/kD = 2.4 (373°C)[17], and the observation of intermediate radical species by ESR it was concluded that the reaction is a new example of a molecule‐induced radical formation (MIRF) process. This is supported by thermochemical data.
Synthesis and Crystal Structures of Copper(I) and Gold(I) Complexes [C(NH2)3]2[M2(1,2–dithiosquarate)2], M = Cu, Au, Containing Short M···M Distances, and of the Gold(III) Complex (cycloPrPh3P)[Au(1,2‐dithiosquarate)2]
Authors: Kleinitz Ulf , Mattes Rainer 
Published: July 2007

AbstractThe new compounds [C(NH2)3]2[Cu2(dtsq)2] (1), [C(NH2)3]2‐[Au2(dtsq)2] · H2O (2), and (cycloPrPh3P)[Au(dtsq)2] (3, cycloPr = cyclopropyl) have been prepared from CuSO4 · 5 H2O, KAuCl4, and K2dtsq · H2O (dtsq = dianion of 1,2‐dithiosquaric acid, C4O2S2−2). Compounds 1 and 2 contain pairs of metal atoms with short intermetallic distances of 2.587(2) (Cu···Cu) and 2.846(2) Å (Au···Au). Cu(I) is trigonally coordinated to three sulfur atoms of three different ligands and lies 0.51 Å above the S3 plane. It is oriented towards the copper atom of a second CuS3 unit related to the first one by a center of inversion. Au(I) shows a linear coordination, leading to the formation of Au2(dtsq)2−2 dimers. These have intermolecular Au···Au distances of 3.259(2) Å. Compound 3 contains isolated Au(dtsq)−2 ions with square planar coordination geometry stacked along the a axis at 4.708 Å distance.
Komplexe von Metallen der dritten Hauptgruppe mit [(en)2MIII(OH)2]‐Liganden (M = Cr, Co)
Authors: Rominger Frank , Müller Annette , Thewalt Ulf 
Published: July 2007

Complexes of Third Group Elements with [(en)2MIII(OH)2] Ligands (M = Cr, Co)Heteronuclear complexes are formed on reaction of cis‐[(en)2‐MIII(OH)(H2O)]2+ (M = Cr, Co; en = ethylenediamine) with A1III, GaIII, InIII, and T1III in aqueous solution. The following salts with tetranuclear cations have been isolated: [A1{(OH)2‐Cr(en)2}3](S2O6)3 · 13 H2O (1), [A1{(OH)2Co(en)2}3](S2O6)3 · 5 H2O (2), [Ga{(OH)2Co(en)2}3](S2O6)3 · 5 H2O (3), [In{(OH)2‐Cr(en)2}3](S2O6)3 · 6 H2O (5), and [In{(OH)2Co(en)2}3]‐(ClO4)4Cl2 · 4 H2O (6). Furthermore, the dinuclear neutral complexes [InCl4{(OH)2Cr(en)2}] (4) and [TlCl4{(OH)2‐Cr(en)2}] · 0.5 H2O (7) are prepared. X‐ray analyses confirm that in all cases the [(en)2MIII(OH)2] groups act as bidentate ligands in the hydroxo‐bridged heterometallic complexes.
Flüchtige Metallalkoxide nach dem Konzept der donorfunktionalisierten Liganden
Authors: Herrmann Wolfgang A. , Huber Norbert W. 
Published: July 2007

Volatile Metal Alkoxides According to the Concept of Donor‐Functionalized LigandsHomoleptic metal(II) alkoxides 3–5 of manganese, iron, cobalt, and zinc are prepared by applying the concept of donor‐functionalized ligands. The trifunctional ether ligands 1 thus form volatile metal alkoxides that sublime below 100°C at 10−2 mbar. Monomeric molecules are present in the gas phase and are likely to occur in the solid state, too. The heterodimetallic alkoxide 6 (Li/Co) sublimes without decomposition.
Synthese und Reaktionen der ersten zweifach überbrückten Fiscellane
Authors: Düll Bernhard , Müllen Klaus 
Published: July 2007

Synthesis and Reactions of the First Doubly‐Bridged FiscellanesThe synthesis of the novel hexacycle 2 containing a fiscellane framework is described. Starting from Weiss' tetraester 6, the fiscellane 2 is build up in six steps by successive chemical transformation of the methoxycarbonyl functions using SEM protecting groups. The behaviour of the novel diol 2 towards introduction of several leaving groups is examined. Upon treatment with methanesulfonyl chloride the highly strained hexacycle 2 undergoes a skeletal rearrangement with formation of the triene 4. Instead of reacting to a doubly‐bridged semibullvalene 3, the diol 2 gives rise to a new heterocyclic π perimeter 5 when the trifluoroacetyl derivative 12 is treated with sodium iodide in acetone.
Cyclische isomere vier‐ und fünfgliedrige heterodinucleare Fischer‐Carbenkomplexe — gebildet aus einem Vinylidentitanocen‐Fragment und Metallcarbonylen
Authors: Beckhaus Rüdiger , Oster Jürgen , Wagner Trixie 
Published: July 2007

Cyclic Isomeric Four‐ and Five‐Membered Heterodinculear Carbene Complexes — Formed from a Titanocene Vinylidene Fragment and Metal CarbonylsThe four‐membered heterodimetallic carbene complexes Cp*2 16 [LnM: Cr(CO)5 (a), Mo(CO)5 (b), W(CO)5 (c), CpRe(CO)2 (f), Mn2(CO)9(g), Re2(CO)9 (h), Fe(CO)4 (i), Rh(acac)(CO) (i)] are easily prepared by trapping the vinylidenetitanocene [Cp*2TiCCH2] fragment 6 with the corresponding metal carbonyls. The vinylidenetitanocene 6 is generated in a favourable manner from Cp*2Ti(CH3)CHCH2 (13) or Cp * (Fv)TiCH = CH2 (14) [Fv: C5(CH3)4CH2] by a 1,3‐H shift (α elimination) at room temperature. The formation of 16 is characterized by a preferred suprafacial [2 + 2] cycloaddition. Starting from Cp*2 (5) or 14 and transition metal carbonyls unexpected isomeric five‐membered titanacycles Cp*2 8 [MLn = a–c, MnCp(CO)2 (d), MnCp′(CO)2 (e), f–i] are obtained at higher temperatures (70–100°C). These oxatitanacyclopentenes 8 are formed also upon heating via the kinetic product 16 with high yield, as a result of a 1,2‐hydrogen shift, proved for c, g, h. From the spectroscopic data an η1‐vinylcarbene structure is deduced, exhibiting a cis‐ (16) or trans‐configurated (8) LnMCCC sequence. An X‐ray structure analysis shows the importance of the acyl resonance form in 8a, typically observed for such heterodimetallic carbene complexes. The reversible liberation of the metal carbonyl is a remarkable property of complexes 16 in solution, whereas the thermodynamic product 8 shows the typical properties of Fischer carbene complexes.
Stereoselectivity of the Transfer of Hydrogen Atoms to Cyclic Alkyl Radicals
Authors: Metzger Jürgen O. , Schwarzkopf Kay , Saak Wolfgang , Pohl Siegfried 
Published: July 2007

AbstractThe addition of cyclohexane to alkylmaleic anhydrides 1a‐f via cyclic radicals 2a‐f gave a mixture of (Z)‐ and (E)‐2,3‐dialkylsuccinic anhydrides 3a‐f. The stereoselectivity of the hydrogen transfer from cyclohexane to radicals 2a‐d was measured in the temperature range of 200‐260°C, and the relative activation parameters of the formation of (Z)‐ and (E)‐3 were determined. The stereoselectivity of the hydrogen transfer from cyclohexylmercuric hydride at 25°C was measured as well. The results are rationalized assuming steric interactions in the transition state of H donor and β substituent and of α and β substituent, respectively. An X‐ray structure analysis of the highly strained addition product (Z)‐3d was performed.
Transanular Interactions in Difunctional Medium Rings, 5. Spectroscopic Investigations of Bicyclic Boraamines
Authors: Wiesmann Reinhard F. , Rademacher Paul 
Published: July 2007

AbstractThe endo‐7‐[(dialkylamino)methyl]‐3‐borabicyclo[3.3.1]nonanes 1 and 2 have been synthesized and their intramolecular complex formation of the corresponding 2‐azonia‐1‐boratatricyclo[4.3.1.14,8]undecanes 3 and 4 has been studied in the gas phase by UV photoelectron spectroscopy and in solution by 11‐NMR spectroscopy. Deviations of the characteristic spectral features from those of the monofunctional bicyclic boranes 5 and amines 6 and 7 indicate that in the gas phase the (dimethylamino)boranes with a B‐alkyl substituent adopt the tricyclic form 3a–c whereas the diethylamino and the B‐methoxy derivatives 1e and 2 prefer the bicyclic structure. In solution some deviations from this behavior are observed.
Ein einfacher Weg zu Silicium in oktaedrischer Sauerstoffkoordination
Authors: Königstein Karsten , Jansen Martin 
Published: July 2007

A Simple Route to Silicon in Octahedral Oxygen CoordinationSyntheses and crystal structures of three new compounds Rb2SiP4O13 (1), Cs2H2Si(P2O7)2 (2), and BaH2Si(P2O7)2 (3) containing silicon in an octahedral oxygen coordination are reported. The structures have been determined by X‐ray structure analyses. All three compounds are constituted of silicophosphate polyanions. The NMR chemical shifts of silicon and hydrogen are measured.
Zinkkomplexe von Aminosäuren und Peptiden, 3. Zinkkomplexe von Peptiden mit N‐terminalem Cystein
Authors: Albrich Hans , Vahrenkamp Heinrich 
Published: July 2007

Zinc Complexes of Amino Acids and Peptides, 3[1]. ‐ Zinc Complexes of Peptides with N‐terminal CysteineConventional methods were used to prepare three dipeptides Cys‐X‐OR (X = Gly, Phe), nine dipeptides Cys‐X‐NH2 (X = Gly, Ala, Val, Leu, Ile, Pro, Phe, Met, Ser), three tripeptides Cys‐X‐OR (X = Gly‐Gly, Phe‐Phe, Met‐Phe), and three tripeptides Cys‐X‐NH2 (X = Gly‐Gly, Gly‐Ala, Gly‐Leu). All these peptides have the unprotected amino acid cysteine at the N terminus. Their reactions with basic zinc carbonate resulted in the formation of mononuclear complexes ZnL2, with L being the peptide anion resulting from SH deprotonation, IR and NMR spectra indicate that in all these complexes the zinc ion is coordinated by the cysteine thiolate and amino functions of two peptide ligands. This tetrahedral ZnN2S2 coordination by two chelating peptides is confirmed by a crystal structure determination of the complex Zn(Cys‐Gly‐NH2)2.
3‐Borolene mit diastereotopen Seiten: Synthese von 4‐(Dialkylamino)‐4‐boratricyclo[5.2.1.02,6]dec‐2(6)‐enen und Struktur des Dimethylamino‐Derivats
Authors: Herberich Gerhard E. , Spaniol Thomas P. , Steffan Uwe 
Published: July 2007

3‐Borolenes with Diastereotopic Faces: Synthesis of 4‐(Dialkylamino)‐4‐boratricyclo[5.2.1.02,6]dec‐2(6)‐enes and Structure of the Dimethylamino DerivativeTwo syntheses of 2,5‐dihyro‐1H‐borole derivatives with diastereotopic faces are described. 2,3‐Dimethylenenorbornane (2) is transformed into the zirconocene complex 5 (≡ Cp2Zr · 2) in a large‐scale preparation; 5 reacts with dichloro‐(dialkylamino)boranes BCl2(NR2) to give 4‐(dialkylamino)‐4‐boratricyclo[5.2.1.02,6]dec‐2(6)‐enes 1 (R = Me, iPr). Alternatively, 2,3‐dimethylnorbornene (santene) (3) or 3‐methyl‐2‐methylenenorbornane (4) can be kaliated by means of Lochmann‐Schlosser base to give a dimetallation product 6 (≡ K2 2); treatment of 6 with BCl2(NR2) also affords the boratricycles 1 (R = Et, iPr). The structure of the dimethylamino derivative 1a has been determined by X‐ray diffraction.
Dithiametacyclophane mit Dreifachbindungen
Authors: Dai Yujia , Kolshorn Heinz , Meier Herbert 
Published: July 2007

Dithiametacyclophanes with Triple BondsSchemes 1 and 2 show the syntheses of dithia[8]metacyclo‐phanes 4a‐d and tetrathia[m.n]metacyclophanes 9, 10 by cyclization reactions applying the cesium effect. All these cyclophanes contain C—C triple bonds which influence the molecular dynamics; especially the halogen substituents in 4b‐d obstruct the topomerization.
Electronic Structure of Mono‐ and Bis(carbonyliron) as well as Bis(cyclopentadienyliron) Complexes of 1,4‐Dihydro‐1,4‐diboranaphthalene
Authors: Gleiter Rolf , Hyla‐Kryspin Isabella , Siebert Walter 
Published: July 2007

AbstractThe structure and bonding of four iron complexes involving the 1,4‐dihydro‐1,4‐diboranaphthalene ligand C8B2H8 (1), namely of the complexes (CO)3Fe(η6‐C8B2H8) (2), (μ, η4,η6‐C8B2H8)[Fe(CO)3]2 (3), (CO)3Fe(μ,η4,η6‐C8B2H8)Fe(CO)2 (4), and of the triple‐decker (μ,η6‐C8B2H8)[Fe(η5‐C5H5)]2 (5), have been investigated by means of the perturbational molecular orbital theory on the basis of the Extended Hückel calculations. Compounds 2 and 3 are 18‐VE complexes, whereas 5 is a 30‐VE species. The structure of 4 can be best described in terms of a 16‐VE complex “Fe(CO)3 heterocycle” and a 18‐VE “Fe(CO)2 carbocycle” unit with its iron centers being not directly bond.
Synthesis and Structure of the New α‐Aminosilanolate [LiOSiMe2(NMe2)]6
Authors: Herberich Gerhard E. , Spaniol Thomas P. , Fischer Andreas 
Published: July 2007

AbstractLithium (dimethylamino)dimethylsilanolate (1) is obtained from trimeric dimethylsiloxane and lithium dimethylamide in quantitative yield. In the crystal 1 is a hexamer [LiOSiMe2(NMe2)]6 with crystallograpic C3i (S6, 3) symmetry. The molecule of 1 consists of a hexagonal prismatic (LiO)6 core and an N,O‐chelating anion.
Zur Reaktion von Isocyaniden mit Nitriliminen[1]
Authors: Moderhack Dietrich , Lorke Michael , Ernst Ludger , Schomburg Dietmar 
Published: July 2007

AbstractOn the Reaction of Isocyanides with Nitrile IminesFour competing reactions have been found to occur when nitrile imines 2 are generated from 1 in the presence of isocyanides 3. The products obtained include i) 1,2,3‐triazolium salts 6, ii) 1,2,4‐triazolium salts 8, iii) dihydrotriazolyl‐substituted pyrazolamines 11, and iv) unstable 1,2‐diazetimine derivatives 12 which in turn give carbodiimides 13, nitriles 14, quinoxalinamines 15, and possibly 1,2,4‐triazoles 16 (after addition of 2). The proportions, in particular those of 6, 8, and 11, depend on the reaction conditions; thus, triethylamine used in excess can oppress the formation of 6 in favour of 8 and 11. ‐ The structure of 11 has been elucidated by means of X‐ray diffraction analyses of 11a and c.
Oxidative Cyclisierung von Anilinopyrazolen zu Pyrazolo[1,5‐a]benzimidazolen
Authors: Kluge Ralph , Schulz Manfred , Pobišova Miroslava , Nüchter Matthias 
Published: July 2007

AbstractFree Radical Reactions of N‐Heterocyclic Compounds, XIV[1]. ‐ Oxidative Cyclization of Anilinopyrazoles to Pyrazolo[1,5‐a]benzimidazolesHerrn Professor Christoph Rüchardt zum 65. Geburtstag gewidmet.
Substituted Anilinopyrazoles 1 were oxidized by dibenzoyl peroxide or lead(IV) oxide. Different oxidation products were isolated depending on the substituents in the anilino group of anilinopyrazoles 1. Intermediate pyrazolyl radicals 5, which could be trapped by triphenylmethyl or phenoxyl radicals, undergo cyclization reaction with formation of pyrazolo[1,5‐a]benzimidazoles 4. The structures of compounds 4 were proven by 1H‐ and 13C‐NMR spectroscopy, 15N labeling and transformation of 4e to the betain 7e.
Carbon‐Carbon Bond Formation Promoted by “Bare” Lanthanide Cations: The Reactions of Ce+ and La+ with Propene in the Gas Phase
Authors: Heinemann Christoph , Schröder Detlef , Schwarz Helmut 
Published: July 2007

AbstractThe cationic butadiene and benzene complexes CeC4H6+ and CeC6H6+ are the main products in the reaction of thermalized Ce+ ions with propene in the gas phase, as shown by FT MS. Following the formation of the primary products, i.e. CeCH2+ and CeC3H4+, selective C‐C coupling processes at the lanthanide cation occur as secondary reactions with high efficiency. Ligand‐exchange reactions and comparative collision‐induced dissociation experiments are applied to probe the structures of the final reaction products of this first example of Ce+ gas‐phase chemistry. The reaction of Ce+ with cyclopropane yields a product distribution very similar to the propene reaction; however, it reacts significantly slower. Furthermore, La+ reacts in nearly the same manner with propene as Ce+ which indicates that the single f electron in the latter ion is chemically inert.