bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of the Reaction Behavior of Nitryl Compounds Towards Azides: Evidence for Tetranitrogen Dioxide, N4O2
Authors: Klapötke Thomas M. , Schulz Axel , Tornieporth‐Oetting Inis C. 
Published: September 2007

AbstractThe reaction behavior of NaN3, AgN3, and Me3SiN3 towards FNO2, CINO2, NO2SbF6, and NO2BF4 was investigated. At ‐30°C or below in a solvent‐free system sodium azide did not react with CINO2, NO2BF4, or NO2SbF6. Below ‐30°C silver azide did not react either with neat C1NO2. Treatment of Me3SiN3 with pure C1NO2 led to the formation of C1N3, N2O, and Me3SiOSiMe3. A mechanism for this reaction has been proposed. Pure chlorine azide was isolated by fractional condensation and identified by its low‐temperature Raman spectrum (liquid state). The reaction of Cp2Ti(N3)2 with C1NO2 also yielded C1N3 as the only azide‐containing reaction product. Treatment of FNO2 with NaN3 at temperatures as low as ‐78°C always ended in an explosion which was probably due to the formation of FN3 as one of the reaction products. The reaction of NO2SbF6 with NaN3 in liquid CO2 (‐55°C· T· ‐35°C) as the solvent afforded a new azide species which was stable at low temperature in solution only and was investigated by means of low‐temperature Raman spectroscopy. The obtained vibrational data give strong evidence for the presence of tetranitrogen dioxide, N4O2, which can be regarded as nitryl azide (NO2N3). The structure and vibrational frequencies of N4O2 were computed ab initio at correlated level (MP2/6‐31 + G*). In liquid xenon (‐100°C· T· ‐60°C) NaN3 did not react with NO2SbF6. A previous literature report on the preparation of N4O2 could not be established.
A New Convenient One‐Step Synthesis of [(SCl)2N]+[SbCl6]− Containing the [(SCl)2N]+ Cation
Authors: Broschag Matthias , Schulz Axel , Klapötke Thomas M. 
Published: September 2007

AbstractThe hexachloroantimonate salt of the [(SCl)2N]+ cation, [(SCl)2N]+[SbCl6]− (1), was prepared in a one‐step reaction from easily available [SCl3]+[SbCl6]− and N(SiMe3)3 and isolated in good yield (60%). The compound was identified by chemical analyses and vibrational spectroscopy (IR, Raman). The geometrical and the vibrational data were also computed ab initio and are in good agreement with the experimental results.
Übergangsmetall‐Silyl‐Komplexe, 5211[1]. Bildung von Kupfer‐Silyl‐ und ‐Stannyl‐Komplexen durch Umsetzung von [Ph3PCuH]6 mit HER3 (E = Si, Sn)
Authors: Schubert Ulrich , Mayer Brigitte , Ruß Claudia 
Published: September 2007

Transition Metal Silyl Complexes, 52[1]. ‐ Formation of Copper Silyl and Stannyl Complexes by Reaction of [Ph3PCuH]6 with HER3 (E = Si, Sn)[Ph3PCuH]6 was used as a source for the Ph3PCu fragment to prepare copper stannyl and silyl complexes. Reaction of [Ph3PCuH]6 with HSnPh3, HSiPh3 or HSiClPh2, respectively, and two equivalents of PPh3 yielded the complexes (Ph3P)3CuER3 (ER3 = SnPh3, SiPh3, SiClPh2).
{6 Lithio(trimethylsilyl)diazomethane· 2 Lithio[4,5‐bis(trimethylsilyl)triazene]· 7 Diethyl Ether}: The First X‐Ray Structure Analysis of a Lithiated Diazoalkane
Authors: Boche Gernot , Harms Klaus , Marsch Michael , Schubert Frank 
Published: September 2007

AbstractThe crystals of {6 lithio(trimethylsilyl)diazomethane· 2 lithio[4,5‐bis(trimethylsilyl)triazene]· 7 diethyl ether} provide for the first time insight into the structure of a lithiated diazomethane, namely that of lithiated (trimethylsilyl)diazomethane (11c). Furthermore, the crystals contain lithiated 4,5‐bis‐(trimethylsilyl)triazene (12), a reaction product of (trimethylsilyl)diazomethane and its Li compound 11c which is analogously found in deprotonation/protonation reactions of other monosubstituted diazomethanes. This structure, together with quantum chemical calculations, leads to a better understanding of the so far rather complex chemistry of lithiated (monosubstituted) diazoalkanes.
Strukturen sterisch überfullter und ladungsgestörter Molekule, 51[1,2]. Oxidative Zersetzung von Tetraisopropyltetrazen: Isolierung und Einkristallstrukturen des Radikalkation‐Salzes [((H3C)2HC)2N‐N=·N‐N(CH(CH3)2)2](SbCl⊖) und des N2‐Eliminierungsproduktes [(H3C)2HC‐HN⊕=C(CH3)2](SbCl⊖)
Authors: Bock Hans , Göbel Ilka , Näther Christian , Solouki Bahman , John Andreas 
Published: September 2007

Structures of Sterically Overcrowded and Charge‐Perturbated Molecules, 51[1,2]. ‐ Oxidative Decomposition of Tetra‐isopropyltetrazene: Isolation and Single‐Crystal Structures of the Radical Cation Salt [((H3C)2HC)2N‐N=⊕N‐N(CH‐(CH3)2)2](SbCl⊖) and of the N2 Elimination Product [(H3C)2HC‐HN+=C(CH3)2](SbCl⊖)The single‐electron oxidation of tetraisopropyltetrazene by the advantageous, oxygen‐free SbCl5/H2CCl2 redox system yields dark‐red crystals of tetraisopropyltetrazenium hexachloroantimonate. Their structure determination at temperatures of 100, 200, and 293 K, the first one of a 2‐tetrazene radical cation, proves a planar skeleton C2N‐N=N‐NC2⊕ with nearly identical NN bond lengths. The reaction of tetraisopropyltetrazene with surplus SbCl5 yields the N2 elimination product isopropylisopropylideneammonium hexachloroantimonate, which also has been crystallized and structurally characterized. Due to the conformation of the C3 subunits perpendicular to each other, the cation (H3C)2HC‐HN⊖ =C(CH3)2 is extremely overcrowded as demonstrated by an angle CNC of 129°. In addition, the thermal decomposition of tetraisopropyltetrazene in the gasphase has been analyzed PE‐spectroscopically, its first and second oxidation potentials have been determined cyclovoltammetrically, and the ESR signal pattern of its radical cation in solution has been recorded and assigned. Based on the experimental data, a possible pathway for the oxidative decomposition of the title compound is discussed.
Aminolyse von 2,5‐Bis(aryloxy)‐3,3aγ4,4‐trithia‐1,6‐diazapentalenen — ein Zugang zu makrocyclischen Heteropentalenen
Authors: Tittelbach Franz , Lutze Gerhard , Graubaum Heinz 
Published: September 2007

Aminolysis of 2,5‐Bis(aryloxy)‐3,3aγ4,4‐trithia‐1,6‐diazapentalenes ‐ an Entry to Macrocyclic HeteropentalenesThe N,N′‐bis(3,3aγ4‐trithia‐1,6‐diazapentalenyl)diamines 6, 7 and azacrown ethers 8, incorporating two sulfur‐containing diazapentalenes, have been synthesized from 2,5‐bis(aryloxy)‐3,3aγ4,4‐trithia‐1,6‐diazapentalenes 1 and diamines. The aminolysis of 1 with amines has also been studied providing 2‐monoamino‐ 3 and 2,5‐diaminoheteropentalenes 4.
Substituent Effects on the C‐C Bond Strength, 15[1] Geminal Substituent Effects, 7[2]. Thermochemistry and Thermal Decomposition of Alkyl‐substituted Tricyanomethyl Compounds
Authors: Rakus Klaus , Verevkin Sergej P. , Beckhaus Hans‐Dieter , Rüchardt Christoph 
Published: September 2007

AbstractThe thermolysis reactions of the tricyanomethyl compounds 10a‐c were studied in solution. 2,2‐Dicyano‐3‐methyl‐3‐phenylbutyronitrile (10a) and 2,2‐dicyano‐3‐methyl‐3‐(4‐nitrophenyl)butyronitrile (10b) decomposed heterolytically into carbenium ions and (CN)3C− anions, while 9‐methyl‐9‐(tricyanomethyl)fluorene (10c) underwent about 11% homolytic C‐C bond cleavage into 9‐methyl‐9‐fluorenyl‐ and tricyanomethyl radicals. The rates of the homolysis were determined by a radical scavenger procedure under conditions of pseudozero order kinetics. From the temperature effect on the rate constants the activation parameters were determined [ΔH (10c) = 155· 2 kJ mol−1, ΔS (10c) = 58· 5 J mol−1 K−1]. Standard enthalpies of formation ΔH (g) were determined for 2,2‐dicyanopropionitrile (2) (422.45 kJ mol−1), 2,2‐dicyanohexanenitrile (3) (349.74 kJ mol−1), 2,2‐dicyano‐3‐phenylpropionitrile (4) (540.75 kJ mol−1), 2‐butyl‐2‐methylhexanentrile (5) (‐133.20 kJ mol−1), 2,2‐dimethylpentanenitrile (6) (‐45.78 kJ mol−1), and 2‐methylbutyronitrile (7) (2.44 kJ mol−1) from the enthalpies of combustion and enthalpies of sublimation/vaporization. From these data and known Δ (g) values for alkanenitriles and ‐dinitriles, thermochemical increments for ΔH (g) were derived for alkyl groups with one, two, or three cyano groups attached. The comparison of these increments with those of alkanes reveals a strong geminal destabilization, which is interpreted by dipolar repulsions between the cyano groups. ‐ From ΔH (g) of 10c and ΔH of its homolytic decomposition the radical stabilization enthalpy for the tricyanomethyl radical 1 RSE (1) = ‐18 kJ mol−1 was determined. Thus, 1 is destabilized, in comparison with the RSEs of tertiary α‐cyanalkyl (23 kJ mol−1) and α,α‐dicyanoalkyl (27 kJ mol−1) radicals, which were recalculated from bond homolysis measurements[4] and the new thermochemical data. This change of RSE on increasing the number of α‐cyano groups is discussed as the result of the additive contributions by resonance stabilization and increasing destabilization by dipolar repulsion. The amount of the dipolar energies was estimated by molecular mechanics (MM2).
Gas/Solid Reactions with Acetone
Authors: Kaupp Gerd , Pogodda Uwe , Schmeyers Jens 
Published: September 2007

AbstractGas/solid reactions of acetone vapor with neutral organic compounds, salts, or host crystals with strict exclusion of solvents are reported. This gas/solid technique largely avoids waste formation and saves resources. Starting hydrochlorides or hydrobromides are also synthesized by gas/solid techniques. Dihydrohalides of o‐phenylenediamines give 1,5‐benzodiazepines 3, aromatic and aliphatic 1,2‐aminothiols (o‐aminothiophenol, penicillamines, cysteine) yield five‐membered thiazolines and thiazolidines 7, 9, 11, 13. Virtually all carbonyl reagents of the primary amino type 14 give quantitatively the imino derivatives 15 and water. Salt formation may be helpful for increasing melting points and sometimes reactivity as in 8, 10, and 12 if surface passivation has to be overcome. In the case of solid 14 the free bases react equally well. Acetone (2) may be quantitatively removed from exhaust gases by using hydroxylaminium phosphate with formation of free acetone oxime at high flow rates. Inclusion of acetone into various hosts (17‐20, but not 16) is more efficient by imbibition from the gas phase than by crystallization from acetone as the solvent. This advantage may be utilized for gas separations. Some further gases (vapors) coexist in imbibed clathrates whereas others do not. The mechanisms of the gas/solid reactions are elucidated using atomic force microscopy (AFM). Phase rebuildings involve anisotropic movements of molecules over large distances and the formation of characteristic features. In some cases surface hydrates catalyze the gas/solid reaction. Solid‐state mechanisms for imbibition from the gas phase into host crystals with formation of clathrates are similar in nature to those of the covalent reactions. These results are correlated with known X‐ray crystal structures where available.
[2.2](4,7)Isobenzofuranophanes ‐ Synthesis, Characterisation, and Reactivity
Authors: König Burkhard , Ramm Sonja , Bubenitschek Peter , Jones Peter G. , Hopf Henning , Knieriem Burkhard , Meijere Armin De 
Published: September 2007

AbstractThe isomeric Diels‐Alder adducts 3, obtained by cycloaddition of tetraphenylcyclopentadienone to the 4,5:12,13‐bis‐(oxanorbornadieno)[2.2]paracyclophanes syn,syn‐ and anti,‐syn‐2The stereochemical descriptors syn and anti refer to the orientation of the oxygen bridge in the oxabicyclo[2.2.1]heptadiene subunits with respect to the [2.2]paracyclophaneskeleton.
, yield the unstable isobenzofuranophane 4 by consecutive extrusion of carbon monoxide and tetraphenylbenzene when heated to 180°C. The molecular ion of 4 was observed in the EI mass spectrum. The stable tetraphenyl‐substituted analogue 10 was synthesized independently from the previously unknown 4,5,12,13‐tetrabenzoyl[2.2]paracyclophane (9). UV/Vis as well as fluorescence spectra and an X‐ray crystal structure analysis of 9 are reported.
Chele‐ und Anticheleselektivität, V[1]. Über die Struktur und Chemoselektivität einiger Übergangsmetall‐Derivate von Carbonsäureestern
Authors: Kauffmann Thomas , Möller Thomas , Wilde Heinz‐Wilhelm 
Published: September 2007

Chele‐ and Anti‐cheleselectivity, V[1]. ‐ On the Structure and Chemoselectivity of Some Transition Metal Derivatives of Carboxylic Acid EstersOn account of the IR spectra of EtO2CCH2FeCl (2a), EtO2CCH2CoCl (3a), and EtO2CCH(Et)CoCl (3b), prepared in situ by transmetalation of the corresponding Li enolates, and EtO2CCH(Et)CrCl2 (5b), obtained in situ by one‐electron oxidative addition of EtO2CCH(Et)Br to CrCl2, it is assumed that these and similar complexes (2b, 2c, 3c) form 8‐membered cyclic dimers of type 11 in THF in analogy to the Reformatzky reagents. Representatives of these complexes and of corresponding Ti complexes were treated (THF, mol ratio 1:1:1) with substrate pairs, consisting of a normal ketone and a ß‐functionalized ketone (Table 2) or alternatively of a normal ketone and an α‐functionalized ketone (Table 3). In the first case high anti‐cheleselectivity was observed, but in the second case high cheleselectivity. The reasons for this different behaviour are discussed.
Concave Reagents, 15[1]. New Concave 1,10‐Phenanthrolines: Catalysts for the Alcohol Addition to Ketenes and Ligands in Transition Metal Complexes
Authors: Lüning Ulrich , Müller Michael , Gelbert Markus , Peters Karl , Schnering Hans Georg Von , Keller Manfred 
Published: September 2007

AbstractBy bridging tetrahydroxy‐1,10‐phenanthrolines 9 by ditosylates 10 or diiodides 11 concave 1,10‐phenanthrolines 1 were synthesized. Their concave shape was proven by X‐ray analyses of 1a and 1c, their basicities were determined by photometric titrations. Compounds 1a‐g are active in the basecatalyzed addition of alcohols to ketenes and form stable metal ion complexes with transition metal salts.
Synthesis and Properties of Kinetically Stabilized Cyclohepta[def]fluorene Derivatives
Authors: Grieser Udo , Hafner Klaus 
Published: September 2007

AbstractThe dihydrocyclohepta[def]fluorene 18 was prepared by starting from 2,7‐di‐tert‐butylfluorene (11). Deprotonation of 18 furnished the dianion 32− in which the charge is mainly localized at the five‐ and seven‐membered rings as evidenced by NMR investigations. Attempts to oxidize 32− to the uncharged species 3 failed. The ketones 26 and 29 were obtained by regioselective oxidation of 18. Deprotonation of 29 and 26 furnished the anions 4 and 5, respectively, which could be described as cyclohepta[def]fluorenes with a strong donor substituent. 13C‐NMR spectroscopic investigations, however, revealed that 4 is described best as an acyl‐substituted fluorenyl anion. In contrast to this, proof of the existence of the anion 5 could be obtained only from a trapping experiment.
Synthesis of New Alkenyl‐Substituted 2‐(tert‐Butyldimethylsiloxy)‐cyclopropanecarboxylates and Their Diastereoselective Conversion into (Hydroxymethyl)cyclopropanes
Authors: Hofmann Bernhard , Reißig Hans‐Ulrich 
Published: September 2007

AbstractVarious new 2‐alkenyl‐substituted methyl 2‐(tert‐butyldimethylsiloxy)cyclopropanecarboxylates 8‐14 were synthesized from siloxy dienes and methyl diazoacetate. Further substitution by deprotonation and reactions with electrophiles provided derivatives 15‐19 in good yields. Reduction of trans‐configurated cyclopropanecarboxylates with LiAlH4 afforded the corresponding trans‐2‐(tert‐butyldimethylsiloxy)‐1‐(hydroxymethyl)cyclopropanes in excellent yields. The related cis‐compounds were not formed, but ring‐opened products derived thereof were isolated. This unexpected influence of the configuration of the starting material on the type of the product formed is discussed.
Characteristic Reactions of 4‐Siloxy‐2,5‐dihydrooxepines: Desilylation, [2 + 2] and [4 + 2] Cycloadditions
Authors: Hofmann Bernhard , Reißig Hans‐Ulrich 
Published: September 2007

AbstractDesilylation of 4‐siloxy‐2,5‐dihydrooxepine 1 with NEt3· HF afforded oxepinone 2. [2 + 2] Cycloadditions of 1 and methyl‐substituted derivative 4 to tetracyanoethylene provided bicyclic products 3 and 5, respectively. Hetero Diels‐Alder reactions of 2,5‐dihydrooxepines 1 and 9 with 1,1,1‐trifluoro‐2‐nitrosopropene furnished the corresponding bicyclic 1,2‐oxazines 8 and 10, resp., in reasonable yields. The considerably higher reactivity of the silyl enol ether unit compared with the endocyclic enol ether moiety as revealed by these cycloadditions is discussed.
Sterically Hindered Double‐Bond Systems, VII[1l]. On the Reaction of Succinic Esters with tert‐Butyllithium
Authors: Hopf Henning , Hänel Ralf 
Published: September 2007

AbstractAddition of tert‐butyllithium to dimethyl (1a) and diethyl succinate (1b), respectively, provides 2,2,7,7‐tetramethyl‐3,6‐octanedione (3) in good yield as well as the ketoesters 5a/b and the cyclized products 6 and 7. The mode of formation of these latter side products is discussed, and several published errors concerning these transformations are corrected.
1,2‐Bis(diisopropylamino)‐1,2‐dihydro‐1,2‐benzodiboret ‐ ein erstes thermisch stabiles 1,2‐Dihydro‐1,2‐diboret
Authors: Kaufmann Dieter E. , Boese Roland , Scheer Alexander 
Published: September 2007

1,2‐Bis(diisopropylamino)‐1,2‐dihydro‐1,2‐benzodiborete ‐ A First Thermally Stable 1,2‐Dihydro‐1,2‐diborete*The synthesis of 1,2‐bis(diisopropylamino)‐1,2‐dihydro‐1,2‐benzodiborete (7) suceeds in good yield by a twofold ipso‐borylation of 1,2‐bis(trimethylsilyl)benzene to give 3, double amination to afford 4 and subsequent coupling with sodium/potassium alloy. Crystalline 7 is thermally stable; an X‐ray crystallographic structure determination has been carried out. In concentrated solution reaction of 4 with sodium/potassium alloy predominantly leads to the formation of the tetraborocine 6 by dimerization. In the presence of (phthalocyaninato)palladium as catalyst 7 reacts with 2 equivalents of dimethylacetylenedicarboxylate to give the benzo‐annulated diborocine 12.
Addition von Aldehyden an aktivierte Doppelbindungen, XXIX1) Neue Methode zur Darstellung symmetrischer 1,4‐Diketone
Authors: Stetter Hermann , Bender Hans‐Jürgen 
Published: September 2007

AbstractPhenyl‐vinyl‐sulfon reagiert unter Thiazoliumsalz‐Katalyse mit aliphatischen, aromatischen und heterocyclischen Aldehyden in einem dreistufigen Additions‐Eliminierungs‐Mechanismus zu 1,4‐Diketonen (1–3) und dem 1,4‐Disulfon (23). Bei Verwendung von Divinyl‐sulfon werden in guter Ausbeute die entsprechenden 1,4‐Diketone (1–1) erhalten.
Nucleoside syntheses, XXII1)Nucleoside synthesis with trimethylsilyl triflate and perchlorate as catalysts
Authors: Vorbrüggen Helmut , Krolikiewicz Konrad , Bennua Bärbel 
Published: September 2007

AbstractThe novel Lewis acids (CH3)3SiOSO2CF3(3), (CH3)5SiOSO2C4F9(6), and (CH3)3SiClO4(4) are highly selective and efficient Friedel‐Crafts catalysts for nucleoside formation form silylated heterocycles and peracylated sugars as well as for rearrangements of persilylated protected nucleosides. With basic silylated heterocycles these new catalysts give much higher yields of the naturalN‐1‐nucleosides than with SnCl4.
Nucleoside Syntheses, XXIII1) On the Mechanism of Nucleoside Synthesis
Authors: Vorbrüggen Helmut , Höfle Gerhard 
Published: September 2007

AbstractDuring the silyl‐Hilbert‐Johnson nucleoside synthesis with Friedel‐Crafts catalysts three processes occur simultanously:

The formation of the electrophilic sugar cation.
The σ‐complex formation between th silylated base and the Friedel‐Crafts catalyst and finally.
The reaction of the electrophilic sugar cation with the silylated base to the nucleoside. Mode and rate of σ‐complex formation between the silylated base and the Friedel‐Crafts catalysts were monitored by 13C‐NMR. The probable mechanism of nucleoside synthesis and the factors which influence course and yield of nucleoside synthesis are discussed.
Di‐ und Polyaminozucker, XXIV1) Synthese und Reaktionen der 2,3‐Diamino‐2,3‐didesoxy‐2,3‐N‐oxalyl‐D‐glucose
Authors: Reckendorf Wolfgang Meyer Zu , Weber Rolf , Hehenberger Helmut 
Published: September 2007

AbstractBei der Umsetzung von Benzyl‐2,3‐diamino‐4,6‐O‐benzyliden‐2,3‐didesoxy‐α‐D‐glucopyranosid (3) mit Oxalsäure‐diethylester entstand das cyclische 2,3‐Oxamid 4, aus dem sich durch Entblockierung die Titelverbindung 9 herstellen ließ. Durch alkalische Hydrolyse konnte der Oxalylrest leicht vollständig entfernt werden (→3), während unter verschiedenen Acetylierungsbedingungen Ringspaltung zu N‐Oxalylderivaten (11, 13, 14, 16‐19).
Ladungsinduzierte Konformationsumwandlungen in Biphenyl‐ und Cyclooctatetraenyl‐System
Authors: Huber Walter , Und Anette May , Müllen Klaus 
Published: September 2007

AbstractIn den strukturverwandten polycyclischen π‐Systemen Biphenyl (1), o‐Terphenyl (2), Dibenzo[a,c]cycloocten (3), Tribenzo[a,c,e]cycloocten (4), und Tetraphenylen (Tetrabenzocycloocten) (5) stehen einer konjugativen Wechselwirkung zwischen den einzelnen Molekülfragmenten erhebliche Spannungseffekte entgegen. Der Übergang zu den bisher unbekannten Dianionen 12− −52− erlaubt eine gezielte Beeinflussung der π‐Bindungssituation, so daß sich die Konkurrenz sterischer und elektronischer Energieterme systematisch verfolgen läßt. Von zentraler Bedeutung für eine derartige Beschreibung der Ionenstrukturen erweist sich die NMR‐spektroskopische Ermittlung der Molekülsymmetrie, der Ladungsverteilung und des dynamischen Verhaltens. Ein bemerkenswertes Resultat ist die ladungsinduzierte Symmetriedeformation innerhalb des Dianions 52−, als deren Folge eine bisher unbekannte Bis(biphenylylen)‐Struktur entsteht.
Thermolyse von Oxazolin‐5‐onen, XI1)N‐Acylimine und Enamide durch Gasphasenpyrolyse von 4‐Alkyl‐2‐oxazolin‐5‐onen
Authors: Jendrzejewski Stefan , Steglich Wolfgang 
Published: September 2007

Abstract4‐Alkyl‐2‐oxazolin‐5‐one 1 liefern bei der Gasphasenpyrolyse unter CO‐Verlust N‐Acylimine 2, die sich beim Vorhandensein α‐ständiger H‐Atome in die stabileren Enamide 3 umlagern. Ist diese Umlagerung durch ein quartäres C‐Atom verhindert, so lassen sich die N‐Acylimine (z.B. 2a) isolieren. Im Falle des 4,4‐dialkylsubstituierten Oxazolinons 1 o entstehen Gemische von N‐Acylimin 2 o und Enamid 3 o, wobei der Anteil des letzteren bei Erhöhung der Pyrolysetemperatur zunimmt.
Metallcarbonyl‐Brückenligand‐Sechsringsysteme
Authors: Trenkle Armin , Vahrenkamp Heinrich 
Published: September 2007

AbstractGezielte Synthesen ergaben zahlreiche Sechsringkomplexe 5, und 9 des Typs Ln M(EMe2E′Me2)2‐M′Ln mit M, M′ = Cr, Mo, W, Mn, Fe, Co, Ni und E, E′ = P, As. Vorstufen waren einkernige metallorganische Lewis‐Basen LnMEMe2E′Me2 und LnM(EMe2E′Me2)2, deren Liganden EMe2‐E′Me2 z. T. am Komplex synthetisiert wurden. Nebenreaktionen der Synthesen lieferten u. a. kettenförmige Mehrkernkomplexe, von denen einige oligomer waren.
Darstellung und Thermolyse P2Me4‐verbrückter Mehrkern‐Carbonylkomplexe
Authors: Trenkle Armin , Vahrenkamp Heinrich 
Published: September 2007

AbstractKettenförmige Dreikernkomplexe 3 und 5 mit einem MPPM′PPMGerüst (M, M′ = Carbonylmetall‐Einheiten, PPP2Me4) ließen sich aus Metallcarbonylen und den monofunktionellen metallorganischen Lewis‐Basen MP2Me4 im Verhältnis 1:2 oder aus Metallcarbonylen und der bifunktionellen Lewis‐Base (CO)4Cr(P2Me4)2 im Verhältnis 2:1 darstellen. Sie wurden ebenso wei die analogen Zweikernkomplexe mit MPPM′‐Gerüst im Einschlußrohr thermisch zersetzt, mit der Absicht, neue MM′‐verknüpfte Mehrkernkomplexe zu erhalten. Die Thermolysen führten unter milderen Bedingungen vorwiegend zum Ligandenaustausch, wobei sich auch Sechsring‐Komplexe mit M(PP)2M′ ‐Gerüst bildeten. Unter schärferen Bedingungen wurden dazu neben zunehmender Zersetzung auch Ligand‐Fragmentierungen beobachtet, die zu einfachen Komplexen oder solchen mit Metall‐Metall‐Bindungen führten. Als neue Komplexe mit Hetero‐Metall‐Metall‐Bindungen wurden (CO)4Cr(μ‐PMe2)2MnCpCO und (CO)4Cr(μ‐PMe2)2Ni(CO)2 isoliert. Der neuen Verbindung Fe2(CO)4(PMe2)4 ordnen wir eine FeFe‐Bindung, eine P2Me4‐ und zwei PMe2‐Brücken zu.