bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Reaktion von Halogen(trimethylsilyl)benzolen mit Elektrophilen und Basen – Carbodesilylierung und Eliminierung als Konkurrenzreaktionen
Authors: Effenberger Franz , Daub Wolfgang 
Published: July 2007

Reaction of Halo(trimethylsilyl)benzenes with Electrophiles and Bases – Carbodestlylation and Elimination as Competitive ReactionsElimination to dehydrobenzenes takes place as competitive reaction in the base‐catalyzed carbodesilylation of 1‐halo‐2‐(trimethylsilyl)benzenes 1 with carbonyl compounds 2 in the presence of furans 3, 6. Elimination is preferred with increasing leaving tendency of the halides (I > Br > > Cl > > F) and with decreasing reactivity of the carbonyl compounds. Exclusive elimination to 1,2‐didehydrobenzenes – which are trapped with furans – occurs in the reaction when no electrophiles are present.
Darstellung von Didehydropyridinen aus (Trimethylsilyl)pyridinen
Authors: Effenberger Franz , Daub Wolfgang 
Published: July 2007

Preparation of Didehydropyridines from (Trimethylsilyl)pyridinesHalogen‐substituted (trimethylsilyl)pyridines 2, 3, 5 – 7 and trifluoromethylsulfonyloxy‐substituted (trimethylsilyl)pyridines 9b, 11b are obtained from 2‐ and 3‐halopyridines 1, 4 or hydroxypyridines 8, 10, and 12. Reactions of the 3‐ and 2‐(trimethylsilyl)pyridines 2,9b and 11b with bases in the presence of furans 15 give only protodesilylation or hydrolysis products but no indication is found for the formation of a 2,3‐didehydropyridine. 3‐Bromo‐4‐(trimethylsilyl)pyridine (5a) reacts with KOCMe3 in the presence of furan (15a) to give a mixture of products from which the isoquinoline derivative 20 and the tert‐butoxypyridines 23, 24 are formed by addition to 3,4‐didehydropyridine. Under comparable conditions far higher yields of 3,4‐didehydropyridines are obtained by treatment of the 3‐halo‐2,4‐bis(trimethylsilyl)pyridines 7 with strong bases.
Metallkomplexe mit Tetrapyrrol‐Liganden, LIX Redoxpotentiale, Nah‐Infrarot‐Absorption, Ionenradien sowie Ring‐Ring‐Abstand in Metall(III)‐bis(tetraphenylporphyrinat)‐Systemen mit Porphyrinringen in unterschiedlichen Oxidationsstufen
Authors: Buchler Johann W. , Hammerschmitt Peter , Kaufeld Isolde , Löffler Jürgen 
Published: July 2007

Metal Complexes with Tetrapyrrole Ligands, LIX. – Redox Potentials, Near‐Infrared Absorption, Ionic Radii, and Ring‐Ring Distance in Metal(III) Bis(tetraphenylporphyrinate) Systems with Porphyrin Rings in Different Oxidation StatesAn extended series of tetrabutylammonium salts of bisporphyrinate double decker anions NBu4[MIII(TPP)2] (M = Y, La – Lu except Pm) is described. The complexes are characterized by UV/Vis/NIR and 1H‐NMR spectroscopy, cyclic voltammetry, and spectroelectrochemistry. The redox potentials of the new sandwich compounds and the near‐infrared absorption energies of their corresponding oxidation products M(TPP)2 and [M(TPP)2]+ are shown to depend linearly on the ionic radii of the central ions. The gradients of the first and second oxidation potentials are positive whereas those of the third and fourth oxidation potentials are negative. This result is interpreted by means of a qualitative molecular orbital diagram describing the ππ interactions of the four frontier orbitals of the two macrocycles in the double decker molecules.
Metallacyclobutene aus η2‐Cyclopropen‐Komplexen des Titanocens und Zirkonocens
Authors: Binger Paul , Müller Patrik , Herrmann Albert T. , Philipps Petra , Gabor Barbara , Langhauser Franz , Krüger Carl 
Published: July 2007

Metallacyclobutenes via η2‐Cyclopropene Complexes of Titanocene and Zirconocene(η2‐Cyclopropene)(trimethylposphane) complexes of titanocene (4, 5) and zirconocene (8) are obtained in good yields by the reaction of 1,2‐diphenylcyclopropene (2) or 4,8‐dioxaspiro[2.5]oct‐1‐ene (3) with bis(trimethylphosphane)titanocene (1) and (1‐butene)(trimethylphosphane)zirconocene (7), respectively. In solution the new complexes 4 and 8 rearrange smoothly above room temperature to give the metallacyclobutene derivatives 6 and 9. All new compounds were characterized by spectroscopic methods (31P, 1H, 13C NMR), and the crystal structure of 9 was determined by an X‐ray analysis.
Protonenaustausch in Re(CO)4(μ‐H)(μ‐PPh2)Mo(η5‐C5H5)(CO)2 gegen Triphenylphosphan‐IB‐Metallkationen
Authors: Haupt Hans‐Jürgen , Flörke Ulrich , Disse Gerd , Heinekamp Christoph 
Published: July 2007

Proton Exchange in Re(CO)4(μ‐H)(μ‐PPh2)Mo(η5‐C5H5)(CO)2 Against Cationic IB Metal Phosphane SpeciesDecacarbonyldirheniumreacts with hexacarbonylbis(η‐cyclopentadienyl)dimolybdenum and diphenylphosphane to give Re(CO)4(μ‐H)(μ‐PPh2)Mo(η5‐C5H5)(CO)2 (1) with a Mo — Re bond as ascertained by an X‐ray structure analysis. The bridging H atom of the heteronuclear metal‐metal bond in 1 is deprotaned with DBU. The redox condensation reaction of the obtained anion1 and triphenylphosphane IB metal cations gave Re(CO)4(μ‐H)(μ‐PPh2)Mo(η5‐C5H5)(CO)2 [M = Au (2), Ag (3), and Cu (4)] containing an MReMo triangle. Their yields increase in the sequence of compounds 4 < 3 < 2. 1, 1‐, and 2 were characterized by cyclovoltammetric measurements, NMR, IR, and UV/Vis spectra.
1,3,2‐Diazaborinium‐Verbindungen — neue Heteroaren‐Kationen des Bors
Authors: Kuhn Norbert , Kuhn Annette , Lewandowski Jörg , Speis Martin 
Published: July 2007

1,3,2‐Diazaborinium Compounds — New Cationic Boron HeteroarenesThe diazaborinium cation 9 is obtained by the reaction of the vinamidine boron chelate 8 with Et2O—BF3. The cyclic aluminium compound 13 forms with the dichloroboranes RBCl2 (R = Cl, Et, Ph) the cations 15,16a, and 16b. AM1 calculations demonstrate the π interaction of the boron with the nitrogen atoms as well as with the fluoro substituent.
Deprotonation of 5,6‐Dihydro‐5‐methylene‐4H‐1,2‐oxazines and Regioselective Reactions with Electrophiles
Authors: Unger Clemens , Zimmer Reinhold , Reißig Hans‐Ulrich , Würthwein Ernst‐Ulrich 
Published: July 2007

Abstract5,6‐Dihydro‐5‐methylene‐4H‐1,2‐oxazine 1 is smoothly converted by n‐butyllithium into 1‐Li which reacts with electrophiles such as D2O, carbonyl compounds, dimethyl sulfide, or an azo diester to give the γ‐adducts 4a–4f. On the other hand, alkylation of 1‐Li occurs exclusively at C‐4 of the heterocycle and provides the α‐adducts 3g and 3h. These reactions require the activation of 1‐Li by tetramethylethylenediamine. Treatment with allyl bromide and methyl acrylate affords mixtures of regioisomers 3 and 4. 1,2‐Oxazine 5 with a conjugated C = C bond is less acidic than 1 but is also converted into 1‐Li, whilst compound 6, lacking the 6‐methoxy group, is not deprotonated under standard conditions. The dianion of 1,2‐oxazine 7 is generated by employing an excess of n‐butyllithium. This dianion displays a similar regiochemical behavior as 1‐Li. Deuterium is exclusively incorporated into the γ‐position to give product 8, while methylation occurs at C‐4 to produce 9. 1,2‐Oxazine 3g with an additional 4‐methyl group can also be metalated and affords γ‐adducts 10 and 11 upon reaction with D2O or acetone. Treatment with methyl iodide gives a 3:1 mixture of regioisomers 12 and 13. Deuteration of 1,2‐oxazines 14 and 16 bearing a 3‐CF3 or 3‐CO2Et substituent requires more severe deprotonation conditions to provide the γ‐adducts 15 and 17 in moderate yields. MNDO calculations of neutral 1,2‐oxazines, the corresponding carbanions, and the lithium compounds allow an insight into the structure and charge distribution of these species, and also an estimation of the relative acidities. The regioselectivity of reactions of 1‐Li is discussed on the basis of these semiempirical calculations and comparison with related ambident nucleophiles.
Photoreaktion von 3,6‐Dihydrophthalsäureanhydrid mit Alkinen
Authors: Askani Rainer , Hoffmann Jochen 
Published: July 2007

Photoreaction of 3,6‐Dihydrophthalic Anhydride with AlkynesThe title compound 1 and various alkynes undergo photocycloadditions to give cyclobutenes 3 and/or tetracyclooctane derivatives 4. The proportion varies from 100% cyclobutene (3d) to 100% tetracyclooctane (4e, 1) according to the substituents on the alkyne and the temperature.
Lösliche (Tetraethylphthalocyaninato)eisen(II)‐ und ‐cobalt(II)‐Verbindungen
Authors: Beck Anton , Mangold Klaus‐Michael , Hanack Michael 
Published: July 2007

Soluble (Tetraethylphthalocyaninato)iron(II) and ‐cobalt(II) CompoundsThe (tetraethylphthalocyaninato)iron and ‐cobalt compounds Et4PcFe (9), Et4PcCo (8), and Et4PcH2(7) have been synthesized starting from 3,4‐dibromoacetophenone (1) via the corresponding dinitrile 5 or isoindolenine6, respectively. Et4PcFe (9) reacts withtBuNC,p‐diisocyanobenzene (dib), and me4dib to form the bisaxially coordinated compound Et4PcFe(tBuNc)2(10) and the oligomers [Et4PcFe(dib)]n(11) and [Et4PcFe‐ (me4dib)]n(12). All of the synthesized compounds, except the oligomers with a chain length of more than 8 – 14 units, are soluble in organic solvents such as chloroform or toluene. The new compounds were characterized by1H‐,13C‐NMR,13C‐CP/NMR, UV/Vis, and IR spectra. In addition the redox properties of Et4PcCo (8) were studied by cyclic voltammetry and spectroelectrochemical methods. The Mößbauer spectra of the (phthalocyaninato)iron compounds9, 11, and12demonstrate the bridged structure of [Et4PcFe(L)]n(L = dib, me4dib) (11,12). The powder conductivity of [Et4PcFe(dib)]n(11) (σRT= 5·10‐6S/cm) is ca. 106times higher than that of Et4PcFe (9) (σRT= 9·10‐12S/cm). After doping with iodine the oligomers11and12show an increase in conductivity of 105and 104, respectively (σRT≈︁ 10‐2S/cm for [Et4PcFe(dib)I0.85]n).
Über die verbesserte Darstellung von Silyl‐ und Germylkalium sowie die Synthese von Silylgermanen
Authors: Lobreyer Thomas , Oeler Johannes , Sundermeyer Wolfgang 
Published: July 2007

An Improved Preparation of Silyl‐ and Germylpotassium and Synthesis of SilylgermanesThe preparation of KSiH3 and KGeH3 is improved, and several syntheses of silylgermane, H3Si – GeH3, are described. A series of other potential processing gases for PE‐CVD is prepared: H3Ge – SiR1R2R3 (R1, R2, R3 = H, H, Me; H, H, Et; H, H, tBu; H, H, Ph; H, Me, Me; Et, Et, Et; H, Me, Ph; H, Me, GeH3). A new method for the preparation of silylgermanes by the reaction of silyl esters of sulfonic acids (RSO3H, R = C4,F9, Me, Ph) with KGeH3 is reported.
Über Metallalkyl‐ und ‐arylverbindungen, 48 Monomeres, tetrameres und polymeres Natriumfluorenid S [S = Me2N(CH2)2N(Me)(CH2)2NMe2, Me2N(CH2)nNMe2 (n = 2, 3)]
Authors: Corbelin Siegfried , Kopf Jürgen , Weiss Erwin 
Published: July 2007

Monomeric, Tetrameric, and Polymeric Sodium Fluorenide · S [S = Me2N(CH2)2N(Me)(CH2)2NMe2, Me2N(CH2)nNMe2 (n = 2, 3)]The metallation of fluorene with sodium butanide (NanBu) in the presence of N bases yields solvated sodium fluorenide. Base adducts with bi‐ and tridentate N‐chelating ligands have been isolated: Na(fluorenide)(pmdta) (1 [PMDTA = Me2N(CH2)2N(Me)(CH2)2NMe2], [Na(fluorenide)(tmeda)]n (2) [TMEDA = Me2N(CH2)2N(Me)(CH2)2NMe2], [Na(fluorenide)(tmeda)]4) (3) [TMPDA = Me2N(CH2)3NMe2]. According to X‐ray diffraction studies monomeric (1), polymeric (2), and cyclic‐tetrameric (3) structures are present in the crystal. These pronounced structural variations are explained on the basis of ionic contact aggregates where together with coulomb interactions the steric requirements of the ligands become rather important. Contact distances between Na ions and several C atoms of the carbanion may vary (ca. 260—300 pm) and definite coordination numbers become meaningless.
Die Berechnung von Resonanzenergien; das MM2ERW‐Kraftfeld
Authors: Roth Wolfgang R. , Adamczak Oliver , Breuckmann Rolf , Lennartz Hans‐Werner , Boese Roland 
Published: July 2007

Resonance Energy Calculation; the MM2ERW Force Field*The additivity of the thermochemical conjugation energy in acyclic systems allows one to extend force‐field calculations to conjugated π systems without embarking on quantum‐mechanical methods. The approach fails with cyclic delocalized systems, where resonance effects become important. Here the method provides the reference value needed to calculate resonance energies.
Retention of Configuration in Two Photochemical Reactions: Formation of Cyclopropanimines by Extrusion of Molecular Nitrogen from Tetraalkyl‐4‐imino‐1‐pyrazolines and [2 + 1] Cycloreversion of Cyclopropanimines to Isocyanides and Alkenes
Authors: Quast Helmut , Fuß Andreas , Heublein Alfred , Jakobi Harald , Seiferling Bernhard 
Published: July 2007

AbstractThe 1‐pyrazolin‐4‐ones 7 and 9 and the pyrazolidin‐4‐one 13 are condensed with alkanamines 8 to produce the imines 3,10 and 12 in high yields. Direct irradiation of 3 with 350‐nm light at 90°C in deuterated hydrocarbon solvents affords the cyclo‐propanimines 4 in almost quantitative yields besides molecular nitrogen and small amounts of the imines 12 as a result of photoreduction. In [D6]acetone, the cyclopropanimine 4b isomerizes in part of the α,β‐unsaturated imine 14. Direct irradiation of 3 with the unfiltered light of the high‐pressure mercury lamp results in quantitative [2 + 1] cycloreversion of the primary photoproducts 4 into the alkene 6 and an isocyanide 5. At low temperature (10°C), photolysis of 3 occurs much more slowly giving rise to photoextrusion of nitrogen (→4) and photoreduction (→12) to about the same extent. – Photolysis of the stereochemically labelled iminopyrazolines cis‐ and trans‐10 (d.e. 99%) at 90°C produces the cyclopropanimines cis‐ and trans‐16 (d.e. 94%) with high stereospecificity. The configuration of cis‐ and trans‐16 is established by a comparison with the corresponding methylenecyclopropanes cis‐ and trans‐19 and the quantitative and completely stereospecific [2 + 1] cycloreversion into methyl isocyanide (5a) and the 3,4‐ dimethyl‐3‐hexenes (Z)‐ and (E)‐17 on irradiation with the unfiltered light of the mercury arc. The necessity of thermal activation for efficient nitrogen extrusion from the 1(n,π*) state of 3 and 10 is indicative of a considerable energy barrier towards the transition into a dissociative state. At low temperature, hydrogen abstraction from the solvent or other molecules becomes important for the deactivation of the 1(n,π*) state, in addition to decay and fluorescence. The stereospecific formation of cis‐ and trans‐16 is interpreted in terms of diastereomeric bis‐orthogonal azatrimethylenemethane diradicals as intermediates which retain the configuration on cyclization. The minor non‐stereospecific path may involve mono‐orthogonal azatrimethylenemethane diradicals. Thus, mechanisms that involve the same types of diradical intermediates can rationalize the photolysis of the iminopyrazolines 3, 10 and of the methylenetriazoline 1 as well. The [2 + 1] cycloreversion of cis‐ and trans‐16 into the alkenes (Z)‐ and (E)‐17 and methyl isocyanide (5a) demonstrates for the first time that such photoreactions can be entirely stereospecific.
Anwendung der Isonitril‐Nitril‐Umlagerung zur Synthese von 2,2,5,5‐Tetramethylcyclopentancarbonsäure, einem Baustein für Süßstoffe auf Aminosäurebasis
Authors: Lüning Ulrich , Müller Michael , Gelbert Markus , Rüchardt Christoph 
Published: July 2007

Use of the Isonitrile‐Nitrile Rearrangement for the Synthesis of 2,2,5,5‐Tetramethylcyclopentanecarboxylic Acid, a Building Block for Sweeteners on the Basis of Amino Acids1)2,2,5,5‐Tetramethylcyclopentanecarboxylic acid (7) was synthesized in four steps from 2,2,5,5‐tetramethylcyclopentanone (3). The key step of the reaction is the gas‐phase rearrangement of 2,2,5,5‐tetramethylcyclopentyl isocyanide (5) to 2,2,5,5‐tetra‐methylcyclopentanecarbonitrile (6), which is hydrolyzed to 7.
Wasserstoffübertragungen, 18 Zur cis‐Selektivität bei der Dehydrierung mit Chinonen
Authors: Wehage Hubert , Heesing Albert 
Published: July 2007

Hydrogen Transfer Reactions, 181). — The cis Selectivity in Dehydrogenation by QuinonesIn contrast to literature results the dehydrogenation of [cis‐ 5,6‐D2]‐1,3‐cyclohexadiene by o‐chloranile proceeds stereo‐selectively. Fast 1,5‐hydrogen shifts in the last pyrolytic step of the synthesis are the cause of the contrary report.
Phosphinalkylene, 491) Chemie und Stereochemie des 9,10,19,20‐Tetrahydro‐tetrabenzo[a,c,g,i]cyclododecens und einiger seiner Derivate
Authors: Bestman Hans Jürgen , Schaper Wolfgang , Ruppert Dieter , Zimmermann Reiner , Burzlaff Hans 
Published: July 2007

Phosphine Alkylidenes, 491). – Chemistry and Stereochemistry of 9,10,19,20‐Tetrahydrotetrabenzo[a,c,g,i]cyclododecene and of Some DerivativesTwofold intermolecular C alkylation of the bis‐ylide 4 with the dibromide 5 and subsequent hydrolysis yields meso‐9,10,19,20‐tetrahydrotetrabenzo[a,c,g,i]cyclododecene (1 b), which isomerizes on heating to give the racemate 1a. From 1a and 1b the isomeric dibromides 7–10 are synthesized. Reaction of 7–10 with phenyllithium leads to the formation of the polycyclic compounds 11, 12, 13, from which 12 may be dehydrogenated to the unsaturated compound 14. Reaction of the dibromides 7–10 with silver acetate occurs with retention yielding the acetates 15–18, which may be hydrolysed to the corresponding alcohols. With the knowledge of the structures of compounds 15–22 the stereochemistry of the synthesis and the Wittig ether rearrangement of the diethers 24 can be elucidated. In the reaction of the dibromides 7–10 with sodium acetate elimination takes place instead of substitution. Starting from 7 and 8 the polycyclic hydrocarbon 31 is formed via the carbenium ion intermediate 26 and subsequent transannular reaction. 31 is dehydrogenated to yield 32, whose X‐ray structural analysis shows a multi helical structure. Reaction of the base potassium tert‐butylate with the dibromides 7–10 leads to the formation of isomers of the diolefin 2.
Neue Wege zum Aza‐nido‐decaboran‐Gerüst
Authors: Müller Jens , Paetzold Peter , Englert Ulli , Runsink Jan 
Published: July 2007

Novel Syntheses of the Aza‐nido‐decaborane SkeletonThe known nido‐NB9H12 (3) can be synthesized by thermolysis of either arachno‐B9H13(NH3) (4) in xylene (11%) or arachno‐B10H12(N3)(NH2) (5) in diglyme (100%). The deprotonation of 5 yields the anion arachno‐[NB10H13(N3)]− (6), whose skeleton is derived from the closed 13‐vertex deltahedron. On protonation, a degradation of 6 is observed to give nido‐NB9H11(N3) (7), which crystallizes in the monoclinic space group P21/c. The borane 3 is attacked by Et3N · BH3 with evolution of H2 and formation of the 6‐BH2 — NEt3 derivative of 3 (8). Both nido‐species 8 and 7 add the isonitrile CNtBu at the position 9 to yield the arachno‐products 9 and 10, respectively. The adduct 11 is formed from 7 and the azadiboriridine (‐ tBuB — BtBu — NtBu —).
7‐Substituierte Cycloheptatriene als Dienophile in der Diels‐Alder‐Cycloaddition mit inversem Elektronenbedarf
Authors: Baumann Luzian , Kämpchen Thomas , Seitz Gunther 
Published: July 2007

7‐Substituted Cycloheptatrienes as Dienophiles in the Diels‐Alder Cycloaddition With Inverse Electron DemandA series of 7‐substituted cycloheptatrienes 1, including CN, CO2CH3, C6H5, C(CH3)3, CH3, CH(OCH3)2, H, N(CH3)2 groups has been submitted to inverse [4 + 2] cycloaddition with 3,6‐bis(trifluoromethyl)‐1,2,4,5‐tetrazine (5). Reaction of 5 with π‐acceptor‐substituted cycloheptatrienes such as 1a–c leads exclusively to cyclopropa[f]phthalazines 8 and 9, whereas 7‐alkylcycloheptatrienes 1d–f give mixtures of cyclopropa[f]phthalazines 10 and 12 and 7H‐cyclohepta[d]pyridazines 11 and 13. Moreover, 7‐methylcycloheptatriene (1e) yields three further products 19, 20, 21, derived from heptafulvene 16, formed intermediately by dehydrogenation of 1e. In contrast to 1a—f, reaction of 5 with cycloheptatriene (1g) yields the corresponding 5H‐cyclohepta[d]pyridazine 22 quantitatively. Surprisingly, no [4 + 2] cycloadducts are observed with the π‐donor‐substituted cycloheptatriene 1h. Instead, the indazol 27 and the triazoles 25 and 28 are formed.
Aminobenzole, 22. Darstellung, physikalische Eigenschaften und Kristallstrukturen von Mono‐, Di‐ und Trichlor‐2,4,6‐tris(dialkylamino)benzolen
Authors: Effenberger Franz , Mündl Gabriele 
Published: July 2007

Aminobenzenes, 22. — Synthesis, Physical Properties, and Crystal Structures of Mono‐, Di‐, and Trichloro‐2,4,6‐tris‐(dialkylamino)benzenesMono‐, di‐ and trichlorotris(dialkylamino)benzenes 2,3, and 4 are prepared selectively by chlorination of triaminobenzenes 1 with one, two, or three equivalents of N‐chlorosuccinimide, resp., in tetrachloromethane. From spectroscopic data it is deduced that the introduction of chloro substituents into symmetrical triaminobenzenes 1 causes a severe steric hindrance for the dialkylamino groups without disturbing the aromatic π system. X‐ray structural analyses of the trichlorotriamino compounds 4a and 4c confirm the spectroscopic interpretation. Among the trichloro compounds 4a—d only for 4c the anodic oxidation is reversible.
Struktur und Reaktivität von Bis(π‐pentamethylcyclopentadienyl)‐(2‐methyliden)titanacyclobutan
Authors: Beckhaus Rüdiger , Flatau Sabine , Trojanov Sergej , Hofmann Peter 
Published: July 2007

Structure and Reactivity of Bis(π‐pentamethylcyclopentadienyl)(2‐methylidene)titanacyclobutaneThe reaction of vinyllithium with bis(π‐pentamethylcyclopentadienyl)titanium dichloride in a molar ratio of 2:1 quantitatively yields the unexpected titanacyclobutane derivative(2) (Cp* = [C5(CH3)5]). The isolated complex2has been characterized by spectroscopic methods and by elemental analysis, and its structure has been confirmed by an X‐ray structure determination. The chemical reactivity of2is characterized by the splitting of the four‐membered ring at higher temperatures, forming a titanocene vinylidene fragment {Cp2*Ti = C = CH2} and ethylene. This cycloreversion is confirmed by the fragmentation behavior in the mass spectrometer, and some aspects of it have been studied by Extended Hückel Model calculations.
Kristallstruktur, Festkörperpolymerisation und Ionenleitung in Alkalisalzen ungesättigter Carbonsäuren, 1. Untersuchungen an wasserfreiem Lithiumacrylat, Lithiumacrylat‐tetartoshydrat und ‐hektonmethanolat
Authors: Beck Horst P. , Trübenbach Peter 
Published: July 2007

Crystal Structure, Solid‐State Polymerization and Ionic Conductivity of Alkali Salts of Unsaturated Carboxylic Acids, 1. — Investigations on Lithium Acrylate, Lithium Acrylate Tetartoshydrate and Lithium Acrylate HektonmethanolateThe structures of lithium acrylate tetartoshydrate C3H3LiO2 · 1/4 H2O (1) and the corresponding hektonmethanolate C3H3LiO2 · 1/6 CH3OH (2) have been determined by single‐crystal X‐ray diffraction. They both consist of a framework of corner‐ and edge‐shared LiO4 tetrahedra. The vinyl groups extend into channels running through the inorganic framework in all three main directions, where they are stacked in a zipper‐like manner. However, the distances between these functional groups are too large for a diffusionless topochemical polymerization. Polymerization takes place thermally at temperatures between 180 and 280°C after loss of solvate molecules. The amorphous polymer is an ionic conductor above 238 °C with an activation energy of 0.57 eV.