bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydroboration of Bis(alkenylcyclopentadienyl)zirconium Dichlorides
Authors: Erker Gerhard , Aul Rainer 
Published: July 2007

AbstractThe reaction of allylcyclopentadienyllithium with 0.5 molar equivalents of MCl4(thf)2 (MZr, Hf) furnished the (η5‐C5H4CH2CHCH2MCl2 complexes 3a (Zr) and 3b (Hf), which cleanly added 9‐borabicyclo[3.3.1]nonane (9‐BBN) to form [η5‐C5H4(CH2)3(9‐BBN)]2MCl2 (10a, b). Treatment of 3 with butadiene‐magnesium led to coupling of one Cp‐bonded allyl unit with butadiene to give 5; the remaining CpCH2CHCH2 group underwent clean H[B(C8H14)] addition when exposed to the 9‐BBN hydroboration reagent. (Alkenyl‐Cp)2ZrCl2 complexes (9a – d) were prepared starting from fulvenes by deprotonation with the help of LDA and reaction with ZrCl4(thf)2. The complexes [η5‐C5H4CHC(CH3)R]2ZrCl2 9b (RCH3) and 9c (RPh) added 9‐BBN to give [η2‐C5H4CH(9‐BBN)CH(CH3)R]2ZrCl2 12 (RCH3, rac;‐/meso;‐ ≈︁ 1:1) and 13 (RPh, threo;‐/erythro;‐ ≈︁ 1:1). The mixtures of diastereoisomers were in each case separated by fractional crystallization. The stereochemical assignments of complexes rac;‐12 and meso;‐12 were achieved by means of the stereochemistry of polypropylene formed at the 12/methylalumoxane‐derived homogeneous Ziegler‐type olefin polymerization catalysts. At – 50°C the catalyst from the achiral meso;‐12 precursor produced isotactic polypropylene only by means of “chain end control” (σ ≈︁ 0.7), whereas the use of rac;‐12 led to a pronounced participation (≈︁ 30%) of effective “enantiomorphic site control” (α=0.95) in the CC‐coupling reaction.
Neue Synthesen für Ibuprofen und Naproxen
Authors: Wolber Erwin K. A. , Rüchardt Christoph 
Published: July 2007

New Syntheses of Ibuprofen and NaproxenA new route for the synthesis of α‐arylpropionic acids, in particular for the two most important non‐steroidal antiinflammatory compounds Ibuprofen (5) as well as racemic and optically active Naproxen (12), has been developed. N‐(1‐Arylethyl)formamides 2, 9 are dehydrated to the corresponding isocyanides 3, 10, and these are rearranged by flash pyrolysis to α‐arylpropionitriles 4, 11 which are converted into α‐arylpropionic acids 5, 12 by hydrolysis under standard conditions. The intermediate 1‐(6‐methoxy‐2‐naphthyl)‐ethylamine is resolved via its tartrate or mandelic salts.
Organometall‐Imide – Höhervalente Derivate der d‐Metall‐Säuren, 1 Neue Organometall‐Imide des Molybdäns und Wolframs — die direkte Einführung der Cyclopentadienyl‐Gruppe durch Maskierung der hohen Oxidationsstufe
Authors: Sundermeyer Jörg 
Published: July 2007

Organometallic Imido Complexes – Higher Valent Derivatives of the d‐Metal Acids, 1. – New Organometallic Imido Complexes of Molybdenum and Tungsten – Direct Introduction of the Cyclopentadienyl Group by Masking the High‐Oxidation StateThe molybdenum(VI)bis(tert‐butylimido) complex MO(NtBu)2‐Cl2 is converted into the novel organomolybdenum(VI) derivative (η5‐C5H5)MO(NtBu)2Cl (1) in excellent yield. The preparation of the pyridine complex W(NtBu)2Cl2py2 (2) provides a convenient starting material for an effective synthesis of the related complex (η5‐C5H5)W(NtBu)2Cl (4).
Tin for Organic Synthesis, 5 A New and Regioselective Synthesis of Aromatic Diazene Derivatives
Authors: Neumann Wilhelm P. , Wicenec Christian 
Published: July 2007

AbstractA new method for the preparation of aromatic diazene derivatives 3a — 1, 5, 7a, b, 9 under very mild conditions is described. The reaction of trialkylarylstannanes with nitro‐substituted benzenediazonium tetrafluoroborates leads, by strict ipso substitution, to the corresponding diaryldiazenes in satisfactory to high yields. Due to the excellent leaving group quality of the stannyl group azo compounds may be prepared which are not accessible by normal electrophilic azo coupling. The products can be valuable precursors, obtained by reduction to the amines or other derivatizations, for consecutive aromatic compounds.
Cathodic Reduction of 1‐Nitroalkenes to Oximes and Primary Amines
Authors: Wessling Michael , Schäfer Hans J. 
Published: July 2007

Abstract1‐Nitroalkenes are reduced in high yields at ‐0.3 to ‐0.5 V (vs. SCE) at a mercury or graphite cathode to oximes. At higher cathodic reduction potentials (‐ 1.1 V) primary amines are selectively obtained in fair yields. Nitroalkadienes are selectively reduced at the double bond conjugated with the nitro group to either the oxime or amine.
Gas‐Phase Substitution of Dichloro‐ and Dibromoethene by Ammonia and Amines via Radical Cations. A Kinetic Study by FT‐ICR Spectrometry
Authors: Thölmann Detlef , Flottmann Dirk , Grützmacher Hans‐Friedrich 
Published: July 2007

AbstractThe gas‐phase reactions of the three isomeric dichloroethene radical cations 1+.‐3+. with NH3 and of the neutral species 1–3 and the isomeric 1,2‐dibromoethenes 4 and 5 with CH3‐NH2+. and (CH3)2NH+., respectively, are studied by Fourier‐Transform Ion‐Cyclotron‐Resonance (FT‐ICR) mass spectrometry. A chloro substituent in 1+.‐3+. is replaced by NH3 in a fast reaction, yielding C2H5NCl+ ions. These substitution reactions are very fast and occur nearly at the collision limit. The 1,1‐dichloroethene radical cations 3+. exchange successively both Cl substituents, yielding C2H7N2+ ions and eventually cluster ions N2H7+. Substitution takes place also by the reaction of neutral haloethenes 1–5 with amine radical cations, although at very different rates. The efficiencies of the reactions of CH3HN2+. with 1–5 are quite large, but those of the reactions of (CH3)2NH+. with 1 and 2 are < 1% and reach only ≤ 10% even in the case of the bromoethenes 4 and 5. 1,1‐Dichlorethene (3) does not react at all. An addition‐elimination mechanism is proposed for all these reactions, giving rise to the formation of intermediate β‐distonic ammonium ions. This reaction path and the stability of the intermediates are supported by MNDO calculations. However, the intermediate β‐distonic ions have to isomerize further by hydrogen shifts before the product ions are eventually formed. MNDO calculations support the assumption that the slow reactions of (CH3)2NH+. with the haloethenes are due to slow rearrangements within the initially formed distonic ions, which have to precede the loss of Cl.
Kurzmitteilung / Short Communication A Convenient Preparation of Acetone Solutions of Dimethyldioxirane
Authors: Adam Waldemar , Bialas Joachim , Hadjiarapoglou Lazaros 
Published: July 2007

AbstractA novel simplified procedure affords consistently 0.09‐0.10 M solutions of distilled dimethyldioxirane in acetone; other than control of the reaction temperature below 15° and vigorous mechanical stirring, no other precautions are maniatory.
Stereoisomeric Dichloro[1‐(hydroxyphenyl)‐2‐phenyl‐1,2‐ethanediamine]platinum(II) Complexes, Part I: Synthesis
Authors: Müller Richard , Gust Ronald , Schönenberger Helmut , Klement Ulrich 
Published: July 2007

AbstractVarious erythro‐ and threo‐configurated dichloro[1‐(hydroxyphenyl)‐2‐phenyl‐1,2‐ethanediamine]platinum(II) complexes were synthesized with the hydroxy group located in either the 2‐, 3‐, or 4‐position of the phenyl ring (38–40). The diastereoisomeric 1‐(3‐hydroxyphenyl)‐2‐phenyl‐1,2‐ethanediamines (31, 32) and threo‐1‐(2‐hydroxyphenyl)‐2‐phenyl‐1,2‐ethanediamine (30) were obtained by reduction of the 1,2‐diazidoethanes and subsequent ether cleavage. The configuration of the threo‐1,2‐diazido‐1‐(2‐methoxyphenyl)‐2‐phenylethane (5) was elucidated by X‐ray analysis. The reduction of the erythro‐1,2‐diaryl‐1,2‐diazidoethanes, substituted with a methoxy group in ortho or para position, results in elimination reactions with formation of side products. The desired 1,2‐diaryl‐1,2‐ethanediamines were finally synthesized via either an aziridine derivative 21 or by reduction of the respective dioximes 27, 28. The diamine ligands were converted into the corresponding dichloroplatinum(II) complexes 38 – 40.
Preparation and Selected Reactions of t‐Butyl 2‐Methylene‐3‐oxoalkanoates
Authors: Martin H. , Hoffmann R. , Gassner Andreas , Eggert Ulrike 
Published: July 2007

AbstractThe title class of 1,1‐diactivated ethylenes has been prepared in two steps from aldehydes and t‐butyl acrylate by (i) DABCO‐catalyzed coupling to give t‐butyl 2‐(hydroxyalkyl)‐2‐propenoates 11 and (ii) low‐temperature Jones oxidation, followed by swift work up at low temperature. The resulting t‐butyl 2‐methylene‐3‐oxoalkanoates 12 are stabilized by sterically demanding and also by aromatic groups R. For primary unhindered alkyl groups, stability is low. The compounds enter into Michael reactions, hetero Diels‐Alder additions with enol ethers, and self‐dimerization.
Photoisomerisierung von Halogendimethylsulfiden
Authors: Maier Günther , Flögel Ulrich , Reisenauer Hans Peter , Andes Hess B. , Schaad Lawrence J. 
Published: July 2007

Photoisomerization of Halogenodimethyl SulfidesPhotolysis of iodo‐ (3a), bromo‐ (3b), and chlorodimethyl sulfide (3c) in an argon matrix at 12 K gives rise to isomeric species 4a — c. Ab initio calculations indicate that in these isomers the halogen has been removed from the carbon atom and forms a weak bond to forms a weak bond to the sulfur atom. This conclusion is based on the comparison of observed and calculated IR spectra of the photoisomers.
Heterocumulene, 6 C5OS (5‐Thioxo‐1,2,3,4‐pentatetraen‐1‐on) ‐ Darstellung und spektroskopische Eigenschaften
Authors: Maier Günther , Schrot Jürgen , Reisenauer Hans Peter 
Published: July 2007

Heterocumulenes, 6. — C5OS (5‐Thioxo‐1,2,3,4‐pentratetraen‐1‐one) — Preparation and Spectroscopic PropertiesC5OS (8) is prepared by flash pyrolysis of the precursor molecules 4, 5, and 7 and by matrix photolysis of 7. The IR‐ and UV/Vis spectra of matrix‐isolated 8 are reported.
On the Utility of 13C (CPMAS) NMR in Conformational Studies of Simple Hydroxy‐, Alkoxy‐ and Acetoxycalixarenes in the Solid State
Authors: Liang Tze‐Ming , Laali Kenneth Khosrow 
Published: July 2007

AbstractThe potentiality of 13C (CPMAS) NMR as a conformational probe for the oligomeric macrocycles p‐(tert‐butyl)calix‐[n]arenes (n = 4, 6, 8) and their alkoxy/acetoxy derivatives in the solid state is explored.
Organophosphorverbindungen, 511) Phosphatriafulvene – Phosphaalkene mit inverser Elektronendichte2)
Authors: Fuchs Eberhard , Breit Bernhard , Heydt Heinrich , Regitz Manfred , Schoeller Wolfgang , Busch Thilo , Krüger Carl , Betz Peter 
Published: July 2007

Organophosphorus Compounds, 511). – Phosphatriafulvenes – Phosphaalkenes with Inverse Electron Density2)Peterson olefination of the sterically hindered cyclopropenones 1 with the lithium phosphides 2 yields the so far unknown phophatriafulvenes 3 and 4, which possess inverse electron densities. They are characterized by transition metal complex formation (→7, 8). Acylation of 3a with the carboxylic acid chlorides 11 leads to a great variety of P‐acylphosphatriafulvenes 13a‐s. They partly dimerize under formation of the 1,3‐diphosphacyclobutanes 13 ⇌ 14.
Small and Medium Rings, 791) 4‐Azatetracyclo[3.3.0.02,8.03,6]octanes: New Hetereocycles by Addition of Sulfonyl Azides to 7‐Substituted Norbornadienes – Experimental Verification of σ Interactions in the Norbornane Skeleton
Authors: Huda Egbert , Martin Hans‐Dieter , Mayer Bernhard , Somnitz Karl‐Heinz , Steigel Alois , Haddad Hatim , Distefano Guiseppe , Modelli Alberto 
Published: July 2007

AbstractThe reaction of six 7‐substituted norbornadienes with seven sulfonyl azides has been investigated. The products consist of either the novel azatetracyclic system 1 or the stereoisomeric bicycles 2 or of a mixture of them. The chemical behaviour of 1 has been studied. Mechanistically the results may be rationalized within the frame of the Mazzocchi‐Houk model. The theoretical predictions of this model, concerning the π*and σ* energies, were confirmed experimentally by using electron‐transmission spectroscopy.
Hydrierwärmen, IV. Zur Frage der Homoaromatizität von Norcaradien und Cycloheptatrien
Authors: Roth Wolfgang R. , Klärner Frank‐Gerrit , Siepert Gerd , Lennartz Hans‐Werner 
Published: July 2007

Heats of Hydrogenation, IV. — Homoaromaticity in Norcaradiene and CycloheptatrieneBy comparison of the heats of hydrogenation of fixed norcaradienes with analogous cyclobutane derivatives and from the difference of experimental heats of formation with values calculated by force‐field methods the homoaromatic stabilization of norcaradienes and cycloheptatrienes are calculated and compared with the equilibrium position of the respective valence isomers.
Zum Kenntnisstand der 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadiene
Authors: Detsch Ralph , Niecke Edgar , Nieger Martin , Reichert Franz 
Published: July 2007

On the Knowledge of the 1,3,5‐Triaza‐2,4‐diphospha‐1,4‐pentadienesHerrn Professor Heinrich Puff zum 70. Geburtstag gewidmet
Nucleophilic substitution reactions of the chloro(arylimino)‐phosphane 1 yield the NH‐functional amino(imino)phosphanes Mes*NPNHR (R = Mes, Ad, CPh3) 2d—f. Upon further reaction with 1 they are converted into the 1,3,5‐triaza‐2,4‐diphospha‐1,4‐pentadienes Mes*NPN(R)PNMes* (R = Mes, Ad) 4d, e and Mes*NPN(Mes*)PNCPh3 5. According to crystal structure determinations all compounds 4a, d, e, 5 exhibit S conformation in the solid state. In addition to the “exo‐endo” arrangement of the substituents (4a, 5) in the case of 4d, e the “endo‐endo” conformation is observed for the first time. In solution, 4d, e and 5 are subject to dynamic rearrangements, whose mechanism is proven by NMR studies of partially 15N‐enriched samples. The reaction of 4a with NorM(CO)4 (M = Cr, Mo) or Ni(CO)4 yields the metallaazadiphosphetidine complexes 6a—c Mes*NPN(tBu)PNMes*M(CO)n [M(CO)n = Cr(CO)4, Mo(CO)4, Ni(CO)2]. The crystal structure of 6a (“exo‐endo‐W”) is described.
Bis(cyclopentadienyl)methan‐verbrückte Zweikernkomplexe, IV. Synthese, Struktur und Reaktivität von Zweikernkomplexen des Rhodiums und Iridiums in der Oxidationsstufe +I und +III mit dem Bis(cyclopentadienyl)methan‐Dianion als Brückenliganden
Authors: Werner Helmut , Treiber Monja , Nessel Angelika , Lippert Ferdinand , Betz Peter , Krüger Carl 
Published: July 2007

Bis(cyclopentadienyl)methane‐Bridged Dinuclear Complexes, IV[1]. — Synthesis, Structure, and Reactivity of Dinuclear Rhodium and Iridium Complexes in the Oxidation State +I and +III with the Bis(cyclopentadienyl)methane Dianion as Bridging LigandThe rhodium compounds [CH2(C5H4)2][Rh(L)(C2H4)]2 (2, 4) were prepared from [RhCl(L)(C2H4)]2 (1, 3) and CH2(C5H4)2Li2 in 92 and 73% yield, respectively. The reaction of 4 with Cl2, Br2, and I2 led to the almost quantitative formation of the dihalogeno derivatives [CH2(C5H4)2][RhX2(PiPr3)]2 (6–8), which on treatment with excess NaBH4 and methanol gave the dihydride [CH2(C5H4)2][RhH2(PiPr3)]2 (10). From [RhCl(C8H14)2]2 (12), PiPr3, and CH2(C5H5)2 the chloro(hydrido)rhodium complex [CH2(C5H4)2][RhH(Cl)(PiPr3)]2 (13) was obtained. Protonation of 10 with CF3CO2H in the presence of NH4PF6 gave the PF6 salt of the hydrido‐bridged cation {[CH2(C5H4)2]‐[RhH(PiPr3)]2(μ‐H)}+ (14) of which the crystal structure was determined. In solution, fluxional behavior of the cation was observed. The dimethyl compound [CH2(C5H4)2][Rh(CH3)2‐(PiPr3)]2 (17), prepared from 6, 7, or 8 and LiCH3 or CH3MgI in 80% yield, reacted with CF3CO2H at — 78° C to give the tri‐fluoroacetato derivative 18; this on treatment with P(OMe)3 and dmpe formed the dicationic complexes 19 and 20, respectively. The dinuclear iridium compounds [CH2(C5H4)2]‐[Ir(olefin)2]2 (26, 27) and [CH2(C5H4)2][Ir(C8H12)]2 (28) were prepared from [IrCl(L)2]2 (23–25) and CH2(C5H4)2Li2 and used for the synthesis of {[CH2(C5H4)2][IrX2]2}n (29, 30). Compounds 29 and 30 served as starting materials for the preparation of the dinuclear derivatives [CH2(C5H4)2][IrX2(L)]2 (31–34) and {[CH2(C5H4)2][IrBr2]2(μ‐dipy)} (35) and finally also for the dihydrido complex [CH2(C5H4)2][IrH2(PiPr3)]2 (36).
Neue Synthesen für isomerenreine Allyl‐ und Propargylcyanide durch Isocyanid‐Cyanid‐Umlagerung[1]
Authors: Wolber Erwin K. A. , Schmittel Michael , Rüchardt Christoph 
Published: July 2007

New Syntheses of Isomerically Pure Allyl and Propargyl Cyanides by Isocyanide‐Cyanide Rearrangement[1]A new route for the synthesis of isomerically pure allyl and propargyl cyanides has been developed. Allylic amines are synthesized from the corresponding alcohols by Mitsunobu or by Overman reaction. Formylation with formic acid derivatives provides N‐substituted formamides, which are dehydrated to isocyanides. 1,2‐Sigmatropic rearrangement by flash pyrolysis provides the isomerically pure allyl and propargyl cyanides.
Verbindungen des Germaniums und Zinns, 10[1] Thermolyse eines Cyclotristannans: Stannylen‐ versus Distannen‐Reaktionen
Authors: Weidenbruch Manfred , Schäfer Annemarie , Kilian Hartmut , Pohl Siegfried , Saak Wolfgang , Marsmann Heinrich 
Published: July 2007

Compounds of Germanium and Tin, 10[1]. — Thermolysis of a Cyclotristannane: Stannylene versus Distannene ReactionsHexakis(2,4,6‐triisopropylphenyl)cyclotristannane (1), first described by Masamune and Sita, is easily accessible by treatment of tin(II) chloride with 2,4,6‐triisopropylphenylmagnesium bromide. The equilibrium between 1 and its cleavage products bis(2,4,6‐triisopropylphenyl)stannylene (2) and tetrakis(2,4,6‐triisopropylphenyl)distannene (3) in toluene has been followed by 119Sn‐NMR spectroscopy at elevated temperatures. Stannylene 2 can be trapped by open‐chain or cyclic diketones as well as by 1,3‐dienes. Reaction of 3 with phenylacetylene proceeds in a [2 + 2] fashion to provide the 1,2‐distannacyclobutene derivative 5 whose structure was confirmed by X‐ray crystallography.
Spaltung sperriger Diarylditelluride mit Brom und Iod[1]; Strukturbestimmung an Et4N+ 2,4,6‐(i‐C3H7)3C6H2TeI−2
Authors: Mont Wolf‐Walther Du , Meyer Hans‐Ulrich , Kubiniok Silvia , Pohl Siegfried , Saak Wolfgang 
Published: July 2007

Cleavage of Bulky Diaryl Ditellurides with Bromine and Iodine; Crystal Structure of Et4N+ 2,4,6‐(i‐C3H7)3C6H2TeI−2Bis(2,4,6‐triisopropylphenyl) ditelluride (1a), obtained from 2,4,6‐triisopropylphenylmagnesium bromide with tellurium followed by oxidation with oxygen, and bis(2,4,6‐tri‐tert‐butylphenyl) ditelluride (1b) react with equimolar amounts of bromine and iodine to provide new monomeric arenetellurenyl halides 2,4,6‐R3C6H2TeX (2a, b, 3a, b: R = i‐C3H7, t‐C4H9; X = Br, I). Both tellurenyl iodides are thermally more stable than the corresponding bromides. Green 2,4,6‐(i‐C3H7)3C6H2TeI (3a) reacts with Et4N+I− to give the stable, red adduct Et4N+ 2,4,6‐(i‐C3H7)3C6H2TeI−2 (4a). An X‐ray crystal structure determination of 4a revealed a T‐shaped structure of the hypervalent aryldiiodotellurate(II) anion. Iodide‐ion transfer between aryldiiodotellurate(II) and arenetellurenyl iodide is a fast process (1H‐NMR time scale). 125Te‐NMR data of this anion and of tellurenyl halides are compared with those of the ditellurides and of lithium benzenetellurolates (LiTeR·(THF)x).
Insertions‐, Isomerisierungs‐ und Cycloadditions‐Reaktionen lithiierter Aminofluorsilane
Authors: Walter Simone , Klingebiel Uwe , Noltemeyer Mathias 
Published: July 2007

Insertion, Isomerization, and Cycloaddition Reactions of Lithiated Aminofluorosilanes*The lithium derivative 2 of (di‐tert‐butylfluorosilyl)(fluorodi‐isopropylsilyl)amine (1) reacts with benzoyl chloride to form the imines 3I and 3II in an insertion reaction. LiF elimination from 2 leads to the cyclodisilazane [(CMe3)2SiFN—Si(CHMe2)2]2 (4). The fluorine atom of the SiF(CHMe2) group in 1 can be substituted by means of LiOSiMe3 to yield 5. The lithium derivative of 5 (6) is a dimer with very short Li—F distances. The lithium derivative 6 reacts with benzaldehyde in a [2 + 2] cycloaddition to give an (SiNCO) four‐membered ring compound (7), which thermally decomposes to yield the imine 8 and a cyclosiloxane, A fluorine/chlorine exchange is observed when Me3SiCl is added to the lithium derivative 6. The resulting unstable lithium derivative of an aminochlorosilane eliminates LiCl to form the cylcodisilazane 9. According to a crystal structure determination the formation of 9 involves isomerization of the intermediate iminosilane followed by dimerization.
Polyol‐Metall‐Komplexe, II[1] Kupfer(II)‐Komplexe mit mehrfach deprotoniertem Ethylenglycol, Anhydro‐erythrit oder Methyl‐α‐D‐mannopyranosid als Liganden
Authors: Habermann Norbert , Jung Gisela , Klaassen Markus , Klüfers Peter 
Published: July 2007

Polyol Metal Complexes, II[1]. – Copper(II) Complexes with Multiply Deprotonated Ethylene Glycol, Anhydro‐erythritol, or Methyl α‐D‐Mannopyranoside as LigandsViolet to blue crystals of the polyolate cuprates Li2[Cu(eth2−)2] · 6 H2O (1), A2[Cu(eryAn2−)2] · 4 H2O, A = Na (2a), K (2b), and Li3[Cu(Me‐α‐manpH2[2,3]2−)(Me‐α‐manpH[2,3,4]3−)] · 5 H2O (3) with anionic ligands derived from ethylene glycol (ethH2), anhydro‐erythritol (eryAnH2), or methyl α‐D‐mannopyranoside (Me‐α‐manpH4), resp., are formed by the reaction of alkali metal hydroxide with cupric hydroxide and the proper polyol in aqueous solution. X‐ray crystal structure determinations were carried out on all new compounds. In 1–3 deprotonated polyols form chelate complexes with copper ions; additonally, the polyolate ligands bind to alkali metal ions and/or they act as acceptors in asymmetric hydrogen bonds. In 3 one of the two O‐2,O‐3‐mannosidato ligands is present as a trianion: O–4 is deprotonated, too, but instead of copper, the O–4‐alkoxide group binds two lithium ions. The new compounds are discussed with respect to copper complexes of cellulose in alkaline media.
Synthese und Struktur von 4,4′‐Bis[phenyl(triphenylphosphonio)methyl]‐biphenyl‐diperrhenat
Authors: Hesse Detlev , Roesky Herbert W. , Noltemeyer Mathias 
Published: July 2007

Synthesis and Structure of 4,4′‐Bis[phenyl(triphenylphosphonio)methyl]biphenyl Diperrhenate(tBu)2Si(OReO3)2 (1) reacts with Ph3P = CPh2 (2) to form the title compound [4‐Ph3PC(Ph)C6H4]2(ReO4)2 (3), the structure of which is confirmed by an X‐ray structural analysis.
4,4′‐Distyrylazobenzol als Mesogen
Authors: Kosteyn Frank , Zerban Georg , Meier Herbert 
Published: July 2007

4,4′‐Distyrylazobenzene as MesogenFrom 3,4‐dihydroxybenzaldehyde (1) the tetraalkoxy‐substituted 4,4′‐distyrylazobenzenes (E,E,E)‐5a – c are synthesized. A similar reaction sequence leads from ethyl 3,4,5‐trihydroxy‐benzoate (6) to the hexaalkoxy‐substituted 4,4′‐distyrylazobenzenes (E,E,E)‐11 b, c. With the exception of 5a all products show thermotropic LC properties. Smectic phases have been characterized by polarizing microscopy and by differential scanning calorimetry.
Synthese und Eigenschaften von σ‐verbrückten Anthracen‐Viologenen[1]
Authors: Effenberger Franz , Götz Gunther , Bäuerle Peter 
Published: July 2007

Synthesis and Properties of of σ‐Bridged Anthracene‐Viologens[1]The synthesis of the donor‐acceptor compounds 2, 7, and 12 where the anthracene donor and the viologen acceptor are linked by a saturated bridge (polymethylene or the bicyclo[2.2.2]octanyl moiety) is described. While the preparation of 2a–c is straightforward, new procedures for the synthesis of the bicyclo compounds 7 and 12 had to be developed. Unexpectedly, the viologens 13d, e could be obtained by direct nucleophilic substitution of the corresponding tertiary and neopentyl‐type alkyl tosylates with 4,4′‐bipyridine. By comparison of the emission spectra of the compounds 2a and 12a, b the strong fluorescence quenching indicates an electron transfer from the donor to the acceptor.