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  • 1
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit übergangsmetall-Komplexen, 51. 1-Metalla-1,3,5-triene und 1-Metalla-1,3-dien-5-ine von Chrom und Wolfram durch Insertion von Alkinen in M=C- bzw. C=C-Bindungen von 1-Metalla-1,3-dienen bzw. 1-Metalla-1-en-2-inen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1229-1236 
    Details
    ISSN: 0009-2940
    Keywords: Carbene complexes of chromium and tungsten ; 1-Metalla-1,3,5-trienes ; 1-Metalla-1,3-dien-5-ynes ; Insertion of alkynes into M=C and C=C bonds ; [2 + 2] Cycloaddition reactions of carbene complexes and alkynes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 51. - 1-Metalla-1,3,5-trienes and 1-Metalla-1,3-dien-5-ynes of Chromium and Tungsten by Insertion of Alkynes into M=C and C=C Bonds of 1-Metalla-1,3-dienes and 1-Metalla-1-en-3-ynes, respectively1-Metalla-1,3,5-trienes LnM=C(NEt2)-C(Me)—C(OEt)-CH=CHPh (3,4) and LnM=C(OEt)- CH=C(NEt2) - C(Me)=CHPh [5, LnM=Cr(CO)5 (a), W(CO)5 (b)] are obtained for the first time from the corresponding 1-metalla-1,3-dienes LnM=C(OEt) - CH=CHPh (1a, b) under very mild conditions by the insertion of the electron-rich alkyne Et2N-C ≡ C - Me (2) into the M=C and the C=C bonds, respectively, of 1. The chelate complex (6b) and the cyclobutenyl carbene complex 7b are isolated as minor side products. 1-Metalla-1,3-dien-5-ynes LnM=C(NEt2) - C(Me)=C(OEt) - C ≡ CPh [9, 10, LnM=Cr(CO)5 (a), W(CO)5 (b)] are formed with high regio- and stereoselectivity on insertion of 2 into the M=C bonds of 1-metalla-1-en-3-ynes 8. X-ray data are given for the tungsten complex 3b.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240541
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  • 2
    Electronic Resource
    Electronic Resource
    Reaktive E = C(p-p)π-Systeme, XXXIII. Side-on-Koordination des Phosphaalkins P ≡ C  -  N(iPr)2 im 16e-Nickel(0)-Komplex Ni(CO)PCy3[PCN(iPr)2] (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 63-65 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkyne, amino- ; Nickel carbonyl phosphane complex ; π Coordination ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive E = C(p-p)π Systems, XXXIII.  -  Side-on Coordination of the Phosphaalkyne P ≡ C  -  N(iPr)2 in the 16e Nickel(0) Complex Ni(CO)PCy3[PCN(iPr)2]The reaction of (diisopropylamino)phosphaethyne P ≡ C  -  N(iPr)2 with the nickel complex [Ni(CO)3PCy3] - in contrast to the analogous reactions with Ni(CO)4 or Ni(CO)3PR3 (R = Me, Ph) - leads to the novel 16e nickel(0) system [Ni{η2-P ≡ C  -  N(iPr2)}(CO)PCy3] with a planar geometry of all skeleton atoms besides the methyl and cyclohexyl groups. Side-on coordination of the P ≡ C triple bond results in an increase of the PC distance to 1.665 Ȧ typical for phosphaalkenes.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260111
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  • 3
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit übergangsmetall-Komplexen, 52 N-Vinylaminocarben- und N-(2-Propenyl)aminocarben-Komplexe durch Addition von Keteniminen an Carben-Eisenkomplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1795-1803 
    Details
    ISSN: 0009-2940
    Keywords: Aminocarbene complexes of iron ; N-Vinylaminocarbene complexes ; π-Allyl,σ-complexes of iron ; N-(2-Propenyl)aminocarbene complexes ; Methylenation of ketene imines by carbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses with Transition Metal Complexes, 52 1). - N-Vinylaminocarbene and N-(2-Propenyl)aminocarbene Complexes by Addition of Ketene Imines to Carbene Iron ComplexesKetene imines R(Me)C = C = NPh (2, R = Me, Et, i-Pr) form 1 : 1 adducts with the carbene iron complex (CO)4,Fe=C(OEt)Ph (1). The initial step of the reaction involves an attack of the nitrogen atom of 2 at the carbene carbon atom of 1 and a subsequent rearrangement to give N-vinylaminocarbene complexes (E/Z)-4. In a parallel process with different regiochemistry the central carbon of the CCN unit is attached to the carbene carbon to yield π-allyl,σ-complexes (E/Z)-3. Alkylation of 3a with [Et3O]BF4 leads to the formation of a cationic N-(2-propenyl)-aminocarbene complex 6a. Protonation of 4 with trifluoroacetic acid results in a ring contraction to give the four-membered metallacycles 7. X-ray data are reported for prototypes (Z)-4c and 6a.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240816
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  • 4
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 71. Methylcarben-Komplexe von Chrom und Wolfram mit Cycloheptatrienyl-, Cyclohexadienyl[Fe(CO)3]- und Cycloheptadienyl[Fe(CO)3]-Resten als α-Substituenten (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 731-738 
    Details
    ISSN: 0009-2940
    Keywords: Methylcarbene complexes of chromium and tungsten ; Cyclohexadienyl tricarbonyliron, carbene derivatives of ; Cycloheptadienyl tricarbonyliron, carbene derivatives of ; Cycloheptatrienyl, carbene derivatives of ; Enol ether, elimination from carbene complexes ; Spirocyclopropanes, elimination from carbene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 71[1].  -  Methylcarbene Complexes of Chromium and Tungsten with Cycloheptatrienyl-, Cyclohexadienyl[Fe(CO)3]- and Cycloheptadienyl[Fe(CO)3] SubstituentsMethylcarbene complexes LnM=C(OEt)CH3 1 [LnM = (CO)5Cr, (CO)5W] react with tropylium tetrafluoroborate (2a) or coordinated olefins of [C6H7Fe(CO)3]BF4 (2c), [C7H9Fe-(CO)3]BF4 (2d), and [C7H7Fe2(CO)6]BF4 (2d) in the presence of Et3N to give complexes LnM=C(OEt)CH2R 3a-e and LnM=C(OEt)CHR2 7a-d by substitution of one or two α-hydrogen atoms. The trimetallic WFe2 carbene complexes 7c, d derived from 1b with 2c, d form three stereoisomers each, which are fully characterized spectroscopically, (R*,R*,S*)-7c additionally also by an X-ray structure analysis, Ligand elimination from 3 and 7 may involve a-and/or β-hydrogen transfer reactions: Thus enol ethers (Z/E)-6 are eliminated from α-monosubstituted methylcarbene complexes 3a, c, d in yields of 62-90% by a pyridine-induced transfer of an α-hydrogen to the carbene carbon atom; with increasing steric demand of R the elimination of the (Z) isomer (Z)-6 from 3 is favoured over the formation of the (E) isomer (E)-6. The enol ether 10 becomes a minor side product in the pyridine-induced ligand elimination from α-disubstituted complexes 7a, b. In these cases the spirocyclopropane 8 is formed as the main product (60-82%) besides the 4,5-homotropylidene 9 by a conformationally directed β-hydrogen transfer reaction.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270424
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  • 5
    Electronic Resource
    Electronic Resource
    Novel dinuclear palladium(II) complexes with the chelating ligand bis(1-methylimidazol-2-yl) ketone (bmik) and pyridine-2-thiolate, pyrimidine-2-thiolate, and 1-methylimidazole-2-thiolate as bridging secondary ligands (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 2355-2361 
    Details
    ISSN: 0009-2940
    Keywords: Dinuclear palladium(II) complexes ; Bis(1-methylimidazol-2-yl) ketone ; Pyridine-2-thione ; Pyrimidine-2-thione ; 4-Imidazoline-2-thione, 1-methyl- ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three novel dinuclear palladium(II) complexes with the chelating ligand bis(1-methylimidazol-2-yl) ketone (bmik) as well as pyridine-2-thiolate (pyt), pyrimidine-2-thiolate (pymt), and 1-methylimidazole-2-thiolate (meimt) as bridging secondary ligands were prepared by reactions of diaqua[bis(1-methylimidazol-2-yl) ketone]palladium(II) nitrate with the ligands in aqueous solution. The thiolates bridge the two metal atoms in the μ-N,S mode. The structures of the following compounds were analyzed by single crystal X-ray diffraction: Bis(μ-pyridine-2-thiolato-N,S)-bis{[bis(1-methyl-imidazol-2-yl) ketone]palladium(II)}nitrate [Pd2(bmik)2-(pyt)2](NO3)2 · 5 H2O (1), bis(μ-pyrimidine-2-thiolato-N1,S)- bis{[bis(1-methylimidazol-2-yl) ketone]palladium(II)} nitrate [Pd2(bmik)2(pymt)2](NO3)2 · 5 H2O (2), and bis(μ-1-methyl-imidazole-2-thiolato-N3,S)-bis{[bis(1-methylimidazol-2-yl) ketone]palladium(II)} nitrate [Pd2(bmik)2(meimt)2](NO3)2 · 4.5 H2O (3). In the cases of 1 and 3 the bridging thiolate ligands show head-to-head orientation. For complex 2 a head-to-tail orientation of the pyrimidine-2-thiolates was found. The metal-metal distances vary from 2.963 Å in complex 3 and 2.915 Å in 1 to the shortest of 2.886 Á in 2. In addition to the X-ray crystallography the three compounds were characterized by 1H-NMR and IR spectroscopy.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941271203
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  • 6
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetall-Komplexen, 54 Cyclopentadiene aus 1-Metalla-1,3-dienen und Alkinen durch Cyclisierung intermediärer 1-Metalla-1,3,5-triene (Metall = Wolfram) (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 2343-2347 
    Details
    ISSN: 0009-2940
    Keywords: Cyclopentadienes, synthesis of ; [3 + 2] Cycloadditions of 1-metalla-1,3-dienes and alkynes ; 1-Metalla-1,3,5-trienes of tungsten, cyclization to cyclopentadiene complexes ; η1-Cyclopentadiene tungsten complexes ; Aminocarbene complexes of chromium and tungsten ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Organic Syntheses via Transition Metal Complexes, 54.  -  Cyclopentadienes from 1-Metalla-1,3-dienes and Alkynes by Cyclization of Intermediate 1-Metalla-1,3,5-trienes (Metal = Tungsten)We report on first examples of the formation of cyclopentadienes from a 1-metalla-1,3-diene LnM=C-C=C [LnM = W(CO)5] and an alkyne in [3 + 2] cycloaddition multistep reactions. In a first step the alkyne Et2N-C=C-Me (2) adds to the 1-metalla-1,3-diene (CO)5W = C(OEt)-CH=CHPh (1b) to give 1-metalla-1,3,5-trienes (CO)5W=C(NEt2)-CMe=C(OEt)-CH=CHPh (3b) and (CO)5W=C(OEt)-CH=C(NEt2)-CMe=CHPh (4b). In a second step 3b cyclizes to thecyclopentadiene complex 5, which has an η1 ylide-type structure as established by an X-ray analysis. Hydrolysis of 5 leads to the formation of a 3-aminocyclopentenone 7. The 1-metalla-1,3,5-triene 4b yields a cyclopentadiene complex 8. In contrast to 5 the carbon skeleton of 8 has a connectivity different from that of the C3 unit of the 1-metalla-1,3-diene 1.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911241030
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  • 7
    Electronic Resource
    Electronic Resource
    Reaktive E = C(p - p)π-Systeme, XXXI Erste Vertreter aminosubstituierter 1,2,4-Diazaphosphole (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 411-414 
    Details
    ISSN: 0009-2940
    Keywords: Phosphaalkyne, amino- ; [3 + 2] Cycloaddition ; 1,2,4-Diazaphospholes ; 1,2,3-Diazaphospholes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactive E = C(p - p)π Systems, XXXII[1].  -  First Representatives of Amino-Substituted 1,2,4-Diazaphospholes(Diisopropylamino)phosphaethyne iPr2N - C≡P reacts at 20° C in a [3 + 2] cycloaddition with (trifluoromethyl)diazomethane (2a) or methyl diazoacetate (2b) to yield a mixture of the corresponding regioisomers 1H-1,2,4-diazaphospholes (5a or 5b) and 1H-1,2,3-diazaphospholes (6a or 6b) in quantitative yields (isomer ratio: 5a/6a = 2:1; 5b/6b = 4:1). X-ray diffraction studies on 5a and 5b indicate a delicate charge balance in the bonding system of 1H-1,2,4,σ2-diazaphospholes under the influence of the exocyclic push/pull substituents iPr2N and CF3 or CO2Me, respectively.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250219
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  • 8
    Electronic Resource
    Electronic Resource
    1,2-Dihydro-1,3,2λ5,4λ5-diazadiphosphet - Synthese, Struktur und Isomerisierung zum „inneren Salz“ von 1,3,2,4λ5-Diazadiphosphetan-2-iumhydroxid* (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2631-2634 
    Details
    ISSN: 0009-2940
    Keywords: 1,2-Dihydro-1,3,2λ5,4λ5-diazadiphosphete ; Isomerization ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,2-Dihydro-1,3,2λ5,4λ5-diazadiphosphete - Synthesis, Structure and Isomerization to the „Inner Salt“ of 1,3,2,4λ5-Diazadiphosphetan-2-ium HydroxideThe photochemical reaction of the azidophosphane (iPr2N)2PN3 (1) with the tetraazaphospholene (3) and the bis(imino)phosphorane (Me3Si)2NP(=NSiMe3)2 (6) proceeds by elimination of N2 to yield (5) and by 1,3-silyl group shift to furnish (8) the structures of which were determined by means of NMR data and, in the case of 5, additionally by X-ray structure analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251202
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  • 9
    Electronic Resource
    Electronic Resource
    Organic Syntheses via Transition Metal Complexes, 74[1] Novel Phosphonium Allenide and 2-Phosphanylethenyl Carbene Chromium and Tungsten Complexes (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 2475-2482 
    Details
    ISSN: 0009-2940
    Keywords: Vinylcarbene complexes ; Chromium complexes ; Tungsten complexes ; Phosphorus ylide complexes ; Alkynylcarbene complexes ; Allene complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Alkynylcarbene complexes (CO)5M≡C(OEt)-C≡C—R 1 (M = Cr, W; R = Ph, tBu, SiMe3) readily add tertiary phosphanes PPhR2′ 4 (R′ = Ph, Me) to form stable zwitterionic phosphonium allenide complexes (CO)5M--C(OEt) = C≡C(R)-P+PhR2′ 5. Complex 5a (M = Cr, R = R′ = Ph) was characterized by X-ray diffraction. The addition of secondary phosphanes PHR2 6 to 1 affords red (2-phosphanyl ethenyl)-carbene complexes (CO)5M≡C(OEt)-CH≡C(R)-PR2 (E)-8 (R = tBu, cC6H11, Ph) in 34-89% isolated yields. Dinuclear complexes (CO)5M≡C(OEt)-CH≡C(R)-P(R2)M(CO)5 (E)-9 are obtained as byproducts. Compounds (E)-8b (M = Cr, R = cC6H11) and (E)-9i (M = Cr, R = Ph) were characterized by X-ray analyses.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941271218
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  • 10
    Electronic Resource
    Electronic Resource
    Matrix-assisted laser desorption/ionization mass spectrometry with additives to 2,5-dihydroxybenzoic acid (1993)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 28 (1993), S. 1476-1481 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Selected benzoic acid derivatives and related substances were used as additives to 2,5-dihydroxybenzoic acid (2,5DHB) and the performance of the mixtures in matrix-assisted laser desorption/ionization mass spectrometry was investigated. Using benzoic acid derivatives substituted at position 2 and/or 5 or related substances as a co-matrix in the 1-10% range with 2,5DHB results in improved ion yields and signal-to-noise ratio of analyte molecules, especially for the high-mass range. The enhanced performance is prominent for 2-hydroxy-5-methoxybenzoic acid and exists for both proteins and oligosaccharides. It is suggested that the improvement is caused by a disorder in the 2,5DHB crystal lattice allowing ‘softer’ desorption. Charge transfer from matrix ions to additive molecules at the expense of analyte ionization gives a simple explanation for the deteriorating effects of some tested additives.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210281219
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