Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Organic Chemistry  (9)
  • [2.2]Metacyclophanes  (3)
  • Calculations, ab initio  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Monomere und dimere 1,3-Diaza-2-phosphaallyllithium-Komplexe: Strukturen und ambidente ReaktivitätHerrn Professor Hans-Friedrich Grützmacher zum 60. Geburtstag gewidmet. (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 1119-1124 
    Details
    ISSN: 0009-2940
    Keywords: 1,3-Diaza-2-phosphaallyllithium ; Calculations, ab initio ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Monomer and Dimer 1,3-Diaza-2-phosphaallyllithium Complexes: Structures and Ambident Reactivity*Metallation of the NH-functional amino(imino)phosphanes Mes*NPNHR (R = CPh3, Ad, tBu) 1a-c yields the 1,3-diaza-2-phosphaallyllithium compounds 2a-c. The crystal structure shows an ether-stabilized monomer of 2a and a solvent-free dimer with an eight-membered ring in the case of 2b, c. The reaction of 2b with chlorodiphenylphosphane yields, dependent on the reaction conditions, (phosphanylamino)iminophosphane 3 or bis(imino)phosphanylphosphorane 4. The structural and reactivity is discussed on the basis of ab initio calculations.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921250522
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Regioselektive Substitution an [2.2]Metacyclophanen via Chromtricarbonyl-Komplexe (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1415-1423 
    Details
    ISSN: 0009-2940
    Keywords: [2.2]Metacyclophanes ; Chromium tricarbonyl complexes ; Chirality, helical, planar ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Regioselective Substitution of [2.2]Metacyclophanes via Chromium Tricarbonyl ComplexesThe [2.2]metacyclophanes 6, 8, and 9 are regioselectively complexed with triammintricarbonylchromium. The complexes are lithiated with nBuLi/TMEDA at -78°C, and the resulting aryllithium complexes are trapped with electrophiles to give new phanes exhibiting substitution patterns, which are not or more difficult available by other routes. Complex 6a gives 5-substitution almost exclusively, while the chiral complex 8a is substituted in positions 5 and 4 in a ratio of 3:1. Steric effects, caused by the large dithiane group, seem to play a role in both complexation and derivatisation of these substrates. An X-ray crystal structure analysis of the chromium tricarbonyl phane complex 11 is performed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Nitro- und Allyloxy-substituierte helicale [2.2]Metacyclophane: Synthese, Circulardichroismus und Röntgen-Kristallstrukturanalysen (1991)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 124 (1991), S. 1585-1590 
    Details
    ISSN: 0009-2940
    Keywords: Charge transfer ; Circular dichroism ; Helical molecules ; [2.2]Metacyclophanes ; Structure-chiroptic relationships ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Nitro- and Allyloxy-Substituted Helical [2.2]Metacyclophanes: Synthesis, Circular Dichroism and Crystal StructuresThe preparations of the title compound 3a, intraannularly nitro-functionalized, of the extraannularly substituted reference compound 3b, and of the sulfone 4 are described. Enantiomeric resolution of these helical phanes was accomplished on (+)-PTrMA and cellulose tris(3,5-dimethylphenyl)carbamate by HPLC. Racemization of the enantiomers of 3b is faster than that of the previously reported extraannularly substituted phanes. The crystal structure of 3a as well as that of the allyl ether 3d show severe distortions of the benzene rings; the CD spectrum of 3a is pointing at an intramolecular charge-transfer complex, an effect that cannot be evaluated from the CD spectrum of 3b.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19911240719
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Tricarbonylchrom-Komplexe von chiralen [2.2]Metacyclophanen: Darstellung, Struktur und chiroptische Eigenschaften (1992)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 125 (1992), S. 2553-2569 
    Details
    ISSN: 0009-2940
    Keywords: Chirality ; Chromium complexes ; Helicity ; Configuration (absolute) ; [2.2]Metacyclophanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tricarbonylchromium Complexes of Chiral [2.2]Metacyclophanes: Syntheses, Structures, and Chiroptical PropertiesHPLC-baseline separations of three racemic cyclophanes 3, 4, and 6 on cellulose tris(3,5-dimethylphenyl)carbamate led to their enantiomers with high optical purity. Complexation of (-)-3 and (+)-3 with triamminetricarbonylchromium yielded chiral Cr(CO)3 complexes (-)-(S)P-(3S)M-3a and (+)-(R)P-(3R)M-3a stereoselectively. Derivatisation of the complexes by lithiation and reaction with electrophiles gave new substituted chiral Cr(CO)3 complexes of [2.2]metacyclophanes regio-selectively. X-ray structure analyses of one chiral chromium complex (-)-(R)P-(5S)M-14a and three chiral chromium-free ligands (-)-(S)P-3, (-)-(S)P-4, and (-)-(S)P-6 led to the assignment of the absolute configurations of all chiral compounds discussed here. The influences of substituents on the chiroptical properties are investigated. The helicity of [2.2]metacyclophanes is discussed. For the first time X-ray structure analyses were performed of a bis-Cr(CO)3 complex (9a) as well as of the first chromium complex 10a of a heteraphane. Dethioketalisation of (-)-(S)P-3 with NBS gave (-)-(S)P-18, the absolute chirality of which has been known, under retention of configuration.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19921251130
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    [n + 2]-Cycloadditionsreaktionen des (Arylimino)phosphenium-Ions, [P≡NAr]+-kationische PN-Heterocyclen mit ungewöhnlicher Struktur und BindungssituationHerrn Professor Eckehard Volker Dehmlow zum 60. Geburtstag gewidmet. (1993)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 126 (1993), S. 1513-1517 
    Details
    ISSN: 0009-2940
    Keywords: [n + 2] Cycloadditions ; Calculations, ab initio ; Phosphenium ions ; 1,3,2,4-Diazadiphosphetidinylium salts ; Tetrazaphospholylium salts ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: [n + 2] Cycloaddition Reactions of the (Arylimino)phosphenium Ion, [P≡NAr]+-Kationic PN Heterocycles with Unusual Structure and Bonding SituationThe iminophosphenium ion [P≡NAr]+ (Ar=2,4,6-tBu3C6H2) (1) reacts with aminoiminophosphanes R2N-P=NtBu (R=iPr, Me3Si) (2) and alkyl azides RN3 (R=tBu, Et3C) (6) to yield the corresponding [n + 2] cycloadducts [R2NP (NAr)P(NtBu)+ (3) and [PN(Ar)NNN(R)]+ (7), respectively. Single-crystal X-ray diffraction studies show that 3a can be considered as an intramolecular donor-acceptor complex while 7 can be regarded as a cyclic diaminophosphenium cation coupled to a diimine fragment, which is in accordance with results of ab initio calculations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19931260703
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Non-Ionic Template Synthesis of Amide-Linked Rotaxanes: Olefinic and Aliphatic Axle Building Blocks (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 2269-2273 
    Details
    ISSN: 0947-3440
    Keywords: Association constant ; Mechanical bonding ; Molecular recognition ; Template synthesis ; Supramolecular chemistry ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first synthesis of amide-linked rotaxanes with non-arene axle building blocks is reported. The threading synthesis of rotaxane 8 with olefinic fumaryl chloride proves that arene moieties are not necessary for non-ionic template syntheses. Mass spectroscopic evidence of a rotaxane bearing an aliphatic axle, derived from succinic acid, revealed that hydrogen bonding, rather than π,π interactions, is the predominant template binding force. 1H-NMR titration studies on the threading synthesis of these mechanically bonded molecules were carried out. The association constants measured suggest that the incorporation of the corresponding monoamide monochloride (cf. 7), rather than the incorporation of the diacid dichloride (cf. 5), plays the key role in these rotaxane syntheses. The X-ray structural analysis of a semi axle (14) reveals hydrogen bonding patterns characteristic of diamides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719971114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Molecular Ribbons Containing Pyridine Rings (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 2115-2121 
    Details
    ISSN: 0947-3440
    Keywords: Cyclophanes ; Macrocycles ; Phanes ; Pyridinophanes ; Ring compounds ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The first synthesis of the ribbon-like compounds 6-10 is described. The new building block diethyl 2,6-bis(bromomethyl)pyridine-3,5-dicarboxylate 1 was prepared and characterized. Single-crystal X-ray structure analyses indicate that these ribbon-like molecules arrange in a folded conformation, with the pyridine and benzene units being folded in a face-to-face manner, and the tosyl units of 8-10 pointing outwards. The “intramolecular self-assembly” (folding) of these molecular ribbons is primarily attributable to the energetically more favourable syn conformation of both the [3.3]metacyclophanes and the pyridinophanes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961225
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Concave Macrobicycles: Absorption Spectra, Luminescence Properties, and Endocavital Complexation of Neutral Organic Guests (1996)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1996 (1996), S. 1697-1704 
    Details
    ISSN: 0947-3440
    Keywords: Alkyne bridges ; Charge transfer ; Host compounds ; Molecular cavities ; Toposelectivity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: By a mild modified Eglinton coupling a series of diynebridged macrobicyclic hosts capable of endocavital complexation were synthesized and their structures and complexation properties investigated by X-ray analysis. The inclusion of DMSO in 7 suggests a direct correlation between steric fit and orientation of the guest. On the basis of this hypothesis, the orientation of acetone in an endocavital inclusion of 2 was predicted and verified by X-ray analysis. Comparison of the single-crystal X-ray structures of the vacant macrobicycle 3 and of a family of macrobicycles showing endocavital or “pocket” complexation of neutral organic guests suggests that torsion of the cavities upon complexation results from induced fit. Hydrogenation of the triple bonds leads to the more flexible macrobicycles 10-12 with collapsable cavities. The absorption and emission spectra of the diynebridged macrobicyclic hosts 1 and 3, of their hydrogenated analogues 11 and 12, and of a hemicage parent compound of 2 (14) were investigated. The macrobicyclic compounds 3, 11, 12 and 14 exhibit a strong fluorescence in CH2Cl2 solution at room temperature. The lack of fluorescence of 2 under such conditions is attributed to the presence of low-energy charge-transfer excited states, as indicated by the charge-transfer bands in the absorption spectrum. In a rigid CH2Cl2 matrix at 77 K all the examined compounds are fluorescent.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199619961102
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    New Biphenylenophanes and Biphenylophanes - 1,8-Dimethylbiphenylene by Continuous Vacuum Pyrolysis (1997)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1997 (1997), S. 1901-1906 
    Details
    ISSN: 0947-3440
    Keywords: Cinnoline pyrolysis ; Circular dichroism ; Cyclophanes ; Dimethylbiphenylene synthesis ; Sulfone pyrolysis ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of 1,8-disubstituted biphenylenes by pyrolysis of azo compounds has been optimized. By means of a continuously working pyrolysis apparatus, the cis isomer 2 can be reliably produced on a gram scale. The chiral syn-[2.2]biphenylenophane 12 has been synthesized by an intermolecular cyclization reaction, subsequent oxidation of the sulfur atoms and pyrolytic extrusion of sulfur dioxide. In an analogous manner, the [2.2]biphenylophane 13 was obtained. The separation of the racemates of the hydrocarbons 12 and 13 could be achieved using a stationary chiral HPLC phase. Compound 12 preferentially adopts a syn conformation in the solid state. The CD spectra of 12 and 13 are compared.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199719970915
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Neuartige Diterpenoide aus den Ritterlingen Tricholoma aurantium und T. fracticum (Agaricales)Herrn Professor Dr. Heinz G. Floss zum 60. Geburtstag gewidmet. (1995)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 77-80 
    Details
    ISSN: 0947-3440
    Keywords: Toadstools ; Tricholoma ; Trichaurantin ; Terpenoids ; Neodolastane, 2,3-seco- ; Dolastanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Novel Diterpenoids from the Toadstools Tricholoma aurantium and T. fracticum (Agaricales)Herrn Professor Dr. Heinz G. Floss zum 60. Geburtstag gewidmet.Two novel diterpenoids trichaurantin (1) and its 6-O-acetyl derivative 2 have been isolated from Tricholoma species. Their structures were established by spectroscopic methods and an X-ray crystal analysis, 1 and 2 appear to be biosynthetically related to the neodolabellane and dolastane group of diterpenes and can be designated as 2,3-seconeodolastane derivatives.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.199519950111
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...