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Der mißratene Ritter
(2001)
Phonology in Potsdam
(2001)
Inhalt:
- Rex Clark: If Humboldt had a Laptop. Moving Knowledge Networks from Print to Digital Media
- Wolf von Engelhardt: Goethe und Alexander von Humboldt - Bau und Geschichte der Erde
- Gerhard Kortum: Humboldt der Seefahrer und sein Marinechronometer. Ein Beitrag zur Geschichte der Nautik und Meereskunde
- Ulrike Leitner: Unbekannte Venezuela-Karten Alexander von Humboldts
- Jose Alberto Navas-Sierra: Comercio y reinserción internacional: los “casos” latinoamericano y colombiano (Una hipótesis de Humboldt)
- Sandra Rebok: Alexander von Humboldt y el modelo de la Historia Natural y Moral
- Michael Zeuske: Humboldt, Historismus, Humboldteanisierung. Der „Geschichtsschreiber von Amerika“, die Massensklaverei und die Globalisierungen der Welt
- Ottmar Ette: Nachwort nach dem 11. September 2001
Inhalt:
- Kurt-R. Biermann und Ingo Schwarz: Der Aachener Kongreß und das Scheitern der indischen Reisepläne Alexander von Humboldts
- Kurt-R. Biermann und Ingo Schwarz: „Sibirien beginnt in der Hasenheide“ – Alexander von Humboldts Neigung zur Moquerie
- Kurt-R. Biermann und Ingo Schwarz: Rezepte des jungen Alexander von Humboldt von 1789 gegen Mangel an Arbeit und an Subsistenz
- Francisco Díaz Solar y Duanel Díaz Infante: Gastón Baquero invita a leer Cosmos, de Alejandro de Humboldt
- Ottmar Ette: The Scientist as Weltbürger: Alexander von Humboldt and the Beginning of Cosmopolitics
- Margot Faak: Alexander von Humboldt. Reise durch Venezuela
- Heinz Krumpel: Zur Aneignung und Verwandlung der Ideen Humboldts und Krauses in Lateinamerika – Gemeinsamkeiten und Unterschiede
- Oliver Lubrich: En el reino de la ambivalencia. La Cuba de Alejandro de Humboldt
- Ursula Thiemer-Sachse: Welche Kunst es ist, Kunst zu begreifen …
Alexander von Humboldts Sicht auf indianische Kunst
- Engelhard Weigl: Alexander von Humboldt and the Beginning of the Environmental Movement
Christoph Heins Lektüren
(2001)
Structural information about the bis(benzo crown ether)s I-VI and their complexes with alkali metal cations was deduced from the 13C NMR chemical shifts, the salt-induced 1H and 13C chemical shifts and the vicinal 1H,1H coupling constants. Especially the isomerism with respect to the amide O=C - NH bonds and imine fragments were assigned by various useful NMR parameters ( C=O, 1JN,H, 1JC,H) and proved to be E,E-anti,anti. Furthermore, stereochemical information about preferred conformations about flexible bonds was obtained from 2D ROESY NMR experiments. The complex formation (2:1 complexes and sandwich-like 1:1 complexes, respectively) were determined also by 23Na NMR spectroscopy. The conformational study of the crown ethers was accompanied and corroborated by molecular dynamics and quantum chemical calculations.
A simple way to prepare cucurbit[5]uril is described. The macrocycles of the cucurbituril type are nearly insoluble in water. The solubilities of cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril in hydrochloric acid, formic acid and acetic acid of different concentrations have been investigated. Due to the formation of complexes between cucurbit[n]urils and protons the solubility increases in aqueous acids. The macrocyclic ligands are able to form complexes with several organic compounds. Thus, the complex formation of the cucurbituril macrocycles with different amines has beenstudied by means of calorimetric titrations. The reaction enthalpy gives noevidence of the formation of inclusion or exclusion complexes. 1H-NMR measurements show that in the case of cucurbit[5]uril and cucurbit[6]uril the organic guest compound is included within the hydrophobic cavity. Decamethylcucurbit[5]uril forms only exclusion complexes with organicamines. This was confirmed by the crystal structure of the decamethylcucurbit[5]uril-1,6- diaminohexane complex. complex formation - cucurbit[5]uril - cucurbit[6]uril - decamethylcucurbit[5]uril - solubility - synthesis
The macrocyclic ring interconversion of four maleonitrile mixed oxadithia crown ethers of variable ring size, mn-12-S2O2, mn-15-S2O3, mn-18-S2O4 and fn-12-S2O2, were studied by 1H and 13C NMR spectroscopy and by molecular modelling. The barriers to ring interconversion were estimated using variable temperature NMR spectroscopy and from the calculated activation energies, together with the spin-lattice relaxation times of the CH2 carbon atoms, conclusions were drawn regarding the intramolecular flexibility of the crown ethers in both the free state as well as the complexed state incorporating either AgI, BiIII, SbIII, PdII or PtII metal cations. Furthermore, both the stoichiometry of the complexes and the coordination sites of the crown ethers to the various cations were also clearly implicated. Molecular modelling was also utilised to ascertain the preferred conformers of the four compounds and their corresponding complexes, the results of which corroborated the experimental NMR results to a high degree.
Social Organization
(2001)
Nachkaufverhalten
(2001)
Umweltzeichen
(2001)
Ökologisches Marketing
(2001)
Öko-Controlling
(2001)
Aporien der Moderne am Ausgang des Jahrtausends: Gesellschaft, Kultur und Politik in der Krise?
(2001)
Paulus
(2001)
Jüdische Aufklärung
(2001)
Aufklärung und "Judenfrage"
(2001)