Das Mikroskop als Hilfsmittel zur Aufklärung der Färbevorgänge

Ohne Zusammenfassung(Umgearbeitet nach dem Vortrag, gehalten am Kongreß der Chemiker-Koloristen in Wien am 16–19. Mai 1912.)     

On the Group of Diffeomorphisms Preserving a Locally Conformal Symplectic Structure

The automorphism group of a locally conformal symplectic structure is studied. It is shown that this group possesses essential features of the symplectomorphism group. By using a special type of cohomology the flux and Calabi homomorphisms are introduced. The main theorem states that the kernels of these homomorphisms are simple groups (for the precise statement, see Section 7). Some of the methods used may also be interesting in the symplectic case.     

The fixation of bis(2-pyridylimino)isoindolato (BPI) ligands to dendritic carbosilanes

Bis(2-pyridylimino)isoindolato (BPI) ligands, containing an alkynyl linker unit which allows their fixation to carbosilane dendrimers and dendrons, were synthesized by reaction of 4-nitrophthalodinitrile with 4-butynol giving the phthalodinitrile derivative containing the linker. These were subsequently reacted with two molar equivalents of 2-amino-4-methylpyridine and 2-amino-4-(t)butylpyridine yielding the respective BPI protioligands 2a and 2b. Lithiation with LDA and reaction with Si-Cl or Si-OTf (OTf=triflate) end groups in core or peripheral positions of dendritic carbosilanes gave the endodendrally and expdendrally functionalized dendrimers. Among these the first and second generation dendrimers [G-1](8-exo)-4-[C[triple bond, length as m-dash]CCH2CH2O]-10-MeBPI (8), [G-1]12-exo-4-[C[triple bond, length as m-dash]CCH2CH2O]-10-MeBPI (9) and [G-2](16-exo)-4-[C[triple bond, length as m-dash]CCH2CH2O]-10-MeBPI (10) were synthesized and fully characterized. The functional dendrimers were metallated by reaction with [(PhCN)2PdCl2] in dichloromethane to give the corresponding pallada-dendrimers.     

Systematic study of the structure-property relationship of a series of ferrocenyl nonlinear optical chromophores

A series of novel nonlinear optical (NLO) chromophores 1-4 incorporating the ferrocenyl (Fc) group as an electron donor and 2-dicyanomethylene-3-cyano-4-methyl-2,5-dihydrofuran (TCF) derivatives as electron acceptors are presented. The use of a constant Fc donor and varied acceptors and bridges makes it possible to systematically determine the contribution of the conjugated bridge and the acceptor strength to chromophore nonlinear optical activity. The X-ray crystal structures of all four chromophores allow for the systematic investigation of the structure-property relationship for this class of molecules. For example, the crystal structures reveal that both cyclopentadienyl groups in the ferrocenyl donor contribute to the electron donating ability. The first-order hyperpolarizabilities beta of these chromophores, measured by hyper-Rayleigh scattering (HRS) relative to p-nitroaniline are reported. These beta values are compared to those calculated by density functional theory (DFT). The excellent agreement between the theoretical and experimental beta values demonstrates that a linear relation exists between the hyperpolarizability and the bond length alternation. An electrooptic coefficient, r(33), of approximately 25 pm/V at 1300 nm, for compound 4, incorporated into a polymer matrix, is competitive with organic chromophores. Moreover, this r(33) is more than 30 times larger than the previously reported value for an organometallic chromophore in a poled polymer matrix. This work not only underscores the potential for Fc donor moieties, which have been underutilized, but also demonstrates that experimental characterization and theoretical simulations are now congruent, viable methods for assessing potential performance of NLO materials.     

Zur Aminolyse von Epoxypropyltheobrominen

Zusammenfassung Die Struktur der bei Umsetzung von 1-Epoxypropyl-8-bromtheobromin (I) mit sekundären Aminen isolierten Verbindungen wird durch eine unabhängige Synthese bewiesen, und zwar durch Spaltung des Epoxidringes von I mit Chlorwasserstoff und Umsetzung des gebildeten Alkohols IV mit Aminen. IV konnte zum entsprechenden Keton oxydiert und damit seine Struktur gesichert werden. Das bei Reaktion von 1-Epoxypropyltheobromin mit 8-Bromtheophyllin als Amin-Komponente erhaltene Nebenprodukt wurde als 2-[8-Brom-theophyllinyl-(7)]-3-[theobrominyl-(1)]-1-propanol identifiziert. Die Struktur der isolierten Verbindungen wird kernresonanzspektroskopisch untersucht.

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Aminolysis of Epoxypropyl-theobromines

The structure of the compounds which have been isolated in the reaction of 1-epoxypropyl-8-bromo-theobromine (I) with secondary amines is proved by an independent synthesis: the epoxide ring of I was cleaved by hydrogen chloride and the alcohol IV converted to amino alcohols. The structure of IV could be confirmed by oxidation. The compound X, isolated as by-product in the reaction of 1-epoxypropyltheobromine with 8-bromo-theophylline as amino component was identified as 2-[8-bromo-theophyllinyl-(7)]-3-[theobrominyl-(1)]-1-propanol. The structure of the isolated compounds has been studied by¹H-NMR-spectra.

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Mit 2 Abbildungen

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Vgl.K. H. Kleine, Dissertat. Univ. Freiburg i. Br., 1969.     

Collision induced decomposition of peptides. Choice of collision parameters

Collision-induced dissociation product ion spectra of a series of doubly charged tryptic peptide ions produced by electrospray ionization were obtained by triple-quadrupole tandem mass spectrometry. The sequence information content of the product ion spectra was explored as a function of collision energy and collision-cell gas pressure for parent ions with molecular masses ranging from 300 to 2000 u. The energy range (at a given pressure) in which the degree of fragmentation is acceptable was found to be narrow for parent ions of a given mass, and the optimal collision energy was observed to exhibit a strong linear correlation with parent ion mass. This observed correlation opens the way for on-line software-controled selection of optimal mass spectrometric conditions in the enzymatic digestion-liquid chromatography-tandem mass spectrometric strategy of amino acid sequencing of proteins.