TY  - JOUR
A1  - Pihlaja, Kalevi
A1  - Lehmann, S.
A1  - Schroth, W.
A1  - Gäber, M.
A1  - Kleinpeter, Erich
T1  - Electron impact induced fragmentation of dibenzo crown ethers
Y1  - 1996
ER  - 
TY  - JOUR
A1  - Grotjahn, Manuela
A1  - Lehmann, S.
A1  - Aurich, Ines
A1  - Holdt, Hans-Joachim
A1  - Kleinpeter, Erich
T1  - NMR spectroscopic and molecular modelling studies of the solution structure and complexational behaviour of some bis(benzocrown ether)s
N2  - 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.
Y1  - 2001
ER  -