Weber, G. and Sheldrick, G. M. and Burgemeister, Thomas and Dietl, F. and Mannschreck, Albrecht and Merz, A. (1984) Crystal structures and solution conformations of the meso-forms of 2,3,11,12-Tetraphenyl-crown-6. Tetrahedron 40 (5), pp. 855-863.
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The X-ray crystal stuctures of the achiral cis-anti-cis and trans-syn-trans diastereoisomers of 2,3,11,12-tetraphenyl--crown-6 and their sodium iodide 1:1 complexes are presented. In the free ligands, the vicinal phenyl groups assume a diaxial- antiperiplanar orientation in the cis-anti-cis isomer and a diequatorial-synclinal one in the trans-syn-trans isomer. The vicinal coupling constants of the benzylic protons in the diphenylethanediyl groups in the three meso-forms, derived from 13C satellites, suggest similar conformations in the solid state and in deuteriotrichloromethane solution. Conformational changes of the crown ethers from the free ligand to their complexes are discussed in the context of previously determined complex association constants.
|Institutions:||Chemistry and Pharmacy > Institut für Organische Chemie > Retired Professors > Prof.Dr. Mannschreck|
|Subjects:||500 Science > 540 Chemistry & allied sciences|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||09 Nov 2010 07:52|
|Last Modified:||09 Nov 2010 07:52|