Dresden 2011 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 23: Electronic Spectroscopy II

MO 23.5: Vortrag

Donnerstag, 17. März 2011, 15:45–16:00, MER 02

Rotationally resolved electronic spectroscopy of 1,4-benzodioxan: the anomeric effect in ground and electronically excited state — •Christian Brand¹, Thi Bao Chau Vu¹, Leo Meerts², and Michael Schmitt¹ — ¹Heinrich-Heine-Universität, Institut für Physikalische Chemie I, Düsseldorf — ²Radboud University, Institute for Molecules and Materials, Nijmegen

The electronic origin of 1,4-benzodixan and three vibrational bands have been investigated using rotationally resolved electronic spectroscopy. By comparison to ab initio calculations all observed features could be assigned to the twist-conformer. Examination of the inertial defect show that the molecule is more planar in the electronic ground state than in the electronically excited singlet state. This effect can be traced back to a competition between the anomeric effect comprising the non-bonding p-type oxygen orbital and the antibonding axial CH-bond and the π-π interaction between the oxygen lone pair and the π-orbitals of the benzene ring.