Hannover 2010 – wissenschaftliches Programm
Q 62.6: Vortrag
Freitag, 12. März 2010, 11:45–12:00, F 102
Chemoselective quantum control of carbonyl bonds in Grignard reactions. — •Markus Kowalewski1, Caroline Gollub2, Sebastian Thallmair1, and Regina de Vivie-Riedle1 — 1Department Chemie und Biochemie, Ludwig-Maximilians-Universität München — 2Institut für Werkstoffwissenschaft und Max-Bergmann-Zentrum für Biomaterialien, Technische Universität Dresden, Max Planck Institut für Physik Komplexer Systeme, Dresden
Under laboratory conditions Grignard reagents like methyl magnesium bromide do not react selectively with respect to different carbonyl bonds. We investigate theoretically the perspectives of selective laser excitation of CO bonds in mixed systems. As an representative example a mixture of cyclohexanone and cyclopentanone is chosen as reagent. The laser is supposed to provide the activation energy and to adopt the function of a protective group. The control aim is to elongate the CO bond of one compound until the bond length required in the transition state is reached. We optimized picosecond laser pulses in the infra red regime with optimal control theory (OCT) which excite only the desired carbonyl bond. From the theoretical results laser assisted chemo-selectivity seems possible to a large extent. To obtain control not only on the final product but also on the excitation mechanism the behavior of the OCT algorithm for various initial conditions and under frequency restrictions is investigated.