Optical resolution of oriented enantiomers via photodissociation: quantum model simulations for H2POSD.
We demonstrate quantum mechanically how to resolve enantiomers from an oriented racemic mixture taking advantage of photodissociation. Our approach employs a femtosecond ultraviolet (UV) laser pulse with specific linear polarization achieving selective photodissociation of one enantiomer from a mixture of L and R enantiomers. As a result, the selected enantiomer is destroyed in the electronically excited state while the opposite enantiomer is left intact in the ground state. As an example we use H2POSD which presents axial chirality. A UV pulse excites the lowest singlet excited state which has nsigma* character and is, therefore, strongly repulsive along the P-S bond. The model simulations are performed using wavepackets which propagate on two dimensional potential energy surfaces, calculated along the chirality and dissociation reaction coordinates using the CASSCF level of theory.
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany. leti@chemie.fu-berlin.de
Leticia
L
González
Jörn
J
Manz
Burkhard
B
Schmidt
Mohamed F
MF
Shibl
D003903:Deuterium / Q000737:chemistry; D007834:Lasers; D008956:Models, Chemical; D063065:Organophosphonates / Q000737:chemistry* / Q000528:radiation effects; D010721:Phosphinic Acids / Q000737:chemistry* / Q000528:radiation effects*; D011789:Quantum Theory; D013237:Stereoisomerism; D013455:Sulfur / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry* / Q000528:radiation effects; D014466:Ultraviolet Rays
D063065:Organophosphonates; D010721:Phosphinic Acids; D013457:Sulfur Compounds; C509588:phosphinothioic acid; D013455:Sulfur; D003903:Deuterium