Absolute configuration of monodentate phosphine ligand enantiomers on Cu(111).
Scanning tunneling microscopy (STM) has been employed to investigate the chirality of monophosphine compounds that are highly efficient chiral ligands in transition-metal-catalyzed organic transformations. The absolute configuration of 1-(2-diphenyphosphino-1-naphthyl)isoquinoline enantiomers with axial chirality was discriminated directly by the "marker" group, PPh(2) substitutes. Although the two enantiomer molecules adsorb on a Cu(111) surface and form well-defined (4 x 4) structures, the positions of PPh(2) substitutes in the molecular adlayers are different. The mirror symmetry between two adlayers is demonstrated. On the basis of STM results, structural models are proposed to interpret the chiral adsorption. The results presented here supply a straightforward method for axial chirality analysis in adsorbed adlayers by STM.
Han
Mei-Juan
MJ
Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.
Wang
Dong
D
Hao
Ju-Min
JM
Wan
Li-Jun
LJ
Zeng
Qing-Dao
QD
Fan
Qing-Hua
QH
Bai
Chun-Li
CL