Biomedical subjects

Qing-Min Xu

Publications and source records attributed to Qing-Min Xu.

4 recordsLinked to original sources

PubMed2004

Direct STM investigation of cinchona alkaloid adsorption on Cu(III).

Scanning tunneling microscopy (STM) combined with cyclic voltammetry has been employed to investigate the adsorption of cinchonine on Cu(111). Similar to cinchonidine, cinchonine forms a long-range ordered adlayer with (4 x 4) symmetry on the substrate. The structural details on molecular adsorption were obtained by high-resolution STM images. On the basis of the previous results and obtained STM images, the quinoline ring is proposed to lie parallel to Cu(111) and serve as an anchoring group. The chiral quinuclidine moiety extends out of the surface to facilitate the interaction with the prochiral reactants.

Adsorption↗

PubMed2003

Tuning molecular orientation with STM at the solid/liquid interface.

Triptycene molecular orientation has been tuned with a STM tip at a Cu(111) surface in solution from flat, to tilt, to vertical. The tuning is completely bias dependent and reversible. The study is important in the fields of nanoscience and technology.

Journal Article↗

PubMed2002

Adsorption mode of cinchonidine on Cu(111) surface.

The adsorption mode of cinchonidine on Cu(111) was directly obtained by in situ STM. The molecules were found to adsorb on the substrate surface and form a long-range ordered adlayer with (4 x 4) symmetry. While the quinoline rings lie parallel to Cu(111), the chiral quinuclidine moiety extends out of the surface. The enantioselectivity of catalysts may relate to this special adsorption conformation of cinchonidine on the surface.

Adsorption↗

PubMed2002

Discriminating chiral molecules of (R)-PPA and (S)-PPA in aqueous solution by ECSTM.

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Journal Article↗