Syntheses,Structures And Magneto-chiral Properties Of Chiral Metal Clusters Co₃Ln₂,Cu₅Ln₄ And Cu₆Ln₃

The connection between the magnetism,light and chirality has been the hotspots of cross-disciplinary research in physics,chemistry,and biology.Magneto-chiral effect,the cross effect of magnetism and chirality,also attracts interests of the scholars.The exploration of the magneto-chiral effect is not only of great importance to explain the source.of chirality of life,but also can provide inspiration for the preparation of new magneto-optical materials.Chiral metal clusters possessing chirality and magnetism simultaneously have gripped our attention.Based on the above background,we have synthesized three chiral cluster systems R/S-Co3Ln2,R/S-Cu5Ln4 and R/S-Cu6Ln3.Then we determined the structures of all compounds and conducted a comparative study in their optical properties and magnetic properties.Besides,initial MChD test of R/S-Co3Ln2 was performed.The main contents are as follows:1.The syntheses of R/S-Co3Ln2,R/S-Cu5Ln4 and R/S-Cu6Ln3 clusters.The chiral Schiff-base ligand R/S-H3LⅠ was synthesized from the o-vanillin and R/S-3-amino-1,2-propanediol.To the resulting ligand formed in situ,different lanthanide salts and cobalt salts were added to prepared the chiral metal clusters R/S-Co3Ln2,and in a similar way the chiral metal clusters R/S-Cu5Ln4 were attained by replacing with copper salts.The R/S-Cu6Ln3 clusters were synthesized by the reaction of different lanthanide salts,copper salts and R/S-H3LⅡ,which was prepared from the o-vanillin and R/S-2-amino-1-propanediol.2.The characterization of three chiral metal cluster systems.The structure and stability of the above three systems were determined.Besides,we have compared the effects of different metal centers on magnetic properties in each system,the difference in magnetic properties between different systems,and the influence of different metal centers on the optical properties between different systems.In view of the UV-Vis spectrum,the CD spectrum and the MCD spectrum,it was found that the above mentioned three systems showed corresponding signals in the absorption bands of transition metal ions,indicating that the three systems may exhibit MChD in the corresponding wavelengths.3.The preliminary study of magneto-chiral dichroism.The MChD test of R/S-Co3Tb2 was carried out at 5K 15000V at the magneto-optical experimental station of National High Magnetic Field Center,Wuhan.The enantiomers exhibit mirror-symmetrical MChD signals at the corresponding absorption band in the Co2+ d-d transition.Although the results need to be further optimized,this is the first time that magneto-chiral dichroism is found in chiral metal clusters.