Synthesis And Characterization Of Copper-Early Lanthanide Metal Heteronuclear Oxo-Clusters

Chirality of mixed-metal materials was recently recognized as a powerful source of unique optical,electronic properties and novel functionalities.In recent years,much attention has been devoted to the design and construct of chiral mixed-metal complexes because introducing chiral characteristic into molecular materials would be of the desirable strategy for the assembly of multifunctional molecule-based magnets.Chiral high-nuclearity 3d-4f complexes occupy a special place among mixed-metal molecular materials for the reason that it can induce a variety of nontrivial phenomena,such as the effect of magnetochiral dichroism?MChD?,ferroelectric properties,or second harmonic generation?SHG?.In light of the excellent properties of the aforementioned materials,People have a great interest in it.Much attention has been devoted recently to fabricating Cu-Ln clusters as members of the 3d-4f clusters because of their aesthetically pleasing structures and the observed single-molecule magnet?SMMs?behavior in some compounds Several 3d-4f clusters with Ln heavier than Nd have been reported:{Cu₉^IILn^III2},{Cu₂₄^IILn₆^III}and{Cu₃₆^IILn₂₄^III}?Ln=Gd,Dy?,{Cu₆^IILn₁₂^III}?Ln=Gd,Tb,Dy?,to name a few;whereas those with trivalent early lanthanides of larger ionic radius?La,Ce,Pr,Nd?remain underexplored.Among a number of approaches to cluster synthesis,the choice of ligands is crucial.Not only does meticulous selection of ligands lead to emerging of new structures,it also avoids the formation of homometallic complexes or mixtures of various species.For above two reasons,the use of polydentate ligands containing both N and O atoms,such as polyaminocarboxylates and acyclic Schiff base derivatives,is successful and thus prevailing.However,,diverse anionic ligands with only oxygen as coordination atoms,even though less studied,should still be sought after.In this paper,polyacid chemistry,pre-metal transition oxo-cluster,post-metal transition oxo-cluster,lanthanide metal oxo-cluster,heteronuclear metal oxo-cluster?mainly transition metal and lanthanide metal?are briefly introduced.In view of the beautiful structure and unique properties of copper and lanthanide metal oxygen clusters,eight copper-lanthanide chiral oxygen clusters with the nuclearity of 26were synthesized in this paper.The research work of this paper is as follows:?1?using copper acetate with nitrate of La,Ce,Pr,Nd and chiral tartaric acid ligand?L-tartaric acid,D-tartaric acid?as raw materials,using three different solution systems HOAc-KOAc?HOAc-KOAc-K₂CO₃/KOH?HOAc-NaOAc-K₂CO₃/KOH,synthesized eight chiral copper-lanthanide oxygen clusters expressed as{L-Cu₂₂La₄K}?{L-Cu₂₂Ce₄K}?{L-Cu₂₂Pr₄K}?{L-Cu₂₂Nd₄K}?{D-Cu₂₂La₄K}?{D-Cu₂₂Ce₄K}?{D-Cu₂₂Pr₄K}?{D-Cu₂₂Nd₄K}were determined by Single-crystal X-ray diffraction?XRD?analysis.The isometric structures of{Cu₂₂Ln₄K}series compounds were further proved by X-ray powder diffraction.?2?A series of{Cu₂₂Ln₄K}compounds were characterized by elemental analysis,solution and solid circular dichroism,thermogravimetric analysis?TGA?,solution ultraviolet and Visible Spectroscopy,dynamic light scattering?DLS?,infrared?KBr as background?and magnetic properties.