Studies On Self-assembly, Structure, Theoretical Calculation And Fluorescence Properties Of Polynuclear Copper(Ⅱ), Cobalt(Ⅱ), And Nickel(Ⅱ) Bis(salamo)-Type Complexes

Since 1893,when Swiss chemist A.Werner founded coordination chemistry,the theory of coordination chemistry has been fully developed and refined in modern times.Many scholars have worked to obtain novel and excellent complexes with novel structures,salen-type ligands and derivatives are well suited to address the above needs.However,as the research gradually deepens,it is found that due to its limitations,the salen-type ligand greatly limits its application in various fields.In order to continue the study of this type of ligands and explore potential applications,oxygen atoms with high electronegativity were introduced into the alkyl chain to change the distribution of electron clouds in the alkyl chain to make it less susceptible to hydrolysis reactions,and thus the salamo-type ligand was obtained.As expected,it has been found that salamo-type complexes have a more novel structure and a richer range of applications than salen-type,making them a constant source of fervor in the field of coordination chemistry.Firstly,we designed and successfully prepared a bis（salamo）-type ligand H3L containing two N₂O₂ coordination cavities,after which we obtained nine structurally excellent coordination single crystals by reaction with various transition metal salts.Complexes 1-5 are Cu（Ⅱ）complexes,where complexes 1 and 2 are prepared by the same Cu（Ⅱ）salt Cu Cl₂·2H₂O,different alcohol solvents,while complex 3 compared to complex 1 is obtained from the halide anion different Cu（Ⅱ）salt Cu Br₂,same solvent.The complexes 1-3were all obtained from partially deprotonated ligand units（HL）^2-,which has a similar metallization unit[Cu₂（HL）X₂]（X=Cl,Br）.Complexes 1 and 3 are binuclear structures,while complex 2 is a tetranuclear structure formed by two metallization units[Cu₂（HL）Cl₂]bridged by two Cl^-ions.It can be seen that the formation of complexes 1-3 is strongly influenced by the solvent effect and the anion effect.Complex 4 is a tetranuclear structure consisting of two fully deprotonated ligand units（L）^3-and four Cu（Ⅱ）atoms.Compared to complexes 1-3,the solvent molecules are not involved in coordination,while the phenoxy atoms bridge the metallization units[Cu₂（L）],respectively.The complex 5 is a mononuclear structure consisting of a fully deprotonated ligand unit（L¹）^2-and a Cu（Ⅱ）atom.Interestingly,the obtained complex 5 was not obtained from the original ligand.Complexes 6 and 7 are Co（Ⅱ）complexes,where complex 6 is a binuclear complex and the halide anion is not involved in the coordination.Complex 7 is a tetranuclear complex,and like complex 5,complex 7 is also not obtained from the original ligand.The new ligands obtained by this way are structurally excellent and rich in coordination sites,which is a new idea for designing ligands.Complexes 8 and 9 are Ni（Ⅱ）complexes,which are obtained from the same Ni（Ⅱ）salt Ni（OAc）₂·4H₂O,with different alcohol solvents.The two structures are similar,but their axial coordination solvents are different,and the solvent effect affects the difference in their structures.Finally,the spectral properties of the complexes 1-9 and the theoretical calculations were investigated in depth.Complex 1:[Cu₂（HL）Cl₂（MeOH）]·MeOH,C₂₉H₃₄Cl₂Cu₂N₄O₉,Mr=780.58,Monoclinic system,space group P 2₁/c;Complex 2:[Cu₄（HL）₂Cl₂（μ₂-Cl）₂]·4Et OH·H₂O,C₆₂H₇₈Cl₄Cu₄N₈O₁₉,Mr=1635.28,Monoclinic system,space group P 2₁/n;Complex 3:[Cu₂（HL）Br₂（MeOH）]·MeOH,C₂₉H₃₄Br₂Cu₂N₄O₉,Mr=869.50,Monoclinic system,space group P 2₁/c;Complex 4:[Cu₄（L）₂]（Cl O₄）₂·2Et OH,C₅₈H₆₂Cl₂Cu₄N₈O₂₄,Mr=1580.21,Monoclinic system,space group P 2₁/n;Complex 5:Cu（L¹）,C₂₁H₂₀Cu N₂O₅,Mr=443.93,Triclinic system,space group P-1;Complex 6:[Co₂（L）（OMe）]·2MeOH,C30H36Co2N4O10,Mr=730.49,Monoclinic system,space group P 2₁/c;Complex 7:[Co₄（L²）₄（CH₃OH）₄],C₄₀H₅₂Co₄N₄O₁₆,Mr=1080.57,Triclinic system,space group P-1;Complex 8:[Ni₂（L）（μ-OAc）（CH₃OH）],C₃₀H₃₂N₄Ni₂O₁₀,Mr=726.01,Triclinic system,space group P-1;Complex 9:[Ni₂（L）（μ-OAc）（H₂O）],C₂₉H₃₀N₄Ni₂O₁₀,Mr=711.99,Orthorhombic crystal system,space group P na 2₁.