Study On The Preparation And Properties Of Cyano/cyanate Bridged Metal Complexes

In the present work,three metal complexes have were synthesized under hydrothermal condition and reflux method.The structures of these complexes characterized by elemental analysis,X-ray diffraction,infrared spectroscopy,thermogravimetric analysis magnetic measurements and antibacterial activities.In addition,theoretical studies on the exploration of relationships between structures and magnetic properties for two compounds were carried out.The main contents in this report can be summarized as follows:?1?Two complexes[Ni₂?CN?₄?2,2'-bpy?]_n?1? and [Fe?2,2'-bpy?₂Ni?CN?₄]n?2? were synthesized by solvothermal method in the reaction of K₃[Fe?CN?₆],Ni?Ac?₂ and 2,2'-bipyridine.The X-ray crystallographic studies suggested that,[Ni?CN?₄]^2-anion and [Ni?2,2'-bpy?]²⁺ cation are alternately linked through cyano groups to form a 2-D layered structure in complex 1,and the Fe²⁺and Ni²⁺ ions are alternately bridged by the cyanide ligands to form a one-dimensional zigzag with 2,2?-bpy terminal ligands in complex 2.Intramolecular antiferromagnetic coupling interactions between metal ions were observed in complexes 1 and 2.The antibacterial activities of complexes 1 and 2 were tested by Escherichia coli?E.coli?,methicillin-resistant staphylococcus aureus?Mrsa?,staphylococcus aureus S.a,pseudomonas aeruginosa?P.a?and enterococcus faecalis?E.f?.The results showed that complexes 1 and 2 have weak antibacterial activities against these five bacteria.?2?The density functional theory?DFT?and the symmetry breaking state method?BS?are combined to carry out theoretical calculations on two cyanate bridged binuclear metal complexes[Ni?L??NCO?]₂?PF₆?₂?3?and[Cu?L??NCO?]₂?PF₆?₂?4??L is N,N-bis?3,5-dimethylpyrazole?aminomethylpyridine?.The results show that the J_abb value is negative,and the antiferromagnetic interaction exists between the metal nickel ions in complex 3.The cyanate bridges the two metal ion nickel centers through an end-to-end coordination mode in the complex 3.This Ni-O-C-N-Ni magnetic channel contributes to the antiferromagnetic interaction of the metal centers in complex 3.The spin delocalization effect exists on the two metal centers of the complex 3.Compared with the complex 3,the ferromagnetic interaction exists between the metal copper centers in the complex 4.The research results show that the cyanate ligands connect the two metal copper centers in an end-on coordination mode to form a Cu-O-Cu magnetic channel in the complex 4.This magnetic channel is beneficial to ferromagnetic interaction between the metal centers,and spin polarization in the complex at the same time.?3?The complex[Zn?2,3-PDC??H₂O??DMIM?·H₂O]n?5?was synthesized by refluxing method with pyridine-2,3-dicarboxylic acid?2,3-PDC? and 2-methylimidazole?DMIM? ligands and Zn?II?ions.The structure of the complex was characterized by IR,UV,fluorescence,thermogravimetric analysis and X-ray single crystal diffraction.At the same time,the antibacterial activity of complex 5,metal salt and its ligand against Escherichia coli?E.coli?,methicillin-resistant staphylococcus aureus?Mrsa?,staphylococcus aureus?S.a?,pseudomonas aeruginosa?P.a?,enterococcus faecalis?E.f?was studied.The results show that,complex,metal salt and ligand have certain antibacterial activity against five kinds of bacteria,but the effect is general.the complex can be further coordinated and substituted to obtain complexes with better antibacterial activity.