Synthesis, Crystal Structure And Antimicrobial Properties Of Rare Earths Aromatic Carboxylic Acid Complexes

A series of ternary complexes of RE(â…¢)(La,Pr,Y,Yb) were synthesized with seven kinds of aromatic carboxylic acids and 1,10-phenanthroline as ligands.The compositions of these complexes were initially defined by elemental analysis(C,H,N) and EDTA titration for rare earth.These complexes were characterized by means of IR,TG-DTG,and bacteriostatic activity methods.In these complexes,the rare earth ions were bonded to the oxygen atoms of carboxylate and the nitrogen atoms of neutral phen ligand.All of these complexes show fine thermal stability.The structures of four ternary complexes[La(o-MBA)₃phen]₂·H₂O(â… ), [Pr(o-MOBA)₃phen·H₂O]₂·3H₂O(â…¡),Pr(m-MOBA)₃phen(â…¢) and Yb(m-MBA)₃phen(â…£) have been determined using X-ray diffraction.All of the complexes exist as binuclear molecules,Ⅰ～Ⅲcrystallize in triclinic,space group P(?);â…£belongs to monoclinic,space group P2(1)/c.The antibacterial properties of twenty-eight aromatic carboxylic acids complexes,rare earths chloride and organic ligands were studied.The results indicate that the complexes show better antibacterial activities to Escherichia Coli and Staphylococcus aureus than the corresponding rare earths chloride.The antibacterial activity of complex Y(p-MBA)₃phen·H₂O is the highest against Escherichia Coli,and Yb(p-MOBA)₃phen is the weakest against Escherichia Coli,while the complexes Yb(p-MBA)₃phen and Yb(o-MBA)₃phen is the highest against Staphylococcus aureus,and Yb(BA)₃phen is the weakest against Staphylococcus aureus.These results would provide valuable information for the synthesis of new effective rare earth bacteriostat and antibacterial drugs.