title: Synthesis, spectral, thermal and magnetic studies of Mn(II), Ni(II) and Cu(II) complexes with some benzopyran-4-one Schiff bases.
abstract: The Schiff bases of N(2)O(2) dibasic ligands, H(2)La and H(2)Lb are prepared by the condensation of ethylenediamine (a) and trimethylenediamine (b) with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one. Also tetra basic ligands, H(4)La and H(4)Lb are prepared by the condensation of aliphatic amines (a) and (b) with 6-formyl-5,7-dihydroxy-2-methylbenzopyran-4-one. New complexes of H(4)La and H(4)Lb with metal ions Mn(II), Ni(II) and Cu(II) are synthesized, in addition Mn(II) complexes with ligands H(2)La and H(2)Lb are also synthesized. Elemental and thermal analyses, infrared, ultraviolet-visible as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly prepared metal complexes. The structures of copper(II) complexes are also assigned based upon ESR spectra study. All the complexes separated with the stoichiometric ratio (1:1) (M:L) except Mn-H(4)La and Mn-H(4)Lb with (2:1) (M:L) molar ratio. In metal chelates of the type 1:1 (M:L), the Schiff bases behave as a dinegative N(2)O(2) tetradentate ligands. Moreover in 2:1 (M:L) complexes, the Schiff base molecules act as mono negative bidentate ligand and binuclear complex is then formed. The Schiff bases were assayed by the disc diffusion method for antibacterial activity against Staphylococcus aureus and Escherichia coli. The antifungal activity of the Schiff bases was also evaluated against the fungi Aspergillus flavus and Candida albicans.
authors.affiliation: Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt. aidansary1@yahoo.com
authors.forename: Aida L
authors.initials: AL
authors.lastname: el-Ansary
authors.forename: Hussein M
authors.initials: HM
authors.lastname: Abdel-Fattah
authors.forename: Nora S
authors.initials: NS
authors.lastname: Abdel-Kader
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000494:pharmacology*; D001424:Bacterial Infections / Q000188:drug therapy; D056831:Coordination Complexes / Q000737:chemistry* / Q000494:pharmacology*; D003374:Coumarins / Q000737:chemistry* / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000187:drug effects; D005658:Fungi / Q000187:drug effects; D017895:Manganese Compounds / Q000737:chemistry / Q000494:pharmacology; D009181:Mycoses / Q000188:drug therapy; D009532:Nickel / Q000737:chemistry / Q000494:pharmacology; D012545:Schiff Bases / Q000737:chemistry / Q000494:pharmacology; D013057:Spectrum Analysis; D013211:Staphylococcus aureus / Q000187:drug effects; D013816:Thermodynamics
chemical_list: D000890:Anti-Infective Agents; D056831:Coordination Complexes; D003374:Coumarins; D017895:Manganese Compounds; D012545:Schiff Bases; D009532:Nickel