title: L-tyrosinatonickel(II) complex: synthesis and structural, spectroscopic, magnetic, and biological properties of 2{[Ni(L-Tyr)2(bpy)]}·3H2O·CH3OH.
abstract: The complex 2{[Ni(L-Tyr)2(bpy)]}·3H2O·CH3OH [1, where L-Tyr = L-tyrosine; bpy = 2,2'-bipyridine (2,2'-bpy)] was obtained in crystalline form and characterized by X-ray and spectroscopic (FT-IR, NIR-vis-UV, and HFEPR) and magnetic methods. The complex crystallized in the hexagonal system with a = b = 12.8116(18) Å, c = 30.035(6) Å, and space group P3221. The six-coordination sphere around the Ni(2+) ion is formed by two N and two O L-tyrosinato atoms and completed by two N atoms of the 2,2'-bpy molecule. Neighboring [Ni(L-Tyr)2(bpy)] units are joined via weak hydrogen bonds, which create a helical polymeric chain. The coordinated atoms form a strongly distorted cis-NiN2N2'O2 octahedral chromophore. The solid-state electronic spectrum of complex 1 was analyzed assuming D2h symmetry, and the observed bands were assigned to (3)B1g → (3)Ag, (3)B1g → (3)B3g, (3)B1g → (3)B2g, (3)B1g → (3)B3g, (3)B1g → (3)B1g, and (3)B1g → (3)B2g transitions for the I and II d-d bands, respectively. The crystal-field parameters found for D2h symmetry are Dq = 1066 cm(-1), Ds = 617 cm(-1), Dt = -93 cm(-1), B22 = 7000 cm(-1), and Racah B = 812 cm(-1). Magnetic studies revealed the occurrence of hydrogen-bonded metal pairs. The spin Hamiltonian parameters D = -3.262 cm(-1) and E = -0.1094 cm(-1), determined from high-field, high-frequency electron paramagnetic resonance spectra, together with a weak antiferromagnetic exchange parameter J = -0.477 cm(-1), allowed us to reproduce the powder magnetic susceptibility and field-dependent magnetization of the complex. The biological activity of 1 has been tested by using the Fusarium solani, Penicillium verrucosum, and Aspergillus flavus fungi strains and Escherichia coli, Pseudomonas fluorescens, Serratia marcescens, and Bacillus subtilis bacterial strains.
authors.affiliation: Faculty of Chemistry, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. agnieszka.wojciechowska@pwr.wroc.pl
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Wojciechowska
authors.forename: Anna
authors.initials: A
authors.lastname: Gągor
authors.forename: Marek
authors.initials: M
authors.lastname: Duczmal
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Staszak
authors.forename: Andrzej
authors.initials: A
authors.lastname: Ozarowski
mesh_terms: D015082:2,2'-Dipyridyl / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D001424:Bacterial Infections / Q000188:drug therapy; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D005658:Fungi / Q000187:drug effects; D006801:Humans; D008958:Models, Molecular; D009181:Mycoses / Q000188:drug therapy; D009532:Nickel / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014443:Tyrosine / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D056831:Coordination Complexes; D014443:Tyrosine; D015082:2,2'-Dipyridyl; D009532:Nickel