Synthesis,Crystal Structures and Magnetic Properties of Copper(II) Complexes with Nitronyl Nitroxide Radicals

Two new copper(II) compounds with imino nitroxide radicals [Cu(IM‐MeImz)₂ · (SCN)] 0.5[Cu(SCN)₄] ( 1 ) and [Cu(IM‐MeImz)₂ · (SCN)]ClO₄ · H₂O ( 2 ) (IM‐meImz = 2‐(5‐methylimidazol‐4‐yl)‐4,4,5,5‐tetramethyl‐2‐imidazoline‐1‐oxyl) have been synthesized and characterized structurally and magnetically. X‐ray analysis demonstrates that complex 1 contains Cu^II ions in both square‐pyramidal and square planar coordination. There are complete charge separation into [Cu(IM‐MeImz)₂(SCN)]⁺ cations and 0.5[Cu(SCN)₄]^? anions, in a 2:1 ratio. The complex 1 was connected as a one‐dimensional polymer by intermolecular interactions. In complex 2 , the coordination around the copper atom is distorted square pyramidal and the apical position is occupied by one nitrogen atom of SCN^? anion. The 2‐D network structure was formed and arranged through intermolecular H‐bonds interactions. The complex 1 exhibits intramolecular weak ferromagnetic coupling between Cu^II ion and the radicals.     

Complexes of Co(II), Ni(II) and Cu(II) with lapachol

Complexes of naturally occurring hydroxynaphtho-quinone, lapachol (2-hydroxy-3(3-methyl-2-buthenyl)-1,4-naphthoquinone = HL) with Co(II), Ni(II) and Cu(II) have been prepared by reaction of the corresponding acetates with the ligand (HL) in ethanol. The molecular and crystal structures were determined for [CoL₂(EtOH)₂] (1), [NiL₂(EtOH)₂] (2), and [CuL₂(py)₂] (3). In all cases the deprotonated lapachol behaves as chelating bidentate ligand. The complexes were also characterized by elemental analyses, cyclic voltammetry, and FAB-MS.     

Magnetic and Spectroscopic Studies on the Complexes of 9-Oxo-10-Acridinemetanophosphonic Ion with Cu (II) Co (II)and Ni (II)

Abstract

Three complexes of 9-oxo-10-acridinemetanophosphonlc ion (PMA⁼ see figure) have been synthesised. The meta1:ligand ratio in the complexes is equal 1:1 and their formulas are (CUPMA) ₂,×5H₂O,NiPMA×4H₂O and CoPMA×4H₂O. The structure of the complexes has been investigated by the IR,FIR, Raman spectroscopy, UV-VIS spectroscopy, magnetic measurements and EPR spectroscopy. The physical properties of the complexes obtained are characteristic for inorganic polymers. The lowering of the ν(P-Q) stretching frequency by about cm^?, in the spectra of the complexes as compared to that of the free ligand suggests that the phosphonlc group takes part in coordination. Data from the EPR spectrum indicate that Cu(II)may form the dimeric, water bridged or even more complicated polymeric structures.     

Synthesis and Physicochemical Properties of the Complexes of Co(II), Ni(II), and Cu(II) with Chrysin

New solid complex compounds of Co(II), Ni(II), and Cu(II) with chrysin were obtained. Their composition and some physicochemical properties were studied (thermogravimetric analysis, ultraviolet, visible and infrared spectroscopy, magnetic properties). During heating, the hydrated complexesM(C₁₅H₉O₄)₂·nH₂O lose some crystallization water molecules in one or two steps, and then decompose to the oxides. A structure for the compounds was proposed.     

含氮配体Co、Fe配合物的合成、结构及性质

报导了四个单核Co（Ⅱ）和Fe（Ⅱ）的配合物[Co（L1）2]（ClO4)2·（CH3CN）（1）,[Fe（L1）2]（ClO4）2·（H2O）（2）,[Co（L2）]（ClO4）2（3）,以及[Fe（L2）]（ClO4）2·2H2O（4）,（其中L1＝4’-苯基-2,2’：6’,2”-三联吡啶,L2＝N,N,N-三-（2-（2-吡啶甲叉氨基）乙基）胺）的合成和性质,以及配合物1、3的晶体结构．配合物1和3的晶体都属于单斜晶系．它们的晶胞参数分别为：1a＝1．0855（4）nm,b＝1．6201（5）nm,c=2.5236（5）nm,β＝92．63（2）°,V＝4．433（1）nm3;3a=2.8351（8）nm,b＝1．0670（3）nm,c＝1．9255（5）m,β＝101．03（4）°,V＝5717（2）nm3．2和4的氧化还原电位分别为E＝0．78V和0．63V‘它们的d-d跃迁吸收最大值分别位于565和521nm处．     

Crystal Structures of Ni(II) and Co(II) cis-Octahedral Complexes with 3-Imidazoline Nitroxide

NiL₂Bipy·1.5EtOH, CoL₂Bipy·1.5EtOH, and CoL₂Phen·0.5EtOH mixed-ligand complexes with a fixed cis` position of paramagnetic ligands (L = 4-(3',3',3'-trifluoro-2'-oxopropylidene)-2,2,5,5-tetramethyl-3-imidazolidine-1-oxyl) have been synthesized and studied by X-ray crystallography.     

Spectroscopic Studies on Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ) Complexes with 4,4'-Bipyridine

Fourier-transform infrared(FTIR),Raman and ultraviolet-visible spectra of 4,4'-bipyridine and its me-tal-organic coordination compounds synthesized from 4,4'-bipyridine and nitrate of Co(Ⅱ),Ni(Ⅱ) and Zn(Ⅱ) were measured and analyzed,respectively.The main FTIR and Raman bands were assigned in detail.The relationship between these characteristic bands and the structure of ligands and coordination compounds were discussed.     

Thermal,Magnetic, FTIR and XRD Study of New Co(II) and Ni(II) Theophyllinato Complexes with Benzylamine or Ethanolamine

Four new theophyllinato (th) complexes of Co(II) and Ni(II) were synthesized containing ethanolamine (2-aminoethanol, ea) or benzylamine (ba). Comprehensive FTIR spectroscopic, powder XRD, magnetic and thermal studies on these mixed ligand complexes have been carried out to get structural information. The almost identical FTIR spectra and XRD patterns of Co and Ni compounds with same composition have indicated that Co(th)2(ba)2·2H2O (1) and Ni(th)2(ba)2·2H2O (2) or Co(th)2(ea)2 (3) and Ni(th)2(ea)2 (4) have very similar structure pair wise. The infrared spectra and X-ray diffraction patterns of thermally dehydrated 1 and 2containing benzylamine have allowed only to suggest that the co-ordination number around the metal centres is four, while the high thermal stability of complexes 3and 4have indicated that they contain two of bidentate ethanolamine molecules in octahedral co-ordination. A big difference observed between the magnetic moments of Co compounds 1and 3have proven that the inner co-ordination sphere of complexes with benzylamine (1and 2) is tetrahedral, whilst that with ethanolamine (3and 4) is basically octahedral, independent of the cation centres (Co or Ni). This revised version was published online in July 2006 with corrections to the Cover Date.     

Coordinating Properties of Co(II) and Zn(II) Complexes with Sterically Hindered Porphyrins

Cobalt(II) and zinc(II) complexes with 5,15-di(o-methoxyphenyl)-3,7,13,17-tetramethyl-2,8,12,18-tetra-n-buthylporphyrin and its capped analogues, where the MN₄ reaction site is shielded by bridging groups containing m-phenylene and dimethoxy-substitutedp-phenylene fragments, were synthesized. Equilibrium constants of additional coordination of pyridine and N-methylimidazole by these metalloporphyrins were determined at 298 K. It was found that steric distortion of the porphyrin core destabilizes extra complexes.     

Structure and Magnetic Properties of Mn(II) Complexes with Enaminoketone Derivatives of 3-Imidazoline Nitroxide

The crystal structures of two manganese complexes with the enaminoketone derivatives of 3-imidazoline nitroxide: MnL ₂ ^COOMe (layered polymeric) and MnL ₂ ^CF3 (DMF)₂ (molecular) have been determined. The polymer structure of MnL ₂ ^COOMe is the result of direct coordination of the nitroxyl O atoms of the neighboring bischelate fragments by the Mn atoms. This forms heterospin exchange clusters >N-O–Mn(II)–O-N< with strong antiferromagnetic interactions between the odd electrons of the paramagnetic centers. The structure of MnL ₂ ^CF3 (DMF)₂ is characterized by ligand cis-coordination in the octahedral coordination polyhedron. Due to the molecular nature of the complex, the solid compound has only weak ferromagnetic intramolecular indirect exchange interactions. The charge states of atoms in coordination units was confirmed by X-ray photoelectron data.     

Cu(II), Ni(II), and Co(II) Complexes of Tetradentate Azomethine Ligands: Chemical and Electrochemical Syntheses,Crystal Structures,and Magnetic Properties

Russian Journal of Coordination Chemistry - Complexes CuL1 ? MeOH (Ia), NiL1 ? MeOH (Ib), CоL1 ? MeOH (Ic), CuL2 (IIa), NiL2 (IIb), and CоL2 (IIc) of the tetradentate...     

Zinc(II) and Nickel(II) Complexes Based on Schiff Base Ligands: Synthesis,Crystal Structure,Luminescent and Magnetic Properties

Three new phenolate oxygen bridged transition metal complexes [Zn₃(HL¹)₃(μ₃‐CH₃O)]·(ClO₄)₂(H₂O)₃ ( 1 ), [Ni₂(HL¹)₂(μ_1,1‐N₃)(o‐vanillin)]·H₂O ( 2 ), [Ni₃(HL²)₂(PhCOO)₂(PhCOOH)₂(EtOH)₂] ( 3 ) have been synthesized by metal ions and potentially multidentate Schiff base ligands (H₂L¹ = 2‐((1‐hydroxy‐2‐methylpropan‐2‐ylimino) methyl)‐6‐methoxyphenol; H₃L² = (E)‐1‐((2‐hydroxy‐3‐methoxy‐benzylidene)amino)ethane‐1,2‐diol). All the three complexes 1 , 2 , and 3 have been characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal X‐ray diffraction studies. Crystal structures reveal that complex 1 is a trinuclear incomplete cubane‐like zinc cluster whereas complex 2 is a dinuclear nickel complex bridged by azide, and compound 3 is a trinuclear nickel complex. The luminescent property for complex 1 and magnetic behaviors for complexes 2 and 3 have been investigated.     

Synthesis, Crystal Structure and Magnetic Properties of Cobalt(II) Complex Involving Imino Nitroxide Radicals

1 INTRODUCTION The synthesis and study of transition metal com-plexes incorporating organic free radicals have arou-sed great interest in the field of molecular magne-tism[1]. Nitronyl nitroxide radicals (NITR), stable or-ganic radicals, have been widely used as molecularunits in the design and construction of magnetic ma-terials[2～5]. These radicals are especially attractivedue to that their donor atoms can assemble an exten-ded coordination geometry with changing magneticcoupling. A…     

Complexes of Mn(II), Co(II), Ni(II) and Cu(II) with 4,4'-bipyridine and dichloroacetates

New mixed-ligand complexes with empirical formulae M(4-bpy)L₂·1.5H₂O (M(II)=Mn, Co), Ni(4-bpy)₂L₂ and Cu(4-bpy) L₂·H₂O (where: 4-bpy=4,4'-bipyridine, L=CC L2HCOO^-) have been isolated in pure state. The complexes have been characterized by elemental analysis, ir spectroscopy, conductivity (in methanol, dimethylformamide and dimethylsulfoxide solutions) and magnetic and x-ray diffraction measurements. The Mn(II) and Co(II) complexes are isostructural. The way of metal-ligand coordinations discussed. the ir spectra suggest that the carboxylate groups are bonded with metal(II) in the same way (Ni, Cu) or in different way (Mn, Co). The solubility in water is in the order of 19.40·10^-3÷1.88·10^-3ł mol dm^-3ł. During heating the hydrate complexes lose all water in one step. The anhydrous complexes decompose to oxides via several intermediate compounds. A coupled TG-MS system was used to analyse the principal volatile products of obtained complexes. The principal volatile products of thermal decomposition of complexes in air are: H₂O₂ ⁺, CO₂ ⁺, HCl⁺, Cl₂ ⁺, NO⁺ and other. This revised version was published online in July 2006 with corrections to the Cover Date.     

Halido-bridged Copper(II) Complexes with 1-tert-Butyl-1H-tetrazole: Crystal Structure and Magnetic Properties

Complex [Cu(tbt)Cl₂]_n (tbt = 1-tert-butyl-1H-tetrazole) was prepared by reaction of tbt with copper(II) chloride in solution. According to single-crystal X-ray analysis, this complex presents 1D coordination polymer, formed at the expense of double chlorido bridges between neighboring pentacoordinate copper(II) cations. 1-tert-Butyl-1H-tetrazole acts as monodentate ligand coordinated by Cu^II cations via the heteroring N⁴ atoms. The temperature-dependent magnetic susceptibility measurements of novel complex [Cu(tbt)Cl₂]_n as well as described previously 1D coordination polymer [Cu(tbt)₂Cl₂]_n, and linear trinuclear complex [Cu₃(tbt)₆Br₆], were carried out. Magnetic studies revealed that the copper(II) ions were weakly ferromagnetically coupled in polymeric copper(II) chloride complexes, whereas complex [Cu₃(tbt)₆Br₆] showed antiferromagnetic coupling.     

Magnetic Properties and Structure of Polynuclear Compounds Based on Macrocyclic Azacyclam Complexes of Nickel(II) and Bridging Oxalate Ions

By X-ray diffraction analysis, we have established the structure of a binuclear complex of nickel(II) with an azacyclam ligand and a bridging oxalate ion. Study of the magnetic properties of a series of complexes of this type with related macrocyclic ligands has allowed us to observe antiferromagnetic coupling between the metal ions and a magnitude of the exchange integral J that varies in the range from –11.8 cm^–1 to –25.6 cm^–1. We have shown that, despite the close structural parameters of the macrocyclic ligands, the complexes are characterized by different magnetochemical behavior.     

Spectroscopic and Molecular Docking Studies of Cu(II), Ni(II), Co(II), and Mn(II) Complexes with Anticonvulsant Therapeutic Agent Gabapentin

New Cu(II), Ni(II), Co(II), and Mn(II) complexes of the gabapentin (Gpn) bidentate drug ligand were synthesized and studied using elemental analyses, melting temperatures, molar conductivity, UV–Vis, magnetic measurements, FTIR, and surface morphology (scanning (SEM) and transmission (TEM) electron microscopes).The gabapentin ligand was shown to form monobasic metal:ligand (1:1) stoichiometry complexes with the metal ions Cu(II), Ni(II), Co(II), and Mn(II). Molar conductance measurements in dimethyl-sulfoxide solvent with a concentration of 10⁻³ M correlated to a non-electrolytic character for all of the produced complexes. A deformed octahedral environment was proposed for all metal complexes. Through the nitrogen atom of the –NH₂ group and the oxygen atom of the carboxylate group, the Gpn drug chelated as a bidentate ligand toward the Mn²⁺, Co²⁺, Ni²⁺, and Cu²⁺ metal ions. This coordination behavior was validated by spectroscopic, magnetic, and electronic spectra using the formulas of the [M(Gpn)(H₂O)₃(Cl)]·nH₂O complexes (where n = 2–6).Transmission electron microscopy was used to examine the nanostructure of the produced gabapentin complexes. Molecular docking was utilized to investigate the comparative interaction between the Gpn drug and its four metal [Cu(II), Ni(II), Co(II), and Mn(II)] complexes as ligands using serotonin (6BQH) and dopamine (6CM4) receptors. AutoDock Vina results were further refined through molecular dynamics simulation, and molecular processes for receptor–ligand interactions were also studied. The B3LYP level of theory and LanL2DZ basis set was used for DFT (density functional theory) studies. The optimized geometries, along with the MEP map and HOMO → LUMO of the metal complexes, were studied.