金属桥联双二茂铁配合物的结构与三阶非线性光学性质研究

三种金属桥联双二茂铁的三核配合物的合成、结构、电化学及三阶非线性光学性质,通过四圆X射线衍射测定,确定了铜配合物的晶体结构。铜配合物为高度畸变的平面四边形构型。双二茂铁处于顺式结构,这种结构由茂环间的π-π相互作用而变得稳定。研究表明,它们的结构、电化学性质及三阶非线性光学性质三者有密切的内在联系。平面型金属配合物桥联双二茂铁体系中电子离域程度高,在电化学上表现为两步连续单电子氧化过程,其三阶非线性光学效应较强,变形四面体型铜配合物桥联双二茂铁只有一个氧化还原过程,其三阶效应也较低。     

双二茂铁-钯配合物的合成，结构和电化学

本文讨论了由二茂铁的C-H…π作用组装的具有类环己烷结构的氨基硫脲钯金属配合物的结构和电化学性能。晶体结构中钯原子以顺式平面正方形的构型分别与两个氨基硫脲配体配位，两个配体中的二茂铁基团位于钯原子同一侧，每个二茂铁与相邻分子中的二茂铁基团通过环戊二烯基环间的C-H…π作用形成由类环己烷结构连结的二维网状结构。对钯的配合物及相关的镍和锌配合物的电化学研究表明，平面正方型的钯和镍可以有效的传递两个茂铁间的氧化-还原性能。     

Preparation,Characterization, Biological Activity and 3D Molecular Modeling of Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Ru(III) Complexes of Some Sulfadrug Schiff Bases

Mn(II), Co(II), Ni(II), Cu(II), Pd(II) and Ru(III) complexes of Schiff bases derived from the condensation of sulfaguanidine with 2,4‐dihydroxy benzaldehyde ( HL1 ), 2‐hydroxy‐1‐naphthaldehyde ( HL2 ) and salicylaldehyde ( HL3 ) have been synthesized. The structures of the prepared metal complexes were proposed based on elemental analysis, molar conductance, thermal analysis (TGA, DSC and DTG), magnetic susceptibility measurements and spectroscopic techniques (IR, UV‐Vis, and ESR). In all complexes, the ligand bonds to the metal ion through the azomethine nitrogen and α‐hydroxy oxygen atoms. The structures of Pd(II) complex 8 and Ru(III) complex 9 were found to be polynuclear. Two kinds of stereochemical geometries; distorted tetrahedral and distorted square pyramidal, have been realized for the Cu(II) complexes based on the results of UV‐Vis, magnetic susceptibility and ESR spectra whereas octahedral geometry was predicted for Co(II), Mn(II) and Ru(III) complexes. Ni(II) complexes were predicted to be square planar and tetrahedral and Pd(II) complexes were found to be square planar. The antimicrobial activity of the ligands and their metal complexes was also investigated against the gram‐positive bacteria Staphylococcus aures and Bacillus subtilis and gram‐negative bacteria, Escherichia coli and Pesudomonas aeruginosa, by using the agar dilution method. Chloramphenicol was used as standard compound. The obtained data revealed that the metal complexes are more or less, active than the parent ligand and standard. The X‐ray crystal structure of HL3 has been also reported.     

Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by ¹H, ¹³C NMR, UV–Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 μm.     

Synthesis and Single Crystal Structure of a New Dinuclear Copper(II) Complex of 1,5-Bis(8-oxaquinoline)-3-methylpentane

A new flexible ligand, 1,5-bis(8-oxaquinoline)-3-methylpentane (C5MeOQ), was synthesized and used in the preparation of the new dinuclear copper(II) complex 1: [Cu₂(μ-OMe)₂(μ-C5MeOQ)(NO₃)₂]. Single crystal X-ray analysis revealed that complex 1 contains dinuclear Cu(II) units with bridging methoxo groups. The ligand, C5MeOQ, takes on a bent conformation in order to connect to and complete the square planar coordination environment of both copper centers; and one of the two Cu(II) centers adopts a distorted square planar configuration as a result of the ligand conformation. The magnetic properties of complex 1 were investigated by variable-temperature magnetic susceptibility measurements in the 100–300 K range. Interestingly, the susceptibility data for complex 1 reveals that the compound is diamagnetic, suggesting the presence of very strong antiferromagnetic coupling interactions between the adjacent Cu(II) centers.     

Synthesis and characterization of self-assembled coordination polymers of N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide

The azo dye ligand N-diaminomethylene-4-(3-formyl-4-hydroxy-phenylazo)-benzenesulfonamide (HL) and Cu(II), Co(II), and Mn(II) coordination polymers were synthesized in addition to a non-polymeric Pd(II) complex. In all complexes, the ligand bonds to the metal ion through the formyl and α-hydroxy oxygen atoms. The sulfonamide oxygen also coordinates to the metal. The complexes are formulated as [ML₂] _n , where M?=?Cu(II), Co(II), and Mn(II), and [ML(Cl)(H₂O)], where M?=?Pd(II). On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry was assigned to Co(II) and Mn(II) complexes, tetragonally elongated octahedral geometry for Cu(II) complex, while the Pd(II) complex was found to be square planar. Crystallization of Cu(II) complex from DMF afforded single crystals of general formula {[Cu(L)₂]?·?3DMF} _n (2). X-ray structural analysis of 2 revealed that each Cu(II) adopts elongated octahedral geometry affording 1-D chains. The chains are connected by hydrogen bonds, resulting in the formation of 2-D supramolecular assemblies. The crystal structure of HL has also been determined and discussed. Cyclic voltammetric behavior of the ligand and some complexes are also discussed.     

Coordination chemistry of [methyl-3-(4-benzyloxyphenyl)methylene]dithiocarbazate with divalent metal ions: crystal structures of the <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">S</Emphasis> Schiff base and of its bis-chelated nickel(II) complex

The condensation of 4-benzyloxybenzaldehyde with S-methyldithiocarbazate (SMDTC) yielded the Schiff base methyl-3-[(4-benzyloxyphenyl)methylene] dithiocarbazate (HL) that, upon reaction with different metal ions, afforded bis-chelated complexes, ML₂ [where M=Ni(II), Cu(II), Zn(II), Cd(II) or Pd(II)]. The ligand and all the metal complexes were characterized by physico-chemical and spectroscopic methods. The Schiff base and its bis-chelated Ni(II) complex were characterized also by single crystal X-ray analyses. The crystallographic results show that the Schiff base exists in thione tautomeric form with the dithiocarbazate fragment adopting an EE configuration with respect to the C=N bond of the group. In the NiL₂ complex, the metal is chelated by two mononegatively charged Schiff bases coordinating via the β-nitrogen and thiolate sulfur anion, generated in situ during the complexation process, and adopts a distorted square planar geometry.     

Coordination of carbonyl oxygen in the complexes of polymeric <Emphasis Type="Italic">N</Emphasis>-crotonyl-2-hydroxyphenylazomethine

The Schiff base N-crotonyl-2-hydroxyphenylazomethine HL, derived from the reaction of acrylamide and salicylaldehyde, was synthesised. Polymeric complexes were obtained from the reaction of polymeric HL with divalent metals. The mode of bonding and overall geometry of the complexes were determined through physico-chemical and spectroscopic methods and compared with that previously reported for the analogous monomeric ligand. These studies revealed tetrahedral geometries around the metal centres for Mn(II), Co(II), Zn(II), Cd(II) and Hg(II) complexes of general formula [M(L)Cl], octahedral for Ni(II) and Cu(II) complexes of general formula [M′(L)Cl(H₂O)₂], and square planar for Pd(II) complex of general formula [Pd(L)Cl].     

Spectroscopic investigations and physico-chemical characterization of newly synthesized mixed-ligand complexes of 2-methylbenzimidazole with metal ions

Some mixed ligand complexes containing 2-methylbenzimidazole and thiocyanate ion were synthesized. Free ligands and their metal complexes were characterized using elemental analysis, determination of metal, magnetic susceptibility, molar conductivity, infrared, UV-VIS, and (¹H, ¹³C) NMR spectra, and X-ray structure analysis. The results suggest that the Ag(I) complex has linear geometry, Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) have tetrahedral geometry, Pd(II) complex has square planar geometry, VO(IV) square pyramidal geometry, Pb(II) irregular tetrahedral geometry, and that the Cr(III) and Mn(II) complexes have octahedral geometry. The following general formulae were proposed for the prepared complexes: [AgBX], [CrB₃X₃], (HB)₂[MnB₂X₄] · 2B and [MB₂X₂], where B = 2-methylbenzimidazole, HB = 2-methylbenzimidazolium, X = thiocyanate ion, and M = VO(IV), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Pd(II), Cd(II), and Pb(II). Molar conductance of a 10⁻³ M solution in N,N-dimethyl formamide (DMF) indicates that all the complexes are non-electrolytes except the Mn(II) complex which is an electrolyte because the molar conductivity of its solution in DMF is high.     

Preparation and characterization of Cu(II)-N-salicylideneanthranilic acids,their reduction products and hydrolysis of the Schiff base

Copper (II) complexes ofN-salicylideneanthranilic acid (I) and its derivatives (II, III) as well as their NaBH₄ reduction products, namelyN-(2-hydroxybenzyl) anthranilic acids (IV–VI) have been prepared and their structures have been determined analytically. Tetracoordinated planar structures of the Cu(II) complexes of the Schiff bases and distorted tetrahedral structures of the Cu(II) complexes of compoundsV–VI have been elucidated by ESR and other spectral methods. During the preparation of the complex the hydrolysis of the Schiff base often takes place in the presence of water giving anthranilates and salicylaldehydates of metals to some extent along with the complexes of the Schiff base. The kinetic data for the hydrolysis ofN-salicylideneanthranilic acid (I) in methanol-water solution also are reported.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995.     

[M{κ2S,S-S2C-piperazine-C2H4N=C(R)}n] {Co(III), Ni(II), Cu(II) or Zn(II)} complexes bearing pendant Schiff base moieties: spectral characterization,fluorescence, cyclic voltammetric and TGA/DTA study

A series of neutral mononuclear complexes [M{κ²S,S-S₂C-piperazine-C₂H₄N=C(R)}_n] {R?=?Ph; M?=?Co(III) 1, Ni(II) 2, Cu(II) 3, Zn(II) 4; R?=?Naph; M?=?Co(III) 5, Ni(II) 6, Cu(II) 7, Zn(II) 8; n = 2 for 2–4, 6–8 and n = 3 for 1, 5} bearing pendant Schiff base moieties were synthesized through self-assembly involving N-[phenylmethylidene]-2-piperazin-1-ylethanamine (L¹) or N-[naphthylmethylidene]-2-piperazin-1-ylethanamine (L²) with two equivalents each of CS₂ and corresponding metal acetates. The complexes 1–8 were characterized by microanalysis, ESI-MS, IR, ¹H, ¹³C NMR, DEPT 135, UV–visible absorption, and emission spectroscopy. Complexes 1, 3, and 8 exhibit fluorescence emissions at 342, 344, and 348 nm upon excitation at 273 (for 1 and 3) and 263 (for 8) with concomitant Stokes shifts of 69, 71, and 85 nm. The spectral and magnetic moment data support octahedral geometry around Co(III) and square planar/tetrahedral geometry around other metal centers. Thermal stabilities of 1–8 have been investigated by thermogravimteric analysis. The cyclic voltammograms clearly suggest that the complexes exhibit electroreduction principally associated with pendant imine moieties except Cu(II) complex 7 which displays quasi-reversible reduction corresponds to the Cu(II)/Cu(I) redox couples, in addition to reversible electroreduction of pendant imine groups associated with the coordinated ligands.     

Studies on Binuclear Co(II) and Cu(II) Complexes of Tridentate N-(2-Carboxyphenyl)Salicylideneimine

Homo Cu(II) and Co(II) binuclear complexes H[MLClMCl₂] formed by using the donor properties of the cis two oxygen atoms of the tridentate N-(2-carboxyphenyl)-salicylaldimine Schiff base derived from salicylaldehyde and anthranilic acid have been synthesized. It was found that the Cu(II) “complexed ligand” readily reacts with CoCl₂ to form mononuclear Co(II) and binuclear oxygen bridged Co(II) complex [Co₂-L₂](H₂O)₂. The structure of the so prepared complexes was investigated using microchemical analysis, molar conductance measurements as well as electronic and vibrational spectral studies. It was concluded that in the Cu(II) binuclear complex, the Cu(II) ion inside the “complexed ligand” has a planar structure while the other Cu(II) ion is distorted away from planarity. In the Co(II) binuclear complex, the Co atom of the “complexed ligand” is distorted from tetrahedral structure when it coordinates to the second Co atom.     

Synthesis,crystal structures,and superoxide dismutase activity of two isostructural copper(II)–zinc(II) complexes derived from N,N′-bis(4-methoxysalicylidene)cyclohexane-1,2-diamine

Two new isostructural copper(II)–zinc(II) complexes, [CuZnLBr₂] (1) and [CuZnLCl₂] (2) (H₂L = N,N′-bis(4-methoxysalicylidene)cyclohexane-1,2-diamine), have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Both complexes crystallize in the P-1 space group. The Cu in each complex is four-coordinate square planar with two imines and two phenolates of L. The Zn in each complex is four-coordinate tetrahedral with two phenolates of L and two halides (Br for 1 and Cl for 2). The superoxide dismutase (SOD) activity of the complexes indicates that both complexes are rudimentary models for SOD.     

Structures of Ni(II), Pd(II) and Cu(II) complexes with 1,2-<Emphasis Type="Italic">bis</Emphasis>(5,5,5-trifluoro-4-oxopent-2-en-2-amino)benzene

A new fluorine-containing tetradentate ligand 1,2-bis(5,5,5-trifluoro-4-oxopent-2-en-2-amino)benzene and its complexes with Ni(II), Pd(II) and Cu(II) are characterized by single crystal X-ray diffraction. It is found that the enaminoketone fragments of the ligand are identical in bond lengths and angles; they are almost planar, and make the angles of 51.3° to the plane of the benzene ring. The structures of Ni(II), Pd(II), and Cu(II) complexes are similar and have a saddle-shape configuration. The metal ions have square planar coordination and are located almost in the center of the N₂O₂ square. The average M-N bond lengths are longer than M-O ones by 0.014 Å and 0.034 Å for the Ni(II) and Cu(II) complexes respectively, while in the Pd(II) complex, M-O is longer than M-N by 0.029 Å. The average chelate angles N-M-O in the complexes are: N-Ni-O 95.12°; N-Pd-O 95.68°; N-Cu-O 93.88°.     

Zinc (II), palladium (II) and cadmium (II) complexes containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline derivatives: Synthesis,characterization and methyl methacrylate polymerization

A series of Zn (II), Pd (II) and Cd (II) complexes, [(L) _n MX ₂ ] _m (L = L‐a–L‐c; M = Zn, Pd; X = Cl; M = Cd; X = Br; n, m = 1 or 2), containing 4‐methoxy‐N‐(pyridin‐2‐ylmethylene) aniline ( L‐a ), 4‐methoxy‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐b ) and 4‐methoxy‐N‐methyl‐N‐(pyridin‐2‐ylmethyl) aniline ( L‐c ) have been synthesized and characterized. The X‐ray crystal structures of Pd (II) complexes [L ₁ PdCl ₂ ] (L = L‐b and L‐c) revealed distorted square planar geometries obtained via coordinative interaction of the nitrogen atoms of pyridine and amine moieties and two chloro ligands. The geometry around Zn (II) center in [(L‐a)ZnCl ₂ ] and [(L‐c)ZnCl ₂ ] can be best described as distorted tetrahedral, whereas [(L‐b) ₂ ZnCl ₂ ] and [(L‐b) ₂ CdBr ₂ ] achieved 6‐coordinated octahedral geometries around Zn and Cd centers through 2‐equivalent ligands, respectively. In addition, a dimeric [(L‐c)Cd(μ ‐ Br)Br] ₂ complex exhibited typical 5‐coordinated trigonal bipyramidal geometry around Cd center. The polymerization of methyl methacrylate in the presence of modified methylaluminoxane was evaluated by all the synthesized complexes at 60°C. Among these complexes, [(L‐b)PdCl ₂ ] showed the highest catalytic activity [3.80 × 10⁴ g poly (methyl methacrylate) (PMMA)/mol Pd hr^?1], yielding high molecular weight (9.12 × 10⁵ g mol^?1) PMMA. Syndio‐enriched PMMA (characterized using ¹H‐NMR spectroscopy) of about 0.68 was obtained with T_g in the range 120–128°C. Unlike imine and amine moieties, the introduction of N‐methyl moiety has an adverse effect on the catalytic activity, but the syndiotacticity remained unaffected.     

Preparations,IR spectra and crystal structures of cyano-bridged bimetallic complexes of zinc(II) and cadmium(II) with tetracyanopalladate(II)

The novel heteronuclear compounds [Zn(hydet-en)₂Pd(CN)₄] (1) and [Cd(hydet-en)₂Pd(CN)₄] (2) {hydet-en: N-(2-hydroxyethyl-ethylenediamine)} have been synthesized and characterized by elemental analyses and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. Structural analysis shows that both compounds have shown a polymeric chain, in which the Zn(II)/Pd(II) and Cd(II)/Pd(II) centres are linked by two CN groups. Both zinc and cadmium atoms are six coordinate with two trans cyanide–nitrogen and four hydet-en N atoms in a distorted octahedron arrangement; the palladium atoms in 1 and 2 are four coordinate with four cyanide-C atoms in a square planar arrangement. The chains in both compounds are connected through weak interchain hydrogen bonds, N–H?···?O, N–H?···?N and O–H?···?N, thereby forming a three-dimensional network.     

Synthesis and complexation of 1,4,7-oxadithiononane-5,6-dionedioxime

A new vic-dioxime 1,4,7-oxadithiononane-5,6-dionedioxime (H₂L) was prepared from reaction of 2,2-oxydiethanthiol with dichloroglyoxime. Mononuclear complexes of H₂L with Ni(II), Co(II), Cu(II), Zn(II), and Cd(II) were also prepared and their structures were determined by means of ¹H?NMR, ¹³C?NMR, IR, and mass spectroscopy. Ni(II), Co(II), and Cu(II) form square planar complexes of 1?:?2 molar ratio of metal to ligand through N,N-chelation, while Zn(II) and Cd(II) form 1?:?1 tetrahedral complexes with a N,O-chelation.     

Nickel(II) and cobalt(II) complexes of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe)

Nickel(II) and cobalt(II) bis-chelates of methyl(2-aminocyclopentene-1-dithiocarboxy)-S-acetate (ACDASAMe) were synthesized and characterized by spectroscopic methods and in the case of the nickel complex, X-ray single-crystal diffraction. The ligand exhibits the (N, S) coordination mode on interacting with the metal centers. The X-ray structure of the nickel(II) complex reveals a NiN₂S₂ distorted square planar coordination geometry with the ligands showing a cis configuration. There is no interaction between the –CH₂COOMe moieties of the ligand and the metal center, however intermolecular hydrogen bonds through the carbonyl group leads to the building of dimeric associations.     

Synthesis,characterization, and biological evaluation of Cu(II) complexes with the proton transfer salt of 2,6-pyridinedicarboxylic acid and 2-amino-4-methylpyridine

A proton transfer compound, (Hamp)⁺(Hdipic)^??·?1.5H₂O (1), and Cu(II) complexes, [Cu(dipic)(amp)(H₂O)]?·?[Cu(dipic)(amp)]?·?H₂O?·?CH₃COOH (2) and [Cu(dipic)(amp)Cu(dipic)(amp)(H₂O)Cu(dipic)(amp)(H₂O)]?·?3H₂O (3), have been synthesized from 2,6-pyridinedicarboxylic acid (H₂dipic) and 2-amino-4-methylpyridine (amp). They have been characterized by elemental, spectral (¹H-NMR, IR, and UV-Vis), and thermal analyses. In addition, magnetic measurements and single crystal X-ray diffraction have been applied to 2 and 3. The crystal structure of 2 consists of two independent and different cationic sites with Cu²⁺ ions. Cu1 is four-coordinate in a distorted square planar geometry and Cu2 is five-coordinate in a distorted square pyramid. Compound 3 has three independent and different cationic sites of Cu²⁺ ions. Cu1 is four-coordinate in a distorted square planar geometry and Cu2 and Cu3 have five-coordinate, distorted square-pyramidal sites. Inhibitory effects of 1, 2, and 3 have been studied and compared with starting compounds (amp and H₂dipic) on bacterial growth of Staphylococcus aureus and Escherichia coli cultures. Compounds 2 and 3 prevent bacterial growth although 1 has no effect. Compounds 2 and 3 are more effective than amp and H₂dipic, at similar concentrations on preventing bacterial growth for both organisms.     

Copper(II) and molybdenum(VI) complexes with 5-bromosalicylaldehyde S-allylisothiosemicarbazone: Syntheses,characterizations and crystal structures

A new tridentate Schiff base, 5-bromosalicylaldehyde S-allylisothiosemicarbazone hydrobromide (H₂L), and several new mononuclear complexes of copper(II) and molybdenum(VI) of this ligand with general formulas ([Cu(L)Im] (1)), ([Cu(L)NH₃]·4H₂O (2)), and ([MoO₂(L)1-MeIm] (3), Imidazole: Im, 1-methylimidazole: 1-MeIm) were prepared and characterized by elemental analyses, IR, proton magnetic resonance Spectroscopy, and ultraviolet–visible techniques. The physico-chemical results suggested that the H₂L coordinates in the dianionic tridentate form. Crystal structures of the Cu(II) complexes reveal a square planar configuration surrounded by the dianionic tridentate isothiosemicarbazone (ONN) and Im and NH₃ for 1 and 2, respectively. The L^2-, two oxo, and 1-methylimidazole are coordinated to molybdenum(VI) in a distorted octahedral geometry in 3. Formation of pure metal oxide residues was confirmed by thermal degradation of the complexes.