Preparation and characterization of octacyanomolybdates(IV and V) and octacyanotungstates(IV and V) with 2,2′-bipyridylium cation

Reaction of protonated 2,2′-bipyridine (bpy) with octacyanometalates(IV and V), [M(CN)₈]ⁿ⁻ (M = Mo or W, n = 3 or 4), gave the following complexes: {(bpyH)₃[M(CN)₈]·4H₂O}, {(bpyH)₃(H₃O)[M(CN)₈]·H₂O}, {(bpyH₂)₂[W(CN)₈]·3H₂O} and {(bpyH₂)K₂[W(CN)₈]·2H₂SO₄·7H₂O}. These salts were characterized by electron absorption and reflectance spectrometry, IR, Raman and ESR spectrometry, thermo gravimetry and differential thermal analysis, cyclic voltammetry and potentiometry. The solubility of the salts in water and some polar organic solvents has been measured. The intensively coloured salts of molybdenum(IV) and tungsten(IV) have been discussed in terms of the bpyH⁺-[M(CN)₈]⁴⁻ ion pairs, which exhibit an outer-sphere electron transfer between adjacent redox sites.     

Structure and properties of di-μ-acetato-dichlorobis(2,2′-bipyridine)dirhodium(II)-trihydrate

Reduction of [Rh₂(-OAc)₂(bpy)₂(H₂O)₂](OAc)₂ and [Rh₂Cl₂(-OAc)₂(bpy)₂] · 3H₂O complexes with ethanol and [Cr₂(OAc)₄(H₂O)₂] has been investigated using e.p.r. and u.v.–vis. spectra. The results indicate that stable complexes containing the [Rh₂ ³⁺] entity are not formed. The X-ray structure of [Rh₂Cl₂(-OAc)₂(bpy)₂] · 3H₂O has been determined. Coordination around the Rh atom is in the form of a distorted octahedron. The complex shows an almost ideal eclipsed conformation. The equatorial coordination sites are occupied by bridging carboxylato ligands and 2,2-bipyridine and axial positions by the Cl ligand and the rhodium atom. The Rh–Rh distance is 2.574 Å.     

Kinetic study of the reaction between protonatedtrans-dioxotetracyanomolybdate(IV) and 2,2′-bipyridyl

Summary The kinetics of the reaction between the protonated forms of [MoO₂(CN)₄]^4– and 2,2-bipyridyl (bpy) have been studied in the 8.5–11.7 pH range. This study showed that the diprotonated form, [MoO(OH₂)(CN)₄]^2– is the only reactive species. The rate-limiting step is the substitution of the aqua ligand. This is followed by fast closure of the chelate ring, accompanied by the substitution of a cyanide ligand. With excess bpy the relatively slow formation of an adduct occurs. The nature of this adduct is discussed.     

Crystal structure of palladium(II) complex with 2,2′-dipyridylamine and 4-toluenesulfonyl-L-serine

The [Pd(dpa)(tsser)] complex (1) is prepared from the reaction of PdCl₂ and 2,2′-dipyridylamine (dpa) with 4-toluenesulfonyl-L-serine (tsserH₂). This complex is characterized by spectral methods (IR, UV-Vis, ¹H NMR, and luminescence), elemental analysis, thermal analysis (TG, DTA), and single crystal X-ray diffraction. X-ray structure determinations show that in this complex, Pd^II atoms are four-coordinated in a distorted square-planar configuration by two N atoms from a bidentate 2,2′-dipyridylamine ligand and one N atom and one O atom from a bidentate tsser^2– ligand.     

Synthesis, crystal structures, and magnetic properties of two three-dimensional octacyanotungstate(IV)- based bimetallic frameworks with 4,4′-bipyridine dioxide (4,4′-dpdo)

The reaction of [HN(n-C4H9)3]3[WV(CN)8]·4H2O, 4,4′-bipyridine dioxide(4,4′-dpdo), and MnCl2·4H2O or CuCl2·2H2O gives two new three-dimensional octacyanometalate-based bimetallic assemblies, {[Mn2 (4,4′-dpdo)(H2O)4] [WIV(CN)8]}·6H2O (1) and {[Cu2(4,4′-dpdo)(H2O)][W(CN)8]}·CH3OH·H2O (2). Compound 1 crystallizes in the orthorhombic system, space group P21212 with cell constants a=10.397(2) -, b= 11.321(2) -, c=12.295(3) - and Z=2, whereas 2 crystallizes in the monoclinic system, space group P21/c with cell con...     

Complexes of Te(IV), Te(II) and Se(II) with 2,2′-iminodiethanoldithiocarbamate

Novel complexes of 2,2′-iminodiethanoldithiocarbamate (DEADTC⁻) with Te(IV), Te(II) and Se(II) having the composition Te(DEADTC)₄, Te(DEADTC)₂I₂, Te(DEADTC)₃I, Te(DEADTC)₂ and Se(DEADTC)₂ were isolated and characterised by X-ray, magnetic, spectral (UV, IR) and conductance and molecular weight measurements. 2,2′-Iminodiethanoldithiocarbamate is shown to be weaker in its ligation behaviour than diethyldithiocarbamate.     

Synthesis and Crystal Structure of Bis(2,2′-Bipyridine-N,N′)Dichloromanganese(II) Complex with Free 2,2′-Bipyridine

The title complex [Mn(bipy)₂Cl₂]·0.5bipy·2.5H₂O, where bipy = 2,2'-bipyridine, has been prepared and its crystal structure has been determined by X-ray diffraction methods. The complex crystallizes in the triclinic space group P-1, with a = 8.814(2), b = 11.335(2), c = 13.347(3) Å, α = 76.85(2), β = 89.55(2), γ = 86.52(2)°. Two chloride and two bipy ligands cis-coordinate to a Mn(II) atom with a distorted octahedral geometry. The crystal consists of Mn(II) complex, free bipy and crystalline water. The complex crystalline water link to each other by H-bonding to form supra-molecular chains, and free bipy molecules locate between parallel chains with a van der Waals contact distance of 3.58(1) Å. A π-π interaction is also observed between adjacent bipy rings. The chelating bipy and free bipy showed different IR absorptions.     

Thermodynamics of 2,2′-dipyridinium ion and its iron(II) complex in ethanol-water mixtures at 298 K

The enthalpies of formation of 2,2′-dipyridinium ion and tris 2,2′-dipyridyl-iron(II) complex in ethanol-water media at 298 K have been determined by calorimetry and used in calculating thermodynamic parameters.     

Synthesis and properties of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with thulium salts

Summary New complexes of 2,2-dipyridyl and 4,4-dipyridyl with thulium salts TmX ₃ (whereX=Cl^–, Br^–, NO ₃ ^– , NCS^–, and ClO ₄ ^– ) have been prepared and their solubilities in water at 21 °C were determined. The IR spectra of these compounds are discussed. The conditions of thermal decomposition of the complexes were also studied.

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Synthese und Eigenschaften von 2,2-Dipyridyl- und 4,4-Dipyridylkomplexen mit Thuliumsalzen

Zusammenfassung Es wurden neue 2,2-Dipyridyl- und 4,4-Dipyridyl-Komplexen mit Thuliumsalzen TmX ₃ (X=Cl^–, Br^– No ₃ ^– , NCS^–, ClO ₄ ^– ) dargestellt und ihre Wasserlöslihkeit bei 21 °C bestimmt. Die IR-Spektren werden diskutiert. Das thermische Verhalten der erhaltenen Komplexe wurde untersucht.

     

Photochemistry of tetramethyl(2,2′-bipyridine)platinum(IV)

It is shown that photolysis of [PtMe₄(bipy)] using incident radiation with λ 436 or 473 nm occurs with high quantum efficiency of 0.8–1.0 to give homolysis of a methylplatinum bond; this has allowed a study of the chemical reactions of the [PtMe₃(bipy)] radical.     

Structure and magnetic properties of homobinuclear gadolinium (Ⅲ) complex of isonicotinoyl hydrazone

The crystal structure of [Gd2(μ-L)3(H2O)2].1.5(NO3).1.5 (OH)-5H2O (where L is an-ion of N, N'-Diisonicotinoyl-2-hydroxy-5-methyl-isophthalaIdehyde dihydrazone) has been determined by X-ray diffraction method. The complex crystallizes in the monoclinic system, space group P21/c with a=1.6654(3), b=1.6904(3), c=2.8039(6) nmβ=91.30(3)°, final R factor is 6.3%. The structrue consists of [Gd2(μ-L)3(H2O)2]3+ cation, one and a half nitrate and 1.5 hydroxyl anions and five water molecules. Within dinuclear cation, Gd(Ⅲ)-Gd(Ⅲ) is bridged by oxygen and nitrogen atoms of the three ligands, resulting in Gd...Gd distance of 0.36353(2) nm. Gd(Ⅲ) exhibits a distorted 1333 stack coordination environment. Magnetic susceptibility measurements in the temperature range 300-4 K revealed the occurrence of weak antiferromagnetic exchange interaction between two Gd(Ⅲ) ions with a J value of -0.22, and g of 1.93.     

Nickel(II) complex containing 5,5′-dimethyl-2,2′-bipyridine: Crystal structure and luminescent properties

[Ni(5,5′-dmbipy)₂Cl₂]·3H₂O (1) complex was obtained from the reaction of NiCl₂·6H₂O with 5,5′-dimethyl-2,2′-bipyridine (5,5′-dmbipy) in a mixture of CH₃OH/CH₃CN. This complex was characterized by elemental analysis, IR, UV-Vis and luminescence spectroscopy, and its structure was determined by the single-crystal diffraction method. The Ni atom has a distorted octahedral coordination by four N atoms from two 5,5′-dmbipy ligands and two Cl^– anions.     

Spectroscopic and structural properties of complexes of 3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine with copper(I) and silver(I)

The pseudo-tetrahedral complexes [CuL₂]PF₆·7H₂O·CH₃OH (1) and [AgL₂]CF₃SO₃·H₂O (2) (L?=?3,3′-bis(2-benzimidazolyl)-2,2′-bipyridine) have been synthesized and characterized through crystal structure analyses, electrochemistry, and spectroscopic methods. X-ray structural analyses of 1 and 2 indicate that sterically constrained N₄ ligands L are cis and behave as bidentate chelates to a single metal ion in a pseudo-tetrahedral fashion through the benzimidazole. As two benzimidazolyl rings exhibit considerable steric hindrance, the bipyridine unit of L remains uncoordinated. The pseudo-tetrahedral cation [CuL₂]⁺ shows a quasi-reversible Cu^I/Cu^II oxidation–reduction wave in the CV in DMF (counter-ion PF₆^?). The fluorescence titration of L with copper(I), silver(I), and also with pH have been conducted to examine the selectivity. The ligand shows remarkably high selectivity and sensitivity for Ag(I).     

Crystal structure,interaction with DNA,and bovine serum albumin of the cobalt(II) complex of demethylcantharate and 2,2′-bipyridine

A new cobalt(II) complex [Co(DCA)(bipy)(H₂O)] (DCA?=?demethylcantharate, 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, C₈H₈O₅; bipy?=?2,2′-bipyridine, C₁₀H₈N₂) was synthesized from cobalt acetate, demethylcantharidin, and bipy. This complex was characterized by elemental analysis, molar conductance, infrared spectra, and X-ray single-crystal diffraction. It crystallized in orthorhombic crystal system and Pbca space group. The DNA binding of the complex was investigated by electronic absorption spectra and viscosity measurements. The complex binds to DNA via partial intercalation with binding constant K _b of 4.02?×?10⁴?L?M^?1. The complex could quench the intrinsic fluorescence of bovine serum albumin through static quenching. The binding constant K _A was 7.28?×?10⁶?L?M^?1 and binding site was one.     

Synthesis and characterization of complexes of the first transition series cations with 2,2′-biimidazole and 2,2′-biimidazolate

Mononuclear [M(hfacac)₂(H₂biim)] complexes, where M = Mn^II, Fe^II, Co^II, Ni^II, Cu^II or Zn^II, hfacac = hexafluoroacetylacetonate, H₂biim = 2,2-biimidazole; dinuclear K₂[M₂(acac)₄(-biim)] (M = Cu^II or Zn^II) and tetranuclear K₂[M₄(acac)₈( ₄-biim)] (M = Co^II or Ni^II) complexes have been prepared and characterized by chemical analysis, conductance measurements, i.r., electronic and e.p.r. spectroscopies and by magnetic susceptibility measurements (in the 2–300 K range). Mn^II, Fe^II and Co^II are in a high spin state. The e.p.r. spectra of Cu^II and Mn^II compounds have been recorded.     

Synthesis,Crystal Structure and Bioactivity of a Pd(Ⅱ) Complex with Demethylcantharate and 2,2′-Bipyridine

A novel crystal with the molecular formula [Pd(DCA)(bipy)]2 [Pd(bipy)Cl2 ]·6.75H2O was formed by PdCl2 with disodium demethylcantharate (Na2 (DCA),DCA2= 7-oxa-bicyclo[2.2.1]heptane-2,3-bicarboxylate) and 2,2-bipyidine (bipy) through the hydrothermal method.The complex was characterized by elemental analysis and infrared spectroscopy.The structure of the complex was determined by single-crystal X-ray diffraction,which is of triclinic system,space group P1 with a=13.6818(7),b=14.8426(8),c=15.0043(8),α=97.319(3),β=92.521(3),γ=105.776(2)°,V=2898.4(3) 3,Dc=1.545 g·cm-3,Z=1,F(000)=1420,S=0.852,the final R=0.0525 and wR=0.1777 for 13634 observer reflections (I>2σ(I)).The binding reaction of the complex with ct-DNA and bovine serum albumin (BSA) was studied by fluorescence spectroscopy.The results indicated that the complex binds to ct-DNA via the partial intercalation.The binding constant K A of the complex interaction with BSA was 3.98×10 5 L·mol-1 and one binding site would be formed.The antiproliferative activity of the complex against human hepatoma cells (SMMC7721) in vitro is much higher than that of Na 2 (DCA).     

Structural characterization of copper (II) tetradecanoate with 2,2′-bipyridine and 4,4′-bipyridine to study magnetic properties

This paper presents synthesis, structural characterization and spintronic applications of copper (II) tetradecanoate derived magnetic complexes. The complexes were prepared by a chemical reaction between [Cu₂(CH₃(CH₂)₁₂COO)₄](EtOH)₂ and 2,2′-bipyridine-4,4′-bipyridine ligands respectively. The complexes were further reacted between the product of the first reaction and 4,4′-bipyridine-2,2′-bipyridine respectively. The structural characterization techniques included elemental analysis, Fourier transformed infrared spectroscopy (FTIR), Ultra-violet–Visible (UV–Vis) spectroscopy, polarized optical microscopy, magnetic moment and thermogravimetric analysis. The structural and characterization results suggested that the synthesized complexes were binuclear and mononuclear covalent complexes of copper(II) with structural formulas [Cu₂(η²-(OOCR)₄](4,4′-bpy)2H₂O] and [Cu(η¹-(OOCR)₂(2,2′-bpy) (4,4′-bpy)] respectively.     

Synthesis and Crystal Structure of a Cadmium(II) Complex with 2,2′-diamino-4,4′-bis-1,3-thiazole

Crystals of the title complex with diaminobithiazole (DABT) were obtained by a solution diffusion method. X-ray diffraction analysis shows the complex to be monoclinic, space group P2₁/c with cell dimensions a=11.684(2), b=13.625(2), c=14.859(1) Å and β=109.970(7)°; R=0.026. The Cd(II) atom lies in a distorted octahedral environment with two DABT and two Cl ligands in a cis arrangement. The average internal dihedral angle of 9.3° between thiazole rings of DABT shows the twisted structure of the ligand in the complex. The Cd(II) atom deviates by some -0.570 Å from the mean plane of the thiazole ring containing N(4), but the Cd-N(4) bond is the shortest among four Cd-N bonds in the structure. Intramolecular H-bonds between Cl atoms and amino groups stabilize the cis-configuration of the complex.     

Kinetics and mechanism of reactions of bis(biguanide)copper(II) ion with 2,2′-bipyridyl and 1,10-phenanthroline in aqueous solution

Summary In aqueous solution [Cu(bigH)₂]²⁺ (bigH=biguanide) reacts with 2,2-bipyridyl (bipy) and 1,10-phenanthroline (phen) through intermediate formation of ternary complexes [Cu(bigH)(L)]²⁺ and [Cu(bipy)(phen)]²⁺ and binary complexes [CuL₂]²⁺ (L=bipy, phen). The rates of the different steps have been followed in borax buffer (pH 8.0±0.1) by stopped-flow spectrophotometry. For each step k_obs=k₀+k_L[L] and the k_L path appears to be associative. H and S values for the k_L path conform to an isokinetic trend.