Hydrothermal synthesis and characterization of a zigzag neodymium-2,2′-bipyridine-3,3′-dicarboxylate-isonicotinate coordination polymer

A new neodymium(III) coordination polymer, {[Nd(bpdc)(iso)(H₂O)₂] ? (H₂O)_2.25} _n (1), was synthesized by treating neodymium oxide with 2,2′-bipyridine-3,3′-dicarboxylic acid (H₂bpdc), and isonicotinic acid (Hiso) under hydrothermal conditions. Single-crystal X-ray diffraction shows that 1 is a 1-D zigzag chain and extends to 2-D network structure through π–π interactions and hydrogen bonds. Thermogravimetric analysis of 1 displays a considerable thermal stability. The variable-temperature magnetic susceptibility of 1 was measured.     

Role of cyanide as a bridging ligand in cis-aquocyanoCo(III) complexes containing 2,2′-bipyridine and 1,10-phenanthroline

Cis-aquocyanobis(2,2′-bipyridine)Co(III) and cis-aquocyanobis(1,10-phenanthroline)Co(III) cations present in their IR spectra as cyano-group band in a Nujol mull at ν = 2200 cm⁻¹. To justify the shift in the frequency from 2140 to 2200 cm⁻¹ of cyanide in these compounds, we have hypothesized that the cyano group is a bridge between the metal atom and one hydrogen atom of the water molecule in the cis position on the Co(III) coordination sphere.     

Kinetics and mechanism of substitution of bis(tptz)iron(II) by 2,2′-bipyridine and 1,10-phenanthroline

The kinetics of substitution of Fe(tptz)²+₂ by 2,2-bipyridine and 1,10-phenanthroline have been investigated in acetate buffers in the 3.6–5.6pH range employing stopped-flow spectrophotometry. These reactions are very fast and complete within 5s. The rate of substitution is linearly dependent on [phen] and [bpy]², and increases with the increase in pH. Suitable mechanisms have been proposed involving the unprotonated form of the entering ligand, viz. bipyridine/phenanthroline as the reactive species. The pK_a values of bipyridine and phenanthroline, determined from the kinetic data, are in agreement with the literature values. It is concluded that the substitutions of iron(II)-diimine complexes also occur by an associative mechanism.     

Synthesis,structure, and characterization of a silver(I) coordination polymer with μ6-bridging 2,2′-bipyridyl-3,3′-dicarboxylate

A silver(I) coordination polymer, [Ag₂(bpdc)] _n (1) (H₂bpdc = 2,2′-bipyridyl-3,3′-dicarboxylic acid), has been synthesized and characterized. Compound 1 exhibits a 2-D network containing 1-D channels. Each (bpdc)^2? is an octadentate μ₆-1igand coordinating with six Ag(I)'s in 1. This coordination of (bpdc)^2? ligand is first observed here. Neighboring networks are arranged in a [ABAB···] pattern to form 3-D supramolecular architecture by π···π stacking. Compound 1 shows intense photoluminescence at room temperature.     

Dioxochromium(V) complexes with 1,10-phenanthroline and 2,2′-bipyridine ligands

cis-[Cr^III(phen)₂(H₂O)₂]³⁺ and cis-[Cr^III(bipy)₂(H₂O)₂]³⁺ (phen = 1,10-phenanthroline and bipy = 2,2-bipyridine) were readily oxidized by either PbO₂ or PhIO to form the chromium(V) complexes [Cr^V(phen)₂(O)₂]⁺ and [Cr^V(bipy)₂(O)₂]⁺ respectively, which were characterized by elemental analysis, i.r. and e.s.r. spectroscopy.     

Nature of the compounds of 2,2′-bipyridyl dioxide 1,10-phenanthroline dioxide and pyridine n-oxide with thallium(III)chloride

Thallium(III)chloride forms compounds of composition TiCl₃·PhenO₂, TlCl₃·BipyO₂, 2TlCl₃·3BipyO₂ and TlCl₃·3PyNO with 1,10-phenanthroline dioxide, 2,2′-bipyridyl dioxide and pyridine N-oxide. From conductance, cryoscopic and IR spectral studies their structural type has been elucidated.     

Molecular structure of a coordination compound tris(phenanthroline)zinc(II) 2,2′-Bipyridyl-5,5′-dicarboxylate dodecahydrate

The [Zn(phen)₃](2,2′-Bipy-5,5′-dicarboxylate)·12H₂O complex is synthesized and its crystal structure is determined by single crystal X-ray crystallography. The crystals of the coordination compound have a monoclinic unit cell with parameters a = 12.2533(14) Å, b = 18.976(2) Å, c = 22.426(3) Å, β = 105.675(2)°, V = 5020.54(300) ų, Z = 4, P2_1/n space group. The environment of the Zn atom is a distorted octahedron of six N atoms belonging to three coordinated phen molecules. In the structure, π-π interactions between phen molecules as well as between phen molecules and 2,2′-bipyridyl-5,5′-dicarboxylate anions give rise to the formation of three-dimensional ensembles. The 2,2′-bipyridyl-5,5′-dicarboxylate anion and twelve water molecules are not coordinated, and the molecules of water of crystallization make clusters.     

Revealing the structural chemistry of the group 12 halide coordination compounds with 2,2′-bipyridine and 1,10-phenanthroline

The coordination compounds of group 12 halides with 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen), 2[CdF₂(bpy)₂]·7H₂O (1), [ZnI(bpy)₂]⁺·I₃^? (2), [CdI₂(bpy)₂] (3), [Cd(SiF₆)H₂O(phen)₂]·[Cd(H₂O)₂(phen)₂]²⁺·F^–·0.5(SiF₆)^2–·9H₂O (4), [Hg(phen)₃]²⁺·(SiF₆)^2–·5H₂O (5), [ZnBr₂(phen)₂] (6), 6[Zn(phen)₃]²⁺·12Br^–·26H₂O (7) and [ZnI(phen)₂]⁺·I^– (8), have been synthesized and characterized by X-ray crystallography, IR spectroscopy, elemental and thermal analysis. Structural investigations revealed that metal?:?ligand stoichiometry in the inner coordination sphere is 1?:?2 or 1?:?3. A diversity of intra- and intermolecular interactions exists in structures of 1–8, including the rare halogen?halogen and halogen?π interactions. The thermal and spectroscopic properties were correlated with the molecular structures of 1–8. Structural review of all currently known coordination compounds of group 12 halides with bpy and phen is presented.     

Di- and trinuclear Ru(II) complexes of 1,10-phenanthroline and 2,2′-bipyridine derivatives; synthesis,photophysical and electrochemical properties

Three heterotopic ligands L¹, L², and L³ based on 1,10-phenanthroline and 2,2′-bipyridine moieties have been synthesized and characterized. The Ru(II) complexes [{Ru(bpy)₂}₃(µ₃-L¹)](PF₆)₆, [{Ru(bpy)₂}₃(µ₃-L²)](PF₆)₆, and [{Ru(bpy)₂}₂(µ₂-L³)](PF₆)₄ (bpy = 2,2′-bipyridine) have been prepared by refluxing Ru(bpy)₂Cl₂·2H₂O with each ligand in ethanol. All three complexes display MLCT absorptions at around 455 nm and emissions at around 618 nm. Electrochemical studies of the complexes reveal one Ru(II)-centered quasi-reversible oxidation at around 1.32 V and three ligand-centered reductions in each case.     

Synthesis,crystal structure,spectroscopic and thermal investigations of neodymium(III) biphenyl-4,4′-dicarboxylate framework

The three-dimensional complex {[Nd(bpdc)_1.5(DMF)]·1.4DMF}_n (DMF=N,N′-dimethylformamide, bpdc=biphenyl-4,4′-dicarboxylate) was synthesized using the solvothermal method. The crystal structure of the neodymium(III) complex has been determined by single-crystal X-ray diffraction method at 100(2) K. The polymeric structure consists of neodymium polyhedra bridged by bpdc ligands. Eight-coordinated Nd(III) atoms are surrounded by seven oxygen atoms from six bpdc moieties and one oxygen atom from the DMF molecule. The 3D structure of the complex contains two types of channels occupied by DMF molecules. Thermal analysis revealed that DMF molecules are lost in a stepwise manner. The infrared spectrum confirmed full deprotonation of acid and presence of DMF molecules in the structure.      

Solubilities and solvation of bis-(2,2′-bipyridyl)- and bis-(1,10-phenanthroline)dicyanoiron(II) in alcohols

Summary Solubilities of bis-(2,2-bipyridyl)- and bis-(1,10-phenanthroline)dicyanoiron(II) are reported for a range of primary aliphatic alcohols, from MeOH to 1-decanol. The established trends are compared with those for other solutes, and for the title compounds in H₂O-alcohol solvent mixtures.     

Antimicrobial mechanism of copper (II) 1,10-phenanthroline and 2,2′-bipyridyl complex on bacterial and fungal pathogens

Copper based metallo drugs were prepared and their antibacterial, antifungal, molecular mechanism of [Cu(SAla)Phen]·H₂O and [Cu(SAla)bpy]·H₂O complexes were investigated. The [Cu(SAla)Phen]·H₂O and [Cu(SAla)bpy]·H₂O were derived from the Schiff base alanine salicylaldehyde. [Cu(SAla)Phen]·H₂O showed noteworthy antibacterial and antifungal activity than the [Cu(SAla)bpy]·H₂O and ligand alanine, salicylaldehyde. The [Cu(SAla)Phen]·H₂O complex showed significant antibacterial activity against Salmonella typhi, Staphylococcus aureus, Salmonella paratyphi and the antifungal activity against Candida albicans and Cryptococcus neoformans in well diffusion assay. The mode of action of copper (II) complex was analyzed by DNA cleavage activity and in silico molecular docking. The present findings provide important insight into the molecular mechanism of copper (II) complexes in susceptible bacterial and fungal pathogens. These results collectively support the use of [Cu(SAla)Phen]·H₂O complex as a suitable drug to treat bacterial and fungal infections.     

2,2′-Dipyridyl and 1,10-phenanthroline in the synergetic extraction of Eu3+

The thermodynamics of the extraction of Eu³⁺ by thenoyltrifluoroacetone (HTTA) and by mixtures of HTTA and bidentate amine bases such as 2,2-dipyridyl (Dipy) and 1,10-phenanthroline (Phen) in benzene from an aqueous phase fixed to 0.1M ionic strength (NaClO₄), pH 3.9, has been investigated. Phenanthroline forms both the Eu(TTA)₃·Phen and Eu(TTA)₃·2Phen species, which are much stronger than the dipyridyl complexes. The diluent effect on the extraction is also studied.     

Hydrothermal synthesis, thermal and luminescent investigations of lanthanide(III) coordination polymers based on the 4,4′-oxybis(benzoate) ligand

In this study, new series of lanthanide 4,4??-oxybis(benzoates) of the general formula Ln₂oba₃·nH₂O, where Ln = lanthanides from La(III) to Lu(III), oba?=?C₁₂H₈O(COO) ₂ ^2? and n?=?3?C6, has been prepared under hydrothermal conditions. The compounds were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction patterns measurements and different methods of thermal analysis (TG, DSC, and TG-FTIR). In addition, photoluminescence properties of the selected complexes have been investigated. Crystalline compounds are isostructural in the whole series. Both carboxylate groups are deprotonated and engaged in the coordination of Ln(III) ions. Heating of the complexes leads to the dehydration and next decomposition processes. Although of the same structure, the removal of water molecules proceeds in different ways. In the nitrogen atmosphere, they decompose releasing water, carbon oxides and phenol molecules. The complexes of Eu(III), Tb(III) and Dy(III) exhibit photoluminescence in the visible range, whereas the compounds of Nd(III) and Yb(III) in the near-infrared region upon excitation by UV light.     

Kinetics and mechanism of the oxidation of tris(2,2′-bipyridine)iron(II) and tris(1,10-phenanthroline)iron(II) complexes by nitropentacyanocobaltate(III) in acidic aqueous medium

The kinetics of the oxidation of tris(2,2′-bipyridyl)iron(II) and tris(1,10-phenanthroline)iron(II) complexes ([Fe(LL)₃]²⁺, LL = bipy, phen) by nitropentacyanocobaltate(III) complex [Co(CN)₅NO₂]^3? was investigated in acidic aqueous solutions at ionic strength of I = 0.1 mol dm^?3 (HCl/NaCl). The reactions were carried out at fixed acid concentration ([H⁺] = 0.01 mol dm^?3) and the temperature maintained at 35.0 ± 0.1 °C. Spectroscopic evidence is presented for the protonated oxidant. Protonation constants of 360.43 and 563.82 dm³ mol^?1 were obtained for the monoprotonated and diprotonated Co(III) complexes respectively. Electron transfer rates were generally faster for [Fe(bipy)₃]²⁺ than [Fe(phen)₃]²⁺. The redox complexes formed ion-pairs with the oxidant with increasing concentration of the oxidant over that of the reductant. Ion-pair constants for these reaction were 160.31 and 131.9 dm³ mol^?1 for [Fe(bipy)₃]²⁺ and [Fe(phen)₃]^2+, respectively. The activation parameters measured for these systems have values as follows: ?H ^≠ (kJ K^?1 mol^?1) = +113.4 ± 0.4 and +119 ± 0.3; ?S ^≠ (J K^?1) = +107.6 ± 1.3 and 125.0 ± 1.6; ?G ^≠ (kJ K^?1) = +81 ± 0.4 and +82.4 ± 0.4; and E _a (kJ mol^?1) = 115.9 ± 0.5 and 122.3 ± 0.6 for LL = bipy and phen, respectively. Effect of added anions (Cl^?, $ {\text{SO}}_{4}^{2 - } $ and $ {\text{ClO}}_{4}^{ - } $ ) on the systems showed decrease in the electron transfer rate constant. An outer-sphere mechanism is proposed for the reaction.     

Highly sensitive spectrophotometric determination of olanzapine using cerium(IV) and iron(II) complexes of 1,10-phenanthroline and 2,2′-bipyridyl

Two highly sensitive spectrophotometric methods have been developed for the determination of olanzapine (OLP) in pharmaceuticals using cerium(IV) and iron(II) complexes of 1,10-phenanthroline and 2,2′-bipyridyl as reagents. The methods are based on the oxidation of OLP in acidic medium by a known excess of cerium(IV) followed by the determination of the unreacted oxidant by reacting with either ferroin and measuring the absorbance at 510 nm (method A) or iron(II)-2,2′-bipyridyl complex and measuring the absorbance at 525 nm (method B). The amount of cerium(IV) reacted corresponds to the amount of OLP. In both the methods, the absorbance is found to increase linearly with OLP concentration as shown by the correlation coefficient (r) of 0.9980 and 0.9958 for method A and method B, respectively. The calibration graphs are linear over the concentration range of 0.2–2.0 μg/mL in both the methods. The calculated molar absorptivity values are 1.00 × 10⁶ and 7.03 × 10⁵ L/mol cm, for method A and method B. The LOD and LOQ values for method A are calculated to be 0.04 and 0.13 μg/mL and the values are 0.07 and 0.22 μg/mL for method B, respectively. The methods were validated as per the current ICH guidelines. Both the methods gave similar results in terms of accuracy and precision. The RSD was less than 3% and the accuracy, obtained from recovery experiments, was 98.76–101.4%. The methods developed were applied to the determination of OLP in tablets and results agreed well with the label claim.     

Hydrothermal Synthesis and Crystal Structure of a Novel Catena Co（ Ⅱ ） Complex Bridged by Biphenyl-2,2′-dicarboxylate Divalent Anion

The title complex, [Co2 (bpdc)2 (bim)4 ]n (bpdc = biphenyl-2,2′-dicarboxylate dianion, bim = benzimidazole), was synthesized in a aqueous solution and its crystal structure was determined by means of X-ray diffraction. There are two different coordinated Co( Ⅱ ) centers in the complex. The Co1 center has a deformed trigonal-bipyramidal geometry, while the Co2 center possesses a tetrahedral geometry. In addition, the two different coordination modes of bpdc ligands act as two kinds of bridges to link Col and Co2, resulting in a catena chain.     

Binuclear cluster complexes of molybdenum containing 2,2′-bipyridine and 1,10-phenanthroline: Synthesis and structure

By the interaction between (Et₄N)₂[Mo₂O₂S₈] and I₂ in DMF with a subsequent addition of 2,2′-bipyridine or 1,10-phenanthroline, new binuclear complexes [Mo₂O₂S₂I₂(bipy)₂] (1) and [Mo₂O₂S₂I₂(phen)₂] (2) are obtained. The structure of [Mo₂O₂S₂I₂(bipy)₂] is determined using single crystal X-ray diffraction. The compounds are characterized by elemental analysis and IR spectra. The [MoO(S₂)₂(bipy)] complex as a product of oxidative destruction of 1 is isolated and characterized.