Bis(2-amino-benzimidazolium) sulfate monohydrate.

In the title hydrated mol-ecular salt, 2C7H8N3 +·SO4 2-·H2O, the components are linked by numerous N-H⋯O and O-H⋯O hydrogen bonds.

Linkage between Fluorescence and Electrochemical Properties of Imidazolium Compounds in Acetonitrile Solution.

The fluorescence properties of some imidazolium derivatives are relevant in photosensing and therefore, the structural analysis of them is a key point for its rational design, which would be useful to prepare new systems with novel applications. Herein we report a multidisciplinary study of the fluorescence and voltammetric properties of three imidazolium compounds {1,3-bis[(R,R)-1'-chloro-1'-phenylpropan-2'-yl]-imidazolium chloride (1), 1,3-bis[(Z)-1'-phenylprop-1'-en-2'-yl]imidazolium chloride (2) 1,3-bis[(R)-1'-chlorobutan-2'-yl]-imidazolium chloride (3)}. Electronic structure calculations and Bader analyses were used to correlate both fluorescence and the capability of the molecules to be reduced through a heterogeneous electron transfer process. Both properties are strongly dependent on the proton in position two of the imidazolium ring, where the electron transfer as well as the excitation of the electrons are carried out. The reactivity in this position is controlled by the N-substituents on the imidazolium ring and is due to single contacts H⋅⋅⋅Cl- , tricentric contacts Cl⋅⋅⋅Cl- ⋅⋅⋅Cl, π-electronic delocalization and π-stacking interactions.

Complexes containing benzimidazolyl-phenol ligands and Ln(III) ions: Synthesis, spectroscopic studies and preliminary cytotoxicity evaluation.

Fourteen new complexes were obtained from Ln(III)(NO3)3∙n-H2O and the chromophores 2-(1H-benzo[d]imidazol-2-yl)-phenol (Bzp1) or 2-(5-methyl-1H-benzo[d]imidazol-2-yl)-phenol (Bzp2). The complete characterization allowed us to assign unequivocally the structures of all the complexes. The techniques used for this purpose were Ultraviolet-Visible (UV-Vis) and Fourier-Transform Infrared (FT-IR) spectroscopies, High-Resolution Mass Spectrometry (HRMS), Magnetic Susceptibility (MS), Elemental Analysis (EA) and Molar Conductivity (MC). HRMS allowed us to find the molecular ion and its isotopic pattern. The FT-IR spectral data suggested that benzimidazolyl-phenol ligands coordinate with Ln(III) ions through iminic nitrogen and phenolic oxygen. Thermogravimetric Analysis (TGA) studies of NdBzp1 and GdBzp2 complexes indicate the presence of lattice water along with three nitrates and two benzimidazolyl-phenol ligands; the thermal decomposition was consistent with the minimal formula suggested by EA. The coordination type of the benzimidazolyl-phenol ligands, the geometry and the structural organization of these coordination complexes have been interpreted by Density Functional Theory (DFT) calculations, and they coincided with the physicochemical data suggesting a coordination number eight for the Ln(III) ions. The cytotoxicity of the chromophores and their coordination complexes was tested against a cancer cell line (HeLa), as compared with structure/support cells (NIH-3T3) and defense cells (J774A.1), revealing that three coordination complexes showed moderate cytotoxicity against the cell lines studied.

Crystal structure of catena-poly[[[tri-aqua-(4-cyano-benzoato-κO)nickel(II)]-µ-4,4'-bi-pyridine-κ(2) N:N'] 4-cyano-benzoate].

In the title polymeric complex salt, {[Ni(C8H4NO2)(C10H8N2)(H2O)3](C8H4NO2)} n , the Ni(II) cation is coordinated by a 4-cyano-benzoate anion, two 4,4'-bi-pyridine ligands and three water mol-ecules in a distorted N2O4 octa-hedral geometry. The 4,4'-bi-pyridine ligands bridge the Ni(II) cations to form polymeric chains of the title complex cations, propagating along the c-axis direction. The dihedral angle between the pyridine rings of the 4,4'-bi-pyridine ligand is 24.9 (6)°. In the crystal, the uncoordinating 4-cyano-benzoate anions link with the complex cations via O-H⋯O hydrogen bonds into a three-dimensional supra-molecular architecture. Weak C-H⋯O, C-H⋯N inter-actions and π-π stacking [centroid-to-centroid distances = 3.566 (4) and 3.885 (4) Å] are also observed in the crystal.

2,6-Bis(2,6-diethylphenyliminomethyl)pyridine coordination compounds with cobalt(II), nickel(II), copper(II), and zinc(II): synthesis, spectroscopic characterization, X-ray study and in vitro cytotoxicity.

Coordination compounds with cobalt(II), nickel(II), copper(II) and zinc(II) and the ligand 2,6-bis(2,6-diethylphenyliminomethyl)pyridine (L) were synthesized and fully characterized by IR and UV-Vis-NIR spectroscopy, elemental analysis, magnetic susceptibility and X-ray diffraction for two representative cases. These novel compounds were designed to study their activity as anti-proliferative drugs against different human cancer cell lines. The tridentate ligand forms heptacoordinated compounds from nitrate metallic salts, where the nitrate acts in a chelating form to complete the seven coordination positions. In vitro cell growth inhibition was measured for Co(II), Cu(II) and Zn(II) complexes, as well as for the free ligand. Upon coordination, the IC50 value of the transition-metal compounds is improved compared to the free ligand. The copper(II) and zinc(II) compounds are the most promising candidates for further in vitro and in vivo studies. The activity against colon and prostate cell lines merits further research, in views of the limited therapeutic options for such cancer types.

Bis(µ2-benzoato-κ(2) O:O')bis-[(benzoato-κ(2) O,O')bis(4,4'-bi-pyridine-κN)cobalt(II)]-benzoic acid (1/6).

In the title compound, [Co2(C7H5O2)4(C10H8N2)4]·6C6H5COOH, the centrosymmetric cobalt dimer co-crystallizes with six mol-ecules of benzoic acid. Each Co(II) atom is coordinated by four O atoms in a distorted square-planar arrangement while the N atoms are located in apical positions. The dihedral angles between the rings comprising each of the 4,4'-bipyridyl ligands are 25.2 (2) and 22.8 (2)°. In the crystal, the three-dimensional network is assembled by O-H⋯O and C-H⋯O hydrogen bonds.

(Furfuryl-amino)-triphenyl-phospho-nium bromide.

In the title salt, C23H21NOP(+)·Br(-), the dihedral angles between the phenyl rings are 70.41 (18), 73.6 (2) and 80.85 (19)°. In the crystal, neighboring mol-ecules are linked through an N-H⋯Br hydrogen bond and four weak C-H⋯Br contacts, forming a three-dimensional network.

Antioxidant activity of butyl- and phenylstannoxanes derived from 2-, 3- and 4-pyridinecarboxylic acids.

In vitro antioxidant activity for 12 stannoxanes derived from Ph(3)SnCl (compounds 1-3), Ph(2)SnCl(2) (compounds 4-6), Bu(3)SnCl (compounds 7-9), and Bu(2)SnCl(2) (compounds 10-12), was assayed qualitatively by the chromatographic profile with 1,1-diphenyl-2-picrylhydrazil (DPPH) method and by two quantitative methods: the DPPH radical scavenging activity and Ferric-Reducing Antioxidant Power (FRAP) assays. The results were compared with those obtained with the starting materials 2-pyridine- carboxylic acid (I), 3-pyridinecarboxylic acid (II) and 4-pyridinecarboxylic acid (III), as well as with standard compounds, such as vitamin C and vitamin E, respectively. The in vitro antiradical activity with DPPH of diphenyltin derivative 5 showed a very similar behavior to vitamin C at a 20 microg/mL concentration, whereas according to the FRAP method, compound 8 was better. This difference is due to the mechanism of the antioxidant process. The Structure-Activity Relationships (SAR) for both methods is also reported.

Coordination chemistry of a bis(benzimidazole) disulfide: eleven membered chelate ring in cobalt(II), zinc(II) and cadmium(II) halide compounds; oxidative disulfide cleavage when coordinated to nickel(II).

Herein we report the synthesis, structural and spectroscopic characterization of coordination compounds with bis[2-(1H-benzimidazol-2-yl)phenyl]disulfide [bis-(2phSbz)] (1) and cobalt(II), zinc(II) and cadmium(II) halides (2-7). Their X-ray diffraction analyses showed that the metal ions present similar distorted tetrahedral structures, with the disulfide ligand coordinated through the imidazolic nitrogen atoms, forming a twisted eleven membered chelate ring. Structures of nickel(II) compounds 8 and 9, showed that the disulfide bond in the ligand was cleaved forming six membered chelates. In 8, the two ligands are sulfides, however in 9 one of them was oxidized to a sulfone. In both compounds the nickel(II) has a distorted square planar geometry and the sulfur atoms are in cis positions. The oxidation reaction of bis-(2phSbz) was performed in KMnO4/NaOH, giving the 2-(1H,3H-benzimidazolium-2-yl)-benzene sulfonate (10). The solid state structure of compounds 2-5 and 7-10 was determined by X-ray diffraction analyses.

Organometallic aluminum compounds derived from 2-(1,3,5-dithiazinan-5-yl)ethanol ligands.

The reactions of AlMe(2)Y (Y = Me or Cl) with new ligands 2-(1,3,5-dithiazinan-5-yl)ethanol (1), 2-(1,3,5-dithiazinan-5-yl)-1-methylethanol (2), and 2-(1,3,5-dithiazinan-5-yl)-1-phenylethanol (3) are described. The ligands are coordinated to aluminum atoms by nitrogen and oxygen atoms, with a nitrogen based spiranic structure. Equimolar reactions gave dimeric structures bearing pentacoordinated aluminum atoms O-(AlMeY)-2-(1,3,5-dithiazinan-5-yl)ethanolates (4-7) as well as monometallic compounds with tetracoordinated aluminum atoms O-(AlMeY)-2-(1,3,5-dithiazinan-5-yl)ethanolates (8-9). Reactions with 2 equiv of the aluminum reagents afforded tetracoordinated dialuminum complexes O-(AlMeY)-O-(AlMe(2)Y)-2-(1,3,5-dithiazinan-5-yl)ethanolate (10-18). The structures of the new compounds were determined by NMR ((1)H,(13)C, and (27)Al) and complemented by X-ray diffraction of compounds 4, 10, and 16-18. Relevant intermolecular interactions C-H...S, C-H...Cl, and C-H...pi found in the crystalline network are reported.