Crystal structure of {bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}chlorido-platinum(II) chloride dihydrate.

The title complex, [PtCl(C14H23N5)]Cl·2H2O, is isomorphous with the Pd(II) compound characterized previously [Mendoza, Bernès & Mendoza-Díaz (2006 ▶). Acta Cryst. E62, m2934-m2936]. The angle between pyrazole mean planes in the main ligand is 88.3 (4)°, similar to that observed in the Pd(II) analogue [87.62 (11)°]. This tridentate ligand adopts a conformation approximating a twofold symmetry, allowing its coordination to the metal atom, together with a chloride ligand, in an almost perfect square-planar geometry. A chloride anion and two water mol-ecules in the asymmetric unit form a hydrogen-bonded network connected to the complex mol-ecules in the crystal via the NH amine groups, forming chains along [100].

Coordination of bis-(pyrazol-1-yl)amine to palladium(II): influence of the co-ligands and counter-ions on the mol-ecular and crystal structures.

The structures of a series of complexes with general formula n[Pd(pza)X]Y·mH2O (n = 1, 2; X = Cl, Br, I, N3, NCS; Y = NO3, I, N3, [Pd(SCN)4]; m = 0, 0.5, 1) have been determined, where pza is the tridentate ligand bis-[2-(3,5-di-methyl-pyrazol-1-yl)eth-yl]amine, C14H23N5. In all complexes, {bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}chlorido-palladium nitrate, [Pd(pza)Cl]NO3, (1), {bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}bromido-palladium nitrate, [Pd(pza)Br]NO3, (2), {bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}iodido-palladium iodide hemihydrate, [Pd(pza)I]I·0.5H2O, (3), azido{bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}palladium azide monohydrate, [Pd(pza)N3]N3·H2O, (4), and bis-[{bis-[2-(3,5-di-methyl-pyrazol-1-yl-κN (2))eth-yl]amine-κN}(thio-cyanato-κN)palladium] tetra-kis-(thio-cyanato-κS)palladate, [Pd(pza)NCS]2[Pd(SCN)4], (5), the [Pd(pza)X](+) complex cation displays a square-planar coordination geometry, and the pza ligand is twisted, approximating twofold rotation symmetry. Although the pza ligand is found with the same conformation along the series, the dihedral angle between pyrazole rings depends on the co-ligand X. This angle span the range 79.0 (3)-88.6 (1)° for the studied complexes. In (3), two complex cations, two I(-) anions and one water mol-ecule of crystallization are present in the asymmetric unit. In (5), the central amine group of pza is disordered over two positions [occupancy ratio 0.770 (18):0.230 (18)]. The complex [Pd(SCN)4](2-) anion of this compound exhibits inversion symmetry and shows the Pd(2+) transition metal cation likewise in a square-planar coordination environment. Compound (5) is also a rare occurrence of a non-polymeric compound in which the pseudohalide ligand NCS(-) behaves both as thio-cyanate and iso-thio-cyanate, i.e. is coordinating either through the N atom (in the cation) or the S atom (in the anion).

5,11-Diisopropyl-2,8-dimethyl-1H,7H-diimidazo[c,h][1,6]diazecine dihydrate.

Crystals of the title compound, C(18)H(30)N(6)·2H(2)O, are composed of units of diimidazo[c,h][1,6]diazecine and two water mol-ecules. The asymmetric unit contains one half-molecule of diazecine and one uncoordinated water molecule in a general position. The complete ten-membered heterocycle is generated by an inversion center.The organic residue and water mol-ecules form a two-dimensional hydrogen-bonded network. The 1,6-diazecine ring shows a chair conformation, with angles and distances in normal ranges.

Synthesis and characterization of bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]sulfide and its coordination behavior toward Cu(II) as a possible approach of a copper site type I.

The synthesis and characterization of a novel ligand, bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]sulfide (bemims), as well as a bemims-containing copper(II) coordination complex are described. In this complex, [Cu(bemims)X(2)] with X = NO(3) (-), bemims acts as a tridentate ligand and two monodentate nitrate ions complete the coordination sphere. Both imidazole N atoms and the thioether S atom of bemims participate in coordination. The Cu(II) ion is five-coordinated with a slightly distorted square-pyramidal geometry (tau = .09). Electrochemical studies and spectroscopic data for this complex are compared with some blue copper proteins in order to assess its ability to mimic the copper center of type I copper proteins.

Synthesis, characterization, and biological activity studies of copper(II) mixed compound with histamine and nalidixic acid.

A mixed copper complex with deprotonated nalidixic acid (nal) and histamine (hsm) was synthesized and characterized by FTIR, UV-Vis, elemental analysis, and conductivity. The crystal structure of [Cu(hsm)(nal)H(2)O]Cl.3H(2)O (chn) showed a pentacoordinated cooper(II) in a square pyramidal geometry surrounded by two N atoms from hsm, two O atoms from the quinolone, and one apical water oxygen. Alteration of bacterial DNA structure and/or associated functions in vivo by [Cu(hsm)(nal)H(2)O]Cl.3H(2)O was demonstrated by the induction of a recA-lacZ fusion integrated at the amyE locus of a recombinant Bacillus subtilis strain. Results from circular dichroism and denaturation of calf thymus DNA (CT-DNA) suggested that increased amounts of copper complex were able to stabilize the double helix of DNA in vitro mainly by formation of hydrogen bonds between chn and the sugars of DNA minor groove. In vivo and in vitro biological activities of the chn complex were compared with the chemical nuclease [Cu(phen)(nal)H(2)O]NO(3) . 3H(2)O (cpn) where phen is phenanthroline.

Chloro(histamine)(1,10-phenanthroline)copper(II) chloride monohydrate.

In the cationic complex present in the title compound, chloro[2-(4-imidazolyl-kappaN(1))ethylamine-kappaN](1,10-phenanthroline-kappa(2)N,N')copper(II) chloride monohydrate, [CuCl(C(5)H(9)N(3))(C(12)H(8)N(2))]Cl.H(2)O, the metal centre adopts a five-coordinate geometry, ligated by the two phenanthroline N atoms, two amine N atoms of the histamine ligand (one aliphatic and one from the imidazole ring) and a chloro ligand. The geometry around the Cu atom is a distorted compressed trigonal bipyramid, with one phenanthroline N and one imidazole N atom in the axial positions, and the other phenanthroline N atom, the histamine amine N atom and the chloro ligand in the equatorial positions. The structure includes an uncoordinated water molecule, and a Cl(-) ion to complete the charge. The water molecule is hydrogen bonded to both Cl(-) ions (coordinated and uncoordinated), and exhibits a close Cu.H contact in the equatorial plane of the bipyramid.

Molecular structures of fructans from Agave tequilana Weber var. azul.

Agave plants utilize crassulacean acid metabolism (CAM) for CO(2) fixation. Fructans are the principal photosynthetic products generated by agave plants. These carbohydrates are fructose-bound polymers frequently with a single glucose moiety. Agave tequilana Weber var. azul is an economically important CAM species not only because it is the sole plant allowed for tequila production but because it is a potential source of prebiotics. Because of the large amounts of carbohydrates in A. tequilana, in this study the molecular structures of its fructans were determined by fructan derivatization for linkage analysis coupled with gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR), and matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF-MS). Fructans were extracted from 8-year-old A. tequilana plants. The linkage types present in fructans from A. tequilana were determined by permethylation followed by reductive cleavage, acetylation, and finally GC-MS analysis. Analysis of the degree of polymerization (DP) estimated by (1)H NMR integration and (13)C NMR and confirmed by MALDI-TOF-MS showed a wide DP ranging from 3 to 29 units. All of the analyses performed demonstrated that fructans from A. tequilana consist of a complex mixture of fructooligosaccharides containing principally beta(2 --> 1) linkages, but also beta(2 --> 6) and branch moieties were observed. Finally, it can be stated that fructans from A. tequilana Weber var. azul are not an inulin type as previously thought.

Degradation of single stranded nucleic acids by the chemical nuclease activity of the metal complex [Cu(phen)(nal)]+.

The chemical design of metal complexes of the type [Cu(phen)(antib)](+) (where antib is a quinolone or a fluoroquinolone) has been carried out in an approach to better understand how the coordination of their components affect the activity of quinolones. The ability of [Cu(phen)(nal)](+) to interact with DNA in vivo and its capacity to promote the degradation of plasmid and chromosomal DNA, under reductive conditions has been previously reported. However whether this compound utilizes other intracellular targets to promote bacterial killing was a question that deserved to be answered. In this paper, the studies of the chemical nuclease properties encoded by the metal complex [Cu(phen)(nal)](+) were extended by using different types of single chain nucleic acids, i.e, ribosomal and tumor mosaic virus RNAs as well as poly-dA-dT. Our results showed that degradation of the nucleic acids occurred only under reductive conditions. Although MPA and [3-mercaptoethanol were the chemical reducers that best assisted the nuclease reaction, other biological compounds such as citric and succinic acid also were shown to act like reducers in that reaction. All.hough the nuclease activity of [Cu(phen)(nal)](+) was comparable to that exhibited by bis copper phenanthroline [Cu(phen)z](2+)our results showed that none of the individual components of [Cu(phen)(nal)](+) was able to promote the degradation of either the RNAs or poly(dA-dT). These results strongly support the hypothesis that the metal complex [Cu(phen)(nal)] uses not only DNA but also RNA as targets to promote bacterial killing.