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ABSTRACT: The crystal structure of the title compound, [Cu(ClO(4))(2)(C(4)H(12)N(2))(2)], (I), is reported at 100, 250 and 400 K. The Cu(II) cation in this complex is coordinated in a distorted octahedral mode characteristic of Jahn-Teller systems. The coordination of the perchlorate ligands via longer, and presumably weaker, axial Cu-O distances varies significantly as a function of temperature. One of the Cu-O distances increases between 100 and 250 K, and one of the Cu-O-Cl angles expands between 250 and 400 K. At all temperatures, the complex forms a two-dimensional N-H···O hydrogen-bond network in the (001) plane.
Acta crystallographica. Section C, Crystal structure communications 09/2012; 68(Pt 9):m251-4. · 0.78 Impact Factor
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ABSTRACT: The enantiomerically pure title complex, [SP-4-4]-(R)-[2-(1-aminoethyl)phenyl-κ(2)C(1),N]chlorido(quinoline-κN)palladium(II) acetone hemisolvate, [Pd(C(8)H(10)N)Cl(C(9)H(7)N)]·0.5C(3)H(6)O, crystallizes with four molecules of the organopalladium complex and two molecules of acetone in the asymmetric unit. This corresponds to a discrete hydrogen-bonded aggregate and to the content of the unit cell in the space group P1. Pronounced pseudo-inversion symmetry relates pairs of these objects in the asymmetric unit.
Acta crystallographica. Section C, Crystal structure communications 08/2012; 68(Pt 8):m223-5. · 0.78 Impact Factor
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ABSTRACT: [ZnCl(2)(3,4,5-trichloropyridine)(2)] features short intermolecular Cl···Cl contacts between halogen atoms of different nature, and a charge density study provides experimental evidence for the accepted model of the halogen bonds: an arene-bonded Cl atom acts as a donor of electron density towards the "sigma hole" of a chlorido ligand attached to a neighbouring Zn(II) cation.
Chemical Communications 05/2012; 48(54):6830-2. · 6.17 Impact Factor
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ABSTRACT: The metal coordination in the mononuclear complex diamminebis(sulfadiazine)zinc shows a unique temperature dependence: High-resolution diffraction data prove that the coordination is almost tetrahedral at 100 K, whereas a fifth longer interaction becomes relevant at 200 K. The change in the geometry is fully reversible and is also reflected in the charge density of the compound.
Inorganic Chemistry 01/2012; 51(2):769-71. · 4.60 Impact Factor
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ABSTRACT: N,N-Dimethylbiguanidinium bis(hydrogensquarate) features an impressive range of hydrogen bonds within the same crystal structure: neighbouring anions aggregate to a dianionic pair through two strong O-H···O interactions; one of these can be classified among the shortest hydrogen bonds ever studied. Cations and anions in this organic salt further interact via conventional N-H···O and nonclassical C-H···O contacts to an extended structure. As all these interactions occur in the same sample, the title compound is particularly suitable to monitor even subtle trends in hydrogen bonds. Neutron and high-resolution X-ray diffraction experiments have enabled us to determine the electron density precisely and to address its properties with an emphasis on the nature of the X-H···O interactions. Sensitive criteria such as the Laplacian of the electron density and energy densities in the bond-critical points reveal the incipient covalent character of the shortest O-H···O bond. These findings are in agreement with the precise geometry from neutron diffraction: the shortest hydrogen bond is also significantly more symmetric than the longer interactions.
Acta crystallographica. Section B, Structural science 12/2011; 67(Pt 6):552-9. · 1.80 Impact Factor
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ABSTRACT: Four new triphenyltin(IV) complexes of composition Ph(3)SnLH (where LH=2-/4-[(E)-2-(aryl)-1-diazenyl]benzoate) (1-4) were synthesized and characterized by spectroscopic (((1))H, ((13))C and ((119))Sn NMR, IR, ((119))Sn Mössbauer) techniques in combination with elemental analysis. The ((119))Sn NMR spectroscopic data indicate a tetrahedral coordination geometry in non-coordinating solvents. The crystal structures of three complexes, Ph(3)SnL((1))H (1), Ph(3)SnL((3))H (3), Ph(3)SnL((4))H (4), were determined. All display an essentially tetrahedral geometry with angles ranging from 93.50(8) to 124.5(2)°; ((119))Sn Mössbauer spectral data support this assignment. The cytotoxicity studies were performed with complexes 1-4, along with a previously reported complex (5) in vitro across a panel of human tumor cell lines viz., A498, EVSA-T, H226, IGROV, M19 MEL, MCF-7 and WIDR. The screening results were compared with the results from other related triphenyltin(IV) complexes (6-7) and tributyltin(IV) complexes (8-11) having 2-/4-[(E)-2-(aryl)-1-diazenyl]benzoates framework. In general, the complexes exhibit stronger cytotoxic activity. The results obtained for 1-3 are also comparable to those of its o-analogs i.e. 4-7, except 5, but the advantage is the former set of complexes demonstrated two folds more cytotoxic activity for the cell line MCF-7 with ID(50) values in the range 41-53 ng/ml. Undoubtedly, the cytotoxic results of complexes 1-3 are far superior to CDDP, 5-FU and ETO, and related tributyltin(IV) complexes 8-11. The quantitative structure-activity relationship (QSAR) studies for the cytotoxicity of triphenyltin(IV) complexes 1-7 and tributyltin(IV) complexes 8-11 is also discussed against a panel of human tumor cell lines.
Journal of inorganic biochemistry 10/2011; 107(1):119-28. · 3.25 Impact Factor
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ABSTRACT: In the crystal structure of the title two-dimensional network, [HgCl(2)(C(11)H(10)N(2)O)](n), the asymmetric unit consists of HgCl(2) dumbbells and one mol-ecule of the quinazoline unit. Pseudo-octa-hedrally coordinated Hg(II) cations are chloride-bridged via a crystallographic inversion centre leading to different Hg-Cl bonds (short and long) and linked by other Cl atoms via translation along the a axis. The quinazoline ligands connect the Hg-Cl-Hg-Cl chains by N and O atoms along the b axis, forming the two-dimensional network structure. The crystal structure is stabilized by weak non-classical C-H⋯Cl hydrogen bonds and aromatic π-π stacking inter-actions [centroid-centroid distances = 3.942 (4) and 3.621 (4) Å].
Acta Crystallographica Section E Structure Reports Online 07/2011; 67(Pt 7):m953-4. · 0.35 Impact Factor
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ABSTRACT: The crystal structure of cholic acid-pentan-3-one (1/1), C(5)H(10)O·C(24)H(40)O(5), has been determined in order to deduce the molecular conformation of the small volatile ketone. Data were collected at 100 K to a resolution of (sin θ)/λ = 0.91 Å(-1). The structure contains a hydrogen-bonded cholic acid host network, forming only van der Waals interactions with the guest pentan-3-one molecules. The ketone molecules are disordered on general positions, with two clearly identifiable conformations. The majority conformer exhibits approximate C(2) symmetry and is similar to that recently observed by microwave spectroscopy in the gas phase.
Acta crystallographica. Section C, Crystal structure communications 06/2011; 67(Pt 6):o206-8. · 0.78 Impact Factor
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ABSTRACT: The title compound, C(33)H(25)N(5), belongs to the family of pyridine-2,6-dicarboxaldehyde Schiff bases which possess a terdentate coordinating site (-N=C-C=N-C-C=N-) similar to terpyridine derivatives. The dihedral angles between pairs of terminal rings are 69.67 (9) and 66.23 (9)°. The shortest distance between the centroids of aromatic rings in neighbouring mol-ecules is 3.8080 (14) Å.
Acta Crystallographica Section E Structure Reports Online 05/2011; 67(Pt 5):o1030. · 0.35 Impact Factor
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ABSTRACT: In the crystal structure of the title complex, [Zn(C(9)H(7)O(4))(2)(H(2)O)(3)]·2H(2)O, the Zn atom and the apical aqua ligand are located on a crystallographic twofold axis, with the Zn(II) ion in a distorted square-pyramidal coordination geometry composed of five O atoms, two from the monodentate methyl-terephthalato group and three from water mol-ecules. The resulting complex and the two hydrate water mol-ecules are inter-connected by O-H⋯O hydrogen bonds.
Acta Crystallographica Section E Structure Reports Online 04/2011; 67(Pt 4):m475-6. · 0.35 Impact Factor
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ChemPhysChem 03/2011; 12(4):761-4. · 3.41 Impact Factor
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ABSTRACT: The protonation of the phosphinito-bridged Pt(I) complex [(PHCy(2))Pt(μ-PCy(2)){κ(2)P,O-μ-P(O)Cy(2)}Pt(PHCy(2))](Pt-Pt) (1) by aqueous HBF(4) or hydrofluoric acid leads selectively to the hydrido-bridged solvento species syn-[(PHCy(2))(H(2)O)Pt(μ-PCy(2))(μ-H)Pt(PHCy(2)){κP-P(OH)Cy(2)}](Y)(2)(Pt-Pt) ([2-H(2)O]Y(2)) {Y = BF(4), F(HF)(n)} when an excess of acid was used. On standing in halogenated solvents, complex [2-H(2)O](BF(4))(2) undergoes a slow but complete isomerization to [(PHCy(2))(2)Pt(μ-PCy(2))(μ-H)Pt{κP-P(OH)Cy(2)}(H(2)O)](BF(4))(2)(Pt-Pt) ([4-H(2)O][BF(4)](2)) having the P(OH)Cy(2) ligand trans to the hydride. The water molecule coordinated to platinum in [2-H(2)O][BF(4)](2) is readily replaced by halides, nitriles, and triphenylphosphane, and the acetonitrile complex [2-CH(3)CN][BF(4)](2) was characterized by XRD analysis. Solvento species other than aqua complexes, such as [2-acetone-d(6)](2+) or [2-CD(2)Cl(2)](2+) were obtained in solution by the reaction of excess etherate HBF(4) with 1 in the relevant solvent. The complex [2-H(2)O](Y)(2) [Y = F(HF)(n)] spontaneously isomerizes into the terminal hydrido complexes [(PHCy(2))Pt(μ-PCy(2)){κ(2)P,O-μ-P(O)Cy(2)}Pt(H)(PHCy(2))](Y)(Pt-Pt) ([6](Y)). In the presence of HF, complex [6](Y) transforms into the bis-phosphanido-bridged Pt(II) dinuclear complex [(PHCy(2))(H)Pt(μ-PCy(2))(2)Pt{κP-P(OH)Cy(2)}](Y)(Pt-Pt) ([7](Y)). When the reaction of 1 with HF was carried out with diluted hydrofluoric acid by allowing the HF to slowly diffuse into the dichloromethane solution, the main product was the linear 60e tetranuclear complex [(PHCy(2)){κP-P(O)Cy(2)}Pt(1)(μ-PCy(2))(μ-H)Pt(2)(μ-PCy(2))](2)(Pt(1)-Pt(2)) (8). Insoluble compound 8 is readily protonated by HBF(4) in dichloromethane, forming the more soluble species [(PHCy(2)){κP-P(OH)Cy(2)}Pt(1)(μ-PCy(2))(μ-H)Pt(2)(μ-PCy(2))](2)(BF(4))(2)(Pt(1)-Pt(2)) {[9][BF(4)](2)}. XRD analysis of [9][BF(4)](2)·2CH(2)Cl(2) shows that [9](2+) is comprised of four coplanar Pt atoms held together by four phosphanido and two hydrido bridges. Both XRD and NMR analyses indicate alternate intermetal distances with peripheral Pt-Pt bonds and a longer central Pt···Pt separation. DFT calculations allow tracing of the mechanistic pathways for the protonation of 1 by HBF(4) and HF and evaluation of their energetic aspects. Our results indicate that in both cases the protonation occurs through an initial proton transfer from the acid to the phosphinito oxygen, which then shuttles the incoming proton to the Pt-Pt bond. The different evolution of the reaction with HF, leading also to [6](Y) or 8, has been explained in terms of the peculiar behavior of the F(HF)(n)(-) anions and their strong basicity for n = 0 or 1.
Inorganic Chemistry 03/2011; 50(8):3539-58. · 4.60 Impact Factor
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ABSTRACT: The presumably "small molecule structure" of the organopalladium complex rac-PdCl(C(6)H(3)-4-OMe-CHMeNH(2))(py) crystallizes with 16 molecules in the asymmetric unit, a highly unusual situation according to the CSD database. The symmetrically independent residues differ with respect to soft conformational degrees of freedom. Packing in the acetonitrile solvate of the same compound is unexceptional.
Chemical Communications 02/2011; 47(13):3846-8. · 6.17 Impact Factor
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Tushar S Basu Baul,
Anup Paul,
Lorenzo Pellerito,
Michelangelo Scopelliti,
Claudia Pellerito,
Palwinder Singh,
Pooja Verma,
Andrew Duthie,
Dick de Vos,
Rajeshwar P Verma, Ulli Englert
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ABSTRACT: A series of tributyltin(IV) complexes based on 2/4-[(E)-2-(aryl)-1-diazenyl]benzoate ligands was synthesized, wherein the position of the carboxylate and aryl substituents (methyl, tert-butyl and hydroxyl) varies. The complexes, Bu(3)SnL(1-4)H (1-4), have been structurally characterized by elemental analysis and IR, NMR ((1)H, (13)C, and (119)Sn) and (119)Sn Mössbauer spectroscopy. All have a tetrahedral geometry in solution and a trigonal bipyramidal geometry in the solid-state, except for Bu(3)SnL(4)H (4) that was ascertained to have tetrahedral coordination by X-ray crystallography. Cytotoxicity studies were carried out on human tumor cell lines A498 (renal cancer), EVSA-T (mammary cancer), H226 (non-small-cell lung cancer), IGROV (ovarian cancer), M19 MEL (melanoma), MCF-7 (mammary cancer) and WIDR (colon cancer). Compared to cisplatin, test compounds 1-4 had remarkably good activity, despite the presence of substantial steric bulk due to Sn-Bu ligands. The quantitative structure-activity relationship (QSAR) studies for the cytotoxicity of organotin(IV) benzoates, along with some reference drug molecules, is also discussed against a panel of human tumor cell lines. Molecular structures of the tributyltin(IV) complexes (1-4) were fully optimized using the PM6 semi-empirical method and docking studies performed with key enzymes associated with the propagation of cancer, namely ribonucleotide reductase, thymidylate synthase, thymidylate phosphorylase and topoisomerase II. The theoretical results are discussed in relation to the mechanistic role of the cytotoxic active test compounds (1-4).
Journal of inorganic biochemistry 09/2010; 104(9):950-66. · 3.25 Impact Factor
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ABSTRACT: In the title compound, [Pd(C(8)H(10)N)(C(2)H(8)N(2))](C(8)H(7)O(2))·H(2)O, the palladium ion is coordinated in a distorted square-planar fashion by the two N atoms from the chelating ethyl-enediamine group and by the N and a C atom of the deprotonated chiral amine. The resulting cationic complex, the 3-methyl-benzoate anion and the hydrate water mol-ecule are inter-connected by N-H⋯O and O-H⋯O hydrogen bonds.
Acta Crystallographica Section E Structure Reports Online 01/2010; 66(Pt 8):m976. · 0.35 Impact Factor
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ABSTRACT: In the title compound, [Pd(C(8)H(10)N)(C(2)H(8)N(2))](C(9)H(9)O(2)), the palladium ion is coordinated in a distorted square-planar fashion by the two N atoms from the chelating ethyl-enediamine group and by the N and a C atom of the deprotonated chiral amine. The resulting cationic complex and the 3,5-dimethyl-benzoate anion are inter-connected by N-H⋯O hydrogen bonds.
Acta Crystallographica Section E Structure Reports Online 01/2010; 66(Pt 8):m977. · 0.35 Impact Factor
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ABSTRACT: The experimental electron-density distributions in crystals of five chain polymers [M(mu-X)2(py)2] (M = Zn, Cd; X = Cl, Br; py = 3,5-substituted pyridine) have been obtained from high-resolution X-ray diffraction data sets (sin theta/lambda > 1.1 A(-1)) at 100 K. Topological analyses following Bader's 'Atoms in Molecules' approach not only confirmed the existence of (3, -1) critical points for the chemically reasonable and presumably strong covalent and coordinative bonds, but also for four different secondary interactions which are expected to play a role in stabilizing the polymeric structures which are unusual for Zn as the metal center. These weaker contacts comprise intra- and inter-strand C-H...X-M hydrogen bonds on the one hand and C-X...X-C interhalogen contacts on the other hand. According to the experimental electron-density studies, the non-classical hydrogen bonds are associated with higher electron density in the (3, -1) critical points than the halogen bonds and hence are the dominant interactions both with respect to intra- and inter-chain contacts.
Acta crystallographica. Section B, Structural science 10/2009; 65(Pt 5):600-11. · 1.80 Impact Factor
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ABSTRACT: "Crystal structure of the free base guanidine determined 148 years after the first synthesis": A prototype structure unveiled--despite its provocative simplicity, the crystal structure of guanidine has not been previously described. 148 years after the first synthesis of guanidine, we now find two Y-shaped symmetry-independent molecules in the unit cell that are interconnected by a hydrogen-bonding network, which results in a fascinating layered structure (see picture).
Chemistry 05/2009; 15(23):5651-5. · 5.93 Impact Factor
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ABSTRACT: The crystal structures of (SP-4-4)-[rac-2-(1-aminoethyl)phenyl-kappa(2)C(1),N]chlorido(pyridine-kappaN)palladium(II), [Pd(C(8)H(10)N)Cl(C(5)H(5)N)], (I), (SP-4-4)-[rac-2-(1-aminoethyl)phenyl-kappa(2)C(1),N]bromido(pyridine-kappaN)palladium(II), [PdBr(C(8)H(10)N)(C(5)H(5)N)], (II), (SP-4-4)-[rac-2-(1-aminoethyl)-5-bromophenyl-kappa(2)C(1),N]bromido(4-methylpyridine-kappaN)palladium(II), [PdBr(C(8)H(9)BrN)(C(6)H(7)N)], (III), and (SP-4-4)-[rac-2-(1-aminoethyl)-5-bromophenyl-kappa(2)C(1),N]iodido(4-methylpyridine-kappaN)palladium(II), [Pd(C(8)H(9)BrN)I(C(6)H(7)N)], (IV), are reported. The latter is the first iodide complex in this class of compounds. All four complexes crystallize in the same space group, viz. I4(1)/a, with very similar lattice parameters a and more flexible lattice parameters c. Their packing corresponds to that of their enantiomerically pure congeners, which crystallize in the t2 subgroup I4(1).
Acta crystallographica. Section C, Crystal structure communications 03/2009; 65(Pt 2):m48-51. · 0.78 Impact Factor
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ABSTRACT: The asymmetric unit of the title compound, C(16)H(14)O(4), consists of one half-mol-ecule of an essentially planar biphenyl-dicarboxylic acid ester, with the complete molecule generated by an inversion centre. The maximum deviation from a least-squares plane through all non-H atoms occurs for the peripheric methyl groups and amounts to 0.124 (2) Å. The solid represents a typical mol-ecular crystal without classical hydrogen bonds. The shortest inter-molecular contacts do not differ significantly from the sum of the van der Waals radii of the atoms involved.
Acta Crystallographica Section E Structure Reports Online 01/2009; 65(Pt 7):o1677. · 0.35 Impact Factor
