Qi-Tao Liu

Crystal structure and anti-cancer activity of a novel mixed-ligand complex [Pd(Phen)(Phe)]Cl · H2O

A mixed-ligand complex [Pd(Phen)(Phe)]Cl·H2O (Phen-o-phenantroline, Phe-L-phenylalanine) is synthesized and structurally characterized by elemental analyses and single-crystal X-ray diffraction. Diffraction data: C21H19ClN3O3Pd, monoclinic, P21/n, a = 9.478(4) Å, b = 22.395(9) Å, c = 9.528 (4) Å, β = 104.358(11)°, V = 1959.3(14) Å3, Z = 4. The Pd atom has planar-square coordination geometry and is surrounded by the Phen and Phe ligand to form a monovalent complex cation, Cl− is filled in the crystal lattice as a counterion. The Cl atom is bonded to the complex cation through an electrostatic interaction and has a very weak hydrogen bond with a water molecule. Hydrogen bonding interactions and π-π stacking interactions stabilize the crystal lattice. The anti-cancer activity of the complex increases with the increasing concentration of the complex, which shows that the complex has strong anti-cancer activity.

Noncovalent interactions of pentafluorobenzoate in the Zn(II) and Cd(II) complexes

Abstract[Zn(Phen)2(Pfbz)(H2O)](Pfbz)(H2O)2 (I) and 2[Cd(Phen)2(Pfbz)(ONO2)][Cd(Phen)2(ONO2)2] (II) (Phen-1,10-phtnanthroline) containing the fluorine type ligand, pentafluorobenzoate (Pfbz) have been synthesized. Elemental analysis, IR spectra, and X-ray crystal structure analysis were carried out to determine the compositions and crystal structures of the two compounds. The crystal packing exhibits intricate intermolecular π-π stacking interactions and various hydrogen bonds. The C-H···F-C interactions and weak F···F interactions play important roles in the formation of the supramolecular network. Emission properties of I and II are also investigated.

Interaction between ligands in ternary complexes of cadmium(II) with phenanthroline and phenylalkylmalonates in solution

The formation and stability of the ternary complexes of cadmium(II) with phenanthroline and malonate, phenylmalonate, benzylmalonate, 2-phenylethylmalonate, and 3-phenylpropylmalonate are studied by the potentiometric pH-titration technique in 40% (v/v) dioxane-water at 25°C and 0.1 mol/l ionic strength (NaNO3). In all systems, there are stable ternary complexes. The complexes possess enhanced stability relative to their statistical values. The possible reasons that lead to these results are discussed in terms of π-electron back donation from metal ions to ligands and the intramolecular ligand-ligand aromatic ring stacking interaction. 1H NMR measurements are used to demonstrate the aromatic ring-stacking interaction. The relative contribution of each interactions to the enhanced stability is also estimated. The results show that there are two weak interactions simultaneously observed in these ternary complexes. The interaction strength of aromatic ring stacking in the ternary complexes increases in the phenylalkylmalonate ligand order: L0 < L1 < L2 ≈ L3 (L0 = phenylmalonate, L1 = benzylmalonate, L2 = 2-phenylethylmalonate, L3 = 3-phenylpropylmalonate).

Ternary Complexes of Cadmium(II) with Phenylalanine and Phenylalkylmalonates in Dioxane–Water Mixtures

The formation and stability of ternary complexes of cadmium(II) with phenylalanine and malonate, phenylmalonate benzylmalonate, 2-phenylethylmalonate, and 3-phenylpropylmalonate, have been studied by the potentiometric pH titration technique in 40% (v/v) dioxane–water at 25°C and 0.10—ionic strength (NaNO3). All systems give stable ternary complexes, and the Δ log K and δK values demonstrated that the complexes possess enhanced stability. The possible reasons that lead to these results are discussed in terms of π–electron back donation from metal ions to ligands and intramolecular ligand–ligand aromatic ring-stacking interactions present in the complexes. The relative contribution of each interactions to the enhanced stability have also been evaluated.

Bis[4-(2-hydroxy­benzyl­amino)phen­yl] ether

The title compound, C26H24N2O3, was synthesized by reduction of the corresponding Schiff base. The molecule does not possess crystallographic or non-crystallographic symmetry. The dihedral angle between the oxygen-bridged benzene rings is 67.98 (8)°. Both hydroxyl groups are involved in O—H⋯O intramolecular hydrogen bonding. The molecules are linked into a two-dimensional network parallel to the (010) plane by N—H⋯O hydrogen bonds.

3,3'-(Ethane-1,2-di-yl)bis-(2-thioxo-1,3-oxazolidin-4-one).

The asymmetric unit of the title compound, C8H8N2O4S2, contains one half of a centrosymmetric molecule. A short C⋯O distance of 3.012 (4) Å between the carbonyl groups of neighbouring molecules indicates the presence of dipole–dipole interactions. The crystal packing exhibits also weak intermolecular O⋯S [3.239 (3) Å] and C—H⋯O interactions.

Bis[1-hydroxy-ethyl-idenediphosphon-ato(1-)](1,10-phenanthroline)nickel(II) mono-hydrate.

In the mononuclear title compound, [Ni(C2H6O7P2)2(C12H8N2)]·H2O, the NiII atom (site symmetry 2) is bonded to two phosphate-based O,O′-bidentate chelate ligands and one N,N′-bidentate 1,10-phenanthroline ligand, resulting in a slightly distorted cis-NiN2O4 octahedral geometry. In the crystal structure, pairs of complexes are linked by double hydrogen bonds, forming a one-dimensional chain-like structure. Aromatic π–π stacking interactions [centroid–centroid separation = 3.768 (2) Å] and further hydrogen bonds generate a two-dimensional structure. The water O atom also lies on a crystallographic twofold axis.