Synthesis, characterization and crystal structure determination of platinum(IV) complexes containing, bipyridine derivatives and chloride, [Pt(5,5′-dmbipy)Cl4] and [Pt(6-mbipy)Cl4]

Assessment of the interaction procedure between Pt(IV) prodrug [Pt(5,5'-dmbpy)Cl4 and human serum albumin: Combination of spectroscopic and molecular modeling technique

In this study, a cytotoxic Pt(IV) complex [Pt(5,5'-dmbpy)Cl₄ (5,5'-dmbpy is 5,5'-dimethyl-2,2'-bipyridine) was selected to investigate its affinity to human serum albumin (HSA) by spectroscopy and molecular docking methods. This complex has a bidentate nitrogen donor ligand with four chloride anions attached to a Pt(IV) metal in a distorted octahedral environment. The fluorescence data showed this complex quench the intrinsic fluorescence of HSA through a static quenching mechanism. The binding constant (K_b) and the number of binding sites (n) were obtained based on the results of fluorescence measurements. UV-vis, circular dichroism spectroscopy, and three-dimensional fluorescence spectroscopy proved that the Pt(IV) complex could slightly change the secondary structure of protein. Thermodynamic parameters show that the Pt(IV) complex binds to HSA through electrostatic and Vander Waals interactions with one binding site. The molecular docking results confirmed the spectroscopic results and showed that Pt(IV) complex is embedded into subdomain IIA of protein. The aim of this study is to describe the performance of effective anti-cancer drugs when faced with proteins such as HSA.

Trichloridothallium(III) Complexes with Bipyridine Derivatives: From Structure to Luminescence Properties

Several new thallium(iii) complexes, [Tl(4,4′-dmbpy)Cl3(DMSO)]·H2O (1), [Tl(4,4′-dtbpy)Cl3(DMSO)] (2), [Tl(5,5′-dmbpy)Cl3(DMSO)]·(5,5′-dmbpy) (3), and [Tl(6-mbpy)Cl3(DMSO)] (4) (4,4′-dmbpy = 4,4′-dimethyl-2,2′-bipyridine, 4,4′-dtbpy = 4,4′-ditert-butyl-2,2′-bipyridine, 5,5′-dmbpy = 5,5′-dimethyl-2,2′-bipyridine, and 6-mbpy = 6-methyl-2,2′-bipyridine) were prepared from the reaction of TlCl3 with the mentioned ligands in DMSO. The four complexes were fully characterised and their structures were determined by X-ray diffraction. These complexes have a bidendate nitrogenous ligand, a DMSO molecule, and three chloride anions (in the facial position) attached to a TlIII metal centre in a distorted octahedral environment. The stability of the complexes in DMSO is evident by a 203,205Tl–1H spin–spin coupling, determined by 1H NMR spectroscopy. Interestingly, six bond hydrogen–thallium coupling was observed with a coupling constant of 6JTlH = 20 Hz. The absorption and emission spectra of the complexes were investigated. These studies revealed that upon coordination to TlIII, the luminescent intensity is increased in comparison with the related unbound ligands.

Dibromido(6-methyl-2,2'-bipyridine-κ(2) N,N')cobalt(II)

In the mol-ecule of the title compound, [CoBr2(C11H10N2)], the Co(II) atom is four-coordinated in a distorted tetra-hedral geometry by two N atoms from a chelating 6-methyl-2,2'-bipyridine ligand and two terminal Br atoms. In the crystal, π-π stacking inter-actions between the pyridine rings along the a-axis direction [centroid-centroid distance = 3.761 (7) Å] and C-H⋯Br hydrogen bonds in the bc plane together generate the three-dimensional packing.

Trichlorido(5,5'-dimethyl-2,2'-bipyridine-κ(2) N,N')(dimethyl-formamide-κO)indium(III) hemihydrate

The asymmetric unit of the title compound, [InCl₃(C₁₂H₁₂N₂)(C₃H₇NO)]·0.5H₂O, contains two independent In^III complex mol­ecules with similar structures and one lattice water mol­ecule. In each complex mol­ecule, the In^III atom is six-coordinated in a distorted octa­hedral geometry, formed by two N atoms from the chelating 5,5′-dimethyl-2,2′-bipyridine ligand, one O atom from a dimethyl­formamide and three facial Cl atoms. In the crystal, the lattice water mol­ecule is linked to the complex mol­ecules via O—H⋯Cl hydrogen bonds. Further weak C—H⋯Cl and C—H⋯O hydrogen bonds result in the formation of a three-dimensional structure.

Dibromido(dimethyl sulfoxide-κO)(6-methyl-2,2'-bipyridine-κ(2)N,N')cadmium

In the title compound, [CdBr(2)(C(11)H(10)N(2))(C(2)H(6)OS)], the Cd(II) atom is five-coordinated in a distorted trigonal-bipyramidal geometry by two N atoms from a 6-methyl-2,2'-bipyridine ligand, one O atom from a dimethyl sulfoxide ligand and two Br atoms. An intra-molecular C-H⋯O hydrogen bond occurs. The crystal structure is stabilized by C-H⋯Br hydrogen bonds and π-π contacts between the pyridine rings [centroid-centroid distances = 3.582 (5) and 3.582 (5) Å].

Dibromido(6-methyl-2,2'-bipyridine-κN,N')zinc(II)

In the title compound, [ZnBr(2)(C(11)H(10)N(2))], the Zn(II) atom is four-coordinated in a distorted tetra-hedral configuration by two N atoms from a 6-methyl-2,2'-bipyridine ligand and two terminal Br atoms. Weak inter-molecular C-H⋯Br hydrogen bonds and π-π stacking inter-actions between the pyridine rings [centroid-centroid distances = 3.763 (5) and 3.835 (6) Å] contribute to crystal-packing effects.

catena-Poly[[(5,5'-dimethyl-2,2'-bi-pyridine-κN,N')cadmium(II)]-di-μ-iodido]

In the title coordination polymer, [CdI₂(C₁₂H₁₂N₂)]_n, the Cd²⁺ ion lies on a twofold rotation axis: it is six-coordinated in a distorted cis-CdN₂I₄ octa­hedral geometry by two N atoms from a chelating 5,5′-dimethyl-2,2′-bipyridine ligands and four bridging iodide anions. The bridging function of the iodide ions leads to a chain structure propagating in [001].