Transition-metal norharmane compounds as possible cytotoxic agents: New insights based on a coordination chemistry perspective.

New first-row transition-metal compounds with the ligand norharmane (9H-Pyrido[3,4-b]indole; Hnor) are reported. The compounds have the general formula [M(LL)(Hnor)(NO3)2](MeOH)0-1 (M=Co, Ni, Cu, Zn; LL=2,2'-bipyridyl (bpy), 1,10-phenanthroline (phen)) and have been characterized by physical and analytical methods. X-ray structural analysis revealed that the compound of formula [Cu(phen)(Hnor)(NO3)2], (1) has a distorted 6-coordinated octahedrally-based geometry, with a planar-based [CuN3O] core, where Cu-L varies between 1.99 and 2.04Å and two weak axial CuO contacts (2.209 and 2.644Å) from two different nitrates. Based on spectroscopic similarities, the other compounds appear to have the same or very similar coordination geometries. The compounds showed clear cell growth inhibitory effects in two different cancer cell lines in vitro, with the copper and zinc complexes being the most toxic and in fact almost comparable to cisplatin. Flow-cytometry analysis confirmed induction of apoptosis in cancer cells treated with the compounds. Interestingly, co-incubation of the cells with metal complexes and CuCl2 induced an increase in the cytotoxic effects, most likely due to the conversion of the metal compounds in the corresponding, and most active, copper analogues.

Synthesis, characterization of α-amino acid Schiff base derived Ru/Pt complexes: Induces cytotoxicity in HepG2 cell via protein binding and ROS generation.

We have synthesized two new complexes of platinum (1) and ruthenium (2) with α-amino acid, l-alanine, and 2,3-dihydroxybenzaldehyde derived Schiff base (L). The ligand and both complexes were characterized by using elemental analysis and several other spectroscopic techniques viz; IR, (1)H, (13)C NMR, EPR, and ESI-MS. Furthermore, the protein-binding ability of synthesized complexes was monitored by UV-visible, fluorescence and circular dichroism techniques with a model protein, human serum albumin (HSA). Both the PtL2 and RuL2 complexes displayed significant binding towards HSA. Also, in vitro cytotoxicity assay for both complexes was carried out on human hepatocellular carcinoma cancer (HepG2) cell line. The results showed concentration-dependent inhibition of cell viability. Moreover, the generation of reactive oxygen species was also evaluated, and results exhibited substantial role in cytotoxicity.

Insights into the strong in-vitro anticancer effects for bis(triphenylphosphane)iminium compounds having perchlorate, tetrafluoridoborate and bis(chlorido)argentate anions.

Three new compounds containing the bis(triphenylphosphane)iminium cation (PPN(+)) with ClO4(-), BF4(-) and [AgCl2](-) as counter anions have been synthesized and structurally characterized. The two derivatives with ClO4(-) and BF4(-) were found to be isostructural by single crystal X-ray diffraction. Interestingly, the three compounds show extremely potent antiproliferative effects against the human cancer cell line SKOV3. To gain insights into the possible mechanisms of biological action, several intracellular targets have been considered. Thus, DNA binding has been evaluated, as well as the effects of the compounds on the mitochondrial function. Furthermore, the compounds have been tested as possible inhibitors of the seleno-enzyme thioredoxin reductase.

MnO(x) Nanoparticle-Dispersed CeO2 Nanocubes: A Remarkable Heteronanostructured System with Unusual Structural Characteristics and Superior Catalytic Performance.

Understanding the interface-induced effects of heteronanostructured catalysts remains a significant challenge due to their structural complexity, but it is crucial for developing novel applied catalytic materials. This work reports a systematic characterization and catalytic evaluation of MnOx nanoparticle-dispersed CeO2 nanocubes for two important industrial applications, namely, diesel soot oxidation and continuous-flow benzylamine oxidation. The X-ray diffraction and Raman studies reveal an unusual lattice expansion in CeO2 after the addition of MnOx. This interesting observation is due to conversion of smaller sized Ce(4+) (0.097 nm) to larger sized Ce(3+) (0.114 nm) in cerium oxide led by the strong interaction between MnOx and CeO2 at their interface. Another striking observation noticed from transmission electron microscopy, high angle annular dark-field scanning transmission electron microscopy, and electron energy loss spectroscopy studies is that the MnOx species are well-dispersed along the edges of the CeO2 nanocubes. This remarkable decoration leads to an enhanced reducible nature of the cerium oxide at the MnOx/CeO2 interface. It was found that MnOx/CeO2 heteronanostructures efficiently catalyze soot oxidation at lower temperatures (50% soot conversion, T50 ∼660 K) compared with that of bare CeO2 nanocubes (T50 ∼723 K). Importantly, the MnOx/CeO2 heteronanostructures exhibit a noticeable steady performance in the oxidation of benzylamine with a high selectivity of the dibenzylimine product (∼94-98%) compared with that of CeO2 nanocubes (∼69-91%). The existence of a strong synergistic effect at the interface sites between the CeO2 and MnOx components is a key factor for outstanding catalytic efficiency of the MnOx/CeO2 heteronanostructures.

Light-stable bis(norharmane)silver(I) compounds: synthesis, characterization and antiproliferative effects in cancer cells.

Four different-anion Ag(I) compounds with the ligand norharmane (9H-Pyrido[3,4-b]indole; Hnor) and having the general formula [Ag(Hnor)2](anion) (anion=ClO4(-), NO3(-) and BF4(-)) [Ag(Hnor)2(MeCN)](PF6) are reported, and studied in detail regarding their coordination mode and in vitro antiproliferative effects. X-ray structural analysis revealed that the complex with the PF6(-) anion has a MeCN solvent molecule weakly coordinated to Ag(I), making the metal coordination T-shaped, while the other compounds present the classical linear Ag(I) coordination. The compounds showed certain cell growth inhibitory effects in two different cancer cell lines, with the perchlorate containing complex being the most toxic and in fact comparable to cisplatin. Notably, the compounds are stable in visible light; and the luminescence in the solid state was found to be extremely weak, whereas in MeOH solution all compounds show a moderate to weak emission band at 375 nm, when excited at 290 nm.

3-Carb-oxy-pyridinium nitrate.

In the crystal structure of the title compound, C(6)H(6)NO(2) (+)·NO(3) (-), the protonated cations are linked by N-H⋯O hydrogen bonds into chains along the b axis. The cations and anions are also linked by N-H⋯O and O-H⋯O hydrogen bonds. C-H⋯O inter-actions also occur. In the cation, the ring makes a dihedral angle of 10.1 (3)° with the carboxylate group.

Copper perchlorate and tetrafluoridoborate compounds with the ligand 1,4,5-triazanaphthalene. Gradual transformation of mononuclear Cu(II) compounds via polynuclear mixed-valence Cu(II)/Cu(I) species to dinuclear Cu(I); syntheses, characterizations and X-ray structures.

When the ligand 1,4,5-triazanaphthalene (abbreviated as tan) is reacted with Cu(II) BF(4)(-) and ClO(4)(-) salts, a variety of mononuclear compounds has been found, all with the [Cu(tan)(4)] unit and varying amounts of weakly coordinating axial ligands and lattice solvents. Reproducible compounds formed include two purple compounds, analyzing as [Cu(tan)(4)](ClO(4))(2)(CH(3)OH)(2)(H(2)O) (1) and [Cu(tan)(4)](BF(4))(2)(CH(3)OH)(1.5)(H(2)O) (3), and two blue compounds, analyzing as [Cu(tan)(4)](ClO(4))(2)(H(2)O)(2) (2) and [Cu(tan)(4)](2)(BF(4))(2)(H(2)O)(2) (4). Upon standing at room temperature, red-coloured, mixed-valence dinuclear-based 3D coordination polymers are formed by conversion of the purple/blue products, of which [Cu(2)(tan)(4)](n)(BF(4))(3n) (5) and the isomorphic methanol-water adduct [Cu(tan)(4)](n)(BF(4))(3n)(CH(3)OH)(n)(H(2)O)(5n) (5A) are presented in this paper. In addition a fully reduced dinuclear Cu(I) compound of formula [Cu(2)(tan)(3)(ClO(4))(2)] (7) has been observed, and structurally characterized, as a rare three-blade propeller structure, with a Cu-Cu distance of 2.504 Å.

2-Chloro-pyrimidin-4-amine.

In the title pyrimidine derivative, C(4)H(4)ClN(3), the 2-chloro and 4-amino substituents almost lie in the mean plane of the pyrimidine ring, with deviations of 0.003 (1) Šfor the Cl atom, and 0.020 (1) Šfor the N atom. In the crystal, molecules are linked via pairs of N-H⋯N hydrogen bonds, forming inversion dimers. These dimers are further linked via N-H⋯N hydrogen bonds, forming an undulating two-dimensional network lying parallel to (100).

1-[1-(3-Methyl-phen-yl)-5-phenyl-4-phenyl-sulfonyl-1H-pyrazol-3-yl]ethanone.

Both the acetyl and phenyl substituents of the central pyrazole ring in the title compound, C(24)H(20)N(2)O(3)S, are twisted with respect to the pyrazole ring, with the twist involving the phenyl ring being greater [67.4 (1) and 29.6 (2)°]. The tolyl substituent is disordered over two positions in a 1:1 ratio; the mean planes of the aromatic ring are aligned at 67.7 (3) and 69.4 (3)° with respect to the pyrazole ring.

N'-(Di-2-pyridylmethyl-ene)benzo-hydrazide.

In the title Schiff base, C(18)H(14)N(4)O, the amido -NH- unit is connected to one of the two pyridyl N atoms at an N(-H)⋯N distance of 2.624 (2) Å. The mol-ecular packing features an inter-molecular C-H⋯N R(2) (2)(6) hydrogen-bonding ring motif.

Triphenylphosphine oxide-1-naphthoic acid (1/1).

In the title compound, C18H15OP.C11H8O2, co-crystallization of triphenylphosphine oxide with 1-naphthoic acid yields a supramolecular structure held together by one O-H...O and three C-H...O hydrogen bonds. The O-H...O hydrogen bond [O...O = 2.592 (2) A] has little effect on the O=P bond distance.

Triphenylphosphine oxide-3-chlorobenzoic acid (1/1).

In the title compound, C(18)H(15)OP.C(7)H(5)ClO(2), the triphenylphosphine oxide molecule forms a single directed hydrogen bond with the 3-chlorobenzoic acid molecule, with an O.O=P distance of 2.607 (2) A. The C-Cl and C=O bonds adopt a cisoid conformation in the 3-chlorobenzoic acid molecule.