Zainal Abidin Fairuz

The influence of R substituents in triphenylphosphinegold(I) carbonimidothioates, Ph3PAu[SC(OR)=NPh] (R = Me, Et and iPr), upon in vitro cytotoxicity against the HT-29 colon cancer cell line and upon apoptotic pathways.

The Ph3PAu[SC(OR)=NPh], R=Me (1), Et (2) and iPr (3), compounds are significantly cytotoxic to the HT-29 cancer cell line with 1 being the most active. Based on human apoptosis PCR-array analysis, caspase activities, DNA fragmentation, cell apoptotic assays, intracellular reactive oxygen species (ROS) measurements and human topoisomerase I inhibition, induction of apoptosis is demonstrated and both the extrinsic and intrinsic pathways of apoptosis have been shown to occur. Compound 1 activates the p73 gene, whereas each of 2 and 3 activates the p53 gene. An additional apoptotic mechanism is exhibited by 2, that is, via the JNK/MAP pathway.

2-(3-Meth­oxy­phen­oxy)pyrimidine

In the title compound, C11H10N2O2, the benzene ring faces towards one of the pyrimidine N atoms, and is almost orthogonal to the plane through the pyrimidine ring [dihedral angle = 84.40 (14)°]. In the crystal, the presence of C—H⋯π and π–π [centroid–centroid separation = 3.7658 (18) Å] interactions leads to a supramolecular array in the ac plane. The layers thus formed interdigitate along the b axis.

N-(4-Methyl­phen­yl)-3-nitro­pyridin-2-amine

Two independent molecules comprise the asymmetric unit of the title compound, C12H11N3O2. These differ in terms of the relative orientations of the benzene rings as seen in the respective dihedral angles formed between the pyridine and benzene rings [17.42 (16) and 34.64 (16)°]. Both molecules are twisted about the amine–tolyl N—C bonds [respective torsion angles = 22.3 (5) and 35.9 (5)°] but only about the amine–pyridine N—C bond in the first independent molecule [respective torsion angles = −11.7 (5) and 0.8 (5)°]. Intramolecular N—H⋯O hydrogen bonds preclude the amine H atoms from forming significant intermolecular interactions. The crystal packing features intermolecular C—H⋯O and C—H⋯π and π–π [centroid–centroid distance: pyridine–benzene = 3.6442 (19) Å and pyridine–pyridine = 3.722 (2) Å] contacts.

Tetra-μ-acetato-κ8O:O′-bis­{[4-methyl-N-(4-methyl­phen­yl)pyridin-2-amine-κN1]copper(II)}

The title complex, [Cu2(CH3COO)4(C13H14N2)2], features a binuclear molecule, which lies about a crystallographic centre of inversion; the four acetate ions each bridge a pair of CuII atoms. The coordination of the metal atom is distorted octahedral within a donor set defined by four O atoms, the heterocyclic N atom and the second Cu atom. The pyridine ring is twisted with respect to the tolyl ring and forms a dihedral angle of 35.34 (9)°. A bifurcated N—H⋯(O,O) hydrogen bond is present, linking the amine group to two carboxylate O atoms derived from different acetate ions. In the crystal, C—H⋯π interactions link molecules into a supramolecular array in the bc plane.

2-(4-Methoxyphenoxy)-3-nitropyridine

In the title molecule, C12H10N2O4, the pyridine and benzene rings are almost orthogonal [dihedral angle = 86.69 (11)°], with the pyridine N atom directed towards the centre of the benzene ring. The –NO2 [O—N—C—C = −26.1 (3)°] and –OMe [C—O—C—C = 166.5 (2)°] substituents are not coplanar with their respective aromatic rings. In the crystal, supramolecular layers in the ab plane are formed via C—H⋯π interactions involving methyl H atoms and the pyridine and benzene rings. Short N—O⋯π contacts (where the π-system is derived from the pyridine ring) occur between layers in the c-axis direction.

N-(2-Pyrid-yl)-4-toluidine.

There are two molecules in the asymmetric unit of the title compound, C12H12N2, with dihedral angles between the aromatic rings of 48.35 (12) and 51.02 (12)°. In the crystal structure, both molecules form inversion dimers, linked by pairs of N—H⋯N hydrogen bonds.

N-(4-Chloro-phen-yl)-3-nitro-pyridin-2-amine.

In the title compound, C11H8ClN3O2, the presence of intramolecular N—H⋯O and C—H⋯N interactions help to establish an almost planar molecule [dihedral angle between the pyridine and benzene rings = 9.89 (8)° and r.m.s. deviation for all 17 non-H atoms = 0.120 Å]. Supramolecular tapes feature in the crystal packing whereby dimeric aggregates sustained by pairs of C—H⋯O interactions are connected by π–π interactions occurring between translationally related pyridine rings and between translationally related benzene rings along the b axis [centroid–centroid distance = length of b axis = 3.8032 (4) Å].

N-(4-Methyl-2-pyrid-yl)-p-toluidine.

In the title compound, C13H14N2, the dihedral angle between the aromatic rings is 48.1 (1)° and the bridging C—N—C bond angle is 127.24 (12)°. In the crystal, intermolecular N—H⋯N hydrogen bonding about a center of inversion generates a hydrogen-bonded dimer.

Tetra-μ-acetato-κ8O:O′-bis­{[4-methyl-2-(m-tolyl­amino)pyridine-κN]copper(II)}

In the crystal structure of the title binuclear complex, [Cu2(CH3COO)4(C13H14N2)2], the four acetate groups each bridge a pair of CuII atoms. The coordination of the metal atoms is distorted square-pyramidal, with the bonding O atoms comprising a square basal plane and the coordinating N atom of the N-heterocycle occupying the apical position. In the two N-hetercycle ligands, the benzene rings are twisted with respect to the pyridine rings, making dihedral angles of 53.1 (2) and 54.2 (2)°. Intramolecular N—H⋯O hydrogen bonding is present between the imino and carboxy groups. The crystal studied was a non-merohedral twin with a minor twin component of 21.4%.

2-(4-Methyl-phen-oxy)-5-nitro-pyridine.

The title molecule, C12H10N2O3, is twisted, the dihedral angle between the rings being 61.16 (13)°. The nitro group is approximately coplanar with the pyridine ring to which it is attached [O—N—C—C torsion angle = −178.1 (3)°]. Supramolecular chains along [010] and mediated by C—H⋯O and π–π [centroid(pyridyl)–(benzene) distance = 3.8259 (18) Å] contacts feature in the crystal packing.