Chemotherapeutic Activities of New η6-p-Cymene Ruthenium(II) and Osmium(II) Complexes with Chelating SS and Tridentate SNS Ligands.

A series of new chelating bidentate (SS) alkylimidazole-2-thione-Ru(II)/Os(II) complexes (3ai, 3aii, 3aiii, 3bii/4aiii, 4bi, 4bii), and the tridentate (SNS) pyridine-2,6-diylimidazole-2-thione-Ru(II)/Os(II) complexes (5bi, 5civ/6bi, 6ci, 6civ) in the forms [MII(cym)(L)Cl]PF6 and [MII(cym)(L)]PF6 (M = Ru or Os, cym = η6-p-cymene, and L = heterocyclic derivatives of thiourea) respectively, were successfully synthesized. Spectroscopic and analytical methods were used to characterize the complexes and their ligands. Solid-state single-crystal X-ray diffraction analyses revealed a "piano-stool" geometry around the Ru(II) or Os(II) centers in the respective complexes. The complexes were investigated for in vitro chemotherapeutic activities against human cervical carcinoma (HeLa) and the non-cancerous cell line (Hek293) using the MTT assay. The compounds 3aii, 5civ, 5bi, 4aiii, 6ci, 6civ, and the reference drug, 5-fluorouracil were found to be selective toward the tumor cells; the compounds 3ai, 3aiii, 3bii, 4bi, 4bii, and 6bi, which were found not to be selective between normal and tumor cell lines. The IC50 value of the tridentate half-sandwich complex 5bi (86 ± 9 µM) showed comparable anti-proliferative activity with the referenced commercial anti-cancer drug, 5-fluorouracil (87 ± 15 µM). The pincer (SNS) osmium complexes 6ci (36 ± 10 µM) and 6civ (40 ± 4 µM) were twice as effective as the reference drug 5-fluorouracil at the respective dose concentrations. However, the analogous pincer (SNS) ruthenium complex 5civ was ineffective and did not show anti-proliferative activity, even at a higher concentration of 147 ± 1 µM. These findings imply that the higher stability of the chelating (SS) and the pincer (SNS) ligand architectures in the complexes improves the biological (anti-proliferative) activity of the complexes by reducing the chance of ligand dissociation under physiological conditions. In general, the pincer (SNS) osmium complexes were found to be more cytotoxic than their ruthenium analogues, suggesting that the anti-proliferative activity of the imidazole-2-thione-Ru/Os complexes depends on the ligand's spatial coordination, the nature of the metal center, and the charge of the metal complex ions.

The Current Status of Heterogeneous Palladium Catalysed Heck and Suzuki Cross-Coupling Reactions.

In the last 30 years, C⁻C cross coupling reactions have become a reliable technique in organic synthesis due their versatility and efficiency. While drawbacks have been experienced on an industrial scale with the use of homogenous systems, many attempts have been made to facilitate a heterogeneous renaissance. Thus, this review gives an overview of the current status of the use of heterogeneous catalysts particularly in Suzuki and Heck reactions. Most recent developments focus on palladium immobilised or supported on various classes of supports, thus this review highlights and discuss contributions of the last decade.

Phase Transition of High-Surface-Area Glycol-Thermal Synthesized Lanthanum Manganite.

Cubic and rhombohedral phases of lanthanum manganite were synthesized in a high-pressure reactor. A mixture of La and Mn nitrates with ethylene glycol at a synthesis temperature of 200 °C and a calcination temperature of up to 1000 °C, resulted in a single-phase perovskite, LaMnO3 validated using X-ray diffraction. Significant changes in unit cell volumes from 58 to 353 Å3 were observed associated with structural transformation from the cubic to the rhombohedral phase. This was confirmed using structure calculations and resistivity measurements. Transmission electron microscopy analyses showed small particle sizes of approximately 19, 39, 45, and 90 nm (depending on calcination temperature), no agglomeration, and good crystallinity. The particle characteristics, high purity, and high surface area (up to 33.1 m2/g) of the material owed to the inherent PAAR reactor pressure, are suitable for important technological applications, that include the synthesis of perovskite oxides. Characteristics of the synthesized LaMnO3 at different calcination temperatures are compared, and first-principles calculations suggest a geometric optimization of the cubic and rhombohedral perovskite structures.

4,6-Bis(diphenyl-phosphan-yl)-2,8-di-methyl-phenoxathiin dichloro-methane monosolvate.

The title compound, C(38)H(30)OP(2)S·CH(2)Cl(2), belongs to the xanthene family of ligands containing S- and O-donor atoms in the central heterocylic ring. Positions 2 and 8 on the xanthene backbone are functionalized with methyl groups to allow for the selective functionalization of the backbone at positions 4 and 6 with diphenyl-phosphanyl units. The title compound shows a significant 'roof-like' bending along the axis of planarity involving the O- and S-donor atoms and the benzene rings, resulting in a dihedral angle between the mean planes of the benzene rings of 32.88 (13)°.

Dicarbon-yl(η(5)-cyclo-penta-dien-yl)(hexa-methyl-enetetra-mine-κN(1))iron(II) tetra-fluoridoborate.

In the structure of the title compound, [Fe(C(5)H(5))(C(6)H(12)N(4))(CO)(2)]BF(4), the arrangement around the Fe(II) atom corresponds to that of a three-legged piano stool. The cyclo-penta-dienyl ligand occupies three coordination sites of the apical position in a η(5) fashion, while two CO ligands and one N atom of the hexa-methyl-ene-tetra-mine ligand occupy the remaining coordination sites to complete a distorted octa-hedral geometry. The asymmetric unit consists of two sets of crystallographically independent cations and anions with the r.m.s. deviations of the overlay of non-H atoms of each pair being 0.081 and 0.120 Å, respectively. The Fe-N bond lengths are 2.0459 (15) and 2.0490 (14) Å, while the Fe-Cp(centroid) distances are 1.7257 (3) and 1.7246 (3) Å. One of the anions displays disorder, with the F atoms having occupancies of 0.58 (4) and 0.42 (4).

6,12,18,24-Tetra-meth-oxy-4,10,16,22-tetra-kis-[(meth-oxy-carbon-yl)meth-oxy]-2,8,14,20-tetra-kis-(2-phenyl-eth-yl)resorcin[4]arene.

The title compound, C(76)H(80)O(16), is a macrocyclic structure. This novel resorcin[4]arene derivative has (meth-oxy-carbon-yl)meth-oxy 'head' groups on the upper rim. The compound has a C(2v) 'boat' geometry and there are a range of C-H⋯O contacts in the crystal structure.

Dicarbon-yl(hexa-methyl-ene-1,3,5,7-tetra-mine-κN(1))(η(5)-penta-methyl-cyclo-penta-dien-yl)iron(II) tetra-fluoridoborate.

In the title compound, [Fe(C(10)H(15))(C(6)H(12)N(4))(CO)(2)]BF(4), the arrangement around the Fe(II) atom corresponds to a three-legged piano stool. The penta-methyl-cyclo-penta-dienyl (Cp*) ligand occupies three coordination sites, while two CO ligands and one N atom of the hexa-methyl-ene-tetra-mine ligand occupy the remaining coordination sites, completing a pseudo-octahedral geometry. Both the complex cation and the BF(4) (-) anion reside on crystallographic mirror planes. The Fe-N bond length is 2.069 (2) and the Fe-Cp*(centroid) distance is 1.7452 (3) Å.

Dicarbon-yl(η(5)-cyclo-penta-dien-yl)(2,3-di-bromo-propanamine-κN)iron(II) tetra-fluoridoborate.

The title compound, [Fe(η(5)-C(5)H(5))(NH(2)CH(2)CHBrCH(2)Br)(CO)(2)](BF(4)) contains an Fe(II) cation with a three-legged piano-stool coordination. The NH(2)CH(2)CHBrCH(2)Br ligand contains a chiral carbon atom. The Fe-N bond length is 2.011 (3) Šand the Fe-Cp centroid distance is 1.7189 (5) Å. In the crystal, the ions are linked via two N-H⋯F inter-actions and a weak N-H⋯Br inter-action.

Synthesis and Characterization of Ag/Al2O3 Catalysts for the Hydrogenation of 1-Octyne and the Preferential Hydrogenation of 1-Octyne vs 1-Octene.

Catalysts featuring 2, 5, and 10 wt % silver supported on alumina were prepared by the deposition precipitation method and activated under hydrogen. All catalysts were characterized by Brunauer-Emmett-Teller (BET) measurements, inductively coupled plasma-optical emission spectrometry (ICP-OES), backscattered electron scanning electron microscopy (BSE-SEM), high-resolution transmission electron microscopy (HR-TEM), hydrogen-temperature-programmed reduction (H2-TPR), H2-chemisorption, thermogravimetric analysis (TGA), infrared (IR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, and isopropylamine (IPA) TPD and evaluated in a continuous plug flow fixed-bed reactor. Metal nanoparticles with average sizes of 4.5, 11.5, and 21.1 nm were identified by HR-TEM for the 2, 5, and 10 wt % Ag/Al2O3 catalysts, respectively. A conversion of 99% was observed for 1-octyne over particles between 10 and 15 nm in size, with stable operation up to 24 h (decreasing thereafter) at a temperature of 140 °C and a pressure of 30 bar in the competitive hydrogenation reaction. No conversion of 1-octene was noted in competitive reactions (mixed 1-octyne and 1-octene feed) but rather a gain of 1-octene throughout the 72 h time-on-stream. The performance of all catalysts was influenced by both the metal and support, where the latter impacted the overall acidity of the catalysts, thus affecting their long-term stability.

Morphology, oxygen vacancies, and other factors affecting the performance of supported bimetallic ceria catalysts.

Here in we report the development of a Pt-V/CeO2 catalyst performing under mild conditions in amide hydrogenation. Ceria with different morphologies was employed as support in this study. We further developed a glycol-thermal technique that yields thermally stable quantum dot ceria, which can be applied as a support. A systematic investigation revealed the importance of proximity between the small crystalline hydrogenating sites (Pt) and oxophilic sites (V). The study showed that oxygen vacancies on the ceria surface oxidize both Pt and V, poisoning the hydrogenation reaction. In contrast, the absence of oxygen vacancies promoted the hydrogenating ability of Pt sites and also improved their ability to participate in the H2 spillover mechanism and in situ formation of oxophilic V3+. This study demonstrates how the engineering of the oxygen vacancies on the surface of the redox support can manipulate the nature of active sites toward specific reactions.

4,6-Bis(diphenyl-phosphan-yl)dibenzo[b,d]furan.

The asymmetric unit of the title compound, C(36)H(26)OP(2), comprises two mol-ecules which have slightly different conformations of the phenyl ring substituents. In both mol-ecules, the dibenzofuran unit is close to being planar, with dihedral angles of 3.20 (3) and 1.86 (2)° for the two mol-ecules. Its planarity affects the intra-molecular distances between P atoms, with P⋯P distances of 5.574 (2) and 5.485 (2) Šfor the two mol-ecules.

2,6-Bis(tosyl-oxymeth-yl)pyridine.

The title compound, C(21)H(21)NO(6)S(2), is organized around a twofold axis parallel to the crystallographic c axis and containing the N atom and a C atom of the pyridine ring. The tosyl moiety and the pyridine ring are both essentially planar [maximum deviations 0.028 (2) and 0.020 (3) Å, respectively]; their mean planes form a dihedral angle of 33.0 (2)°.

4,6,10,12,16,18,22,24-Octa-O-methyl-2,8,14,20-tetra-pentylresorcin[4]arene.

The complete molecule of the title compound, C(56)H(80)O(8), is generated by a crystallographic inversion centre. The dihedral angle between the aromatic ring and the unique half of the molecule is 81.52 (16)°. There are no π-π inter-actions in the crystal structure.

1-(2-Amino-eth-yl)-3-phenyl-thio-urea.

In the crystal structure of the title compound, C(9)H(13)N(3)S, mol-ecules are linked through N-H⋯S and N-H⋯N hydrogen bonds, forming hydrogen-bonded tapes along the b axis. The dihedral angle between the phenyl ring and the thiourea group is 44.9 (2)°.

3,3'-Diphenyl-1,1'-(butane-1,4-di-yl)dithio-urea.

The asymmetric unit of the title compound, C(18)H(22)N(4)S(2), contains one half-mol-ecule, the complete mol-ecule being generated by crystallographic inversion symmetry. The crystal structure features two inter-molecular N-H⋯S hydrogen-bonding inter-actions, the first generating an infinite chain along the b axis and the second an infinite chain along the a axis, together forming an inter-locking structure.

1,1'-(Propane-1,3-di-yl)bis-(3-phenyl-urea).

The title compound, C(17)H(20)N(4)O(2), has crystallographic inversion symmetry. In the crystal structure, inter-molecular hydrogen bonding between adjacent urea groups gives rise to infinite polymeric chains diagonally across the bc plane. With a centroid-centroid distance of 3.295 (2) Å, π-π stacking is present in the crystal along the same plane.

4,5,6,10,11,12,16,17,18,22,23,24-Dodeca-kis-[(meth-oxy-carbon-yl)meth-oxy]-2,8,14,20-tetra-pentyl-resorcin[4]arene.

The title compound, C(84)H(112)O(36), has a macrocyclic structure. It has 12 (meth-oxy-carbon-yl)meth-oxy 'head groups' in the upper rim and exhibits a flattened boat geometry. Intra-molecular C-H⋯O hydrogen bonds occur. In the crystal, inter-molecular C-H⋯O contacts occur. The 'head groups' and the pentyl 'feet' contain disordered (0.5:0.5 occupancy ratio) atoms.

1,1'-(Ethane-1,2-di-yl)bis-(3-phenyl-thio-urea).

The complete molecule of the title compound, C(16)H(18)N(4)S(2), is generated by crystallographic inversion symmetry. The dihedral angle between the phenyl ring and the thio-urea group is 52.9 (4)°. The crystal structure displays inter-molecular N-H⋯S hydrogen bonding, which generates sheets in the ab plane.

4,10,16,22-Tetra-kis(2-chloro-acet-oxy)-6,12,18,24-tetra-meth-oxy-2,8,14,20-tetra-pentyl-resorcin[4]arene.

The title compound, C(60)H(76)Cl(4)O(12), has a macrocyclic structure and both the upper and lower rim have disordered atoms. There are no hydrogen bonds or π-π stacking inter-actions in the crystal.