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.

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.

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.

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.

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.

Continuous Flow Preferential Hydrogenation of an Octanal/Octene Mixture Using Cu/Al2O3 Catalysts.

γ-Alumina-supported catalysts with varying copper loadings (5-25 wt %) were prepared by incipient wet impregnation and characterized by various characterization techniques. These catalysts were tested for the selective hydrogenation of octanal in a mixture containing 10 wt % octanal and 2 wt % octene diluted in octanol. The reactions were carried out in a continuous flow fixed-bed reactor in a down flow mode with varying pressures, liquid hourly space velocities, and hydrogen (H2)-to-aldehyde molar ratios. The catalyst activities were assessed over a temperature range between 100 and 180 °C using hydrogen gas as the hydrogen source. The results obtained showed that under these experimental conditions, copper preferentially hydrogenates the aldehyde and the copper content exhibited no significant influence on the catalyst activity or product selectivity. Kinetic modeling revealed that both octanal and octene hydrogenation were first-order reactions, although octene conversion was very low until octanal conversion had reached a significant level. The activation energy for octanal hydrogenation is higher than the octene hydrogenation. A maximum octanal conversion of >99% was obtained at 160 °C, and the best selectivity toward octanol of 99% was achieved at 100 °C (53% conversion). The pressure played a small role with regards to octanal conversion and selectivity toward octanol, whereas it exhibited a significant influence on the octene conversion. Increasing the hydrogen-to-aldehyde ratio was found to have a direct influence on both octanal and octene conversion.

Synthesis, characterization, antiproliferative and molecular docking study of new half sandwich Ir(III), Rh(III) and Ru(II) complexes.

The new carbazole N,N' ligand containing [(η(5)-C5Me5)MCl(L)]PF6, (M=Ir (1) and Rh (2)) and [(η(6)-C6H6)RuCl(L)]PF6 (3) (C5Me5=pentamethylcyclopentadienyl, L=9-ethyl-N-(pyridine-2-yl methylene)-9H-carbazole-3-amine) complexes has been synthesized and characterized by (1)H NMR, (13)C NMR, 2D NMR, melting point analysis, electronic absorption, infrared spectroscopy, HR-Mass spectroscopy and elemental analyses. The crystal structure of the [(η(5)-C5Me5)RhCl(L)]PF6 has been confirmed by single crystal XRD. The anticancer study of the synthesized complexes 1-3 clearly showed a potent inhibitor of human breast cancer cells (MCF-7) under in vitro conditions. The inhibitory concentrations (IC50) of the complexes 1-3 were determined at low (5, 6 and 8µM) concentration against the MCF-7 human breast cancer cell line. Further cytotoxic, cell cycle and nuclear studies confirmed that the novel half sandwich Ir(III), Rh(III) and Ru(II) complexes could be effective against MCF-7 human breast cancer cell proliferation. Moreover the results indicate that anticancer in vitro activity of complexes 1-3 falls in the order of 1>2>3. A molecular docking study of the complexes 1-3 showed the nature of binding energy, H-bond and hydrophobic interactions with the cyclooxygenase-2 (COX-2) receptor.

Synthesis and structural elucidation of a novel polymorph of alcaftadine.

In this study, we have synthesized and elucidated the structure of the H1 histamine antagonist, 2-(1-methylpiperidin-4-ylidene)-4,7-diazatricyclo[8.4.0.0((3,7))]tetradeca-1(14),3,5,10,12-pentaene-6-carbaldehyde in the solution and solid-state. We have also studied the thermal dilapidation of the compound. Solution structure analysis was achieved by employing NMR spectroscopy including 2D experiments NOESY, HSQC and HMBC, while solid state investigations were undertaken using SXRD, PXRD, TGA, DSC, and IR spectroscopy. For the first time the single crystal structure of alcaftadine has now been solved. Crystallographic data are as follows: monoclinic, Cc, a=11.5694(6)Å, b=14.5864(6)Å, c=10.2688(4)Å, α=90°, ß=111.793(3)°, γ=90°, V=1609.07(13)Å(3), Z=4. The Hirshfeld surface analyses also have been performed using the crystal structure.

Coordination chemistry of Co complexes containing tridentate SNS ligands and their application as catalysts for the oxidation of n-octane.

The selective oxidation of saturated hydrocarbons to terminal oxygenates under mild catalytic conditions has remained a centuries long challenge in chemical catalysis. In an attempt to address this challenge, two series of tridentate donor ligands {2,6-bis(RSCH2)pyridine and bis(RSCH2CH2)amine [R = alkyl, aryl]} and their respective cobalt complexes {Co[2,6-bis(RSCH2)pyridine]Cl2 and Co[bis(RSCH2CH2)amine]Cl2} were synthesized and characterized. Crystal structures of Co[2,6-bis(RSCH2)pyridine]Cl2 [R = -CH3 (), -CH2CH3 (), -CH2CH2CH2CH3 () and -C6H5 ()] are reported in which crystallized as a homo-bimetallic dimer that incorporated two bridging chloride atoms in an octahedral geometry around each cobalt center, while , and crystallized as mono-metallic species characterized by trigonal bipyramidal arrangement of ligands around each cobalt center. As catalysts for the homogeneous selective oxidation of n-octane, the catalysts yielded ketones as the dominant products with a selectivity of ca. 90% for the most active catalyst Co[bis(CH2CH2SCH2CH2)amine]Cl2 () at a total n-octane conversion of 23%. Using tert-butyl hydroperoxide (TBHP) as an oxidant, optimization of reaction conditions is also reported.

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).

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.

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)°.

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.

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.

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.

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)°.

(µ-Formato-κO:O')bis-[dicarbon-yl(η-cyclo-penta-dien-yl)iron(II)] tetra-fluoridoborate.

In the structure of the title compound [Fe(2)(C(5)H(5))(2)(CHO(2))(CO)(4)]BF(4), each Fe(II) atom is coordinated in a pseudo-octa-hedral three-legged piano-stool fashion. The cyclo-penta-dienyl ligand occupies three fac coordination sites while the two carbonyl ligands and formate O atom occupy the remaining three sites.