A μ‐chloro‐bridged dinuclear ruthenium complex with 9H‐carbazole: the formation of one‐dimensional linear chains of star‐shaped edge‐fused rings

The title complex, di‐μ‐chloro‐bis­[chloro­(η⁶‐p‐cymene)ruthenium(II)]–9H‐carbazole (1/2), [Ru₂Cl₄(C₁₀H₁₄)₂]·2C₁₂H₉N, is composed of one [RuCl₂(η⁶‐p‐cymene)]₂ and two 9H‐carbazole mol­ecules. There are one‐half of a dinuclear complex and one 9H‐carbazole mol­ecule per asymmetric unit. In the dinuclear complex, each of the two crystallographically equivalent Ru atoms is in a pseudo‐tetra­hedral environment, coordinated by a terminal Cl atom, two bridging Cl atoms and the aromatic hydro­carbon, which is linked in a η⁶ manner; the Ru⋯Ru separation is 3.688 (3) Å. The title complex has a crystallographic centre of symmetry located at the mid‐point of the Ru⋯Ru line. Inter­molecular N—H⋯Cl and π–π stacking inter­actions are observed. These inter­actions form a four‐pointed star‐shaped ring and one‐dimensional linear chains of edge‐fused rings running parallel to the [100] direction, which stabilize the crystal packing.     

Pyrimidines,Part XXXI . Synthesis,reactions and properties of 6-acyl-1,3-dimethylpyrrolo[2,3-d]pyrimidine-2,4-diones

Acylations of 1,3-dimethyl- ( 1 ) and 1,3,7-trimethylpyrrolo[2,3-d]pyrimidine-2,4-dione ( 2 ) with anhydrides in the presence of trifluoroacetic acid proceed well to give in good yields the corresponding 7-acyl derivatives 3–11 . The 6-trichloroacetyl derivatives 5 and 6 are sensitive towards nucleophiles, which displace the trichloromethyl group easily by formation of the corresponding 6-carboxylic acid derivatives 12–23. The newly synthesized compounds have been characterized by elemental analysis, uv and ¹H nmr spectra and pK_a, determinations.     

Computation of Rotation Matrices Making Lined‐Up to the Local Cartesian Coordinates

Rotation matrices were expressed in terms of Gaunt coefficients and complex spherical harmonics. The rotation matrices were calculated using two different ways. In the first, Gaunt coefficients and normalized complex spherical harmonics were directly calculated using binomial coefficients; in the second, Gaunt coefficients and complex spherical harmonics were recursively calculated. The methods were compared with respect to accuracy and computation time (CPU) for low and very high quantum numbers.     

Synthesis, structural characterization and electrochemical studies of new macrocyclic Schiff base containing pyridine head and its metal complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:13,14-tribenzo-9,12-dioksa-cyclopentadeca-1,5-diene was synthesized by reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by the template effect by the reaction of 2,6-diaminopyridine and 1,2-bis(2-carboxyaldehyde phenoxy)ethane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La(NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV-Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra, and cyclic voltammetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(II) was oxidized to Co(III). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process, while copper and cobalt complexes gave irreversible reduction processes in DMSO solution.     

Thermal computations of temperature distribution and bulb heat transfer in an automobile headlamp

In this study, experimental and numerical analysis was performed to define thermal deformation inside the head lamp because of usage plastic materials and thermal loads. Buoyancy, radiation and conjugate effects were considered. Velocity and temperature distributions were obtained and possible hot points and condense regions can be determined. Nusselt number distribution on cylindrical bulb were computed and compared with literature. Relatively important heat transfer increase in natural convection was found.     

Ruthenium(II) complexes derived from 2‐phenylthiazoline‐4‐carboxylic acid: structure and catalytic activity for transfer hydrogenation reaction

Piano‐stool ([(p‐cymene)Ru(thz)Cl], 2 ) and six‐coordinated ([Ru(thz)₂(PPh₃)₂], 3 ) ruthenium complexes derived from 2‐phenylthiazoline‐4‐carboxylic acid (Hthz, 1 ) were synthesized for the first time, and fully characterized using conventional methods. Also, the molecular structure of complex 3 was determined using X‐ray analysis. These complexes were evaluated as catalysts for transfer hydrogenation of carbonyl compounds in the presence of isopropyl alcohol and KO^tBu. Complex 2 was found to be more active than 3 in transfer hydrogenation. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis, thermal stability, electronic features, and antimicrobial activity of phenolic azo dyes and their Ni(II) and Cu(II) complexes

Four water soluble azo dyes, 4-(isopropyl)-2-[(E)-(4-chlorophenyl)diazenyl]phenol (L ¹), 4-(isopropyl)-2-[(E)-(2,4-dichlorophenyl)diazenyl]phenol (L²), 4-(sec-butyl)-2-[(E)-(4-chlorophenyl) diazenyl]phenol (L ³), 4-(sec-butyl)-2-[(E)-(2,4-dichlorophenyl)diazenyl]phenol (L ⁴), and their Cu(II) and Ni(II) complexes were synthesized and characterized using spectroscopic methods. Examination of their thermal stability revealed similar decomposition temperature of approximately 260–300°C and that they were more thermally stable than their metal complexes. Ni(II) complexes of ligands L² and L⁴ were more stable than the other coordination compounds. Among the synthesized ligands, L² and the complexes Cu(L³)₂ and Ni(L⁴)₂ showed both antimicrobial and antifungal activity. However, the other ligands and the complexes were poorly active against selected microorganisms.     

Defect Chemistry of Singly and Doubly Doped Ceria: Correlation between Ion Transport and Energetics

Earlier studies have shown a strong correlation between the enthalpy of formation, ΔH_f,ox, and the ionic conductivity, σ_i, near room temperature in doped ceria systems, which are promising solid electrolytes for intermediate‐temperature solid oxide fuel cells (IT‐SOFCs). The present work demonstrates that this correlation holds at the operating temperature of IT‐SOFCs, 600–700 °C. Solid solutions of Ce_1?xNd_xO_2?0.5x, Ce_1?xSm_xO_2?0.5x, and Ce_1?xSm_0.5xNd_0.5xO_2?0.5x are studied. The ΔH_f,ox at 702 °C is determined by considering the excess heat content between 25 and 702 °C combined with the value of ΔH_f,ox at 25 °C. Both σ_i and ΔH_f,ox show maxima at x=0.15 and 0.20 for the singly and doubly doped ceria, respectively, suggesting that the number of mobile oxygen vacancies in these solid solutions reaches a maximum near those compositions. An increase in temperature results in a shift of the maximum in both ΔH_f,ox and σ_i towards higher concentrations. This shift results from a gradual increase in dissociation of the defect associates.     

Identification of radical structures on 1‐pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide and 1,3‐bis(pentamethylbenzyl)‐4,5‐dimethylbenzimidazoliumsilver(I)bromide exposed to gamma rays: an EPR study

1‐Pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide and 1,3‐bis(pentamethylbenzyl)‐4,5dimethylbenzimidazoliumsilver(I)bromide and their Ag⁺ complexes were synthesized and their polycrystal forms were produced by recrystallization in dichloromethane/Et₂O solvent system. Structural determinations were carried out by ¹H NMR and ¹³C NMR with a Varian 400 NMR system using tetramethylsilane as internal standard and CDCl₃ as solvent. The disappearance of acidic N‐heterocyclic carbene proton showed the formation of Ag(I) complexes. Also, elemental analyses were carried out. Electron paramagnetic resonance (EPR) measurements were performed to determine the formed radical structure on the samples irradiated at the room temperature for 72 h by using ⁶⁰Co‐source with dose rate of 0.680 kGy. The EPR measurements were carried out in the temperature range of 200 K–450 K. Identical radicals were determined on the irradiated compounds. It was observed that the shapes of the spectra of the samples were independent of the temperature but, the resonance line intensities changed linearly with the temperature. Also, it was detected that the free radical on the 1‐pentamethylbenzyl‐3‐ethylimidazoliumsilver(I)bromide is not stable compared to that on the 1,3‐bis(pentamethylbenzyl)‐4,5dimethylbenzimidazoliumsilver(I)bromide. Copyright © 2016 John Wiley & Sons, Ltd.