Internal path investigation of the acting electrons during the photocatalysis of panchromatic ruthenium dyes in dye-sensitized solar cells

A series of heteroleptic Ru(II) complexes were theoretically investigated using time-dependent density functional theory. These dyes, including K8 and N3, are based on a common motif formed by Ru center, NCS, and polypyridyl ligands, but differ only by the nature of the added group in para position of each pyridyl. The presence of these ligands will enable the evaluation of the electronic effects ±I and ±M. This work focuses on the localization of the part, among the metal, the NCS, the polypyridyl ligands, and the added group R, which is most actively involved in the photocatalysis process. We dealt with both ground and excited states as well as the electronic transitions between them. To illustrate the effect of each functional group R on its photophysical properties, the geometries of five dyes were optimized in the molecular and univalent cationic states. All molecules are asymmetrical in shape with a distorted octahedral coordination of the RuN6 core. Atomic charge and spin density distributions show that a charge transfer process occurs from the NCS/Ru to polypyridyl ligand. Analysis of the electronic absorption spectra reveals that the band with the highest wavelength value is assigned to metal-to-ligand charge transfer transition. On the contrary, two other bands are assigned to multitransitions Ru/NCS to polypyridyl–π*. These attributions have been confirmed by the localization of all atoms intervening in them. We also introduced an adapted way to estimate the ionization probability values in each atomic center in the ground and first excited states. Phenomenal properties such as mobility, redox potential, electronic spectrum, ionization potential, and optical gap of the most efficient dye, which is the N3, fit well with experimental values.     

Dynamic light scattering studies of additive effects on the microstructure of aqueous gemini micelles

Dynamic light scattering (DLS) measurements have been performed at 30 degrees C to see the effects of additives on the microstructure of gemini alkanediyl-alpha,omega-bis(dimethylcetylammonium bromide) surfactants, (Br-, n-C16H33N+Me2-(CH2)s-Me2- N+n-C16H33, Br-, 16-s-16, where s = 4, 5, 6). In pure aqueous solutions, the hydrodynamic diameter, Dh, was found to increase rapidly with geminis in comparison to their monomeric counterpart cetyltrimethylammonium bromide (n-C16H33N+Me3, Br-, CTAB) on increasing surfactant concentration. The additives considered in the present study are n-alcohols (C4-C6OH) and n-hexylamine (C6NH2) on the micellar growth of 0.03 M 16-4-16 in the presence and absence of 0.001 M KBr. The presence of 0.001 M KBr or organic additives at lower concentrations singly or jointly has little effect on the micellar size. As the chain length of the additive increases, the size increases with the increase of additive concentration, the magnitude being substantial in the presence of 0.001 M KBr. However, for equal chain length additives (C6OH, C6NH2), the effect was greater for C6OH. In case of C6NH2, the value of Dh reaches to almost constancy when the concentration of the additive was increased. Increased effectiveness of additives in the presence of added salt (KBr) is discussed in light of electrostatic and hydrophobic forces operating in the solution, which are always responsible for growth processes.     

Production of thermostable multiple enzymes from Bacillus amyloliquefaciens KUB29

A strain of Bacillus amyloliquefaciens KUB29 was identified by 16S ribosomal RNA sequencing (Genbank: MF772779.1). Production of thermostable protease, amylase and lipase were done by the isolated strain. The produced enzymes were partially purified by ammonium precipitation followed by dialysis process. Protease and lipase enzymes are effectively used in bio-oil extraction from proteinaceous sample followed by transesterification to produce methyl ester. Amylase enzyme is widely used in food and laundry industry. The produced enzymes are active at thermophilic condition of 55 °C. Use of these enzymes in biofuel production process will make the process cleaner and greener.     

Valuation theory of exponential Hardy fields I

We describe the valuation theoretic properties of the Hardy fields associated to models of , where T is the theory of a polynomially bounded o-minimal expansion of the reals and is the real exponential function. We deduce that has levels with parameters and is exponentially bounded. We establish a maximality property of , the Hardy field of the expansion by the restricted analytic functions and power functions. Received: 10 July 2000 ; in final form: 15 April 2002/Published online: 24 February 2003 RID="*" ID="*" This paper was written while both authors were partially supported by a Canadian NSERC research grant.     

B(C6F5)3-Catalyzed E-Selective Isomerization of Alkenes

Herein, we report the B(C₆F₅)₃-catalyzed E-selective isomerization of alkenes. The transition-metal-free method is applicable across a diverse array of readily accessible substrates, giving access to a broad range of synthetically useful products containing versatile stereodefined internal alkenes. The reaction mechanism was investigated by using synthetic and computational methods.     

New Nitro-Laterally Substituted Azomethine Derivatives; Synthesis,Mesomorphic and Computational Characterizations

Two new homologues series, based on two rings of the azomethine central group bearing the terminal alkoxy group of various chain lengths, were prepared. The alkoxy chain length varied between 6 and 16 carbons. The other terminal wing in the first series was the F atom, and the compound is named N-4-florobenzylidene-4-(alkoxy)benzenamine (In). The second group of compounds included a lateral NO₂ substituent in addition to the terminal F atom, named N-(4-fluoro-3-nitrobenzylidene)-4-(alkyloxy)aniline (IIn). Mesomorphic and optical properties were carried out via differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Elemental analyses, FT-IR, and NMR spectroscopy were carried out to elucidate the molecular structures of the synthesized groups. Mesomorphic investigations indicated that all the synthesized homologues (In) were monomorphic, possessing the smectic A (SmA) phase monotropically, while the second group (IIn) members were non-mesomorphic. The experimental data indicated that the formation of the mesophase is affected by the protrusion of the lateral nitro group. The disruption of the mesophase in the second group was attributed to the increase of its molecular width, which affects its lateral intermolecular interactions. The computational simulations were in agreement with the experimental data. On the other hand, the location of NO₂ group within the molecular geometry increased the melting temperature of the molecule, and thus, affected their thermal and physical properties. By discussing the estimated parameters, it was found that the molecular architecture, the dipole moment, and the polarizability of the investigated compounds are highly affected by the electronic nature and position of the terminal and lateral substituents as well as their volumes.     

Recrystallization of Zeolite Y to Analcime and Zeolite P with <SC>d</SC>‐Methionine as Structure‐Directing Agent (SDA)

In this study, the synthesis of template free zeolite Y and its recrystallization to two types of pure zeolite P and analcime in the presence of the amino acid d‐methionine as structure‐directing agent were investigated. The recrystallization occurred solely when specific heating cycles were applyed. A completely crystallized phase of zeolite Y for the mixture of zeolite P and analcime was observed in the presence of d‐methionine at a concentration of 0.015 <SC>m</SC>. The effect of different Si/Al ratios (2.3–9.3), crystallization temperatures (40–160 °C), and crystallization times (28–96 hours) on the achievement of two different zeolite types were studied as well. Pure zeolite P was obtained during conventional heating to 100 °C for 42 hours, whereas pure analcime zeolite was achieved by heating the mixture to 160 °C for 96 hours. The products were characterized by X‐ray diffraction, scanning electron microscopy, and IR spectroscopy.     

Synthesis,Crystal Structure,Quantum Chemical Analysis,Electrochemical Behavior,and Antibacterial and Photocatalytic Activity of Co Complex with Pyridoxal-(S-Methyl)-isothiosemicarbazone Ligand

New complex Co(III) with ligand Pyridoxal-S-methyl-isothiosemicarbazone, (PLITSC) was synthesized. X-ray analysis showed the bis-ligand octahedral structure of the cobalt complex [Co(PLITSC-H)₂]BrNO₃·CH₃OH (compound 1). The intermolecular interactions governing the crystal structure were described by the Hirsfeld surface analysis. The structure of compound 1 and the corresponding Zn complex (([Zn(PLTSC)(H₂O)₂]SO₄·H₂O)) were optimized at the B3LYP/6–31 + G (d,p)/LanL2DZ level of theory, and the applicability was assessed by comparison with the crystallographic structure. The natural bond orbital analysis was used for the discussion on the stability of formed compounds. The antibacterial activity of obtained complexes towards S. aureus and E. coli was determined, along with the effect of compound 1 on the formation of free radical species. Activity of compound 1 towards the removal of methylene blue was also investigated. The voltammograms of these compounds showed the reduction of metal ions, as well as the catalyzed reduction of CO₂ in acidic media.     

Impact of phase out of leaded gasoline on the air quality in Budapest

As part of an air pollution study in Budapest, size-fractionated aerosol samples were collected by stacked filter units and cascade impactors, and some criteria pollutants and meteorological parameters were recorded in 1996, 1998 and 1999. The samplings were performed at three urban locations including an urban background site, a downtown site, and a tunnel. Elemental composition of the aerosol samples was measured by instrumental neutron activation analysis and/or particle-induced X-ray emission spectrometry; and black carbon (BC) was determined by a light reflectance technique. Since leaded gasoline was completely phased out in Hungary on 1 April 1999, the atmospheric concentrations of some typical transportation-related air pollutants (i.e. Pb, Br, BC and CO) were used for overviewing the actual impact of the phase out on the air quality and on the aerosol characteristics. For the background site, mean concentration of Pb and Br was not changed significantly. In the downtown site, the phase out resulted in a concentration decrease by a factor of 3–4 for Pb and Br. For the tunnel, concentrations of Pb and Br were decreased by a factor up to 9 and 28, respectively. Correlation between the pollutants, their crustal enrichment factors, and average elemental mass size distributions are also presented and discussed.