Voltage enhancement in dye-sensitized solar cell using (001)-oriented anatase TiO2 nanosheets

A nanocrystalline TiO₂ (anatase) nanosheet exposing mainly the (001) crystal faces was tested as photoanode material in dye-sensitized solar cells. The nanosheets were prepared by hydrothermal growth in HF medium. Good-quality thin films were deposited on F-doped SnO₂ support from the TiO₂ suspension in ethanolic or aqueous media. The anatase (001) face adsorbs a smaller amount of the used dye sensitizer (C101) per unit area than the (101) face which was tested as a reference. The corresponding solar cell with sensitized (001)-nanosheet photoanode exhibits a larger open-circuit voltage than the reference cell with (101)-terminated anatase nanocrystals. The voltage enhancement is attributed to the negative shift of flatband potential for the (001) face. This conclusion rationalizes earlier works on similar systems, and it indicates that careful control of experimental conditions is needed to extract the effect of band energetic on the current/voltage characteristics of dye-sensitized solar cell.     

Task-specific nitrite and azide ionic liquids for the efficient one-pot synthesis of 1,2,3-triazoles from the aniline derivatives

An efficient, fast, and straightforward procedure for the synthesis of aromatic azides and in situ preparation of 1,2,3-triazoles under mild conditions is described. Aniline derivatives have been treated with task-specific [bmim]NO(2) and [bmim]N(3) ionic liquids to give the related phenyl azides which, on further in situ reaction with 1,3-diketones and ethylacetoacetate, afforded 1,2,3-triazoles in very good to excellent yields in very short reaction time. This procedure, which generates azides followed by azide in situ cycloaddition with diketone, has become an attractive option. In this protocol, [bmim]N(3) is used instead of the highly toxic reagent NaN(3).     

Top local cohomology modules and Gorenstein injectivity with respect to a semidualizing module

Let ${(R, \mathfrak{m})}$ be a commutative Noetherian local ring of Krull dimension d, and let C be a semidualizing R-module. In this paper, it is shown that if R is complete, then C is a dualizing module if and only if the top local cohomology module of ${R, H _{\mathfrak{m}} ^{d} (R)}$ , has finite G _C -injective dimension. This generalizes a recent result due to Yoshizawa, where the ring is assumed to be complete Cohen-Macaulay.     

k-torsionless modules with finite Gorenstein dimension

Let R be a commutative Noetherian ring. It is shown that the finitely generated R-module M with finite Gorenstein dimension is reflexive if and only if M _p is reflexive for p ∈ Spec(R) with depth(R _p) ? 1, and $G - {\dim _{{R_p}}}$ (M _p) ? depth(R _p) ? 2 for p ∈ Spec(R) with depth(R _p) ? 2. This gives a generalization of Serre and Samuel’s results on reflexive modules over a regular local ring and a generalization of a recent result due to Belshoff. In addition, for n ? 2 we give a characterization of n-Gorenstein rings via Gorenstein dimension of the dual of modules. Finally it is shown that every R-module has a k-torsionless cover provided R is a k-Gorenstein ring.     

Fatty acid hydrazides in heterocyclic synthesis: Synthesis of 1,2‐diazepine and pyridazine derivatives

1,2‐Diazepinone derivatives 6a–d, 8a,b, and 10a–c were synthesized from the reaction of olefines carrying EWG as ethoxymethylene malononitrile, ethoxymethylene cyanoacetate, and tetracyanoethylene with 1a–f respectively. Also, 5‐alkyl‐6‐oxotetrahydropyridazine‐4,4‐dicarboxylate derivatives 12a–c were afforded via the reaction of 1d–f with diethyl ethoxymethylene malonate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:259–264, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20294     

Inverse Gas Chromatographic Study of the Oxidation Stability of Lubricating Base Oils via Solubility Parameter Calculations

 The Flory-Huggins interaction parameter (χ∞1,2) and solubility parameter (δ2) and its hydrogen bonding sensing component (δh) were determined using inverse gas chromatography (IGC). These parameters were successfully used in the probes of chemical changes that occur during the oxidation of naphthenic and paraffinic base oils in a GC column. Changes in χ∞1,2 values reflect the different types of intermolecular interactions (dispersive, polar, hydrogen bonding) of the given lubricating base oil during oxidation. The obtained results showed that δh component of solubility parameter is the most important parameter for probing the oxidative-chemical changes during the oxidation of given lubricating oils.     

Mono‐ and dinuclear oxime palladacycles bearing diphosphine ligands: An unusual coordination mode for dppe

Three new oxime‐based palladacycles, namely [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(dppm)]ClO₄ ( 1 ), [Pd₂{C,N‐C₆H₄{C(Me)?NOH}‐2}₂(dppe)₂(μ‐dppe)](ClO₄)₂ ( 2 ) and [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(dppmS₂)]ClO₄ ( 3 ), were synthesized by the reaction of dinuclear oxime complex [Pd{C,N‐C₆H₄{C(Me)?NOH}‐2}(μ‐Cl)]₂ with different diphosphine ligands (dppm, dppe and dppmS₂). The synthesized complexes were characterized using Fourier transform infrared, ³¹P NMR, ¹H NMR and ¹³C NMR spectroscopic methods and elemental analyses, and their molecular structures were elucidated using X‐ray crystallography. The structure of 2 is worthy of note as it is the first oxime palladacycle where there are both bridging (P–) and chelating (P^P) dppe ligands, giving rise to a dinuclear complex. The palladium atom is in a five‐coordinate, square pyramidal P₃NC environment, while in 3 the palladium atom is in a distorted square planar environment, coordinated by the oxime ligand and a chelating (S^S) dppmS₂ ligand. These complexes were employed as efficient catalysts for the Suzuki–Miyaura cross‐coupling reaction of several aryl bromides with phenylboronic acid. The in vitro cytotoxicity of the compounds was also evaluated against human tumour cell lines (HT29, A549 and HeLa) using the MTT assay method. The results indicate that the dinuclear complex 2 has greater catalytic and anticancer activity in comparison with the mononuclear complexes 1 and 3 .     

2D ZnO/Fe3O4 nanocomposites as a novel catalyst-promoted green synthesis of novel quinazoline phosphonate derivatives

In this research a novel and efficient procedure for the preparation of phosphonate derivatives using the reaction of 2,4-dihydroxyacetophenone, isopropenylacetylene, 2-amino-N-alkyl benzamide, dialkyl acetylenedicarboxylates and trimethyl phosphite or triphenyl phosphite in the presence of reusable 2D ZnO/Fe₃O₄ nanocomposites in water at room temperature was investigated. The 2D ZnO/Fe₃O₄ nanocomposites were synthesized using ionic liquid [OMIM]Br as a stabilizer and soft template. In addition, the power of antioxidant for some prepared compounds was studied using trapping of radicals by DPPH and a ferric reduction activity potential experiment. As a result, compound 6f displayed a noteworthy power for trapping of free radicals and 6b exhibited excellent reducing power compared with standards (BHT and TBHQ). Moreover, the antimicrobial power of some prepared quinazolinone phosphonates was proved by employing the disk diffusion experiment on two kinds of bacteria, Gram-positive and -negative bacteria. The obtained outcomes of disk diffusion test showed that these compounds prevented bacterial growth. Some advantages of this procedure are: short time of reaction, high yields of product and easy separation of catalyst and products.     

Tetrazole derivatives synthesis using Fe3O4@fibroin-SO3H as a magnetically separable green solid acid nanocatalyst under solvent-free conditions

Research on Chemical Intermediates - In the present study, a magnetically separable potent solid acid nanocatalyst with a facile preparation technique was fabricated via incorporation of fibroin as...