Non-uniform mass transfer or wall enthalpy into a compressible flow over a rotating sphere

A study for the effect of non-uniform slot injection/suction and non-uniform total enthalpy at the wall for a steady non-similar laminar compressible boundary layer flow over a rotating sphere is presented. The effects of rotation and free stream Mach number have also been considered. Non-similar solutions have been obtained from the starting point of the stream wise coordinate to the point of separation using an implicit finite difference scheme in combination with the quasi-linearization technique. The results indicate that the separation can be delayed by non-uniform slot suction and also by moving the slot downstream but the non-uniform slot injection has just the opposite effect. An increase of rotation and total enthalpy at the wall causes separation to occur earlier while cooling delays it. An increase of the Mach number shifts the point of separation upstream due to the adverse pressure gradient. The non-uniform total enthalpy at the wall has a very little effect on the skin friction and hence on the point of separation.     

Nanostructured copper particles-incorporated Nafion-modified electrode for oxygen reduction

The electrocatalytic activity of nanostructured copper particles (represented as Cu_nano) incorporated Nafion (Nf) film-coated glassy carbon (GC) electrode (GC/Nf/Cu_nano) towards oxygen reduction was investigated in oxygenated 0.1 M phosphate buffer (pH 7.2). The electrodeposited Cu_nano in Nf film was characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activity of Cu_nano at the modified electrode towards oxygen reduction was studied using cyclic voltammetry technique. The molecular oxygen reduction at the GC/Nf/Cu_nano-modified electrode started at a more positive potential than at a bare GC electrode. A possible reaction mechanism was proposed in which oxygen reduction may proceed through two-step two-electron processes at the GC/Nf/Cu_nano electrode. The GC/Nf/Cunano electrode shows higher stability for oxygen reduction in neutral solution and the electrode may find applications in fuel cells.     

Synthesis,characterization, and antimicrobial activity of novel (<Emphasis Type="Italic">E</Emphasis>)-1-(aryl)-3-{3, 5-dimethoxy-4-[(1-(aryl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)methoxy]phenyl}prop-2-en-1-ones

The new chalcone derivatives containing the 1,2,3-triazole ring system, namely, (E)-1-(aryl)-3-{3,5-dimethoxy-4-[(1-(aryl)-1H-1,2,3-triazol-4-yl)methoxy]phenyl}prop-2-en-1-ones, were synthesized in 65–88% yield by the “click chemistry” reactions of substituted acetophenones, 4-hydroxy-3,5-dimethoxy-benzaldehyde, and different substituted azides. The structure of the compounds was determined by the FT-IR, ¹H NMR, ¹³C NMR, and mass spectroscopic analyses. Compounds 6a–6l were screened for in vitro antimicrobial activity by the agar disc diffusion method.     

Benzyl group conformation in 4-benzyl-4-hydroxypiperidines

The high-resolution ¹H and ¹³C NMR spectra of eight 4-benzyl-4-hydroxypiperidines 1–8 were recorded in CDCl₃ and analyzed. In 2, the conformation of the equatorial benzyl group at C(4) was established as an equilibrium mixture of A [the phenyl group is gauche with respect to OH and C(5)] and B [the phenyl group is gauche with respect to OH and C(3)], whereas in 3-alkyl-4-benzyl-4-hydroxypiperidines 3–8, the favored conformation of the benzyl group at C(4) is A. In 1, the axial benzyl group at C(4) adopts the gauche conformations A′ [the phenyl group is gauche with respect to OH and C(3)] and B′ [the phenyl group is gauche with respect to OH and C(5)], in which the phenyl ring of the benzyl group is gauche with respect to the OH group. The HF/DFT B3LYP/6-3G* hybrid calculations of model systems 1′–3′ also support these conformations. The ¹³C data reveal that the equatorial methyl group at C(3) exerts a shielding influence on the methyl-bearing carbon and the magnitude of the α effect was found to be approximately ?1.5 ppm. The parameters of the ¹³C substituent in the benzyl group show that the the α effect of the equatorial benzyl group is considerably higher in 3-ethyl tertiary alcohol 7 than in 3-methyl tertiary alcohol 3 and 4-benzyl-t(4)-hydroxypiperidine 2. This may be explained if we take into account the different conformations of the ethyl group in t(4)-hydroxy-3-ethyl-2,6-diphenylpiperidine 12 and 3-ethyl tertiary alcohol 7.     

Synthesis of novel isoindolone‐based medium‐sized macromolecules and triazole containing heterocyclic compounds

A series of novel isoindolone‐based macromolecules of medium‐sized heterocyclic rings, such as 7,8‐dihydro‐6H‐benzo[4,5][1,6,3]dioxazonino[2,3‐a]isoindol‐14(9aH)‐one derivatives ( 5a‐l ), were synthesized and its frame work incorporating with a triazole moiety on phenol, ie, 2‐(4‐((1‐(2‐methoxyphenyl)‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)isoindoline‐1,3‐dione ( 9a‐f ) and also a triazole moiety on carboxylic acid, ie, (1‐(2‐methoxyphenyl)‐1H‐1,2,3‐triazol‐4‐yl)methyl 4‐(1,3‐dioxoisoindolin‐2‐yl)benzoate derivatives ( 13a‐e ) with various substitutions on aryl ring system have synthesized. All the synthesized compounds were characterized and confirmed with IR, ¹H NMR_, ¹³C NMR, and ESI mass spectral analysis.     

Synthesis of Novel 2-Iminothiazolidin-4-ones

Abstract

Thiazolidin-4-ones are known to exhibit diverse biological activities such as antimicrobial, anticancer, antidiarrheal, anticonvulsant, antidiabetic, antihistaminic, and antifungal activities. In the present investigation, a series of 2-haloacetamides was prepared by reacting chloroacetyl chloride with amines in dry benzene under reflux conditions. The formed 2-haloacetamides reacted with potassium thiocyanate in refluxing dry acetone to afford new 2-iminothiazolidin-4-ones. The 5-arylidene-2-imino-3 (napthalen-2yl)-thiazolidin-4-ones were prepared by condensing 2-iminothiazolidin-4-ones with substituted benzaldehydes. All the products were characterized by infrared, mass, and ¹H and ¹³C NMR techniques.     

Design,synthesis of (Z)‐3‐benzyl‐5‐((1‐phenyl‐3‐(3‐((1‐ substituted phenyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)‐1H‐pyrazol‐4‐yl)methylene)thiazolidine‐2,4‐dione analogues as potential cytotoxic agents

In an attempt to achieve promising cytotoxic agents, a series of new (Z)‐3‐benzyl‐5‐((1‐phenyl‐3‐(3‐((1‐substituted phenyl‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)‐1H‐pyrazol‐4‐yl)methylene)thiazolidine‐2,4‐diones 10 a‐n were designed, synthesized, and characterized by ¹H NMR, ¹³C NMR, IR, and ESI‐MS techniques. These compounds synthesized from appropriate reaction procedures with better yields. All the novel synthesized compounds 10a‐n were evaluated for their cytotoxic activity against the MCF‐7 cell line (Human breast cancer cell line) at different concentrations of 0.625, 1.25, 2.5, 5, and 10 μM, respectively. The cytotoxic evaluation assay is presented in terms of IC₅₀ values and percentage cell viability reduction compared against standard drug cisplatin. Among all novel synthesized compounds 10a‐n , some of the representative analogues particularly 10g and 10e exhibit remarkable cytotoxic activity with IC₅₀ values 0.454 and 0.586 μM, comparable to that of the standard drug cisplatin, and some analogues 10d , 10f , 10k, and 10m also have shown significant activity.     

Synthesis and characterization of novel bis-triazolyl quinazolinones

Russian Journal of General Chemistry - A series of 2-methyl-1-[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl]-2-(4-{[(1-phenyl-1H-1,2,3-triazol-4-yl)methyl}amino]phenyl)-2,3-dihydroquinazolin-4(1H)-ones...     

l-Cystine hydrochloride: A novel semi-organic nonlinear optical material for optical devices

A new semi-organic nonlinear optical (NLO) material l-cystine hydrochloride (LCHCl) was grown in large size measuring 19 × 5 × 3 mm³ by slow solvent evaporation technique for the first time in literature. The cell parameter values were determined by single crystal X-ray diffraction studies. Fourier Transform Infrared spectroscopic analysis was carried out on the grown sample to ascertain the fundamental functional groups. Thermal behavior of the grown LCHCl sample was analyzed by TG & DTA analysis. The mechanical properties of the grown crystals have been studied using Vickers microhardness tester. The optical transmission studies and second harmonic generation (SHG) efficiency studies justified the device quality of the grown crystal and the SHG study reveals that the grown sample has nearly 1.2 times higher efficiency than that of potassium dihydrogen phosphate (KDP), a well known NLO material.