Construction of a Bifunctional Pd(0)-CALB@SiO2 Hybrid Catalyst for the Synthesis and Arylation of Imidazo[1,2-a]pyridine in One Pot

Herein, we describe an efficient strategy for the construction of enzyme-metal biohybrid catalyst [Pd(0)-CALB@SiO₂] via encapsulation of Candida antarctica lipase B and Pd(0) within silica. Next, the applicability of the newly constructed biohybrid was demonstrated by catalyzing the sequence of Groebke-Blackburn-Bienayme (GBB) multicomponent reaction and Suzuki-Miyaura coupling in a single-pot to produce clinically significant imidazo[1,2-a]pyridine derivatives. Interestingly, both entities, i.e., CALB enzyme and Pd(0)-metal of hybrid catalyst, exhibited good catalytic activity during this approach. Further, the generality of this protocol was explored by using differently substituted boronic acid, which gave related products in 49–87 % isolated yield. Next, the synthetic utility was proved by set-up a gram scale reaction which provided the complementary product in 81 % yield. Also, the developed biohybrid was found to be reusable up to five catalytic cycles.     

X-ray characterization of Te(S2CNC5H10)2 and TeI2[(C13H10N2S)2] · 4C4H8TeI2; the first Te–C bond cleaved products obtained in the substitution reactions of organo(heterocyclic)tellurium(IV) derivatives

The reaction of organo(heterocyclic)tellurium(IV) derivative: C₈H₈TeI₂(1,3-dihydro-2λ⁴-benzotellurole-2,2-diyl diiodide) with NH₄S₂CNC₅H₁₀ (ammonium piperidine dithiocarbamate) gives C₈H₈Te(S₂CNC₅H₁₀)₂ (1) and Te(S₂CNC₅H₁₀)₂ (2) or C₈H₈TeI(S₂CNC₅H₁₀) (5) according to the reaction conditions. In such type of metathetical reactions, the formation of 2 is unprecedented and it corresponds to the first Te–C cleaved product. The reaction of 2 with CH₃I, yields the oxidative addition product, CH₃TeI(S₂CNC₅H₁₀)₂ (8). The formation of 2 is also supported through Quantum Chemical calculations. Another Te–C bond cleaved product TeI₂[(C₁₃H₁₀N₂S)₂] · 4C₄H₈TeI₂ (9) is obtained in the reaction of C₄H₈TeI₂ (1,1,2,3,4,5-hexahydro-1,1-diiodotellurophene) with NH₄S₂CNHC₆H₅ (ammonium aniline dithiocarbamate). The reaction of 1,1,2,3,4,5,6-heptahydro-1-iodo-1-(morpholine dithiocarbamato) tellurane [C₅H₁₀TeI(S₂CNC₄H₈O)] (10) with 1,10-phenanthroline gives an unusual product C₁₂H₈N₂ · C₄H₁₀INO (11). The structures of the new complexes 2, 8, 9, 10 and 11 have been determined by the X-ray analysis.     

Extracting the frequencies of the pinna spectral notches in measured head related impulse responses

The head related impulse response (HRIR) characterizes the auditory cues created by scattering of sound off a person's anatomy. The experimentally measured HRIR depends on several factors such as reflections from body parts (torso, shoulder, and knees), head diffraction, and reflection/ diffraction effects due to the pinna. Structural models (Algazi et al., 2002; Brown and Duda, 1998) seek to establish direct relationships between the features in the HRIR and the anatomy. While there is evidence that particular features in the HRIR can be explained by anthropometry, the creation of such models from experimental data is hampered by the fact that the extraction of the features in the HRIR is not automatic. One of the prominent features observed in the HRIR, and one that has been shown to be important for elevation perception, are the deep spectral notches attributed to the pinna. In this paper we propose a method to robustly extract the frequencies of the pinna spectral notches from the measured HRIR, distinguishing them from other confounding features. The method also extracts the resonances described by Shaw (1997). The techniques are applied to the publicly available CIPIC HRIR database (Algazi et al., 2001c). The extracted notch frequencies are related to the physical dimensions and shape of the pinna.     

Random Games Under Elliptically Distributed Dependent Joint Chance Constraints

Journal of Optimization Theory and Applications - We study an n-player game with random payoffs and continuous strategy sets. The payoff function of each player is defined by its expected value and...     

Recycled de-Oiled Algal Biomass Extract as a Feedstock for Boosting Biodiesel Production from <Emphasis Type="Italic">Chlorella minutissima</Emphasis>

The investigation for the first time assesses the efficacy of recycled de-oiled algal biomass extract (DABE) as a cultivation media to boost lipid productivity in Chlorella minutissima and its comparison with Bold’s basal media (BBM) used as control. Presence of organic carbon (3.8 ± 0.8 g/l) in recycled DABE resulted in rapid growth with twofold increase in biomass productivity as compared to BBM. These cells expressed four folds higher lipid productivity (126 ± 5.54 mg/l/d) as compared to BBM. Cells cultivated in recycled DABE showed large sized lipid droplets accumulating 54.12 % of lipid content. Decrement in carbohydrate (17.76 %) and protein content (28.12 %) with loss of photosynthetic pigments compared to BBM grown cells were also recorded. The fatty acid profiles of cells cultivated in recycled DABE revealed the dominance of C16:0 (39.66 %), C18:1 (29.41 %) and C18:0 (15.82 %), respectively. This model is self-sustained and aims at neutralizing excessive feedstock consumption by exploiting recycled de-oiled algal biomass for cultivation of microalgae, making the process cost effective.     

Luminescence studies on europium- and dysprosium-doped di-strontium magnesium silicate phosphor

Research on Chemical Intermediates - Europium- and dysprosium-doped strontium magnesium silicate powder with different concentration ratios of dysprosium were synthesized using solid-state...