On (N, p, q) summability factors of infinite series

In this paper a necessary and sufficient condition has been obtained for Σa_n∈_n to be summable |N, q| whenever Σa_n is bounded (N, p, q).     

Magnetic-Bottle and Velocity-Map Imaging Photoelectron Spectroscopy of APS- (A=C14H10 or Anthracene): Electron Structure,Spin-Orbit Coupling of APS·, and Dipole-Bound State of APS-

Gaseous dibenzo-7-phosphanorbornadiene P-sulfide anions APS^-(A=C₁₄H₁₀ or anthracene) were generated via electrospray ionization, and characterized by magnetic-bottle photoelectron spectroscopy, velocity-map imaging (VMI) photoelectron spectroscopy, and quantum chemical calculations. The electron affinity (EA) and spin-orbit (SO) splitting of the APS^· radical are determined from the photoelectron spectra and Franck-Condon factor simulations to be EA=(2.62±0.05) eV and SO splitting=(43±7) meV. VMI photoelectron images show strong and sharp peaks near the detachment threshold with an identical electron kinetic energy (eKE) of 17.9 meV at three different detachment wavelengths, which are therefore assigned to autodetachment from dipole-bound anion states. The B3LYP/6-31++G(d, p) calculations indicate APS^· has a dipole moment of 3.31 Debye, large enough to support a dipole-bound electron.     

Optical rotation calculated with time-dependent density functional theory: the OR45 benchmark

Time-dependent density functional theory (TDDFT) computations are performed for 42 organic molecules and three transition metal complexes, with experimental molar optical rotations ranging from 2 to 2 × 10(4) deg cm(2) dmol(-1). The performances of the global hybrid functionals B3LYP, PBE0, and BHLYP, and of the range-separated functionals CAM-B3LYP and LC-PBE0 (the latter being fully long-range corrected), are investigated. The performance of different basis sets is studied. When compared to liquid-phase experimental data, the range-separated functionals do, on average, not perform better than B3LYP and PBE0. Median relative deviations between calculations and experiment range from 25 to 29%. A basis set recently proposed for optical rotation calculations (LPol-ds) on average does not give improved results compared to aug-cc-pVDZ in TDDFT calculations with B3LYP. Individual cases are discussed in some detail, among them norbornenone for which the LC-PBE0 functional produced an optical rotation that is close to available data from coupled-cluster calculations, but significantly smaller in magnitude than the liquid-phase experimental value. Range-separated functionals and BHLYP perform well for helicenes and helicene derivatives. Metal complexes pose a challenge to first-principles calculations of optical rotation.     

Effect of hydrophilic macro-RAFT agent in surfactant-free emulsion polymerization

Here we report, synthesis of different molecular weight poly (styrene sulfonate) based macro-RAFT agents and their use as shell material in surfactant-free emulsion polymerization of styrene. Concentration and molecular weight of hydrophilic macro-RAFT agent has an influence on colloidal stability, particle size distribution and self-assembly. Microscopic and zeta-potential studies of colloids reveal that, the macro-RAFT agents used with low molecular weight (M_n = 1200) are comparable more efficient than high molecular weight (M_n = 46,800 and 116,000) for imparting narrow particle size distribution with good colloidal stability.     

Catalytic activities of Schiff base aquocomplexes of copper(II) towards hydrolysis of amino acid esters

Summary Solid aquo Cu^II complexes of Schiff bases derived from amino acids have been prepared and characterized. Using a pH-stat method, the kinetics of base hydrolysis of the amino acid esters H₂NCH₂CO₂Me·HCl (GE), (HO)-C₆H₄CH₂(NH₂)CO₂Me·HCl (TE), MeS(CH₂)₂CH(NH₂)-CO₂Me·HCl (ME), HSCH₂CH(NH₂)CO₂Et·HCl (CE), C₃H₃N₂CH₂CH(NH₂)CO₂Me·2HCl (HE) and [—SCH₂-CH(NH₂)CO₂Me]₂·2HCl (CysE) have been studied. The complexes enhanced the rate of hydrolysis substantially, the values of the second-order rate constants being some 10–50 times greater than those obtained in the presence of the simple Cu^II ion.     

Simultaneous Quantitation of Piperine and Piperlongumine in the Fruit of Piper longum Linn. by Validated High-Performance Thin-Layer Chromatography—Densitometric Method

JPC – Journal of Planar Chromatography – Modern TLC - The fruit of Piper longum Linn. (family: Piperaceae), known as pippali in India, is a reputed drug of Ayurveda (the Indian system...     

Fundamental understanding and modeling of spin coating process: A review

A mathematical model is derived to elucidate the dominant mechanism governing film formation. It leads to a relation between film thickness and film radius spreading with time. Inclusion of evaporation and shear stress was made with extension to non-Newtonian fluid. The advantages and disadvantages of this process with applications are reviewed.      

Facile synthesis of seven to nine-membered-fused tricyclic quinolones and quinolinium salts under phase transfer catalyzed conditions

Phase transfer catalyzed one-pot syntheses of fused oxazepino, oxazocino, and oxazonino quinolinium cations and quinolones were achieved from 8-hydroxy quinoline derivatives with 1,ω-dihaloalkanes. Structures of all the products were elucidated by spectroscopic analysis. Single crystal X-ray crystallographic analysis of three compounds and graphical superposition of the structures indicate that products having seven-membered ring are less planar compared to the product having eight-membered ring.     

Ultrasonication--a complementary 'green chemistry' tool to biocatalysis: a laboratory-scale study of lycopene extraction

Lycopene is bequeathed with multiple bio-protective roles, primarily attributed to its unique molecular structure. The concomitant exploitation of two of the green chemistry tools viz., sonication and biocatalysis is reported here for the laboratory scale extraction of lycopene from tomato peel. The coupled system improved the extraction by 662%, 225% and 150% times over the unaided, only cellulase ‘Onozuka R-10’ treated and only sonication treated samples respectively. The sonication parameters (duration, cycle and amplitude) during the coupled operation were optimized using response surface methodology (RSM). Derivative UV-visible spectra (i.e., dA/dλ and d²A/dλ² against λ), FTIR analysis, and DPPH scavenging test suggested that the reported extraction protocol did not affect the molecular structure and bioactivity of the extracted lycopene. The influence of sonication on the probable structural modulation (through UV-visible spectral analysis) and activity of the enzyme were also analyzed. A plausible mechanism is proposed for the enhanced extraction achieved via the coupled system.     

Development and Validation of HPTLC Densitometric Method for Identification and Quantification of Geraniol in Palmarosa Oil

JPC – Journal of Planar Chromatography – Modern TLC - India is the main producer of palmarosa oil obtained from rosha grass (Cymbopogan martini var. motia) of family Graminae. The...