Excess heat capacities and excess molar enthalpies of the mixtures containing tetrahydropyran,piperidine and cyclic alkanones

Journal of Thermal Analysis and Calorimetry - In the present study, molar heat capacities, $$\left( {C_{\text{P}}^{{}} } \right)_{123}$$ , at T/K = 293.15–308.15 K...     

Differential content of secondary metabolites in diploid and tetraploid cytotypes of Siegesbeckia orientalis L.

Siegesbeckia orientalis L. is an annual herb widely distributed throughout the world and has many medicinal properties. In Chinese traditional system, it is popularly known as Xi-Xian and used for its anti-inflammatory properties. In the present study, two cytotypes (diploid and tetraploid) have been investigated for their secondary metabolites. The different plant parts have been explored in terms of total phenolics, total flavonoids, DPPH radical scavenging acitivity and total antioxidant capacity. Out of different plant parts, leaves have the maximum amount of secondary metabolites and antioxidant potential. HPTLC technique has been applied to quantify six marker compounds in the two cytotypes. Tetraploid cytotype has been compared with diploid cytotype, which shows that tetraploid has the maximum amount of studied secondary metabolites with high antioxidant potential.     

Contiguous relations, continued fractions and orthogonality

We examine a special linear combination of balanced very-well-poised basic hypergeometric series that is known to satisfy a transformation. We call this and show that it satisfies certain three-term contiguous relations. From two of these contiguous relations for we obtain fifty-six pairwise linearly independent solutions to a three-term recurrence that generalizes the recurrence for Askey-Wilson polynomials. The associated continued fraction is evaluated using Pincherle's theorem. From this continued fraction we are able to derive a discrete system of biorthogonal rational functions. This ties together Wilson's results for rational biorthogonality, Watson's -analogue of Ramanujan's Entry 40 continued fraction, and a conjecture of Askey concerning the latter. Some new -series identities are also obtained. One is an important three-term transformation for 's which generalizes all the known two- and three-term transformations. Others are new and unexpected quadratic identities for these very-well-poised 's.

     

Spectroscopy of50V with (p,nγ) reaction

Information on the low-lying levels up to ～1.9 MeV excitation of the doubly odd nucleus⁵⁰V has been obtained through the Ge (Li)-Ge (Li) coincidence study with the⁵⁰Ti(p, nγ)⁵⁰V reaction. Branching ratios have been measured and tentative spin-parity assignments have been made. A detailed comparison with other measurements reported recently has also been made. Using the lowest seniority wave functions with (f_7/2) _p ³ (f _7/2) _n ^?1 configuration, energy levels and electromagnetic properties have been calculated. These have been compared with the present and earlier experimental data.     

Structure of a liquid crystal of 4-cyano-4′-n-octyloxybiphenyl

The structure of a liquid crystal of 4-cyano-4′-n-octyloxybiphenyl (C₂₁H₂₅NO) is determined by X-ray diffraction analysis. The compound crystallizes in the triclinic crystal system with unit cell parameters a = 7.322(1) Å, b = 12.693(3) Å, c = 20.393(2) Å, α = 92.45(1)°, β = 99.96(1)°, γ = 99.35(2)°, and space group $P\bar 1$ . The structure is solved by the direct method and refined to R = 0.057. Two independent molecules are located in the asymmetric unit. No short intermolecular contacts are observed in the crystal packing.     

Spectroscopy: the study of DNA cleavage by newly synthesized polydentate macrocyclic ligand and its copper(II) complexes

A novel hexadentate nitrogen donor [N6] macrocyclic ligand, i.e. 2,6,12,16,21,22-hexaaza-3,5,13,15-tetramethyl-4,14-diethyl-tricyclo-[15.3.1.1(7-11)]docosane-1(21),2,5,7(22),8,10,12,15,17,19-decaene (L), has been synthesized. Copper(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, 1H NMR (ligand), IR, electronic, and EPR spectral studies. On the basis of molar conductance the complexes may be formulated as [Cu(L)X2] [X = Cl(-), Br(-), NO3(-) and CH3COO(-)] due to their nonelectrolytic nature in N,N'-dimethylformamide (DMF). All the complexes are of the high spin type and are six coordinated. On the basis of IR, electronic and EPR spectral studies tetragonal geometry has been assigned to the Cu(II) complexes. The interaction of these complexes with calf thymus DNA has been explored by using absorption, emission, viscosity measurements, electrochemical studies and DNA cleavage. All the experimental results suggest that the complexes bind to DNA and also promote the cleavage plasmid pBR 322, in the presence of H2O2 and ascorbic acid.     

HClO4 x SiO2 catalysed synthesis of alkyl 3-deoxy-hex-2-enopyranosides from 2-hydroxy glucal ester: application in the synthesis of a cis-fused bicyclic ether and a 4-amino-C-glucoside

A variety of alcohols react with 2,3,4,6-tetra-O-acetyl-1,5-anhydro-D-arabino-hex-1-enopyranose 1 in the presence of a catalytic amount of HClO(4) supported on silica gel to give the corresponding alkyl 3-deoxy-hex-2-enopyranosides 2 in high yield, with short reaction times (10-45 mins) and good alpha-selectivity. Work-up merely involves filtration of the reagent, followed by chromatographic purification of the crude product. This methodology has also been employed in the synthesis of a bicyclic ether, a useful precursor for cyclic polyethers, and a 4-amino-C-glucoside.     

A double ring-closing olefin metathesis approach to [3]catenanes

A [3]catenane with peripheral olefinic macrocycles was conveniently synthesized via a double ring-closing olefin metathesis. Highlights of this work include the synthesis of a 65-membered macrocycle featuring two phenanthroline ligands, a Cu(I)-templated synthesis of a [3]pseudorotaxane, and the key double ring-closing olefin metathesis to afford the desired [3]catenane in 71% yield.