Two new 2'-oxygenated flavones, 5,2',6'-trihydroxy-7-methoxyflavone (3) and skullcapflavone I 2'-O-beta-D-(4"-E-cinnamyl) glucopyranoside (5), together with three known flavones, 7-O-methylwogonin (1), skullcapflavone I (2) and skullcapflavone I 2'-O-beta-D-glucopyranoside (4) were isolated from the whole plant of Andrographis elongata, and the structures were elucidated by FAB-MS and one- and ...

Negative ion photoelectron spectra are reported for the heteronuclear alkali dimer and trimer anions, NaK-, KRb-, KCs-, RbCs-, Na$-, and KzCsat 488 nm. In addition to assigning all ofthe electronic transitions observed in the mixed dimer anion spectra, vertical detachment energies, adiabatic electron affmities, and dimer anion dissociation energies have also been determined. A linear correlatio...

This Letter reports significant excitation of C homonuclear double-quantum coherence in a solid-state magic-angle-spinning NMR experiment, acquired without heteronuclear decoupling of abundant H spins. The heteronuclear decoupling efficiency of a group of existing homonuclear polarization transfer sequences are investigated and optimal schemes are identified. Since the approach permits the appl...

Studies on the chemical constituents of roots of Urtica triangularis HAND-MASS have led to the isolation of four new compounds. The structures, including the absolute configurations, of these constituents have been elucidated through spectral studies including (1)H-NMR, (13)C-NMR, 2D-NMR experiments (heteronuclear single-quantum coherence, heteronuclear multiple bonding connectivity and nuclear...

Abstract Three series of new ionic liquids (ILs), namely imidazolium‐, pyrazolium‐, and bis‐benzimidazolium‐containing ILs, were prepared from low‐cost, unprotected carbohydrates. Information on anion‐cation interactions solvation shell obtained via diffusion NMR heteronuclear Overhauser correlation maps (HOESY), respectively.

In order to represent the potential energy function over the whole range of R, many potentialenergy functions have been proposed. In the present paper, we employ many potential energyfunctions, to use Numerov method for solving the nuclear Schrödinger equation for the IFmolecule, as an example of a heteronuclear diatomic molecules. Then we determine thespectroscopic constants eω , e e x ω , e B...

The problem to design efficient heteronuclear decoupling sequences is studied using optimal control methods. A generalized version of the gradient ascent engineering (GRAPE) algorithm is presented that makes it possible to design complex non-periodic decoupling sequences which are characterized by tens of thousands of pulse sequence parameters. In contrast to conventional approaches based on av...