Magnetic field sweeps are used to transfer parahydrogen-induced polarization from hydrogen atoms onto heteronuclear spins such as carbon-13. In this work we describe and implement constant adiabaticity sweep profiles for purpose.

We have investigated cold ionizing heteronuclear collisions in dilute mixtures of metastable (2 S1) He and He atoms, extending our previous work on the analogous homonuclear collisions [R. J. W. Stas et al., PRA 73, 032713 (2006)]. A simple theoretical model of such collisions enables us to calculate the heteronuclear ionization rate coefficient, for our quasi-unpolarized gas, in the absence of...

A new purine 3,7-dimethylguanine (1) has been isolated from the marine sponge Zyzzya fuliginosa, along with the known metabolites, makaluvamines A, C, K (2--4), 4-hydroxyphenylacetic acid (5), methyl ester of 4-hydroxyphenylacetic acid (6), 4-hydroxyphenethyl alcohol (7), L-phenylalanine (8) and L-tryptophan (9). The structure of 3,7-dimethylguanine (1) was elucidated by analysis of 1D and 2D (...

Two new clerodane-type diterpenoids trivially named as ballotenic acid (1) and ballodiolic acid (2) have been isolated from Ballota limbata along with three the known compounds; beta-amyrin, oleanolic acid, and beta-sitosterol. The structure elucidation of the new compounds was based primarily on two-dimensional (2D)-NMR techniques including correlation spectroscopy (COSY), heteronuclear multip...

While heteronuclear broadband decoupling by composite pulse sequences is a well established method in isotropic liquids [ l-41, analogous decoupling sequences for oriented systems have been introduced only recently [ 5-91. Those sequences [ 891, termed COMARO, were derived from a theoretical analysis of heteronuclear decoupling in the presence of homonuclear interactions like dipole-dipole and ...

An enhanced version of the X (omega1) half-filtered TOCSY experiment for measurement of long-range heteronuclear coupling constants is proposed which yields high-quality spectra with substantially increased sensitivity and resolution. The modified method features gradient-enhanced X filtering sequences, broadband homonuclear decoupling during t1, optional 1JXH scaling in the F1 domain, and grad...

A series of phenylphenalenone type compounds, known to play a role as phytoalexins in plants of the Musaceae family, have been identified for the first time in the leaf fibers of abaca (Musa textilis). Among the phenylphenalenone type compounds identified, the structure of a novel compound, (1R)-2,3-dihydro-4,9-dihydroxy-8-methoxy-1-phenylphenalene, has also been described in abaca fibers. Its ...

A nuclear magnetic resonance method is presented which produces linear, isotropic proton-detected local-field spectra for INS spin systems in powdered samples. The method, heteronuclear isotropic evolution (HETIE), refocuses the anisotropic portion of the heteronuclear dipolar coupling frequencies by evolving the system under a series of specially designed Hamiltonians and evolution pathways. T...