The aromaticity of the dianion (2) and the antiaromaticity of the dication (3) of tetrabenzo[5.5]fulvalene have been evaluated through magnetic criteria, (1)H NMR shifts, nucleus-independent chemical shifts, NICS, and magnetic susceptibility exaltation, Lambda. The sum of the NICS values, using the GIAO (gauge-independent atomic orbital) method, for 2 is -35.2; that of 3 is +38.2, indicating th...

For a long time, NMR chemical shifts have been used to identify protein secondary structures. Currently, this is accomplished through comparing the observed (1)H(alpha), (13)C(alpha), (13)C(beta), or (13)C' chemical shifts with the random coil values. Here, we present a new protocol, which is based on the joint probability of each of the three secondary structural types (beta-strand, alpha-heli...

background: mediodorsal (md) thalamic nucleus, which is considered to take place between extra pyramidal and limbic feedback circuit, receives projective fibers from ventrolateral neurons of reticular part of substantia nigra (snr). in order to better understand the influence and chemical reaction of these fibers upon md nucleus, the morphology and synaptology of them were examined in the prese...

Hyperpolarization can increase the sensitivity of NMR/MRI experiments, but the primary limitation is the T(1) decay of magnetization. Due to its long T(1), the hyperpolarized (89)Y nucleus makes an excellent candidate as an in vivo spectroscopy/imaging probe. Here we report the (89)Y chemical shift dependence upon pH for two hyperpolarized (89)Y(III) complexes and demonstrate how such complexes...

A comparative analysis of nuclear chemical shift predictions of proteins in the solid state by rapid algorithms trained on and verified with solution-state NMR assignments is presented. The precision of predictions by four dedicated computer programs (SHIFTS, PROSHIFTS, SHIFTX and SPARTA) was found to be close to values obtained for proteins in solution. Correlation coefficients depend on the N...

A theory of nuclear magnetic resonance (NMR) in graphene is presented. The canonical form of the electron-nucleus hyperfine interaction is strongly modified by the linear electronic dispersion. The NMR shift and spin-lattice relaxation time are calculated as a function of temperature, chemical potential, and magnetic field, and three distinct regimes are identified: Fermi-, Dirac-gas, and extre...

Porous carbonaceous materials have many important industrial applications including energy storage, water purification, and adsorption of volatile organic compounds. Most their rely upon the molecules or ions within interior pore volume carbon particles. Understanding behaviour properties adsorbate species on molecular level is therefore key for optimising porous materials, but this very challe...

Introduction: The anomalous abundances observed, notably for Mg, Si, Ca, Ti, Cr, Sr, Ba, Nd, and Sm in the so-called FUN inclusions (see [1] for a review), epitomize the occurrence of isotopic anomalies in early nebular condensates. Some isotopic anomalies cannot, however, be accounted for by nucleosynthetic processes [1,2] and we therefore explore the possibility that they may instead be due t...

in this research at the first metoprolol drug and its fullerene derivative were optimized. natural bond orbital (nbo), nuclear indepndent chemical shift (nics) and finally ir calculations, for these compounds were carried out at the b3lyp/6-31g* quantum chemistry level. different parameters such as energy levels, the amount of chemical shift in different atoms, the amount of homo/lumo, chemical...