Density functional theory calculations were applied to investigate 13C Chemical Shielding (CS) tensors in cryptolepine (1) and its sulfur (2) and oxygen (3) isosteres. The results showed that the CS of carbon nuclei in these compounds may be divided into three types. First, carbons type α,are those directly bonded to X (X= NH, S, O) and σ 33 shielding component of these carbons are deshield...

The Al siting in the ZSM-5 zeolite was investigated by (27)Al 3Q MAS NMR spectroscopy and QM/MM calculations. It was found that the occupation of the framework T-sites by Al and the concentration of Al in these T-sites are neither random nor controlled by a simple rule. They both depend on the conditions of the zeolite synthesis. At least 12 out of the 24 distinguishable framework T-sites of ZS...

sulforaphane, an isothiocyanate found in broccoli and other cruciferous vegetables. it is an antioxidantand anti-cancer agent, and reduces blood pressure, and also has anti-allergic effects.in this article, six theoretical methods have been used for calculation of physical parameters insolforaphane and several similar compounds. we calculated physical parameters like atomic charges.energy (ae) ...

chemical hardness () and absolute electronegativity () have important applications in chemistry. inthe conceptual density functional theory (dft), these concepts has been associated with electronicenergy and the relationship with ionization energy (i) and electron affinity (a) of these concepts hasbeen given. in this study, graphical method was used in order to see the relationship with the a...

A cluster model for active site of nanotube (C48) was presented and investigated the geometricstructure and thermochemical parameters. Quantum-mechanical calculations were performed at theHF / 510-30, 6-310, 6-3 IG• and 6-310" levels of theory in the gas phase and three solvents atfour temperatures. Also, nuclear shielding parameters of the active site of nanotube have been takeninto account us...

As drug delivery systems Nanoparticulan widely investigated because of many advantages such as smaller size,controlled drug release potentiaL targeting ability, enhancement of therapeutic efficacy and reduction oftoxicity. So, carbon nanotubes have recently received considerable attention as alternative drug delivery carrierIn this study we investigate interaction of tamoxifen with open-end of ...

The Al siting in the ZSM-5 zeolite was investigated by Al 3Q MAS NMR spectroscopy and QM/MM calculations. It was found that the occupation of the framework T-sites by Al and the concentration of Al in these T-sites are neither random nor controlled by a simple rule. They both depend on the conditions of the zeolite synthesis. At least 12 out of the 24 distinguishable framework T-sites of ZSM-5 ...

Transition metal hydrides are of great interest in chemistry because of their reactivity and their potential use as catalysts for hydrogenation. Among other available techniques, structural properties in transition metal (TM) complexes are often probed by NMR spectroscopy. In this paper we will show that it is possible to establish a viable methodological strategy in the context of density func...

We present ProCS15: a program that computes the isotropic chemical shielding values of backbone and Cβ atoms given a protein structure in less than a second. ProCS15 is based on around 2.35 million OPBE/6-31G(d,p)//PM6 calculations on tripeptides and small structural models of hydrogen-bonding. The ProCS15-predicted chemical shielding values are compared to experimentally measured chemical shif...