nowadays nmr spectroscopy becomes a powerful tool in chemistry because of the nmr chemical shifts. hartree–fock theory and the gauge-including atomic orbital (giao) methods are used in the calculation of 29si nmr chemical shifts of various silicate species in the silicate solution as initial components for zeolite synthesis both in gas and solution phase. calculations have been performed at geo...

bcn compounds have been researched theoretically and experimentally widely. in this paper, weintroduce the theoretical prediction of ternary b-c-n compounds. nmr spectroscopy was employedextensively to study these ternary nanostructures. we discuss the utilization of chemical shiftinformation as well as ab initio calculations of nuclear shielding for h20134c9n4 structuredetermination. we calcul...

Friedelin (1), 3beta-friedelinol (2), 28-hydroxyfriedelin (3), 16alpha-hydroxyfriedelin (4), 30-hydroxyfriedelin (5) and 16alpha,28-dihydroxyfriedelin (6) were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl(3) solution, 16alpha-hydroxyfriedelin (4) reacted turning into 3-oxo-16-methylfriedel-16-ene (7). This is the first re...

The structure of a novel antibiotic, epiderstatin, was determined as 4-[3-((Z)-3,5-dimethyl-2-oxopiperidin-6-ylidene)-2-oxopropyl]-2, 6-piperidinedione by spectroscopic analyses of 1H NMR, 13C NMR, 1H-1H correlation spectroscopy (COSY), 13C-1H COSY, heteronuclear multiple bond correlation spectroscopy, UV and IR spectra. The antibiotic belongs to the glutarimide antibiotics, however, the charac...

A group of a-anilinoketones, 2-aminoalcohols, a-anilinoesters and a-anilinoamides were successfully synthesized and characterized by NMR spectroscopy and mass spectrometry. The yields were, in general, moderate to good (up to 75.4%), except for the a-anilinoesters (16.9-35.6%). The a-halocarbonyl starting materials showed different chemical reactivities. a-Haloketones and a-chloroacetates affor...

The copolymers of iV-vinylcarbazole/vinyl acetate (V/A) of different compositions were prepared by solution polymerization using AIBN as an initiator. The copolymer composition was determined from quantitative "Cf'H} NMR spectroscopy. Reactivity ratios for the comonomers were calculated using the Kelen-Tudos (KT) and non-linear error in variable (EVM) methods. Two-dimensional heteronuclear sing...

Protein molecules are highly diverse communication platforms and their interaction repertoire stretches from atoms over small molecules such as sugars and lipids to macromolecules. An important route to understanding molecular communication is to quantitatively describe their interactions. These types of analyses determine the amounts and proportions of individual constituents that participate ...

A central problem in the emerging field of metabolomics is how to identify the compounds comprising a chemical mixture of biological origin. NMR spectroscopy can greatly assist in this identification process, by means of multi-dimensional correlation spectroscopy, particularly total correlation spectroscopy (TOCSY). This Communication demonstrates how non-negative matrix factorization (NMF) pro...

Inclusion compounds of some 4-substituted benzoic acid and benzaldehyde drugs with beta-cyclodextrin were prepared and characterized by IR spectroscopy, powder X-ray diffraction, thermogravimetry, and 1H-NMR spectroscopy. The thermal stability and chemical stability of these drugs were strikingly improved after inclusion. The effect of inclusion on the chemical-shifts of protons H-3 and H-5 in ...

In recent years the applications of NMR spectroscopy to the analysis of living systems have grown at a rapid pace. Initially these measurements were limited to excised tissues, and later extended to studies of perfused organs. With the new improvements in magnet technology and FT NMR techniques, in vivo measurements of intact animals and humans became possible. Most of these studies concentrate...