Lanthanide-induced phosphorus-31 NMR downfield chemical shifts of lysophosphatidylcholines are sensitive to lysophospholipid critical micelle concentration

19F NMR based pH probes: lanthanide(III) complexes with pH-sensitive chemical shifts.

Experimental measurements and theoretical analysis of magnetic properties, structural dynamics and acid-base equilibria for several lanthanide(III) complexes with tetraazacyclododecane derivatives as 19F NMR chemical shift pH probes are presented; pKa values vary between 6.9 and 7.7, with 18 to 40 ppm chemical shift differences between the acidic and basic forms for Ho(III) complexes possessing...

Quantum chemical calculations of (31)P NMR chemical shifts: scopes and limitations.

The aim of this work is to convince practitioners of (31)P NMR methods to regard simple GIAO quantum chemical calculations as a safe tool in structural analysis of organophosphorus compounds. A comparative analysis of calculated GIAO versus experimental (31)P NMR chemical shifts (CSs) for a wide range of phosphorus containing model compounds was carried out. A variety of combinations (at the HF...

H Chemical Shifts in NMR

Correlation Analysis of 31 P NMR Chemical Shifts with Substituent Effects of Phenols

Over 60 lignin-related model compounds were phosphitylated with 2chloro-4,4,5,5-tetramethyldioxaphospholane, a sterically hindered analogue of 2-chloro-1,3,2-dioxaphospholane used in earlier work, and their 31P chemical shifts were recorded. Excellent resolution between the chemical shifts of phosphitylated carboxylic acids, phenols and aliphatic alcohols was obtained. The correlations of the p...

Phosphorus-31 NMR studies of E. coli ribosomes.

Phosphorus-31 nuclear magnetic resonance spectra, relaxation times and nuclear Overhauser (NOE) enhancement have been measured for E. coli ribosomes, subunits and rRNA. NOE and T1 experiments reveal that the phosphorus relaxation in this organelle is largely dipolar in origin. Moreover these results imply the presence of internal motion within the RNA chain with a correlation time of about 3-5 ...