I have a simple, completely conjugated pyridinium salt with MW of ~300 g/mol. The molecule consists of regular non-labeled atoms (only C, H, N).
- If the 1H T1 relaxation time for this molecule is measured in DMSO-d6 the T1 values of all of the protons are within the expected range (9 sets of protons with T1 values of 1.4-2.1 s).
- However if the 1H T1 relaxation time for exacty the same molecule is measured in CDCl3 the relaxation times differ up to 20 times (9 sets of protons with T1 values of 0.04-1.9 s). The 1H relaxation is especially fast at the pyridinium ring (2 sets of pyridinium ring protons with T1 values of 0.04 and 0.07 s and further removed protons from the pyridinium have T1 values of 1.5-1.8s).
From what I have read in the literature the relaxation times usually differ up to 2-fold. Any ideas why this is the case?