Hi all,
First of all I would like to express my gratitude to Walt Niemczura, who
figured out my network problem and enabled me to post in ammrl community.
Below is a short summary about my post "record proton high field shift".
Karen Ann Smith: I suggest you look in the paramagnetic literature. There
is a spectrum on my desk with protons at +320 and -280 ppm.
Jeff Simpson: Deuterium (2H) chemical shifts of +79.2ppm and -128.9ppm were
observed in a compound containing two uranium atoms sandwiching a
naphthalene ring. Presumably the 1H shifts would have also been the same.
Bernhard Jaun: If you include NMR of paramagnetic species, you can get much
larger shifts.My personal high field record is ca. -485 ppm (at -40°C) for
the protons of a methyl group attached to d8 high spin Ni(II) center.
Alan Kenwright: It depends to some extent what you class as a "chemical
shift". The shifts of ligand protons in stable lanthanide complexes can be
quite high. For example, the lowest frequency peak in the spectrum of
DyDOTA comes at around -500 ppm, but then the purists would say that's a
pseuso-contact shift, not a chemical shift.
Donald Linn, Martha Morton, Boris Itin, William C. Stevens also addressed
this questions.
Thank you all for sharing your experiences and ideas.
Guangyu
Received on Sun Dec 07 2008 - 20:49:31 MST