Thanks Herb!
Yes, there is a lot of data out there that relates 17O-NMR and proposed
structure of water in cells or associated with proteins, etc... However,
none that specifically relate the linewidth with structure- i.e. pentagonal
or hexagonal specifically- in the bulk solution. There are also papers that
report hexagonal water using FTIR and lasers where the timescale of the
experiment is much faster than the NMR timescale. This does not mean that
any of those structures can exist for any significant period of time longer
than that experimental timescale. Rodger, Sheppard, McFarlane & McFarlane
in their chapter "Group VI- Oxygen, Sulphur, Selenium and Tellurium" in
"NMR of the Periodic Table" (Harris' & Mann's Eds., p383, Academic Press,
New York (1978)) give a good accounting of early 17O-NMR work and its
basics- for those who are unfamiliar with 17O-NMR. Herb's data correlates
well with that in this chapter.
I'm mostly concerned about scientific education/literacy and this whole
issue just doesn't "hold water" for me- pardon the pun. I am the Chair of
the Educational Affairs Committee of the Southern California ACS (SCALACS)
and would like to improve the understanding of the importance of knowing
how even a modicum of science can be beneficial to the average person as
you point out.
Thanks for the info you provide here Herb!
Best regards,
Paul
-----Original Message-----
> From: "Dr. Herbert Schwartz" <schwah_at_rpi.edu>
> Sent: Oct 14, 2004 1:25 PM
> To: ammrl_at_chemnmr.colorado.edu
> Subject: more on O-17 NMR of water
I almost forgot to answer Paul Shin's basic question about water line
width. Yes, it does does tell you "something" about the bulk water
structure, but the atomic details are still subject to a lot of
interpretation. If you take a very small amount of water, and dissolve in a
non oxygen containing solvent (to maximize sensitivity of detection), I had
used acetonitrile, you can get even smaller O-17 NMR linewidths, probably
indicating lack of water-water hydrogen bonds and exchange of same. I
didn't look it up but, my memory seems to recall widths of 25 to 30 Hz, and
the ability to actually resolve the J coupling from the protons. (80 Hz
coupling, again, depending on my somewhat failing memory).
-----Original Message-----
> From: "Dr. Herbert Schwartz" <schwah_at_rpi.edu>
> Sent: Oct 14, 2004 1:13 PM
> To: ammrl_at_chemnmr.colorado.edu
> Subject: Hexagonal Water
I wanted to thank Paul Shin for bringing my attention to the O-17
experiments he did concerning "hexagonal water". I had never heard of this
particular "product" before. As one who had one a lot of O-17 NMR research
in my postdoctoral days (not saying how long ago) and my first few years
here at RPI, i found it very interesting. I think the kind of questioning
Paul is doing very essential to maintain the integrity of science, when so
called "scientific" claims are made.
In looking over the web pages supporting hexagonal water, the claims
of "good" vs "bad" proteins, depending on what type of water surrounded
them stuck out at me as a very testable (although strange) concept. Some
proteins could be dissolved in normal distilled, deionized water, vs the
commercially sold "hexagonal" water, to see if any structural differences
at all could be noted, via chem. shift differences. If nothing else, this
might prove an interesting project for some undergrads, and also, maybe an
exercise in general chemistry class as to WHY its important for the general
public to know at least a little bit of chemistry and physics.
Dr. Herb Schwartz
Dept. of Chemistry and Chemical Biology
RPI
Paul Shin, Ph.D.
Department of Chemistry SC4312
California State University, Northridge
18111 Nordhoff Street
Northridge, California 91330
818-677-6887 Office
818-677-4068 Fax
Received on Thu Oct 14 2004 - 17:46:21 MST