Subject: Re: CCL:compilations of NMR data for organometallics

From: <[email-masked]>
Date: Wed, 03 Aug 1994 10:48:05 -0500 (CDT)

>Dear netters,
>
>We have embarked on a project of calculating ligand NMR chemical shifts
>for organometallics "ab initio" using density functional techniques. 
>Right now, we are in the process of validation of the method, i.e.
>calculating a reasonably large number of molecules to see
>how good our method works.
>
>Regards, Martin Kaupp
>
This sounds like an interesting and potentially very significant project.  
Might I suggest as a family of complexes which would be of great
interest to experimental and comp inorganic chemists alike, those complexes
which have a multiple bond between a transition metal and a main group element.
Many of these complexes are intermediates in a variety of catalytic,
biochemical and advanced materials pathways.  Hence many of them are often not
stable enough for structural characterization, but often one can get an NMR
and try to deduce something about their chemistry that way.  Having a comp
scheme to compare with proposed intermediates such as this would be very 
valuable.
	The book by Nugent and Mayer is a good starting point.

Nugent, W. A.; Mayer, J. M. "Metal-Ligand Multiple Bonds;" Wiley: New York,
1988.
	Wigley (Arizona) has a review on imido (M=N) complexes due out soon 
with a section on NMR.  Imido complexes are notoriously difficult to probe 
with IR and thus an NMR scheme would be very useful.  The review is due out 
soon in Progress in Inorganic Chemistry.  There is also a clever little paper
by Nugent et al. (Inorg Chim Acta 1982, 65, L91) in which the NMR shifts of
imido complexes are used to probe the bonding of imidos; this is probably one
of the most insightful papers on imido bonding.
	Barfield (arizona) published a paper several years ago (in J Chem Phys)
on predicting the NMR of oxo (M=O) and sulfido (M=S) complexes.  Many of these
systems are small and symmetrical which might be of use in calibrating the 
methods.
	Finally, there has been much interst in probing the bonding in
phosphinidene complexes by looking at the 31P shifts of the multiply bonded 
P.  I can provide exptl refs if you are interested.
	Hope the various ramblings are of some use.

Tom

------------------------------------------------------------------------------
Thomas R. Cundari                          Address until the end of August
Asst. Professor of Chemistry               Tom Cundari
Computational Inorganic Chemistry Lab      Visiting Scientist
University of Memphis                      CST-3, C346
Memphis, TN 38152                          Los Alamos National Lab
phone: 901-678-2629                        Los Alamos, NM 87545
fax:   901-678-3447                        phone: 505-665-8014
e-mail: [email-masked]        fax:   505-665-3688
http://www.memst.edu/chemistry/umchem.html e-mail: same as always
-------------------------------------------------------------------------------