Subject: Re: CCL:descriptors for the 'shape' and 'size' of molecules

From: David Livingstone <[email-masked]>
Date: Thu, 2 Apr 1998 11:12:59 +0100

Norman, you wrote:

> I am looking for a simple (!?) method to describe the 'size' and
> topology of a molecule.
> The aim is to establish a correlation between experimentally observed
> retention times (by liquid cromatography) and the 'shape' of several
> pure hydrocarbons
> (bigger species including 'disk' and umbrella-shaped molecules).
> 
> I have no experience in this field of research, whatsoever, so any hints
> or comments
> would be appreciated.

I think you will find that quite a lot has already been done by 
others in modelling retention times (of all sorts) often using 
hydrophobicity descriptors of one form or another (retention times 
are frequently used as hydrophobicity descriptors themselves).  I 
guess you need to do a search.

As for shape descriptors (and others) I suggest you have a look at 
some QSAR reviews and/or books.  I wrote one in 1991:

D.J. Livingstone, "Quantitative Structure-Activity Relationships" in:
Similarity Models in Organic Chemistry, Biochemistry and Related
Fields (Eds, R.I. Zalewski, T.M. Krygowski & J. Shorter), Elsevier,
1991, pp 557-627).  

You could also try:

The  book by Hansch & Leo (Exploring QSAR Fundamentals and
Applications in Chemistry and Biology, ACS, 1995, ISBN 
0-8412-2987-2).  Chapter 3 (Parameters) of Hugo Kubinyi's book (QSAR: Hansch Analysis
and related Approaches, VCH, Weinheim, 1993, ISBN 3-527-30035-X) and 
it might pay to take a look at "Partition Coefficient Determination and Estimation", (Eds W. Dunn, J.
Block & R. Pearlman), Pergamon, 1986, ISBN ???? - although this is 
perhaps a little dated now.

Hope this helps,

		Dave.

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