Date:
From: Jose Angel Sordo <jasg@uniovi.es>
To: 'E. Arunan' <
Subject: RE: Hydrogen bond
Dear Arunan,
Thank you for the information about the PISA IUPAC workshop.
Let me just make some short comments on the three points you
mention in your note:
1. I fully agree with the definition of hyfrogen
bonding. However, it is a little bit inconsistent to answering "a mandate
to categorize intermolecular interaction ... based on the physical forces
involved" without mentioning any physical force at all!
2. I find appropriate to define
2. In my opinion, "van der Waals interactions" is
a concept with very deep historial roots which are
going to be very difficult to change. I think that "weakly bound
interactions" should be much better for covering, in a general manner, all
kinds of intermolecular interactions.
I hope all the above helps.
With my best wishes,
José
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Date:
From: E. Arunan <
To: Jose Angel Sordo <jasg@uniovi.es>
Subject: RE: Hydrogen bond
Dear José,
Thanks for the response. Surely, they will be helpful.
Let me respond to some of the points
> 1. I fully agree with the definition of hyfrogen bonding. However, it is a little bit inconsistent to answering "a mandate to
> categorize intermolecular interaction ... based on the physical forces involved" without mentioning any physical force at all!
If you remember the comment made by Pavel
Hobza after (during?) your talk, he pointed out that
hydrogen bonding was not one of the physical forces. That is a fact. For the
first row hydrides, electrostatics dominate. For
second row, role of dispersion could be more important and of course in FHF- covalency is important.
> 2. I find appropriate to define
> forces. However, in another part
of the document I can read "... arising EXCLUSIVELY due to Loondon dispersive forces".
> In my opinion, this latter definition is more dangerous and should be avoided.
Point well taken. I will keep
primarily instead of exclusively.
> 2. In my opinion, "van der Waals interactions" is a concept with very deep historial roots which are going to be very difficult to
> change. I think that "weakly bound interactions" should be much better for covering, in a general manner, all kinds of
> intermolecular interactions.
Pavel has been advocating non-covalend interactions. In any case, my objective is to
state what is van der Walls interactions. Do you think it should be limited to
dispersion or should it cover other physical forces as well.
cheers,
Arunan.
Date:
From: JOSE ANGEL SORDO GONZALO <jasg@uniovi.es>
To: E. Arunan <
Subject: Re: RE: Hydrogen bond
Dear Arunan,
Let me be a little more specific in point #1.
The point is that there is no a single physical force
responsible for hydrydrogen bonding. That was one of
the main points in my seminar (as you remark, Pavel
agreed with that). However, I showed that the relative contributions from the
different forces can help to differenciate the different
types of bonding.
I agree that we should find a global name for what we call
"weakly bound interactions", "non-covalent interactions"
(ionic interactions are non-covalent interactions too!!!)... The problem is
that, in my opinion, "van der waals interactions" can be problematic
for historical reasons.
Best wishes
José
Date:
From: E. Arunan <
To: JOSE ANGEL SORDO GONZALO <jasg@uniovi.es>
Subject: Re: RE: Hydrogen bond
Dear José,
Received both your emails.
1) Precisely for this reason (ionic bonding), I don't prefer
the non-covalent interactions. Would van-der Waals be acceptable? This term
means different things in different fields. Some people like it to infer only
dispersion. If you have a copy of my Introduction talk at
2) Do you want to exclude systems in which dispersion plays
a major role from hydrogen bonding, even when
the H atom is 'bonded' and you see spectroscopic shifts and other 'evidences'...?
regards,
Arunan.
Date:
From: JOSE ANGEL SORDO GONZALO <jasg@uniovi.es>
To: E. Arunan <
Subject: Re: RE: Hydrogen bond
Dear Arunan,
1. As
I mentioned in my previous mail "van der Waals" has a
very specific connotation and may be a problem. I suggest "weakly bound sytems/interactions" as this term has been widely used
(and accepted) in the literature with no distorsions.
2. I do believe that no weakly bound system should be
excluded. I generic designation is desirable. The question is to find an
appropriate denomination. Weakly bound systems/interactions is
just a pesonal proposal. I am sure there will be also
alternative proposals from the very prestigious colleagues attending the
Tomorrow, at my office, I will check your introduction (I
already did it some time ago but I cannot remember it well)
Jose A. Sordo