Date:
From: E. Arunan <
To: Task Group
Subject: H bond
Dear Colleagues,
I have updated the webpage with all the recent emails
and also some comments from experts
outside the task
group. For your information the
following webpage has
all the details.
http://ipc.iisc.ernet.in/~arunan/iupac/
This email is slightly longish.
I would like to know if we have a consensus on some
of the following statements. Kindly
send your views
sometime this week:
1) There is no unique physical force that can be
described
as 'hydrogen bonding'
2) Electron deficient hydrogen: I should have pointed
out
Dannenberg's objection to these words in my
earlier
email. Would 'electropositive' or 'a hydrogen
atom
that carries a partial postive charge' be
acceptable
to all members, especially Scheiner and
Dannenberg.
Do all hydrogen bonds involve some X-H
groups
that has a dipole moment with H being the
positive
end?
3)
is
a defining characterestic of H bond. There are
some
blue-shifting H bonds that show reduction
in X-H intensity.
4) In the F-(H2) (fluoride ion complexed
with H2), the
structure
is linear. Though H2 has no dipole or electro-
positive
Hydrogen atom, I think in the F(-)H-H complex
the
H bonded to F will acquire a partial positive
charge.
Would this qualify as a H bonded complex?
5) Should we propose
for
molecules that are primarily bound by dispersive
forces?
There could be 'H bonded complexes' that may
come
under this list and I don't see that as a problem.
6) Can van der Waals forces be used to describe all
intermolecular
(non bonded intra-molecular) interactions?
Scheiner and I had
some interesting exchange on this
issue.
I welcome your comments.
with best regards,
Arunan.