From: Jacob Zabicky (zabicky$##$bgumail.bgu.ac.il)
Date: Tue Sep 18 2001 - 16:44:45 EDT
Hello Joao,
No example comes to my mind for organic molecules in a fluid state,
either pure or in solution. In the solid state some examples may be
produced, however, you may claim they are not precisely to the point.
Hydrogen bonding is claimed to exist when the B-H...B (B is an atom
acting as a base for proton binding) distances are shorter than the sum
of atomic radii. In certain polymorphs the stength of H-bonding (and
the corresponding bond lengths) vary from one crystalline phase to the
other. The same applies to intra vs. intermolecular H-bonding in all
states; this can certainly be interpreted as a different conformation of
the B-H link. I've possibly seen some gold and silver organometallics
that change the metal-to-metal atom distances and therefore their
bonding with changing conformation, but that needs checking some files I
do not have at hand at present (I'm abroad).
All the best,
Jacob
"J.Aires de Sousa" wrote:
> Does anyone know an experimental or theoretical example in which
> conformation has a significant influence on bond length, i.e., two
> conformations of the same molecule with different bond lengths ?
>
> Any information on this topic would be helpful.
>
> --
> Dr. Joao Aires de Sousa
>
> e-mail:jas$##$mail.fct.unl.pt
> Departamento de Quimica, Fac. Ciencias e Tecnologia,
> Univ. Nova de Lisboa, 2825 - 114 Caparica, Portugal
> __________________
>
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