Minutes of the of the task group meeting held on 9 September 2005. 

IUPAC project (No: 2004-026-2-100)

 

The task group meeting was held at the Airone Pisa Park Hotel, Pisa, Italy in the forenoon of 9 September 2005.  The members present in the meeting:

 

E. Arunan, Co-Chairman of the Task group

Ibon Alkorta,

Joe Dannenberg

Henrik Kjaergaard

Roger Klein

Benedetta Mennucci

David Nesbitt

Joanna Sadlej

 

Other task group members, A. C. Legon, G. R. Desiraju and D. C. Clary participated in the IUPAC workshop held between September 5-8 at the same venue.  Legon and Desiraju had given their views during the meeting, but had to depart before the day of task group meeting due to pre-occupation.  Clary made a 30 minute presentation on September 8, but had to leave soon due to pre-occupation.  Crabtree and Kleinermaans could not participate in the meeting.  Crabtree and Sadlej had earlier sent their views by email to Arunan.  Other co-chairman of the task group, S. Scheiner had to cancel his participation in the last minute due to unforeseen circumstances.

 

All through the meeting and the discussions, it was clear that a definition similar to what was given by Pimental, with some modification would be widely accepted.  It was decided that, the definition could be followed with a short write-up giving typical examples and some notes. Legon suggested using an isoelectronic series such as Ne-HF; HF-HF and FHF- to show the range and diversity of interactions that could be referred as hydrogen bonding.

 

A possible definition: A hydrogen bond exists when hydrogen is found to have attractive interactions with more than one electron rich region.

 

The following concerns were expressed by members.  Klein opined that the use of van der Waals radii should be discouraged to identify a hydrogen bond.  Kjaergaard mentioned that some limits could be specified.  Arunan felt that the word ‘electron deficient hydrogen’ could be used instead of hydrogen.  Nesbitt indicated that H2O-H2 complex shows a minimum in the intermolecular potential surface corresponding to H2O---H-H interaction.  Mennucci wondered if all non-covalent interactions involving an H atom be called hydrogen bonding?  Dannenberg pointed out that co-operativity is not unique to H bonding. Klein said it is an important but not exclusive property.