Hello, Does anyone have any insights into close intermolecular contacts involving Cl atoms in crystal structures? There may be some basis for close contacts (~ 2.5Å) in the phenomenon so-called halogen bonding [ref-1] but this does not explain close C-Cl contacts observed in some structures for example (among many):
1XVF - monomer B: Thr213-O-gamma - ligand Cl In this example, there seems to be very weak electron density for the Cl atom (and indeed a negative difference map peak at 8 sigma). 2HVX (for example; and a number of others) have a ligand Cl at a difference map peak -6 sigma. Are these simply poorly modeled/poorly supported by the experimental data? Radiation damage? Or does anyone know why Cl atoms would scatter poorly (for some reason that I cannot imagine)? Thank you for your input. Mike Gretes PhD Candidate University of British Columbia [ref-1. Lu et al. Ab initio investigation of the complexes between bromobenzene and several electron donors: some insights into the magnitude and nature of halogen bonding interactions. The journal of physical chemistry A (2007) vol. 111 (42) pp. 10781-8]
