title: Direct evidence of a multicentre halogen bond: unexpected contraction of the P-XXX-P fragment in triphenylphosphine dihalides.
abstract: Triphenylhalophosphonium halides, Ph(3)PX(2), form crystals comprising bridged linear cations [Ph(3)P-X-X-X-PPh(3)](+) where the X(3) bridge is shortened from 6.56 Å in Cl-Cl-Cl to 6.37 Å in the Br-Br-Br system. It is proposed that this structure is stabilised by five-centre/six-electron (5c-6e) hypervalent interactions.
authors: Centre for Synthesis and Chemical Biology, School of Chemistry and Chemical Biology, University College Dublin, Ireland. kirill.nikitin@ucd.ie
authors: Kirill
authors: K
authors: Nikitin
authors: Helge
authors: H
authors: Müller-Bunz
authors: Declan
authors: D
authors: Gilheany
mesh_terms: D001965:Bromides / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry; D018360:Crystallography, X-Ray; D006219:Halogens / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009943:Organophosphorus Compounds / Q000737:chemistry*
chemical_list: D001965:Bromides; D002712:Chlorides; D006219:Halogens; D009943:Organophosphorus Compounds; C061896:triphenylphosphine