title: Effect of methylation on the coordination of copper by small azacryptands; the role of geometrically constrained hydrogen bonding in stabilizing terminally coordinated oxygen species.
abstract: Treatment of N-methyl substituted aminocryptand hosts with copper(II) generates monocopper(II) cryptates where copper(II) coordinates an oxygen-centered species, formally H3O+, which is also strongly hydrogen bonded to three aminocryptand N-methyl atoms via bonds which may best be viewed as NH(delta+)...O(delta-) in consequence of charge transfer. The strength of this hydrogen bonding precludes successful competition of another copper ion for the second coordination site thus suppressing formation of any Cu-Cu bonded average-valent system.
authors.affiliation: Dept. of Chemistry, Queens University, Belfast BT9 5AG, UK.
authors.forename: David
authors.initials: D
authors.lastname: Farrell
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Harding
authors.forename: Vickie
authors.initials: V
authors.lastname: McKee
authors.forename: Jane
authors.initials: J
authors.lastname: Nelson