title: Encapsulation of the Be(II) cation: spectroscopic and computational study.
abstract: The structures of a series of tetracoordinate beryllium(II) complexes with ligands derived from tertiary-substituted amines have been computationally modeled and their (9)Be magnetic shielding values determined using the gauge-including atomic orbital (GIAO) method at the 6-311++g(2d,p) level. A good correlation was observed between calculated (9)Be NMR chemical shifts when compared to experimental values in polar protic solvents, less so for the values recorded in polar aprotic solvents. A number of alternative complex structures were modeled, resulting in an improvement in experimental versus computational (9)Be NMR chemical shifts, suggesting that in some cases full encapsulation on the beryllium atom was not occurring. Several of the synthesized complexes gave rise to unexpected fluorescence, and inspection of the calculated molecular orbital diagrams associated with the electronic transitions suggested that the rigidity imparted by the locking of certain conformations upon Be(II) coordination allowed delocalization across adjacent aligned aromatic rings bridged by Be(II).
authors.affiliation: Chemistry Institute of Fundamental Sciences, Massey University, Turitea Campus, Private Bag 11 222, Palmerston North, New Zealand 4442.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Shaffer
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Davidson
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Burrell
authors.forename: T Mark
authors.initials: TM
authors.lastname: McCleskey
authors.forename: Paul G
authors.initials: PG
authors.lastname: Plieger