title: Three overcrowded zinc(II) complexes with potentially hexadentate polypyridyl ligands.
abstract: In each of [N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine-kappa(6)N]zinc(II) bis(perchlorate) 0.67-hydrate, [Zn(C(26)H(28)N(6))](ClO(4))(2) x 0.67 H(2)O, (I), [N,N,N'-tris(2-pyridylmethyl)-N'-(2-quinolylmethyl)ethane-1,2-diamine-kappa(6)N]zinc(II) bis(perchlorate), [Zn(C(30)H(30)N(6))](ClO(4))(2), (II), and [N,N'-bis(2-pyridylmethyl)-N,N'-bis(2-quinolylmethyl)ethane-1,2-diamine-kappa(6)N]zinc(II) bis(perchlorate) monohydrate, [Zn(C(34)H(32)N(6))](ClO(4))(2) x H(2)O, (III), the Zn atom is coordinated to all six N atoms of the ligand. Compound (I) has one complex cation in a general position and one on a twofold axis. The coordination environments are intermediate between a regular octahedron and a pentagonal bipyramid which lacks one equatorial bond; complexes (II) and (III) are shown to be closer to the latter description. The quinolyl groups are in equatorial positions and the deviation from octahedral geometry increases with the number of these groups. This study demonstrates the systematic changes in the geometry at the central Zn atom as the overlap between the ligands increases.
authors.affiliation: Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Arhus C, Denmark. ach@chem.au.dk
authors.forename: Alan
authors.initials: A
authors.lastname: Hazell
authors.forename: Ole
authors.initials: O
authors.lastname: Mønsted
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Rasmussen
authors.forename: Hans
authors.initials: H
authors.lastname: Toftlund