title: Synthesis and transition metal coordination chemistry of a novel hexadentate bispidine ligand.
abstract: Reported is the new bispidine-derived hexadentate ligand (L = 3-(2-methylpyridyl)-7-(bis-2-methylpyridyl)-3,7-diazabicyclo[3.3.1]nonane) with two tertiary amine and four pyridine donor groups. This ligand can form heterodinuclear and mononuclear complexes and, in the mononuclear compounds discussed here, the ligand may coordinate as a pentadentate ligand, with one of the bispyridinemethane-based pyridine groups un- or semi-coordinated, or as a hexadentate ligand, leading to a pentagonal pyramidal coordination geometry or, with an additional monodentate ligand, to a heptacoordinate pentagonal bipyramidal structure. The solution and solid state data presented here indicate that, with the relatively small Cu(II) and high-spin Fe(II) ions the fourth pyridine group is only semi-coordinated for steric reasons and, with the larger high-spin Mn(II) ion genuine heptacoordination is observed but with a relatively large distortion in the pentagonal equatorial plane.
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), INF 270, D-69120 Heidelberg, Germany. peter.comba@aci.uni-heidelberg.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
authors.forename: Henning
authors.initials: H
authors.lastname: Rudolf
authors.forename: Hubert
authors.initials: H
authors.lastname: Wadepohl
mesh_terms: D053961:Azabicyclo Compounds / Q000737:chemistry*; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D053961:Azabicyclo Compounds; D056831:Coordination Complexes; D028561:Transition Elements