title: Synthesis and Coordination Chemistry of Hexadentate Picolinic Acid Based Bispidine Ligands.
abstract: The synthesis and CuII, NiII, ZnII, CoII, and GaIIIcoordination chemistry of the two isomeric hexadentate N5O ligands 6-[[9-hydroxy-1,5-bis(methoxycarbonyl)-7-methyl-6,8-bis(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonan-3-yl]methyl]picolinic acid (Hbispa1a) and 6-[[9-hydroxy-1,5-bis(methoxycarbonyl)-7-methyl-2,4-bis(pyridin-2-yl)-3,7-diazabicyclo[3.3.1]nonan-3-yl]methyl]picolinic acid (Hbispa1b), picolinic acid-appended bispidines, are described. The two ligands are highly preorganized for octahedral coordination geometries and are particularly well suited for tetragonal symmetries, i.e., for Jahn-Teller labile ground states. This is confirmed by all data presented: solid-state structures, solution spectroscopy, electrochemistry, and CuIIcomplex stabilities. Differences in the preorganization of the two isomers for the Jahn-Teller labile CuIIcenters are thoroughly analyzed on the basis of the crystal structures and an angular-overlap-model-based ligand-field analysis.
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-69120 Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Comba
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-69120 Heidelberg, Germany.
authors.forename: Laura
authors.initials: L
authors.lastname: Grimm
authors.affiliation: Medicinal Inorganic Chemistry Group, Department of Chemistry, University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Orvig
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-69120 Heidelberg, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Rück
authors.affiliation: Universität Heidelberg, Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing, INF 270, D-69120 Heidelberg, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Wadepohl