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Synthesis and Coordination Chemistry of Hexadentate Picolinic Acid Based Bispidine Ligands

TitleSynthesis and Coordination Chemistry of Hexadentate Picolinic Acid Based Bispidine Ligands
Publication TypeJournal Article
Year of Publication2016
AuthorsComba, P, Grimm, L, Orvig, C, Rueck, K, Wadepohl, H
JournalInorg. Chem.
Volume55
Pagination12531-12543
Date PublishedDEC 19
ISSN0020-1669
Abstract

The synthesis and Cu-II, Ni-II, Zn-II, Co-II, and Ga-III coordination chemistry of the two isomeric hexadentate N5O ligands 6-{[}{[}9-hydroxy-1,5-bis(methoxycarbony1)-7-methyl-6,8-bis(pyridin-2-yl )-3,7-diazabicyclo{[}3.3.1]nonan-3-yl]methyl] picolinic acid (Hbispa(1a)) and 6-{[}{[}9-hydroxy-1,5-bis(methoxycarbony1)-7-methyl-2,4-bis(pyridin-2-yl )-3,7-diazabicyclo{[}3.3.1]nonan-3-yl]methyl]picolinic acid (Hbispa(1b)), 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 CuII complex stabilities. Differences in the preorganization of the two isomers for the Jahn-Teller labile Cu-II centers are thoroughly analyzed on the basis of the crystal structures and an angular-overlap-model-based ligand-field analysis.

DOI10.1021/acs.inorgchem.6b01787