Synthesis and transition metal coordination chemistry of a novel hexadentate bispidine ligand?

Dalton Transactions Pub Date: 2014-11-14 DOI: 10.1039/C4DT03262D

Abstract

Reported is the new bispidine-derived hexadentate ligand L (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 CuII and high-spin FeII ions the fourth pyridine group is only semi-coordinated for steric reasons and, with the larger high-spin MnII ion genuine heptacoordination is observed but with a relatively large distortion in the pentagonal equatorial plane.

Graphical abstract: Synthesis and transition metal coordination chemistry of a novel hexadentate bispidine ligand
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